APRIL 2015
Volume 24, Number 2

C O M M E N TA RY
IN THIS ISSUE
Commentary
International
Fourth Quarter2014  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2Global Horse
Transportation  .  .  .  .  .  . 3National
Re-emergent
Diseases .  .  .  .  .  .  .  .  .  .  .  .  . 3Equine Urinary
Disease .  .  .  .  .  .  .  .  .  .  .  .  .  . 4KentuckyKentucky EquineMarket  .  .  .  .  .  .  .  .  .  .  .  .  .  . 5W

hen an equine patient needs to be hospitalized we expect the best care possible. Yet, justlike human hospitals there are unique challenges in
keeping the patient safe and healthy. One of theseissues is hospital-acquired infections. It is estimatedthat 5% of patients in human hospitals will experience a healthcare-associated infection. We assume
that similar rates occur in equine hospital settings.
There are a few key issues to remember. Opportunistic microorganisms (bacteria, fungi, andviruses) can affect the hospitalized horse. Manyof these “bugs” can be carried by one hospitalized patient and not cause illness in that patientbut can be shed into the housing environment,
contaminating diagnostic or treatment equipment
and other materials. Also, some animals might beincubating an infectious disease and shedding into
the environment prior to actually having clinicalsigns. This emphasizes the need for routine cleaning, disinfection, and good hand hygiene in allareas of equine hospitals.
Secondly, despite our best efforts some hospitalacquired infections occur. Equine hospitals aredifferent than human hospitals. We have hay,
dust, and stalls made of wood and concrete.
Our equine patient is large (1,200 lb. or more)with thick hair coats and produce 50 pounds ofmanure and urine per day. Infection control is achallenge even in human hospitals where almost
every surface is easily cleaned and disinfected.
Hospital-acquired infections are a risk wheneverhorses are hospitalized. Some equine patients may
have a compromised immune system and are
more at risk for opportunistic infections. As such,
veterinarians need to discuss these potential risks
for any hospitalized horses to their clients. Often
owners of hospitalized horses receive admission
and discharge information about the potential for
hospital-associated infections.

Also, consider the sophisticated and intensive
procedures we can now perform on horses. These
include long-term intravenous therapy, oxygen
support, and mechanical ventilation as some of theadvanced therapies available for critically illpatients. The longer a patient is hospitalized thegreater the potential to acquire an opportunistic
infection.
Hospital infections can be costly. In a recent
survey, 31 of 38 veterinary teaching hospitals
reported an outbreak in the five years prior to thesurvey. Some of these outbreaks were in equine
facilities resulting in hospital closure. As such, mostequine hospitals will have procedures in place toreduce the likelihood of environmental contamination and follow strict isolation and quarantine
procedures. We need to respect these policies
which may impact a client’s ability to visit thehospital and their animal. Owners should refrainfrom interacting with other hospitalized horses
and recognize that their clothes, hands, and boots
can transport potential pathogens to the hospitalenvironment and to other horses. Owners may
be asked to put on protective coveralls, shoe covers, and gloves prior to visiting their hospitalized
animal as a biosecurity protocol.
Overall, hospital-acquired infections can be
reduced by recognizing the risk, having appropriate
cleaning and disinfection protocols, and practicing
good hand hygiene. Clients need to recognize theserisks and in addition, take measures to improvetheir own farm biosecurity to limit pathogen
spread.
CONTACT
Dr. Jeff Bender(612) 625-6203
bende002@umn.edu
University of Minnesota
Veterinary Medical Center
St. Paul, Minnesota

2

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

Fourth Quarter Report 2014*

T

Equine Disease Quarterly
Editors

Roberta Dwyer
Alan LoynachanPeter Timoney

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://www.ca.uky.edu/
gluck/index.htm
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 Collating Centre, Newmarket, United Kingdom, and other sources
reported the following disease outbreaks.
Outbreaks of African horse sickness were reported in four provinces in South Africa in which
the disease is considered endemic.
The USA recorded continued vesicular stomatitis activity, all involving the New Jersey serotypeof the virus. The disease was confirmed on an
additional 68 premises including 60 in Colorado,
seven in Texas, and one in Nebraska. In 2014, 17
counties were affected in Colorado, 13 in Texasand one in Nebraska, with infection confirmed
in 584 equines and 60 bovines on 433 premises.
France, Germany, Ireland, Switzerland, and the
USA recorded outbreaks of strangles. A total of 23
outbreaks were confirmed in 18 regions in France.
Isolated cases were reported in three regions inGermany; Ireland confirmed 14 cases between theprovinces of Leinster and Munster. Two outbreaks
were recorded in Switzerland, one involving 50 of
100 at-risk horses. The disease is endemic in the
USA with 41 cases confirmed on 22 premises inseven states.
Equine influenza outbreaks were reported by
France, the UK and the USA. France confirmed
four outbreaks. Some 18 outbreaks were confirmed
in 15 counties in the UK (horses, ponies anddonkeys), many involving unvaccinated animals.
Endemic in the USA, outbreaks were recorded in
Florida, Kentucky, Oregon, and Washington.
Equine herpesvirus (EHV)-1 related diseases
were reported by France, Germany, Japan, South
Africa, Switzerland, the UK and the USA. Respiratory disease was confirmed in France (sixoutbreaks), Germany (two outbreaks), Switzerland(one case), the UK (three outbreaks all involving
donkeys) and the USA. Cases of abortion werediagnosed in Japan (isolated cases on five premises,
all in vaccinated Thoroughbreds), South Africa(one case) and the USA (two cases). One outbreakof EHV-1 myeloencephalopathy involving two
horses was confirmed in Idaho, USA. Outbreaksof EHV-4 respiratory disease were reported by
France (11 outbreaks in five regions), Germany(single cases on two premises), and the UK (oneoutbreak involving three Thoroughbred yearlings).
Multiple cases of EHV-2 and -5 infections wereconfirmed in Texas and Kentucky in the USA.
Germany confirmed persistent equine arteritis
virus infection in one stallion and Switzerland
reported one case of this infection.
Equine infectious anemia was diagnosed in
France (one Friesian) and the USA (one Quarter
Horse racehorse).
Equine piroplasmosis was reported as endemic
in France and the United Arab Emirates.
A case of leptospiral abortion was diagnosed in a
Thoroughbred mare in France. The USA recorded
two cases of nocardioform placentitis and abortion.
Salmonella abortus equi infection was reported
by Singapore in five non-Thoroughbred malehorses on the same premises; they were part of aperformance circus group. Ireland confirmed threeoutbreaks of salmonellosis on separate premises,
and Switzerland recorded one case of salmonellosis(S. enteritidis).
The USA confirmed several cases of clostridial
enteritis due to C. perfringens type A, and of equine
proliferative enteropathy in foals.
Eastern equine encephalomyelitis was reportedby the USA, with 25 out of an annual total of 139
cases diagnosed in the fourth quarter of 2014. The
majority of cases were in Florida, Louisiana, New
York, and North Carolina.
The USA confirmed 74 cases of West Nile
encephalitis out of an estimated annual total of140. Texas, Oklahoma, California and Missouri
had the highest numbers of cases.
One case of Hendra virus infection was confirmed in Queensland, Australia.
Japan recorded single cases of tetanus on two
premises.
An outbreak of Getah virus infection was confirmed in a group of horses at a training center inJapan. The disease, which was diagnosed in 25 outof 49 febrile horses, was not life-threatening.
Rhodococcal disease was reported as endemic
in the USA. Switzerland recorded one case of borreliosis in a horse with anemia that was successfully
treated.
*Third Quarter Report for Australia

Global Horse Transportation IssuesT

he number of high-value insured horses travellinginternationally is difficult to quantify, making
true “risk assessment” for insurance purposes a problematic exercise. A record number of 1,003 United
Kingdom-based Thoroughbred racehorses competedinternationally in 2014. They travelled to France(417), Ireland (249), Dubai (144), Channel Islands(75), USA (34), Germany (22), Australia (15), Turkey(12), Switzerland (9), Canada (7), Sweden (7), Hong
Kong (5), Italy (2), Singapore (2), Czech Republic(1), Japan (1), and Spain (1). There were 350 FEI
international events in 1996 and this number grewprogressively to 657 in 1999, 1,530 in 2006, and3,215 by 2011. Stallions shuttle between both Northern and Southern hemispheres. Equine transportation
data for other equestrian disciplines and horse-related
activities are much less well documented, but long
distance transport occurs within national frontiers,
as in the USA, within Japan and Australia.
Long-distance travel has its own potential complications for horses. Confinement in a lorry or in
an airframe does not provide immunity from all the
problems that can occur in the normal day-to-day
lives of horses. Possible injury, colic, and disease are
ever-present and are arguably increased as hazards
when these “creatures of habit” are exposed to unfamiliar circumstances and travelling companions.
Quarantine and isolation, although always advocated, are not observed consistently, unless they aremandatory, as in the case of international travel.
However, there are no guarantees. Even measures
imposed by the animal health authorities in Japanand Australia failed to prevent the introduction ofequine influenza into Australia in 2007.

3

However, the principal problem associatedwith long-distance transport is the combination of
pleurisy and pneumonia that is known colloquially to horsemen everywhere as “shipping fever.”This condition creates a potentially problematicdifferential diagnosis for the attending equineclinician, who has to decide, often in the absenceof sophisticated diagnostics, whether a post-arrival
fever is a treatable shipping fever or a potentially
imported exotic disease. Reports of the incidenceof shipping fever demonstrate the magnitude ofthis problem. Between 11 and 12% of U.S. imported horses that arrived into either New Yorkor Los Angeles were febrile on arrival, and 60%
of horse flights into Hong Kong had at least one
case of shipping fever that was evident on arrival.
Advances in diagnostics, increased awareness,and better therapy mean that the majority of theseshipping fever cases make an uneventful recovery
provided treatment is initiated promptly. Delay canbe fatal and the earlier the diagnosis is made andtreatment is initiated, the more likely a successful
outcome. Prompt identification is facilitated by theprovision of veterinary services provided by experienced equine clinicians, in flight or at intermediatestops in long-haul road transport. Veterinarians do
not accompany all high-value shipments. It is ininsurers’ best interests to insist that they do so.
CONTACT
Dr. D.P. Leadon
dleadon@equine-centre.ie
Consultant, Irish Equine Centre
Specialist in Equine Medicine
Johnstown, Co. Kildare, Ireland

N AT I O N A L

Re-emergent DiseasesThe terms “emergent” and “re-emergent”
frequently are used interchangeably without
apparent appreciation of the meaning of each term
as a descriptor of a specific infectious disease. It is
important to make a distinction between the terms
insofar as they are not synonymous. “Emergent”
refers to the first recorded appearance and recognition of a disease in a population for which there
are no previous published reports. “Re-emergent”
diseases, on the other hand, are those that havebeen experienced in the past but either have reappeared in a more virulent form or have occurredin a different epidemiological setting.
A wide range of factors involving infectious
agent, host, or the environment can contributeto the occurrence of an emergent or re-emergent
disease. These can include: microbial change andadaption, host susceptibility to infection, modulation of climate, altered ecosystems, population
demographics, trends in international trade and

MATT BARTON, AGRICULTURAL C

4land use. The number of emergent and re-emergent
diseases of humans, animals, and plants continues
to increase as more sophisticated technologies become available that enable detection of previously
undiscovered infectious agents in the host and theenvironment.
There are various examples of re-emergent diseases, some of which are host restricted to membersof the family Equidae, whereas others can infectdifferent domestic and/or wildlife species besides
the horse. The majority of the better-known examples are viral diseases. The emergence of a strainof equine influenza virus, influenza-A/equine/
Jilin/89 (H3N8), in China in 1989 gave rise tovery high morbidity and associated case-fatality
rates in the equine population exposed to thisparticular strain of virus. Very fortunately, theJilin/89 strain of H3N8 virus did not spreadoutside of China.
Other examples that qualify as re-emergent were
the outbreaks of Venezuelan equine encephalomyelitis caused by subtype 1E strains of the virus that
occurred in Chiapas and Oaxaca states in Mexico
in 1993 and 1996. Both disease events were associated with unprecedented clinical-attack rates
and moderate case-fatality rates. Prior to theseoccurrences, subtype 1E strains of the virus were
not known to cause significant disease and losses
in horses.
The most widely known re-emergent diseaseof horses is equine herpesvirus-1 myeloencephalopathy. The occurrence of more virulent strains of
the virus has been responsible for major outbreaksof disease especially over the past 15 years, bothin Europe and North America. Enhanced neuropathogenicity is largely associated with a single
point mutation in the catalytic subunit of
the viral polymerase gene. Infection with thesestrains of virus has on occasion resulted insignificant clinical disease and a high mortality
rate.
As previously mentioned, diseases are also regarded as re-emergent if they occur in a different
epidemiologic setting. Examples of two diseases
that meet this criterion and which are of particular
relevance to the horse include West Nile encephalitis and equine encephalosis.
West Nile virus, first discovered in the USA
in 1999, has been responsible for significant annual losses in unvaccinated horses. Confirmationof equine encephalosis in Israel in 2008 was thefirst time this disease was reported outside of theAfrican continent.
Undoubtedly, there will be additional new andre-emergent equine diseases in the years to come,some of which may have significant economic
consequences for the equine industry in certain
countries. Early recognition of such diseases isof paramount importance if their impact is to beminimized.
CONTACT
Dr. Peter Timoney(859) 218-1094
ptimoney@uky.edu
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky

Equine Urinary DiseaseP
AL COMMUNICATIONS, UNIVERSITY OF KENTUCKY

rimary renal disease remains uncommon inequids; however, development of acute kidney injury (AKI) with other disease processes is aserious complication that can increase morbidity
and mortality. Of the approximately 2,000 horses
presented to Michigan State University’s Veterinary
Medical Center each year, approximately 4% haveincreased amounts of waste products in their blood
due to kidney insufficiency (azotemia with a serum
creatinine concentration [Cr] >2.5 mg/dL [220µmol/L]), and 1% have more severe azotemia
with Cr levels exceeding 5.0 mg/dL (440 µmol/L).
Researchers have found that horses that presented with colic or colitis and had persistent azotemia(failure of azotemia to resolve after three days oftreatment) were three times more likely to die orbe euthanized as compared to patients in which
azotemia resolved. Thus, prompt recognition ofcompromised renal function, minimizing the useof kidney damaging (nephrotoxic) medications,and institution of appropriate supportive care are
critical to improve patient outcome.
Non-steroidal anti-inflammatory drugs(NSAIDs) that have a greater inhibitory action
against cyclooxygenase-2 (COX-2) have beendeveloped in attempt to limit the unintended side
effects of NSAIDs. A misconception has developedthat these medications exert less adverse effects onrenal function than non-selective COX inhibitors(phenylbutazone and flunixin meglumine). However, COX-2 plays an essential role in maintenanceof renal blood flow, thus use of COX-2 selective
NSAIDs should not be considered renoprotective
therapy.
Chronic kidney disease (CKD) may develop
as a consequence of incomplete resolution of AKI
leading to tissue degeneration and fibrosis (>90%cases) or immune-mediated renal disease (<10%cases), with rare cases associated with anomalies ofdevelopment (renal aplasia, hypoplasia, dysplasia,

5or polycystic kidney disease). Presenting complaints for CKD are vague and include decreased
performance or loss of condition. However, a diagnosis of CKD is easily supported by characteristic
laboratory abnormalities including azotemia, hypercalcemia, unconcentrated urine (isosthenuria),
abnormal ultrasonographic findings, and the presence of kidney stones (nephroliths). Unlike people,
removal of nephroliths is rarely helpful for horses
with CKD unless they obstruct urine outflow.
CKD, by nature, is a progressive disease but therate of progression varies widely between patients.
Supportive treatment is focused on maintaining
body condition through nutrition (pasture is
the ideal diet) and avoiding use of nephrotoxic
medications. In patients with immune-mediatedrenal disease and proteinuria, treatment with corticosteroids and angiotensin converting enzyme
inhibitors may also be helpful. Supplementation
with omega-3 fatty acids also merits consideration
as this approach slows progression of CKD in dogs
and cats (pasture is an ideal source of omega-3 fatty
acids). Although long-term prognosis for CKD ispoor, horses can do well for months to several years.
Finally, lower urinary tract disorders, including
bladder stones (cystolithiasis), urinary incontinence, and blood in the urine (hematuria), areactually more common than upper tract disease.

Considering that horses normally excrete large
amounts of calcium carbonate and oxalate crystals
in urine, it is somewhat surprising that urinarystones (urolithiasis) are less common in horses
than dogs. Nevertheless, cystolithiasis in equids
appears to have a recurrence rate approaching 50%,
suggesting a genetic predisposition in affectedhorses. Horses with bladder muscle dysfunction
due to foaling or trauma, neurological disease,or unknown cause, develop progressive bladderenlargement and overflow incontinence. Affectedpatients may also accumulate a large concretionof urine crystals into a mass that can be confusedwith a cystolith. However, this problem (sabulous
urolithiasis), can be treated by dissolution throughbladder lavage and affected horses should not be
subjected to an unnecessary cystotomy surgery.
Lastly, an emerging syndrome of life-threatening
idiopathic renal hematuria has been recognized in
Arabian and part-Arabian horses. The author is trying to determine whether there may be a hereditarybasis for this disorder, and would appreciate being
contacted by anyone aware of suspected cases.
CONTACT
Dr. Harold Schott II(517) 353-9710
schott@cvm.msu.edu
Michigan State University Veterinary Medical Center
East Lansing, Michigan

KENTUCKY

Kentucky Equine Market Continues to Show ImprovementH

orses have been one of the signature sectorsof Kentucky’s agricultural economy for many
years. Equine receipts were the top agricultural commodity in the Bluegrass State for several years following the tobacco buyout and are typically one of the
major economic contributors. However, like most
sectors of the economy, equine markets were heavily
impacted by the recession. Keeneland sales, a major
driver of Kentucky equine receipts, fell by 53% from2007 to 2010. Since that time period, equine markets
have been largely in a state of recovery. Keenelandsales for 2014 were up by 40% from those reduced
2010 levels. Figure 1 shows the decrease in sales levels
from 2007 to 2010 and the rally through 2014.
In addition to sales, stud fees are also a significant revenue stream for the equine sector. Figure
2 below shows an estimate of stud fee revenues in
Kentucky based on the Kentucky Thoroughbred

Breeder’s Incentive Fund payouts. These estimates
are likely conservative, since not all breeding activity is subject to sales taxes, such as using shipped
semen, the stallion and mare both having thesame owner, and the use of season shares and foal
shares. However, the trend in revenues is likely areasonable representation of the trend in breeding
activity during this time period. According to Figure 2, stud fee revenues followed a similar patternof weakness from 2007 to 2010, but have shown
some improvement since then.
Recall that stud fee revenues are based on two
factors: the stud fee and the number of mares
bred. The only definitive way to increase stud
fee revenues is an improvement in both of thosefactors. While stud fees may have been trending
upward in the past few years, according to 2015
Kentucky Fact Book produced by The Jockey Club

Equine Disease Quarterly Newsletter
Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099
Address Service Requested

CONTACT
Dr. Kenny Burdine(859) 257-7273
kburdine@uky.edu
Dr. C. Jill Stowe(859) 257-7256
jill.stowe@uky.edu
Department of Agricultural Economics
University of Kentucky
Lexington, Kentucky

Millions ($)

Figure 1. Annual Keeneland sales totals (2006-2014).
900
800
700
600
500
400
300
200
100
0

2006

2007

2008

2009

2010 2011 2012 2013 2014
Year
Source: Keeneland, www.keeneland.com/sales

Figure 2. Estimated revenue from stud fees in Kentucky (2006-2013).
350
300
Millions ($)

Stud, the number of mares bred to Kentucky stallions reached a near-peak in 2008 and fell steadily
afterwards, only showing its first upward trend in
2013.
The fact that the improved sales levels of 2013
were sustained for 2014 was certainly a good signfor the equine markets last year and likely signals
a significant recovery from the 2008 to 2010 time
period. Improved sales also bode well for studfees in the coming years, which have not seen thelevel of improvement that sales have. Widespread
improvement in the equine markets would be
welcome news in Kentucky, where equine typicallyaccounts for a significant portion of the state’s agricultural cash receipts and has significant secondary
and tertiary effects on the state’s economy.

250
200
150
100
50
0

2006

2007

2008

2009

2010
2011
2012
2013
Year
Source: Kentucky Horse Racing Commission