Equine Disease Quarterly Newsletter

5

Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099

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59

Cases

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F U N D E D B Y U N D E R W R I T E R S AT L LOY D ' S , LO N D O N

APRIL 2021
Volume 30, Number 2

0
Placentitis

Pneumonia

Gutturalpouch
mycosisKeratitis

Gastrointestinal Rhinititis

Dermatitis

C O M M E N TA RY

Equine fungal infections in Central Kentucky, 2009-2019.

complicated delivery due to dystocia. A fungalorganism was cultured in 18 cases, Candida sp.
was isolated in two cases, Rhodotorula sp. in one
case, and Aspergillus sp. in 15 cases. Age of thebroodmare was generally not reported.
Thirty-nine cases of pneumonia were identified in horses ranging from three days to 25 yearsof age. Horses with fungal pneumonia often had
a history of concurrent gastrointestinal disease(21/39 cases). Gastrointestinal diseases included
prior surgery for large colon volvulus, colitis, andenteritis. Concurrent infectious agents identified in
the gastrointestinal tract included Lawsonia intracellularis (one case), Neorickettsia risticii (one case),
Clostridioides difficile (one case) and Salmonellasp. (five cases). The association between colitis,
particularly due to salmonellosis, and pneumonia
has been previously reported. Horses with fungal
pneumonia but without a history of gastrointestinal disease presented with a range of conditions
including nerve paralysis, immune mediated hemolytic anemia and dystocia. Treatment protocols
were not provided often enough to determine how
many horses received corticosteroids as part ofclinical management.
Cases of guttural pouch infection ranged fromtwo weeks to 23 years of age. Of 33 cases, 23 did
not have co-morbidities outside of the guttural
pouch. Where present, additional diseases included
encephalitis, laminitis, uveitis, pneumonia andcolitis, neuropathy, equine multinodular pulmonary fibrosis, basioccipital bone fracture, and small
intestinal volvulus.

Twenty-six horses presented with fungal keratitis with an age range of 1-24 years. These were
submitted as biopsy cases with minimal clinicalhistories and culture performed at external laboratories.
Twenty cases of gastrointestinal fungal infection
were identified. Affected animals ranged from threedays to 30 years of age and included four cases offungal colitis, two of enteritis, nine of gastritis,
one of enterocolitis, three of glossitis, and one ofesophagitis. All but two cases had a more significant primary disease that included acute respiratory distress syndrome, sepsis, Tyzzer’s disease, or
diaphragmatic rupture.
Cases of rhinitis (14 cases) and dermatitis (21cases) were submitted through the biopsy service,and sufficient clinical histories weren’t routinely
provided for analysis.
In summary, fungal infections, localized andsystemic, continue to be an uncommon but important cause of disease in equids. It appears thatprimary infections of the dermis, nasal cavity, andguttural pouch frequently do not present withco-morbidities while those of the gastrointestinal
and lower respiratory tract often occur with serious
disease of other organ systems. Fungal placentitis
continues to be a recognized cause of abortionand premature birth. In many cases culture isunrewarding and diagnosis is dependent on demonstration of the organism microscopically.
CONTACT:
Rebecca Ruby, MSc, BVSc, Dipl. AVCP
Rebecca.ruby@uky.edu(859) 257-8283
University of Kentucky Veterinary Diagnostic Laboratory
Lexington, Kentucky

IN THIS ISSUECOMMENTARY: continued from the front page

This is exemplified by two such studies
cited in this publication. One involves two
extensive surveys by the Korean Animal
and Plant Quarantine Agency and the
Korean Racing Authority and the othera survey by the Japan Racing Association
and Japanese horseracing industry.
CONTACT:
Peter J. Timoney, MVB, MS, PhD, FRCVS
ptimoney@uky.edu(859) 218-1094
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky

ADDENDA

Korea: The Korean Animal and Plant Quarantine

Agency and Korean Racing Authority carried out aserological survey in 2020 to investigate the presenceof the following diseases in 1,323 Thoroughbred
stallions, broodmares, racing horses, and ponies
and riding horses raised in the country: African
horse sickness, vesicular stomatitis, equine infectious
anemia, equine viral arteritis, Japanese encephalitis,
West Nile Fever, and equine influenza. All samples
tested negative for these diseases.
A qPCR survey of 2,232 samples from Thoroughbred stallions and mares for contagious equine
metritis identified one positive horse that has notbeen in service and has since undergone treatment.
Japan: In 2020, the Japan Racing Association andJapanese horseracing industry carried out a survey
for evidence of equine infectious anemia in a totalof 899 horses from 15 training centres or racecourses
in Japan. All results were negative.

In an era of globalization of trade and expansion in the volume of international movement
Commentaryof horses for the purpose of competing in performance events or for breeding, the need forInternational
reporting disease events by countries worldwide
Fourth Quarter2020  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2 has never been more important. The continued
growth and success of the equine industry is
Effects of COVID-19
on Equine Markets .  .  . 3 critically dependent on the timely sharing of information on disease occurrences, if horses are to
move internationally with minimal impediment.
National
Movement can only take place in an environment
Equine Fungal
Keratitis  .  .  .  .  .  .  .  .  .  .  .  .  . 3 in which the risk of disease transfer, inherent intrade between countries, can be mitigated to an
Kentuckyacceptable and safe level.
Equine Fungal
Disease transfer can take place either from
Infections inanimported equid to the resident population inCentral Kentucky .  .  .  . 4the importing country, or vice versa, where an
imported horse is infected following entry into a
country. Critical to mitigation of disease transfer
in either instance, is the availability of information on the disease status of the exporting andimporting countries. In turn, mitigation is dependent on each country assuming responsibility
for reporting occurrence of equine diseases listedby the World Organisation for Animal Health or
Office International des Epizooties (OIE), to thatorganization. It is in a country’s best interest froman international trade viewpoint, to notify the
OIE of occurrences of listed diseases in a timely,
College of Agriculture, transparent, and detailed manner.
Food and Environment
Moreover, there are equine diseases additional
Department ofto those listed by the OIE that warrant internaVeterinary Sciencetional reporting because of their animal healthsignificance and potential economic impact.
Two entities, the International Collating Centre(ICC), Newmarket, United Kingdom, and Réseau
d’Epidémio Surveillance en Pathologie Equine
Lloyd’s—An international
insurance market for(RESPE) in France currently post alerts on the
bloodstock and otherspecialist insurance.

internet of confirmed occurrences of OIE listed aswell as other equine diseases as they are reported
from different sources.
An increasing number of countries besides the
UK and France have developed national equine
surveillance and reporting programs such as theEquine Disease Communication Center (EDCC)
in the USA, that serve as reference sources of reliable information, reporting disease events for theirrespective equine industries in a timely manner.
Notwithstanding the widely acknowledged
importance of international reporting of equinedisease events, regrettably only a small number ofcountries do so on a regular basis as evident fromthe quarterly summaries reported elsewhere in thispublication. All countries need to be encouraged
to participate in the sharing of disease events via
current channels of communication such as theOIE (official) and the ICC or RESPE (unofficial).
Timely reporting and dissemination of such information is crucial to contain disease outbreaks
and minimize the risk of international spread of
diseases. Furthermore, addressing deficiencies in
the known global distribution of various equinediseases will require more widespread participationby countries; this is critical if the health of equine
populations worldwide is to be safe-guarded in thelonger term.
Not to be overlooked in any consideration of theneed for access to information on the occurrenceof equine diseases at a national and international
level, is the importance of periodic surveillanceof a country’s resident equine population for aparticular disease or range of diseases. Surveillance provides a snapshot of the disease status ofa country’s equine population at a point in time.

continued on the back page

Short- and Long-term Effects
of COVID-19 Restrictions on Equine Markets

2

I N T E R N AT I O N A L

Fourth Quarter 2020

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Rebecca Ruby

Staff

Diane Furry
Tawana Brown
Dennis Duross

Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Thoroughbred Breeders
Federation, International Collating Centre,
Newmarket, United Kingdom, and other sources
reported the following equine disease events.
The Republic of South Africa (RSA) reported
that African horse sickness was endemic except
for the controlled area in the Western Cape Province. A limited number of cases were recorded inGauteng and Mpumalanga provinces.
Canada, France, Germany, the Netherlands,
UK, and the USA confirmed outbreaks of equine
influenza. The number ranged from two (Canada
and the Netherlands), three (France, Germany andthe UK), to at least 16 in the USA, where the diseaseis endemic. One outbreak in California involving
40 burros had a very high case-fatality rate.
Strangles is considered endemic in many countries with outbreaks confirmed by Belgium (one),
Canada (one), France (five), Germany (eight cases),
the Netherlands, and the USA (13 apiece). The majority of outbreaks were comprised of a single case.
Equine herpesvirus 1 (EHV-1) related diseases
are endemic in most countries. Outbreaks of EHV1 abortion were diagnosed in France and Germany(three each), Japan (five outbreaks involving seven
Thoroughbreds of which six were vaccinated), theNetherlands (two), the UK (one), and the USA(four). EHV-1 neurologic disease was reported by
the Netherlands (single case) and the USA (sevenoutbreaks in California, Florida, Michigan, andOregon). California had three outbreaks involving 11 cases, and single cases were recorded in theremaining states.
Outbreaks of equine herpesvirus 4 (EHV-4)
respiratory disease was reported by Belgium (two),France (14, all but three were single cases), Germany (one), the Netherlands (three, one involving
four foals), and the USA (numerous states, mostly
in foals).
Germany and the USA recorded cases of equine
herpesvirus 2 and/or 5 infection. Infections wereassociated with respiratory disease in both countries and one case of EHV-2 associated keratitis in
Germany. Equine infectious anemia was confirmedin Romania (one outbreak, two cases) and the USA(six outbreaks, five involving single cases and one,
two cases), all in Texas.
The RSA recorded that equine piroplasmosis
was endemic, occurring sporadically in eightprovinces. Highest numbers were diagnosed inGauteng and Western Cape provinces.
Germany reported a case of equine arteritis
virus infection in a Warmblood stallion and Taylorella equigenitalis carrier state in three Icelandic
stallions. Several cases of nocardioform placentitis
and abortion due to Amycolatopsis spp. or Crossiellaequi were confirmed by the USA.
France, Switzerland, and the USA recorded
cases of leptospirosis. France (a case) and the USA(two cases) diagnosed cases of abortion. France also
confirmed two outbreaks (single cases) of uveitis.
Switzerland recorded a case of leptospirurea.
The USA recorded one case of Neorickettsia
risticii abortion and three other outbreaks in which
horses presented with fever, anorexia, depression,and diarrhea.
Salmonellosis was reported by the USA (threecases, two involving serogroup C1 and one ofundetermined serogroup). Rotaviral diarrhea wasreported by Argentina (one outbreak involving 40
vaccinated 20-40 day-old foals) and the USA (onecase).
Clostridial enterocolitis was reported by theUSA; nine cases were associated with Clostridium
perfringens and two with Clostridiodes difficile. The
USA confirmed 13 cases of proliferative enteropathy caused by Lawsonia intracellularis.
Canada (two outbreaks) and the USA (22outbreaks) confirmed cases of Eastern equine encephalomyelitis (EEE), all were single cases. A caseof dual infection with EEE and West Nile viruses
was diagnosed in a vaccinated horse in Florida.
Outbreaks of West Nile virus infection were reported by Austria, France, and Italy (two outbreaks
each, all single cases), Germany (four outbreaks),
Spain (11 outbreaks) and the USA (16 outbreaks,
all single cases).
Two outbreaks of vesicular stomatitis, Indiana
serotype, were confirmed by the USA in Texas andMissouri.
Rhodococcus equi related diseases were reportedby Germany (two cases of bronchopneumonia in
foals), and the USA in which the disease is endemic
and widespread.
Canada (one case) and the USA (11 outbreaks
in Washington State) recorded occurrences of
Pigeon fever, Corynebacterium pseudotuberculosis
infection. Japan recorded one case of tetanus.

C

OVID-19 pandemic-related restrictions produced a recession, which economists typicallydefine as two consecutive quarters of decline in
GDP (gross domestic product) growth. Like every
other business sector across the globe, the equine
industry has been affected by COVID-19 related
restrictions. We are now only starting to be able
to assess short-term impacts, and it will be sometime before the long-term impacts are fully understood. While we can look to recoveries from past
recessions for insight, the contraction initiated by
COVID-19 shutdowns is far different from earlier
recessions, rendering historical information lesspredictive of the recovery path.
Across the globe, restrictions faced by equine
industry participants have varied. Some governments mandated the closure of equine facilities toreduce the spread of the virus and minimize risks
of injury, while others delegated responsibility toequine enterprise owners and managers. The complete closure of equine facilities has been especiallydamaging, as these operations bear significant
ongoing expenses with no source of revenue.
Staggering early unemployment rates precipitated concerns of an impending equine welfare crisis.
However, while some horse owners have certainly
struggled to make ends meet due to unexpected
job loss, much of this unemployment was temporary, and a large-scale crisis appears to have been
avoided. Moreover, some organizations specializing
in re-homing horses actually reported an increasein adoptions during the initial shutdown.
A handful of preliminary studies are underway
across the U.S. to assess short-term COVID-19
related impacts. One such study is focused on
breeding, boarding/training/lesson, and competition enterprises in Kentucky across all breeds anddisciplines. Preliminary results suggest that while

not escaping the effects entirely, it appears thatbreeding and boarding/training/lesson operations
were minimally impacted. However, enterprises
related to competition, both racing and nonracing, appear to have sustained much greater
financial hardship. In addition to direct job loss,
the widespread cancellation of local, national, andinternational competitions has had a ripple effecton regional economies. Events able to operateshouldered increased costs associated with following health guidelines and were required to function
with limited or no spectators, which are often asource of revenue.
Some consider commercial sales and breeding
activity a bellwether for the health of the industry.
In North American Thoroughbred auction markets
in 2020, average prices for weanlings were down
6.2%, yearlings were down 20.3%, two-year-olds
in training were down 26.7%, and broodmares
were down 1.7%. Stud fees for North American
sires standing for $2,500 or more were down 3.7%
overall. While contractions are never welcome, thedecline was less drastic than some were anticipating.
The long-term impacts of COVID-19 restrictions
will ultimately depend on the shape of the generalmarket’s recovery. While GDP growth responded
quickly when the economy reopened, the recovery
has not been uniform across sectors. Some parts ofthe economy, most notably service and tourismrelated industries, continue to struggle. Any businesscycle that affects disposable income will ultimately
affect the equine industry as well, since it is centeredon what economists consider a “luxury” good.

3

Figure 1. Fungal ulcer characterized by a yellow, irregular area.

F

Equine Fungal KeratitisF

is a corneal scraping for cytology. If the ulcer
is infected, a specific inflammatory cell called aneutrophil, is present. In some cases, cytology canalso help determine if the infection is bacterial or
fungal. If fungal keratitis is suspected, an antifungal agent should be included in the treatment plan.
The choice of an antifungal agent is based on theantimicrobial sensitivity of fungi in the area andlevel of the veterinarian’s suspicion of the presenceof a fungal infection. Many general practitioners
will not have a topical antifungal agent on theirtruck. In such instances, silver sulfadiazine (acommon wound cream) or miconazole (typicallyavailable at your local pharmacy) can be used until
a more appropriate antifungal medication can beordered. In the case of any ocular infection, it ishighly important that whatever medication(s)are used, are approved for application to the eye.
Where treatment proves difficult, placement of a
subpalpebral lavage catheter can be considered tofacilitate successful treatment. In cases of severe
fungal disease, referral to an ophthalmologist
should be discussed with the client to determine
if surgical intervention is required. Even in severecases, surgical intervention can be successful inpreserving vision.
CONTACT:
Nikki Scherrer, DVM, DACVO
scherrer@vet.upenn.edu(317) 691-7339
New Bolton Center
University of Pennsylvania
Kennett Square, Pennsylvania

Equine Fungal infections in Central Kentucky (2009-2019)CONTACT:
Jill Stowe, PhD
jill.stowe@uky.edu
Department of Agricultural Economics
University of Kentucky
Lexington, Kentucky

fungal keratitis in horses is much higher than inother domestic species. It is suspected that this occurs because horses have fungi living normally on
the surface of the eye and the environment horses
live in exposes them to fungi on a more frequentbasis. Without a pre-existing wound or ulcer, thepresence of fungi is not normally a problem for thehorse. However, when a corneal ulcer is present,
organisms normally on the anterior surface of theeye can result in an infection. Infection of the cornea can be devastating due to the often aggressive
nature of fungi. Fungi release collagenolytics thatbreak down the cornea and antiangiogenic factorsthat stop the growth of healing blood vessels into
the cornea.
Fungal keratitis can result in two types of lesions, an ulcer or abscess. A fungal ulcer is usuallywhitish-yellow and irregular in shape; it is often
surrounded by a groove (Figure 1). A stromal
abscess generally starts as a corneal ulcer whose
superficial layer heals and essentially traps thefungus within the cornea making it more difficult
to treat. Affected eyes present with a smooth, yellow haze (Figure 2).
Initial treatment for a corneal ulcer usuallyconsists of a topical antibacterial medication toprevent more commonly encountered bacterial infections. A simple corneal ulcer should heal within
5-7 days. If it does not, it becomes a complicatedulcer. Geographic location of a horse alone may
influence a veterinarian’s concern about a fungal
infection. In the United States, it has been shownthat Mid-Atlantic and Southeastern states havea high prevalence of keratitis, whereas the problem is much less common in the western states.
There are many reasons for the development of acomplicated ulcer. One of the tests a veterinariancan do to determine why an ulcer is not healing

KENTUCKYN AT I O N A L

ungal keratitis is an infection of the clear outersurface of the eye (the cornea) caused by afungus; the most common culprits are Aspergillus
sp. and Fusarium sp. If not treated quickly andaggressively, fungal keratitis can lead to loss of vision or even loss of the eye itself. The incidence of

4

Figure 2. Corneal abscess characterized by the smooth, yellow
appearance. Often these abscesses are caused by a fungal infection.

ungal infections in horses are considerably lesscommon than infections caused by bacterial
or viral agents. Fungal organisms are typicallyencountered in the animal’s normal environment,
and the clinical manifestation of disease often
reflects the route of exposure (skin, respiratory
tract or reproductive tract). In some cases, immunodeficiency or immunosuppression may
predispose an individual to fungal infection, whilein other cases, there is no identifiable predisposing
risk factor. Overt signs of disease will typically be
associated with an inflammatory response at thesite of infection and may lead to generalized illness,abortion, or death.
A search of submissions to the University of
Kentucky Veterinary Diagnostic Laboratory for theperiod from 2009-2019 turned up 241 cases that
had fungal involvement. The most common sites
of infection were the placenta, lungs, eye, guttural
pouch, skin, and nose. Less commonly represented
were the gastrointestinal tract, nervous system, andmultiorgan infections.
Fifty-nine cases of fungal placentitis wereidentified. Gestational ages ranged from 180 to
351 days, and the majority of cases presented asabortions four to one month prior to the mare’s
due date. The immediate/short term outcome forthe foal was reported in 53 cases, of which 30 wereborn dead or euthanized. Live foals were frequently
born early with gestational ages ranging from 310
days to full term. Five foals were born following
premature placental separation, and three had aShort- and Long-term Effects
of COVID-19 Restrictions on Equine Markets

2

I N T E R N AT I O N A L

Fourth Quarter 2020

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Rebecca Ruby

Staff

Diane Furry
Tawana Brown
Dennis Duross

Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Thoroughbred Breeders
Federation, International Collating Centre,
Newmarket, United Kingdom, and other sources
reported the following equine disease events.
The Republic of South Africa (RSA) reported
that African horse sickness was endemic except
for the controlled area in the Western Cape Province. A limited number of cases were recorded inGauteng and Mpumalanga provinces.
Canada, France, Germany, the Netherlands,
UK, and the USA confirmed outbreaks of equine
influenza. The number ranged from two (Canada
and the Netherlands), three (France, Germany andthe UK), to at least 16 in the USA, where the diseaseis endemic. One outbreak in California involving
40 burros had a very high case-fatality rate.
Strangles is considered endemic in many countries with outbreaks confirmed by Belgium (one),
Canada (one), France (five), Germany (eight cases),
the Netherlands, and the USA (13 apiece). The majority of outbreaks were comprised of a single case.
Equine herpesvirus 1 (EHV-1) related diseases
are endemic in most countries. Outbreaks of EHV1 abortion were diagnosed in France and Germany(three each), Japan (five outbreaks involving seven
Thoroughbreds of which six were vaccinated), theNetherlands (two), the UK (one), and the USA(four). EHV-1 neurologic disease was reported by
the Netherlands (single case) and the USA (sevenoutbreaks in California, Florida, Michigan, andOregon). California had three outbreaks involving 11 cases, and single cases were recorded in theremaining states.
Outbreaks of equine herpesvirus 4 (EHV-4)
respiratory disease was reported by Belgium (two),France (14, all but three were single cases), Germany (one), the Netherlands (three, one involving
four foals), and the USA (numerous states, mostly
in foals).
Germany and the USA recorded cases of equine
herpesvirus 2 and/or 5 infection. Infections wereassociated with respiratory disease in both countries and one case of EHV-2 associated keratitis in
Germany. Equine infectious anemia was confirmedin Romania (one outbreak, two cases) and the USA(six outbreaks, five involving single cases and one,
two cases), all in Texas.
The RSA recorded that equine piroplasmosis
was endemic, occurring sporadically in eightprovinces. Highest numbers were diagnosed inGauteng and Western Cape provinces.
Germany reported a case of equine arteritis
virus infection in a Warmblood stallion and Taylorella equigenitalis carrier state in three Icelandic
stallions. Several cases of nocardioform placentitis
and abortion due to Amycolatopsis spp. or Crossiellaequi were confirmed by the USA.
France, Switzerland, and the USA recorded
cases of leptospirosis. France (a case) and the USA(two cases) diagnosed cases of abortion. France also
confirmed two outbreaks (single cases) of uveitis.
Switzerland recorded a case of leptospirurea.
The USA recorded one case of Neorickettsia
risticii abortion and three other outbreaks in which
horses presented with fever, anorexia, depression,and diarrhea.
Salmonellosis was reported by the USA (threecases, two involving serogroup C1 and one ofundetermined serogroup). Rotaviral diarrhea wasreported by Argentina (one outbreak involving 40
vaccinated 20-40 day-old foals) and the USA (onecase).
Clostridial enterocolitis was reported by theUSA; nine cases were associated with Clostridium
perfringens and two with Clostridiodes difficile. The
USA confirmed 13 cases of proliferative enteropathy caused by Lawsonia intracellularis.
Canada (two outbreaks) and the USA (22outbreaks) confirmed cases of Eastern equine encephalomyelitis (EEE), all were single cases. A caseof dual infection with EEE and West Nile viruses
was diagnosed in a vaccinated horse in Florida.
Outbreaks of West Nile virus infection were reported by Austria, France, and Italy (two outbreaks
each, all single cases), Germany (four outbreaks),
Spain (11 outbreaks) and the USA (16 outbreaks,
all single cases).
Two outbreaks of vesicular stomatitis, Indiana
serotype, were confirmed by the USA in Texas andMissouri.
Rhodococcus equi related diseases were reportedby Germany (two cases of bronchopneumonia in
foals), and the USA in which the disease is endemic
and widespread.
Canada (one case) and the USA (11 outbreaks
in Washington State) recorded occurrences of
Pigeon fever, Corynebacterium pseudotuberculosis
infection. Japan recorded one case of tetanus.

C

OVID-19 pandemic-related restrictions produced a recession, which economists typicallydefine as two consecutive quarters of decline in
GDP (gross domestic product) growth. Like every
other business sector across the globe, the equine
industry has been affected by COVID-19 related
restrictions. We are now only starting to be able
to assess short-term impacts, and it will be sometime before the long-term impacts are fully understood. While we can look to recoveries from past
recessions for insight, the contraction initiated by
COVID-19 shutdowns is far different from earlier
recessions, rendering historical information lesspredictive of the recovery path.
Across the globe, restrictions faced by equine
industry participants have varied. Some governments mandated the closure of equine facilities toreduce the spread of the virus and minimize risks
of injury, while others delegated responsibility toequine enterprise owners and managers. The complete closure of equine facilities has been especiallydamaging, as these operations bear significant
ongoing expenses with no source of revenue.
Staggering early unemployment rates precipitated concerns of an impending equine welfare crisis.
However, while some horse owners have certainly
struggled to make ends meet due to unexpected
job loss, much of this unemployment was temporary, and a large-scale crisis appears to have been
avoided. Moreover, some organizations specializing
in re-homing horses actually reported an increasein adoptions during the initial shutdown.
A handful of preliminary studies are underway
across the U.S. to assess short-term COVID-19
related impacts. One such study is focused on
breeding, boarding/training/lesson, and competition enterprises in Kentucky across all breeds anddisciplines. Preliminary results suggest that while

not escaping the effects entirely, it appears thatbreeding and boarding/training/lesson operations
were minimally impacted. However, enterprises
related to competition, both racing and nonracing, appear to have sustained much greater
financial hardship. In addition to direct job loss,
the widespread cancellation of local, national, andinternational competitions has had a ripple effecton regional economies. Events able to operateshouldered increased costs associated with following health guidelines and were required to function
with limited or no spectators, which are often asource of revenue.
Some consider commercial sales and breeding
activity a bellwether for the health of the industry.
In North American Thoroughbred auction markets
in 2020, average prices for weanlings were down
6.2%, yearlings were down 20.3%, two-year-olds
in training were down 26.7%, and broodmares
were down 1.7%. Stud fees for North American
sires standing for $2,500 or more were down 3.7%
overall. While contractions are never welcome, thedecline was less drastic than some were anticipating.
The long-term impacts of COVID-19 restrictions
will ultimately depend on the shape of the generalmarket’s recovery. While GDP growth responded
quickly when the economy reopened, the recovery
has not been uniform across sectors. Some parts ofthe economy, most notably service and tourismrelated industries, continue to struggle. Any businesscycle that affects disposable income will ultimately
affect the equine industry as well, since it is centeredon what economists consider a “luxury” good.

3

Figure 1. Fungal ulcer characterized by a yellow, irregular area.

F

Equine Fungal KeratitisF

is a corneal scraping for cytology. If the ulcer
is infected, a specific inflammatory cell called aneutrophil, is present. In some cases, cytology canalso help determine if the infection is bacterial or
fungal. If fungal keratitis is suspected, an antifungal agent should be included in the treatment plan.
The choice of an antifungal agent is based on theantimicrobial sensitivity of fungi in the area andlevel of the veterinarian’s suspicion of the presenceof a fungal infection. Many general practitioners
will not have a topical antifungal agent on theirtruck. In such instances, silver sulfadiazine (acommon wound cream) or miconazole (typicallyavailable at your local pharmacy) can be used until
a more appropriate antifungal medication can beordered. In the case of any ocular infection, it ishighly important that whatever medication(s)are used, are approved for application to the eye.
Where treatment proves difficult, placement of a
subpalpebral lavage catheter can be considered tofacilitate successful treatment. In cases of severe
fungal disease, referral to an ophthalmologist
should be discussed with the client to determine
if surgical intervention is required. Even in severecases, surgical intervention can be successful inpreserving vision.
CONTACT:
Nikki Scherrer, DVM, DACVO
scherrer@vet.upenn.edu(317) 691-7339
New Bolton Center
University of Pennsylvania
Kennett Square, Pennsylvania

Equine Fungal infections in Central Kentucky (2009-2019)CONTACT:
Jill Stowe, PhD
jill.stowe@uky.edu
Department of Agricultural Economics
University of Kentucky
Lexington, Kentucky

fungal keratitis in horses is much higher than inother domestic species. It is suspected that this occurs because horses have fungi living normally on
the surface of the eye and the environment horses
live in exposes them to fungi on a more frequentbasis. Without a pre-existing wound or ulcer, thepresence of fungi is not normally a problem for thehorse. However, when a corneal ulcer is present,
organisms normally on the anterior surface of theeye can result in an infection. Infection of the cornea can be devastating due to the often aggressive
nature of fungi. Fungi release collagenolytics thatbreak down the cornea and antiangiogenic factorsthat stop the growth of healing blood vessels into
the cornea.
Fungal keratitis can result in two types of lesions, an ulcer or abscess. A fungal ulcer is usuallywhitish-yellow and irregular in shape; it is often
surrounded by a groove (Figure 1). A stromal
abscess generally starts as a corneal ulcer whose
superficial layer heals and essentially traps thefungus within the cornea making it more difficult
to treat. Affected eyes present with a smooth, yellow haze (Figure 2).
Initial treatment for a corneal ulcer usuallyconsists of a topical antibacterial medication toprevent more commonly encountered bacterial infections. A simple corneal ulcer should heal within
5-7 days. If it does not, it becomes a complicatedulcer. Geographic location of a horse alone may
influence a veterinarian’s concern about a fungal
infection. In the United States, it has been shownthat Mid-Atlantic and Southeastern states havea high prevalence of keratitis, whereas the problem is much less common in the western states.
There are many reasons for the development of acomplicated ulcer. One of the tests a veterinariancan do to determine why an ulcer is not healing

KENTUCKYN AT I O N A L

ungal keratitis is an infection of the clear outersurface of the eye (the cornea) caused by afungus; the most common culprits are Aspergillus
sp. and Fusarium sp. If not treated quickly andaggressively, fungal keratitis can lead to loss of vision or even loss of the eye itself. The incidence of

4

Figure 2. Corneal abscess characterized by the smooth, yellow
appearance. Often these abscesses are caused by a fungal infection.

ungal infections in horses are considerably lesscommon than infections caused by bacterial
or viral agents. Fungal organisms are typicallyencountered in the animal’s normal environment,
and the clinical manifestation of disease often
reflects the route of exposure (skin, respiratory
tract or reproductive tract). In some cases, immunodeficiency or immunosuppression may
predispose an individual to fungal infection, whilein other cases, there is no identifiable predisposing
risk factor. Overt signs of disease will typically be
associated with an inflammatory response at thesite of infection and may lead to generalized illness,abortion, or death.
A search of submissions to the University of
Kentucky Veterinary Diagnostic Laboratory for theperiod from 2009-2019 turned up 241 cases that
had fungal involvement. The most common sites
of infection were the placenta, lungs, eye, guttural
pouch, skin, and nose. Less commonly represented
were the gastrointestinal tract, nervous system, andmultiorgan infections.
Fifty-nine cases of fungal placentitis wereidentified. Gestational ages ranged from 180 to
351 days, and the majority of cases presented asabortions four to one month prior to the mare’s
due date. The immediate/short term outcome forthe foal was reported in 53 cases, of which 30 wereborn dead or euthanized. Live foals were frequently
born early with gestational ages ranging from 310
days to full term. Five foals were born following
premature placental separation, and three had aShort- and Long-term Effects
of COVID-19 Restrictions on Equine Markets

2

I N T E R N AT I O N A L

Fourth Quarter 2020

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Rebecca Ruby

Staff

Diane Furry
Tawana Brown
Dennis Duross

Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Thoroughbred Breeders
Federation, International Collating Centre,
Newmarket, United Kingdom, and other sources
reported the following equine disease events.
The Republic of South Africa (RSA) reported
that African horse sickness was endemic except
for the controlled area in the Western Cape Province. A limited number of cases were recorded inGauteng and Mpumalanga provinces.
Canada, France, Germany, the Netherlands,
UK, and the USA confirmed outbreaks of equine
influenza. The number ranged from two (Canada
and the Netherlands), three (France, Germany andthe UK), to at least 16 in the USA, where the diseaseis endemic. One outbreak in California involving
40 burros had a very high case-fatality rate.
Strangles is considered endemic in many countries with outbreaks confirmed by Belgium (one),
Canada (one), France (five), Germany (eight cases),
the Netherlands, and the USA (13 apiece). The majority of outbreaks were comprised of a single case.
Equine herpesvirus 1 (EHV-1) related diseases
are endemic in most countries. Outbreaks of EHV1 abortion were diagnosed in France and Germany(three each), Japan (five outbreaks involving seven
Thoroughbreds of which six were vaccinated), theNetherlands (two), the UK (one), and the USA(four). EHV-1 neurologic disease was reported by
the Netherlands (single case) and the USA (sevenoutbreaks in California, Florida, Michigan, andOregon). California had three outbreaks involving 11 cases, and single cases were recorded in theremaining states.
Outbreaks of equine herpesvirus 4 (EHV-4)
respiratory disease was reported by Belgium (two),France (14, all but three were single cases), Germany (one), the Netherlands (three, one involving
four foals), and the USA (numerous states, mostly
in foals).
Germany and the USA recorded cases of equine
herpesvirus 2 and/or 5 infection. Infections wereassociated with respiratory disease in both countries and one case of EHV-2 associated keratitis in
Germany. Equine infectious anemia was confirmedin Romania (one outbreak, two cases) and the USA(six outbreaks, five involving single cases and one,
two cases), all in Texas.
The RSA recorded that equine piroplasmosis
was endemic, occurring sporadically in eightprovinces. Highest numbers were diagnosed inGauteng and Western Cape provinces.
Germany reported a case of equine arteritis
virus infection in a Warmblood stallion and Taylorella equigenitalis carrier state in three Icelandic
stallions. Several cases of nocardioform placentitis
and abortion due to Amycolatopsis spp. or Crossiellaequi were confirmed by the USA.
France, Switzerland, and the USA recorded
cases of leptospirosis. France (a case) and the USA(two cases) diagnosed cases of abortion. France also
confirmed two outbreaks (single cases) of uveitis.
Switzerland recorded a case of leptospirurea.
The USA recorded one case of Neorickettsia
risticii abortion and three other outbreaks in which
horses presented with fever, anorexia, depression,and diarrhea.
Salmonellosis was reported by the USA (threecases, two involving serogroup C1 and one ofundetermined serogroup). Rotaviral diarrhea wasreported by Argentina (one outbreak involving 40
vaccinated 20-40 day-old foals) and the USA (onecase).
Clostridial enterocolitis was reported by theUSA; nine cases were associated with Clostridium
perfringens and two with Clostridiodes difficile. The
USA confirmed 13 cases of proliferative enteropathy caused by Lawsonia intracellularis.
Canada (two outbreaks) and the USA (22outbreaks) confirmed cases of Eastern equine encephalomyelitis (EEE), all were single cases. A caseof dual infection with EEE and West Nile viruses
was diagnosed in a vaccinated horse in Florida.
Outbreaks of West Nile virus infection were reported by Austria, France, and Italy (two outbreaks
each, all single cases), Germany (four outbreaks),
Spain (11 outbreaks) and the USA (16 outbreaks,
all single cases).
Two outbreaks of vesicular stomatitis, Indiana
serotype, were confirmed by the USA in Texas andMissouri.
Rhodococcus equi related diseases were reportedby Germany (two cases of bronchopneumonia in
foals), and the USA in which the disease is endemic
and widespread.
Canada (one case) and the USA (11 outbreaks
in Washington State) recorded occurrences of
Pigeon fever, Corynebacterium pseudotuberculosis
infection. Japan recorded one case of tetanus.

C

OVID-19 pandemic-related restrictions produced a recession, which economists typicallydefine as two consecutive quarters of decline in
GDP (gross domestic product) growth. Like every
other business sector across the globe, the equine
industry has been affected by COVID-19 related
restrictions. We are now only starting to be able
to assess short-term impacts, and it will be sometime before the long-term impacts are fully understood. While we can look to recoveries from past
recessions for insight, the contraction initiated by
COVID-19 shutdowns is far different from earlier
recessions, rendering historical information lesspredictive of the recovery path.
Across the globe, restrictions faced by equine
industry participants have varied. Some governments mandated the closure of equine facilities toreduce the spread of the virus and minimize risks
of injury, while others delegated responsibility toequine enterprise owners and managers. The complete closure of equine facilities has been especiallydamaging, as these operations bear significant
ongoing expenses with no source of revenue.
Staggering early unemployment rates precipitated concerns of an impending equine welfare crisis.
However, while some horse owners have certainly
struggled to make ends meet due to unexpected
job loss, much of this unemployment was temporary, and a large-scale crisis appears to have been
avoided. Moreover, some organizations specializing
in re-homing horses actually reported an increasein adoptions during the initial shutdown.
A handful of preliminary studies are underway
across the U.S. to assess short-term COVID-19
related impacts. One such study is focused on
breeding, boarding/training/lesson, and competition enterprises in Kentucky across all breeds anddisciplines. Preliminary results suggest that while

not escaping the effects entirely, it appears thatbreeding and boarding/training/lesson operations
were minimally impacted. However, enterprises
related to competition, both racing and nonracing, appear to have sustained much greater
financial hardship. In addition to direct job loss,
the widespread cancellation of local, national, andinternational competitions has had a ripple effecton regional economies. Events able to operateshouldered increased costs associated with following health guidelines and were required to function
with limited or no spectators, which are often asource of revenue.
Some consider commercial sales and breeding
activity a bellwether for the health of the industry.
In North American Thoroughbred auction markets
in 2020, average prices for weanlings were down
6.2%, yearlings were down 20.3%, two-year-olds
in training were down 26.7%, and broodmares
were down 1.7%. Stud fees for North American
sires standing for $2,500 or more were down 3.7%
overall. While contractions are never welcome, thedecline was less drastic than some were anticipating.
The long-term impacts of COVID-19 restrictions
will ultimately depend on the shape of the generalmarket’s recovery. While GDP growth responded
quickly when the economy reopened, the recovery
has not been uniform across sectors. Some parts ofthe economy, most notably service and tourismrelated industries, continue to struggle. Any businesscycle that affects disposable income will ultimately
affect the equine industry as well, since it is centeredon what economists consider a “luxury” good.

3

Figure 1. Fungal ulcer characterized by a yellow, irregular area.

F

Equine Fungal KeratitisF

is a corneal scraping for cytology. If the ulcer
is infected, a specific inflammatory cell called aneutrophil, is present. In some cases, cytology canalso help determine if the infection is bacterial or
fungal. If fungal keratitis is suspected, an antifungal agent should be included in the treatment plan.
The choice of an antifungal agent is based on theantimicrobial sensitivity of fungi in the area andlevel of the veterinarian’s suspicion of the presenceof a fungal infection. Many general practitioners
will not have a topical antifungal agent on theirtruck. In such instances, silver sulfadiazine (acommon wound cream) or miconazole (typicallyavailable at your local pharmacy) can be used until
a more appropriate antifungal medication can beordered. In the case of any ocular infection, it ishighly important that whatever medication(s)are used, are approved for application to the eye.
Where treatment proves difficult, placement of a
subpalpebral lavage catheter can be considered tofacilitate successful treatment. In cases of severe
fungal disease, referral to an ophthalmologist
should be discussed with the client to determine
if surgical intervention is required. Even in severecases, surgical intervention can be successful inpreserving vision.
CONTACT:
Nikki Scherrer, DVM, DACVO
scherrer@vet.upenn.edu(317) 691-7339
New Bolton Center
University of Pennsylvania
Kennett Square, Pennsylvania

Equine Fungal infections in Central Kentucky (2009-2019)CONTACT:
Jill Stowe, PhD
jill.stowe@uky.edu
Department of Agricultural Economics
University of Kentucky
Lexington, Kentucky

fungal keratitis in horses is much higher than inother domestic species. It is suspected that this occurs because horses have fungi living normally on
the surface of the eye and the environment horses
live in exposes them to fungi on a more frequentbasis. Without a pre-existing wound or ulcer, thepresence of fungi is not normally a problem for thehorse. However, when a corneal ulcer is present,
organisms normally on the anterior surface of theeye can result in an infection. Infection of the cornea can be devastating due to the often aggressive
nature of fungi. Fungi release collagenolytics thatbreak down the cornea and antiangiogenic factorsthat stop the growth of healing blood vessels into
the cornea.
Fungal keratitis can result in two types of lesions, an ulcer or abscess. A fungal ulcer is usuallywhitish-yellow and irregular in shape; it is often
surrounded by a groove (Figure 1). A stromal
abscess generally starts as a corneal ulcer whose
superficial layer heals and essentially traps thefungus within the cornea making it more difficult
to treat. Affected eyes present with a smooth, yellow haze (Figure 2).
Initial treatment for a corneal ulcer usuallyconsists of a topical antibacterial medication toprevent more commonly encountered bacterial infections. A simple corneal ulcer should heal within
5-7 days. If it does not, it becomes a complicatedulcer. Geographic location of a horse alone may
influence a veterinarian’s concern about a fungal
infection. In the United States, it has been shownthat Mid-Atlantic and Southeastern states havea high prevalence of keratitis, whereas the problem is much less common in the western states.
There are many reasons for the development of acomplicated ulcer. One of the tests a veterinariancan do to determine why an ulcer is not healing

KENTUCKYN AT I O N A L

ungal keratitis is an infection of the clear outersurface of the eye (the cornea) caused by afungus; the most common culprits are Aspergillus
sp. and Fusarium sp. If not treated quickly andaggressively, fungal keratitis can lead to loss of vision or even loss of the eye itself. The incidence of

4

Figure 2. Corneal abscess characterized by the smooth, yellow
appearance. Often these abscesses are caused by a fungal infection.

ungal infections in horses are considerably lesscommon than infections caused by bacterial
or viral agents. Fungal organisms are typicallyencountered in the animal’s normal environment,
and the clinical manifestation of disease often
reflects the route of exposure (skin, respiratory
tract or reproductive tract). In some cases, immunodeficiency or immunosuppression may
predispose an individual to fungal infection, whilein other cases, there is no identifiable predisposing
risk factor. Overt signs of disease will typically be
associated with an inflammatory response at thesite of infection and may lead to generalized illness,abortion, or death.
A search of submissions to the University of
Kentucky Veterinary Diagnostic Laboratory for theperiod from 2009-2019 turned up 241 cases that
had fungal involvement. The most common sites
of infection were the placenta, lungs, eye, guttural
pouch, skin, and nose. Less commonly represented
were the gastrointestinal tract, nervous system, andmultiorgan infections.
Fifty-nine cases of fungal placentitis wereidentified. Gestational ages ranged from 180 to
351 days, and the majority of cases presented asabortions four to one month prior to the mare’s
due date. The immediate/short term outcome forthe foal was reported in 53 cases, of which 30 wereborn dead or euthanized. Live foals were frequently
born early with gestational ages ranging from 310
days to full term. Five foals were born following
premature placental separation, and three had aEquine Disease Quarterly Newsletter

5

Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099

60
50

59

Cases

40
39

30

Presorted Standard
US Postage Paid
Permit 51
Lexington KY

Address Service Requested

33
26

20
10

21

20
14

F U N D E D B Y U N D E R W R I T E R S AT L LOY D ' S , LO N D O N

APRIL 2021
Volume 30, Number 2

0
Placentitis

Pneumonia

Gutturalpouch
mycosisKeratitis

Gastrointestinal Rhinititis

Dermatitis

C O M M E N TA RY

Equine fungal infections in Central Kentucky, 2009-2019.

complicated delivery due to dystocia. A fungalorganism was cultured in 18 cases, Candida sp.
was isolated in two cases, Rhodotorula sp. in one
case, and Aspergillus sp. in 15 cases. Age of thebroodmare was generally not reported.
Thirty-nine cases of pneumonia were identified in horses ranging from three days to 25 yearsof age. Horses with fungal pneumonia often had
a history of concurrent gastrointestinal disease(21/39 cases). Gastrointestinal diseases included
prior surgery for large colon volvulus, colitis, andenteritis. Concurrent infectious agents identified in
the gastrointestinal tract included Lawsonia intracellularis (one case), Neorickettsia risticii (one case),
Clostridioides difficile (one case) and Salmonellasp. (five cases). The association between colitis,
particularly due to salmonellosis, and pneumonia
has been previously reported. Horses with fungal
pneumonia but without a history of gastrointestinal disease presented with a range of conditions
including nerve paralysis, immune mediated hemolytic anemia and dystocia. Treatment protocols
were not provided often enough to determine how
many horses received corticosteroids as part ofclinical management.
Cases of guttural pouch infection ranged fromtwo weeks to 23 years of age. Of 33 cases, 23 did
not have co-morbidities outside of the guttural
pouch. Where present, additional diseases included
encephalitis, laminitis, uveitis, pneumonia andcolitis, neuropathy, equine multinodular pulmonary fibrosis, basioccipital bone fracture, and small
intestinal volvulus.

Twenty-six horses presented with fungal keratitis with an age range of 1-24 years. These were
submitted as biopsy cases with minimal clinicalhistories and culture performed at external laboratories.
Twenty cases of gastrointestinal fungal infection
were identified. Affected animals ranged from threedays to 30 years of age and included four cases offungal colitis, two of enteritis, nine of gastritis,
one of enterocolitis, three of glossitis, and one ofesophagitis. All but two cases had a more significant primary disease that included acute respiratory distress syndrome, sepsis, Tyzzer’s disease, or
diaphragmatic rupture.
Cases of rhinitis (14 cases) and dermatitis (21cases) were submitted through the biopsy service,and sufficient clinical histories weren’t routinely
provided for analysis.
In summary, fungal infections, localized andsystemic, continue to be an uncommon but important cause of disease in equids. It appears thatprimary infections of the dermis, nasal cavity, andguttural pouch frequently do not present withco-morbidities while those of the gastrointestinal
and lower respiratory tract often occur with serious
disease of other organ systems. Fungal placentitis
continues to be a recognized cause of abortionand premature birth. In many cases culture isunrewarding and diagnosis is dependent on demonstration of the organism microscopically.
CONTACT:
Rebecca Ruby, MSc, BVSc, Dipl. AVCP
Rebecca.ruby@uky.edu(859) 257-8283
University of Kentucky Veterinary Diagnostic Laboratory
Lexington, Kentucky

IN THIS ISSUECOMMENTARY: continued from the front page

This is exemplified by two such studies
cited in this publication. One involves two
extensive surveys by the Korean Animal
and Plant Quarantine Agency and the
Korean Racing Authority and the othera survey by the Japan Racing Association
and Japanese horseracing industry.
CONTACT:
Peter J. Timoney, MVB, MS, PhD, FRCVS
ptimoney@uky.edu(859) 218-1094
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky

ADDENDA

Korea: The Korean Animal and Plant Quarantine

Agency and Korean Racing Authority carried out aserological survey in 2020 to investigate the presenceof the following diseases in 1,323 Thoroughbred
stallions, broodmares, racing horses, and ponies
and riding horses raised in the country: African
horse sickness, vesicular stomatitis, equine infectious
anemia, equine viral arteritis, Japanese encephalitis,
West Nile Fever, and equine influenza. All samples
tested negative for these diseases.
A qPCR survey of 2,232 samples from Thoroughbred stallions and mares for contagious equine
metritis identified one positive horse that has notbeen in service and has since undergone treatment.
Japan: In 2020, the Japan Racing Association andJapanese horseracing industry carried out a survey
for evidence of equine infectious anemia in a totalof 899 horses from 15 training centres or racecourses
in Japan. All results were negative.

In an era of globalization of trade and expansion in the volume of international movement
Commentaryof horses for the purpose of competing in performance events or for breeding, the need forInternational
reporting disease events by countries worldwide
Fourth Quarter2020  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2 has never been more important. The continued
growth and success of the equine industry is
Effects of COVID-19
on Equine Markets .  .  . 3 critically dependent on the timely sharing of information on disease occurrences, if horses are to
move internationally with minimal impediment.
National
Movement can only take place in an environment
Equine Fungal
Keratitis  .  .  .  .  .  .  .  .  .  .  .  .  . 3 in which the risk of disease transfer, inherent intrade between countries, can be mitigated to an
Kentuckyacceptable and safe level.
Equine Fungal
Disease transfer can take place either from
Infections inanimported equid to the resident population inCentral Kentucky .  .  .  . 4the importing country, or vice versa, where an
imported horse is infected following entry into a
country. Critical to mitigation of disease transfer
in either instance, is the availability of information on the disease status of the exporting andimporting countries. In turn, mitigation is dependent on each country assuming responsibility
for reporting occurrence of equine diseases listedby the World Organisation for Animal Health or
Office International des Epizooties (OIE), to thatorganization. It is in a country’s best interest froman international trade viewpoint, to notify the
OIE of occurrences of listed diseases in a timely,
College of Agriculture, transparent, and detailed manner.
Food and Environment
Moreover, there are equine diseases additional
Department ofto those listed by the OIE that warrant internaVeterinary Sciencetional reporting because of their animal healthsignificance and potential economic impact.
Two entities, the International Collating Centre(ICC), Newmarket, United Kingdom, and Réseau
d’Epidémio Surveillance en Pathologie Equine
Lloyd’s—An international
insurance market for(RESPE) in France currently post alerts on the
bloodstock and otherspecialist insurance.

internet of confirmed occurrences of OIE listed aswell as other equine diseases as they are reported
from different sources.
An increasing number of countries besides the
UK and France have developed national equine
surveillance and reporting programs such as theEquine Disease Communication Center (EDCC)
in the USA, that serve as reference sources of reliable information, reporting disease events for theirrespective equine industries in a timely manner.
Notwithstanding the widely acknowledged
importance of international reporting of equinedisease events, regrettably only a small number ofcountries do so on a regular basis as evident fromthe quarterly summaries reported elsewhere in thispublication. All countries need to be encouraged
to participate in the sharing of disease events via
current channels of communication such as theOIE (official) and the ICC or RESPE (unofficial).
Timely reporting and dissemination of such information is crucial to contain disease outbreaks
and minimize the risk of international spread of
diseases. Furthermore, addressing deficiencies in
the known global distribution of various equinediseases will require more widespread participationby countries; this is critical if the health of equine
populations worldwide is to be safe-guarded in thelonger term.
Not to be overlooked in any consideration of theneed for access to information on the occurrenceof equine diseases at a national and international
level, is the importance of periodic surveillanceof a country’s resident equine population for aparticular disease or range of diseases. Surveillance provides a snapshot of the disease status ofa country’s equine population at a point in time.

continued on the back pageEquine Disease Quarterly Newsletter

5

Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099

60
50

59

Cases

40
39

30

Address Service Requested

33
26

20
10

21

20
14

F U N D E D B Y U N D E R W R I T E R S AT L LOY D ' S , LO N D O N

APRIL 2021
Volume 30, Number 2

0
Placentitis

Pneumonia

Gutturalpouch
mycosisKeratitis

Gastrointestinal Rhinititis

Dermatitis

C O M M E N TA RY

Equine fungal infections in Central Kentucky, 2009-2019.

complicated delivery due to dystocia. A fungalorganism was cultured in 18 cases, Candida sp.
was isolated in two cases, Rhodotorula sp. in one
case, and Aspergillus sp. in 15 cases. Age of thebroodmare was generally not reported.
Thirty-nine cases of pneumonia were identified in horses ranging from three days to 25 yearsof age. Horses with fungal pneumonia often had
a history of concurrent gastrointestinal disease(21/39 cases). Gastrointestinal diseases included
prior surgery for large colon volvulus, colitis, andenteritis. Concurrent infectious agents identified in
the gastrointestinal tract included Lawsonia intracellularis (one case), Neorickettsia risticii (one case),
Clostridioides difficile (one case) and Salmonellasp. (five cases). The association between colitis,
particularly due to salmonellosis, and pneumonia
has been previously reported. Horses with fungal
pneumonia but without a history of gastrointestinal disease presented with a range of conditions
including nerve paralysis, immune mediated hemolytic anemia and dystocia. Treatment protocols
were not provided often enough to determine how
many horses received corticosteroids as part ofclinical management.
Cases of guttural pouch infection ranged fromtwo weeks to 23 years of age. Of 33 cases, 23 did
not have co-morbidities outside of the guttural
pouch. Where present, additional diseases included
encephalitis, laminitis, uveitis, pneumonia andcolitis, neuropathy, equine multinodular pulmonary fibrosis, basioccipital bone fracture, and small
intestinal volvulus.

Twenty-six horses presented with fungal keratitis with an age range of 1-24 years. These were
submitted as biopsy cases with minimal clinicalhistories and culture performed at external laboratories.
Twenty cases of gastrointestinal fungal infection
were identified. Affected animals ranged from threedays to 30 years of age and included four cases offungal colitis, two of enteritis, nine of gastritis,
one of enterocolitis, three of glossitis, and one ofesophagitis. All but two cases had a more significant primary disease that included acute respiratory distress syndrome, sepsis, Tyzzer’s disease, or
diaphragmatic rupture.
Cases of rhinitis (14 cases) and dermatitis (21cases) were submitted through the biopsy service,and sufficient clinical histories weren’t routinely
provided for analysis.
In summary, fungal infections, localized andsystemic, continue to be an uncommon but important cause of disease in equids. It appears thatprimary infections of the dermis, nasal cavity, andguttural pouch frequently do not present withco-morbidities while those of the gastrointestinal
and lower respiratory tract often occur with serious
disease of other organ systems. Fungal placentitis
continues to be a recognized cause of abortionand premature birth. In many cases culture isunrewarding and diagnosis is dependent on demonstration of the organism microscopically.
CONTACT:
Rebecca Ruby, MSc, BVSc, Dipl. AVCP
Rebecca.ruby@uky.edu(859) 257-8283
University of Kentucky Veterinary Diagnostic Laboratory
Lexington, Kentucky

IN THIS ISSUECOMMENTARY: continued from the front page

This is exemplified by two such studies
cited in this publication. One involves two
extensive surveys by the Korean Animal
and Plant Quarantine Agency and the
Korean Racing Authority and the othera survey by the Japan Racing Association
and Japanese horseracing industry.
CONTACT:
Peter J. Timoney, MVB, MS, PhD, FRCVS
ptimoney@uky.edu(859) 218-1094
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky

ADDENDA

Korea: The Korean Animal and Plant Quarantine
Agency and Korean Racing Authority carried out aserological survey in 2020 to investigate the presenceof the following diseases in 1,323 Thoroughbred
stallions, broodmares, racing horses, and ponies
and riding horses raised in the country: African
horse sickness, vesicular stomatitis, equine infectious
anemia, equine viral arteritis, Japanese encephalitis,
West Nile Fever, and equine influenza. All samples
tested negative for these diseases.
A qPCR survey of 2,232 samples from Thoroughbred stallions and mares for contagious equine
metritis identified one positive horse that has notbeen in service and has since undergone treatment.
Japan: In 2020, the Japan Racing Association andJapanese horseracing industry carried out a survey
for evidence of equine infectious anemia in a totalof 899 horses from 15 training centres or racecourses
in Japan. All results were negative.

In an era of globalization of trade and expansion in the volume of international movement
Commentaryof horses for the purpose of competing in performance events or for breeding, the need forInternational
reporting disease events by countries worldwide
Fourth Quarter2020  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2 has never been more important. The continued
growth and success of the equine industry is
Effects of COVID-19
on Equine Markets .  .  . 3 critically dependent on the timely sharing of information on disease occurrences, if horses are to
move internationally with minimal impediment.
National
Movement can only take place in an environment
Equine Fungal
Keratitis  .  .  .  .  .  .  .  .  .  .  .  .  . 3 in which the risk of disease transfer, inherent intrade between countries, can be mitigated to an
Kentuckyacceptable and safe level.
Equine Fungal
Disease transfer can take place either from
Infections inanimported equid to the resident population inCentral Kentucky .  .  .  . 4the importing country, or vice versa, where an
imported horse is infected following entry into a
country. Critical to mitigation of disease transfer
in either instance, is the availability of information on the disease status of the exporting andimporting countries. In turn, mitigation is dependent on each country assuming responsibility
for reporting occurrence of equine diseases listedby the World Organisation for Animal Health or
Office International des Epizooties (OIE), to thatorganization. It is in a country’s best interest froman international trade viewpoint, to notify the
OIE of occurrences of listed diseases in a timely,
College of Agriculture, transparent, and detailed manner.
Food and Environment
Moreover, there are equine diseases additional
Department ofto those listed by the OIE that warrant internaVeterinary Sciencetional reporting because of their animal healthsignificance and potential economic impact.
Two entities, the International Collating Centre(ICC), Newmarket, United Kingdom, and Réseau
d’Epidémio Surveillance en Pathologie Equine
Lloyd’s—An international
insurance market for(RESPE) in France currently post alerts on the
bloodstock and otherspecialist insurance.

internet of confirmed occurrences of OIE listed aswell as other equine diseases as they are reported
from different sources.
An increasing number of countries besides the
UK and France have developed national equine
surveillance and reporting programs such as theEquine Disease Communication Center (EDCC)
in the USA, that serve as reference sources of reliable information, reporting disease events for theirrespective equine industries in a timely manner.
Notwithstanding the widely acknowledged
importance of international reporting of equinedisease events, regrettably only a small number ofcountries do so on a regular basis as evident fromthe quarterly summaries reported elsewhere in thispublication. All countries need to be encouraged
to participate in the sharing of disease events via
current channels of communication such as theOIE (official) and the ICC or RESPE (unofficial).
Timely reporting and dissemination of such information is crucial to contain disease outbreaks
and minimize the risk of international spread of
diseases. Furthermore, addressing deficiencies in
the known global distribution of various equinediseases will require more widespread participationby countries; this is critical if the health of equine
populations worldwide is to be safe-guarded in thelonger term.
Not to be overlooked in any consideration of theneed for access to information on the occurrenceof equine diseases at a national and international
level, is the importance of periodic surveillanceof a country’s resident equine population for aparticular disease or range of diseases. Surveillance provides a snapshot of the disease status ofa country’s equine population at a point in time.

continued on the back page

Short- and Long-term Effects
of COVID-19 Restrictions on Equine Markets

2

I N T E R N AT I O N A L

Fourth Quarter 2020

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Rebecca Ruby

Staff

Diane Furry
Tawana Brown
Dennis Duross

Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Thoroughbred Breeders
Federation, International Collating Centre,
Newmarket, United Kingdom, and other sources
reported the following equine disease events.
The Republic of South Africa (RSA) reported
that African horse sickness was endemic except
for the controlled area in the Western Cape Province. A limited number of cases were recorded inGauteng and Mpumalanga provinces.
Canada, France, Germany, the Netherlands,
UK, and the USA confirmed outbreaks of equine
influenza. The number ranged from two (Canada
and the Netherlands), three (France, Germany andthe UK), to at least 16 in the USA, where the diseaseis endemic. One outbreak in California involving
40 burros had a very high case-fatality rate.
Strangles is considered endemic in many countries with outbreaks confirmed by Belgium (one),
Canada (one), France (five), Germany (eight cases),
the Netherlands, and the USA (13 apiece). The majority of outbreaks were comprised of a single case.
Equine herpesvirus 1 (EHV-1) related diseases
are endemic in most countries. Outbreaks of EHV1 abortion were diagnosed in France and Germany(three each), Japan (five outbreaks involving seven
Thoroughbreds of which six were vaccinated), theNetherlands (two), the UK (one), and the USA(four). EHV-1 neurologic disease was reported by
the Netherlands (single case) and the USA (sevenoutbreaks in California, Florida, Michigan, andOregon). California had three outbreaks involving 11 cases, and single cases were recorded in theremaining states.
Outbreaks of equine herpesvirus 4 (EHV-4)
respiratory disease was reported by Belgium (two),France (14, all but three were single cases), Germany (one), the Netherlands (three, one involving
four foals), and the USA (numerous states, mostly
in foals).
Germany and the USA recorded cases of equine
herpesvirus 2 and/or 5 infection. Infections wereassociated with respiratory disease in both countries and one case of EHV-2 associated keratitis in
Germany. Equine infectious anemia was confirmedin Romania (one outbreak, two cases) and the USA(six outbreaks, five involving single cases and one,
two cases), all in Texas.
The RSA recorded that equine piroplasmosis
was endemic, occurring sporadically in eightprovinces. Highest numbers were diagnosed inGauteng and Western Cape provinces.
Germany reported a case of equine arteritis
virus infection in a Warmblood stallion and Taylorella equigenitalis carrier state in three Icelandic
stallions. Several cases of nocardioform placentitis
and abortion due to Amycolatopsis spp. or Crossiellaequi were confirmed by the USA.
France, Switzerland, and the USA recorded
cases of leptospirosis. France (a case) and the USA(two cases) diagnosed cases of abortion. France also
confirmed two outbreaks (single cases) of uveitis.
Switzerland recorded a case of leptospirurea.
The USA recorded one case of Neorickettsia
risticii abortion and three other outbreaks in which
horses presented with fever, anorexia, depression,and diarrhea.
Salmonellosis was reported by the USA (threecases, two involving serogroup C1 and one ofundetermined serogroup). Rotaviral diarrhea wasreported by Argentina (one outbreak involving 40
vaccinated 20-40 day-old foals) and the USA (onecase).
Clostridial enterocolitis was reported by theUSA; nine cases were associated with Clostridium
perfringens and two with Clostridiodes difficile. The
USA confirmed 13 cases of proliferative enteropathy caused by Lawsonia intracellularis.
Canada (two outbreaks) and the USA (22outbreaks) confirmed cases of Eastern equine encephalomyelitis (EEE), all were single cases. A caseof dual infection with EEE and West Nile viruses
was diagnosed in a vaccinated horse in Florida.
Outbreaks of West Nile virus infection were reported by Austria, France, and Italy (two outbreaks
each, all single cases), Germany (four outbreaks),
Spain (11 outbreaks) and the USA (16 outbreaks,
all single cases).
Two outbreaks of vesicular stomatitis, Indiana
serotype, were confirmed by the USA in Texas andMissouri.
Rhodococcus equi related diseases were reportedby Germany (two cases of bronchopneumonia in
foals), and the USA in which the disease is endemic
and widespread.
Canada (one case) and the USA (11 outbreaks
in Washington State) recorded occurrences of
Pigeon fever, Corynebacterium pseudotuberculosis
infection. Japan recorded one case of tetanus.

C

OVID-19 pandemic-related restrictions produced a recession, which economists typicallydefine as two consecutive quarters of decline in
GDP (gross domestic product) growth. Like every
other business sector across the globe, the equine
industry has been affected by COVID-19 related
restrictions. We are now only starting to be able
to assess short-term impacts, and it will be sometime before the long-term impacts are fully understood. While we can look to recoveries from past
recessions for insight, the contraction initiated by
COVID-19 shutdowns is far different from earlier
recessions, rendering historical information lesspredictive of the recovery path.
Across the globe, restrictions faced by equine
industry participants have varied. Some governments mandated the closure of equine facilities toreduce the spread of the virus and minimize risks
of injury, while others delegated responsibility toequine enterprise owners and managers. The complete closure of equine facilities has been especiallydamaging, as these operations bear significant
ongoing expenses with no source of revenue.
Staggering early unemployment rates precipitated concerns of an impending equine welfare crisis.
However, while some horse owners have certainly
struggled to make ends meet due to unexpected
job loss, much of this unemployment was temporary, and a large-scale crisis appears to have been
avoided. Moreover, some organizations specializing
in re-homing horses actually reported an increasein adoptions during the initial shutdown.
A handful of preliminary studies are underway
across the U.S. to assess short-term COVID-19
related impacts. One such study is focused on
breeding, boarding/training/lesson, and competition enterprises in Kentucky across all breeds anddisciplines. Preliminary results suggest that while

not escaping the effects entirely, it appears thatbreeding and boarding/training/lesson operations
were minimally impacted. However, enterprises
related to competition, both racing and nonracing, appear to have sustained much greater
financial hardship. In addition to direct job loss,
the widespread cancellation of local, national, andinternational competitions has had a ripple effecton regional economies. Events able to operateshouldered increased costs associated with following health guidelines and were required to function
with limited or no spectators, which are often asource of revenue.
Some consider commercial sales and breeding
activity a bellwether for the health of the industry.
In North American Thoroughbred auction markets
in 2020, average prices for weanlings were down
6.2%, yearlings were down 20.3%, two-year-olds
in training were down 26.7%, and broodmares
were down 1.7%. Stud fees for North American
sires standing for $2,500 or more were down 3.7%
overall. While contractions are never welcome, thedecline was less drastic than some were anticipating.
The long-term impacts of COVID-19 restrictions
will ultimately depend on the shape of the generalmarket’s recovery. While GDP growth responded
quickly when the economy reopened, the recovery
has not been uniform across sectors. Some parts ofthe economy, most notably service and tourismrelated industries, continue to struggle. Any businesscycle that affects disposable income will ultimately
affect the equine industry as well, since it is centeredon what economists consider a “luxury” good.

3

Figure 1. Fungal ulcer characterized by a yellow, irregular area.

F

Equine Fungal KeratitisF

is a corneal scraping for cytology. If the ulcer
is infected, a specific inflammatory cell called aneutrophil, is present. In some cases, cytology canalso help determine if the infection is bacterial or
fungal. If fungal keratitis is suspected, an antifungal agent should be included in the treatment plan.
The choice of an antifungal agent is based on theantimicrobial sensitivity of fungi in the area andlevel of the veterinarian’s suspicion of the presenceof a fungal infection. Many general practitioners
will not have a topical antifungal agent on theirtruck. In such instances, silver sulfadiazine (acommon wound cream) or miconazole (typicallyavailable at your local pharmacy) can be used until
a more appropriate antifungal medication can beordered. In the case of any ocular infection, it ishighly important that whatever medication(s)are used, are approved for application to the eye.
Where treatment proves difficult, placement of a
subpalpebral lavage catheter can be considered tofacilitate successful treatment. In cases of severe
fungal disease, referral to an ophthalmologist
should be discussed with the client to determine
if surgical intervention is required. Even in severecases, surgical intervention can be successful inpreserving vision.
CONTACT:
Nikki Scherrer, DVM, DACVO
scherrer@vet.upenn.edu(317) 691-7339
New Bolton Center
University of Pennsylvania
Kennett Square, Pennsylvania

Equine Fungal infections in Central Kentucky (2009-2019)CONTACT:
Jill Stowe, PhD
jill.stowe@uky.edu
Department of Agricultural Economics
University of Kentucky
Lexington, Kentucky

fungal keratitis in horses is much higher than inother domestic species. It is suspected that this occurs because horses have fungi living normally on
the surface of the eye and the environment horses
live in exposes them to fungi on a more frequentbasis. Without a pre-existing wound or ulcer, thepresence of fungi is not normally a problem for thehorse. However, when a corneal ulcer is present,
organisms normally on the anterior surface of theeye can result in an infection. Infection of the cornea can be devastating due to the often aggressive
nature of fungi. Fungi release collagenolytics thatbreak down the cornea and antiangiogenic factorsthat stop the growth of healing blood vessels into
the cornea.
Fungal keratitis can result in two types of lesions, an ulcer or abscess. A fungal ulcer is usuallywhitish-yellow and irregular in shape; it is often
surrounded by a groove (Figure 1). A stromal
abscess generally starts as a corneal ulcer whose
superficial layer heals and essentially traps thefungus within the cornea making it more difficult
to treat. Affected eyes present with a smooth, yellow haze (Figure 2).
Initial treatment for a corneal ulcer usuallyconsists of a topical antibacterial medication toprevent more commonly encountered bacterial infections. A simple corneal ulcer should heal within
5-7 days. If it does not, it becomes a complicatedulcer. Geographic location of a horse alone may
influence a veterinarian’s concern about a fungal
infection. In the United States, it has been shownthat Mid-Atlantic and Southeastern states havea high prevalence of keratitis, whereas the problem is much less common in the western states.
There are many reasons for the development of acomplicated ulcer. One of the tests a veterinariancan do to determine why an ulcer is not healing

KENTUCKYN AT I O N A L

ungal keratitis is an infection of the clear outersurface of the eye (the cornea) caused by afungus; the most common culprits are Aspergillus
sp. and Fusarium sp. If not treated quickly andaggressively, fungal keratitis can lead to loss of vision or even loss of the eye itself. The incidence of

4

Figure 2. Corneal abscess characterized by the smooth, yellow
appearance. Often these abscesses are caused by a fungal infection.

ungal infections in horses are considerably lesscommon than infections caused by bacterial
or viral agents. Fungal organisms are typicallyencountered in the animal’s normal environment,
and the clinical manifestation of disease often
reflects the route of exposure (skin, respiratory
tract or reproductive tract). In some cases, immunodeficiency or immunosuppression may
predispose an individual to fungal infection, whilein other cases, there is no identifiable predisposing
risk factor. Overt signs of disease will typically be
associated with an inflammatory response at thesite of infection and may lead to generalized illness,abortion, or death.
A search of submissions to the University of
Kentucky Veterinary Diagnostic Laboratory for theperiod from 2009-2019 turned up 241 cases that
had fungal involvement. The most common sites
of infection were the placenta, lungs, eye, guttural
pouch, skin, and nose. Less commonly represented
were the gastrointestinal tract, nervous system, andmultiorgan infections.
Fifty-nine cases of fungal placentitis wereidentified. Gestational ages ranged from 180 to
351 days, and the majority of cases presented asabortions four to one month prior to the mare’s
due date. The immediate/short term outcome forthe foal was reported in 53 cases, of which 30 wereborn dead or euthanized. Live foals were frequently
born early with gestational ages ranging from 310
days to full term. Five foals were born following
premature placental separation, and three had a