Title: Avian influenza in cats

{{Short description|none}}
'''Cats with avian influenza''' exhibit symptoms that can result in death. The [[avian influenza]] viruses [[cat]]s may get include H5N1 or H7N2,&lt;ref&gt;{{Cite journal |last=Lee |first=Christopher T |date=28 July 2017 |title=Outbreak of Influenza A(H7N2) Among Cats in an Animal Shelter With Cat-to-Human Transmission—New York City, 2016 |url=https://academic.oup.com/cid/article/65/11/1927/4049509 |access-date=2024-05-16 |journal=Clinical Infectious Diseases|volume=65 |issue=11 |pages=1927–1929 |doi=10.1093/cid/cix668 |pmid=29020187 }}&lt;/ref&gt; notable pathogenic subtypes of the virus. In order to get the virus, a cat would need to be in contact with infected waterfowl, poultry, or uncooked poultry.&lt;ref name=&quot;SD Belak Boucraut-Baralon&quot;&gt;{{cite journal|last=Thiry|first=Etienne|author2=Addie, Diane|author3=Belák, Sándor|author-link3=:hu:Belák Sándor (állatorvos)|author4=Boucraut-Baralon, Corine|author5=Egberink, Herman|author6=Frymus, Tadeusz|author6-link=:pl:Tadeusz Frymus|author7=Gruffydd-Jones, Tim|author8=Hartmann, Katrin|author9=Hosie, Margaret J.|author10= Lloret, Albert|title=H5N1 avian influenza in cats. ABCD guidelines on prevention and management|journal=Journal of Feline Medicine &amp; Surgery|date=1 July 2009|volume=11|issue=7|pages=615–618|doi=10.1016/j.jfms.2009.05.011|pmid=19481042|pmc=7128855}}&lt;/ref&gt; Two of the main organs that the virus affects are the lungs and liver.&lt;ref name=&quot;SD Marchall Hartmann&quot;&gt;{{cite journal|last1=Marschall|first1=J|last2=Hartmann|first2=K|title=Avian influenza A H5N1 infections in cats|journal=Journal of Feline Medicine &amp; Surgery|date=1 August 2008|volume=10|issue=4|pages=359–365|doi=10.1016/j.jfms.2008.03.005|pmid=18619884|s2cid=29347001|pmc=10832898}}&lt;/ref&gt; In May 2024, two indoor-only cats living in [[Michigan]] developed avian flu and died. Their owners were [[dairy farming|dairy farm workers]] who had symptoms of H5N1 bird flu before their cats, but did not want to be tested.&lt;ref name=&quot;mmwr&quot;&gt;{{Cite journal |last=Naraharisetti |first=Ramya |date=February 2025 |title=Highly Pathogenic Avian Influenza A(H5N1) Virus Infection of Indoor Domestic Cats Within Dairy Industry Worker Households — Michigan, May 2024 |url=https://www.cdc.gov/mmwr/volumes/74/wr/mm7405a2.htm?s_cid=mm7405a2_w |access-date=2025-02-21 |journal=MMWR. Morbidity and Mortality Weekly Report |language=en-us |volume=74 |issue=5 |pages=61–65 |doi=10.15585/mmwr.mm7405a2 |doi-access=free |pmc=12370256 }}&lt;/ref&gt;

==History==
{{see also|Global spread of H5N1#Felidae (cats)}}

[[Avian influenza]] has been found in China, Thailand, Vietnam, Indonesia, Iraq, Austria, Germany, and Poland. Besides being found in [[domestic cats]], the virus has infected a variety of wild cats such as the [[Asiatic golden cat]], the [[clouded leopard]], [[tigers]], and [[leopards]].&lt;ref name=&quot;PM Harder Vahlenkamp&quot;&gt;{{cite journal |vauthors=Harder TC, Vahlenkamp TW |title=Influenza virus infections in dogs and cats |journal=Vet. Immunol. Immunopathol. |volume=134 |issue=1–2 |pages=54–60 |date=March 2010 |pmid=19896216 |doi=10.1016/j.vetimm.2009.10.009 }}&lt;/ref&gt; In 2024, twenty [[big cat]]s died due to an outbreak in a sanctuary in the United States.&lt;ref&gt;{{Cite web |last1=Kaye |first1=Randi |author-link1=Randi Kaye |last2=Anderson |first2=Nic |date=2024-12-25 |title=Bird flu kills more than half the big cats at a Washington sanctuary |url=https://edition.cnn.com/2024/12/25/us/bird-flu-washington-cats-cases/index.html |access-date=2024-12-29 |website=[[CNN]] |language=en}}&lt;/ref&gt;

H5N1 was first discovered in domestic and wild cats in Asia in 2007,&lt;ref name=&quot;PM Thiry Zicola&quot;&gt;{{cite journal  |vauthors=Philippa J, Baas C, Beyer W, etal  |title=Vaccination against highly pathogenic avian influenza H5N1 virus in zoos using an adjuvanted inactivated H5N2 vaccine |journal=Vaccine |volume=25 |issue=19 |pages=3800–8 |date=May 2007 |pmid=17403559 |doi=10.1016/j.vaccine.2007.01.121 }}&lt;/ref&gt; specifically in 2003 in the Thai zoo where two tigers and two leopards died. In 2004, the Thai zoo had 147 tigers that died or were euthanized.&lt;ref name=&quot;PM Yee Carpenter&quot;&gt;{{cite journal |vauthors=Yee KS, Carpenter TE, Cardona CJ |title=Epidemiology of H5N1 avian influenza |journal=Comp. Immunol. Microbiol. Infect. Dis. |volume=32 |issue=4 |pages=325–40 |date=July 2009 |pmid=18448168 |doi=10.1016/j.cimid.2008.01.005 }}&lt;/ref&gt; This was then followed by an outbreak in Germany in 2006, where three stray cats were found to be either dying or dead during the peak time of the virus outbreak.&lt;ref name=&quot;SD Starick Beer&quot;&gt;{{cite journal|last=Starick|first=E. |author2=Beer, M. |author3=Hoffmann, B. |author4=Staubach, C. |author5=Werner, O. |author6=Globig, A. |author7=Strebelow, G. |author8=Grund, C. |author9=Durban, M. |author10=Conraths, F.J. |author10-link=:de:Franz J. Conraths |author11=Mettenleiter, T. |author11-link=:de:Thomas Mettenleiter |author12=Harder, T.|title=Phylogenetic analyses of highly pathogenic avian influenza virus isolates from Germany in 2006 and 2007 suggest at least three separate introductions of H5N1 virus|journal=Veterinary Microbiology|date=1 April 2008|volume=128|issue=3–4|pages=243–252|doi=10.1016/j.vetmic.2007.10.012|pmid=18031958|url=https://hal.archives-ouvertes.fr/hal-00532340/file/PEER_stage2_10.1016%252Fj.vetmic.2007.10.012.pdf }}&lt;/ref&gt; As of June 2023, there was an ongoing outbreak in Poland with at least 9 confirmed cases and multiple deaths. &lt;ref&gt;{{cite web |last1=Schnirring |first1=Lisa |title=Polish officials probe H5N1 avian flu link to cat deaths |url=https://www.cidrap.umn.edu/avian-influenza-bird-flu/polish-officials-probe-h5n1-avian-flu-link-cat-deaths |website=Center for Infectious Disease Research and Policy |date=26 June 2023 |publisher=University of Minnesota |access-date=28 June 2023}}&lt;/ref&gt; 
In May 2024, two indoor-only cats living in [[Michigan]] developed avian flu and died. Their owners were [[dairy farming|dairy farm workers]] who had symptoms of H5N1 bird flu before their cats, but did not want to be tested.&lt;ref name=&quot;mmwr&quot;/&gt;

In December 2024, 20 big cats in a wildlife sanctuary in [[Shelton, Washington]] died from the infection.&lt;ref&gt;{{Cite news |last=Rosman |first=Rebecca |date=26 December 2024 |title=Bird flu has killed 20 big cats including cougars at a U.S. wildlife sanctuary |url=https://www.npr.org/2024/12/26/nx-s1-5239841/bird-flu-kills-20-cats-washington-sanctuary#:~:text=It%20said%20bird%20flu%20poses,other%20animals%20across%20the%20sanctuary. |access-date=26 December 2024 |work=NPR}}&lt;/ref&gt; Also in December 2024, Los Angeles County public health officials detected H5N1 in cats that had consumed [[raw milk]] that had been recalled due to an outbreak, indicating that the virus can be transmitted between mammal species via milk consumption.&lt;ref&gt;{{Cite web |title=LISTING OF DEPARTMENT OF PUBLIC HEALTH PRESS RELEASES |url=http://publichealth.lacounty.gov/phcommon/public/media/mediapubhpdetail.cfm?prid=4908 |access-date=2024-12-26 |website=publichealth.lacounty.gov}}&lt;/ref&gt; President Trump's communications ban on [[CDC]] had held the MMWR report back initially.&lt;ref&gt;{{Cite news |last1=Mandavilli |first1=Apoorva |last2=Anthes |first2=Emily |date=2025-02-06 |title=C.D.C. Posts, Then Deletes, Data on Bird Flu Spread Between Cats and People |url=https://www.nytimes.com/2025/02/06/health/cdc-bird-flu-cats-people.html |access-date=2025-02-21 |work=The New York Times |language=en-US |issn=0362-4331}}&lt;/ref&gt;

From December 2024 to February 2025, three cats in [[Iceland]] were diagnosed with [[Influenza A virus subtype H5N5|H5N5]].&lt;ref&gt;{{cite web|url=https://www.mast.is/is/um-mast/frettir/frettir/ny-greining-a-fuglainfluensu-i-ketti|date=14 February 2025|access-date=24 February 2025|publisher=Matvælastofnun|lang=is|title=Ný greining á fuglainflúensu í ketti}}&lt;/ref&gt;

Because the virus infects the lungs of cats, it is one of the preferred [[model animals]] to study the effects of H5N1 in humans.&lt;ref name=&quot;PM Harder Vahlenkamp&quot; /&gt;

==Virus transmission==
Avian influenza is a [[zoonosis|zoonotic agent]]. The most common way a cat can obtain H5N1 is by consuming an infected bird. This has been studied in the 2006 and 2007 cases in Germany and Austria, where the strains between the cat and the infected birds were not different between the species.&lt;ref name=&quot;SD Starick Beer&quot; /&gt;  A cat is able to then transfer the virus via the respiratory tract and the digestive tract to other cats. However, studies suggest that a cat cannot transfer the virus to a dog, and vice versa, while sharing a food bowl.&lt;ref name=&quot;PM Harder Vahlenkamp&quot; /&gt; Though there was no concrete evidence as of 2010, there is a potential link between the transmission of the virus between poultry, wild birds, and humans.&lt;ref name=&quot;PM Kalthoff&quot;&gt;{{cite journal |vauthors=Kalthoff D, Globig A, Beer M |title=(Highly pathogenic) avian influenza as a zoonotic agent |journal=Vet. Microbiol. |volume=140 |issue=3–4 |pages=237–45 |date=January 2010 |pmid=19782482 |doi=10.1016/j.vetmic.2009.08.022 |url=https://hal.archives-ouvertes.fr/hal-00556054/document}}&lt;/ref&gt;

Once the cat is infected, after an [[incubation period]] of 2 to 3 days,&lt;ref name=&quot;PM Thiry Zicola&quot; /&gt; the virus can be found in the respiratory tissues, attached to the [[type II pneumocyte]]s and alveolar [[macrophages]],&lt;ref name=&quot;PM Harder Vahlenkamp&quot; /&gt; as well as the intestinal tissues. In some cases where the virus has been found in the brain and other systems in the body.&lt;ref name=&quot;PM Belser models&quot;&gt;{{cite journal |vauthors=Belser JA, Tumpey TM |title=H5N1 pathogenesis studies in mammalian models |journal=Virus Res. |volume= 178|issue= 1|pages= 168–85|date=February 2013 |pmid=23458998 |doi=10.1016/j.virusres.2013.02.003 |pmc=5858902 }}&lt;/ref&gt;

==Studies in cats==
One epidemiological study, conducted in Germany and Austria in 2008, found that out of 171 living cats tested, fewer than 1.8% had H5N1. Of the same sample, fewer than 2.6% had antibodies to H5N1. Even though Germany and Austria are among the countries that have had naturally occurring cases, this study shows that very few cats have contracted the disease and survived.&lt;ref name=&quot;SD Marschall Schulz&quot;&gt;{{cite journal|last1=Marschall|first1=J|last2=Schulz|first2=B |last3=Harderprivdoz|first3=T |last4=Vahlenkampprivdoz|first4=T|last5=Huebner|first5=J|last6=Huisinga|first6=E |last7=Hartmann|first7=K |title=Prevalence of influenza A H5N1 virus in cats from areas with occurrence of highly pathogenic avian influenza in birds|journal=Journal of Feline Medicine &amp; Surgery|date=1 August 2008|volume=10|issue=4|pages=355–358|doi=10.1016/j.jfms.2008.03.007|pmid=18640861|s2cid=6326717|doi-access=free|pmc=10832910}}&lt;/ref&gt;

There have also been studies looking at the [[T cell]]s, specifically CD4 and CD8, in the cat after viral infection. Though the mechanism is not fully known, there seems to be an inverse relationship with the amount of T cells present and the amount of infected cells.&lt;ref name=&quot;T-cell Giese&quot;&gt;{{cite journal|last=Giese|first=Matthias|author2=Harder, Timm C.|author3= Teifke, Jens P.|author4= Mettenleiter, Thomas C.|author4-link=:de:Thomas Mettenleiter|author5= Vahlenkamp, Thomas W.|author5-link=:de:Thomas W. Vahlenkamp|title=The role of T cells in avian influenza H5N1 infected cats|journal=Veterinary Immunology and Immunopathology|date=1 March 2009|volume=128|issue=1–3|pages=343|doi=10.1016/j.vetimm.2008.10.282}}&lt;/ref&gt;

Another study to test whether the ALVAC [[Canarypox#Mammalian_medicine| recombinant canarypox virus]] could prime the cat immune system was performed. This vaccine has the same [[Hemagglutinin (influenza)|hemagglutinin]] as the H5N1 virus, and therefore worked on preventing death from two different strains of the virus, HPAIV A/Vietnam/1194/2004 and HPAIV A/Indonesia/05/2005. However, some of the cats that were vaccinated did exhibit hyperthermia and weight loss, and all of the cats did have some disease change (assuming lesions) in their lungs. All of the cats, except one, still excreted the virus even after being vaccinated.&lt;ref name=&quot;SD Stittelaar Lacombe&quot;&gt;{{cite journal|last=Stittelaar|first=Koert J.|author2=Lacombe, Valérie|author3=van Lavieren, Rob|author4=van Amerongen, Geert|author5=Simon, James|author6=Cozette, Valérie|author7=Swayne, David E.|author8=Poulet, Hervé|author9= Osterhaus, Albert D.M.E.|author9-link=Ab Osterhaus|title=Cross-clade immunity in cats vaccinated with a canarypox-vectored avian influenza vaccine|journal=Vaccine|date=1 July 2010|volume=28|issue=31|pages=4970–4976|doi=10.1016/j.vaccine.2010.05.028|pmid=20566392}}&lt;/ref&gt;

==Symptoms==
A cat that is infected with a high dose of the virus can show signs of [[fever]], [[Fatigue (medical)|lethargy]], and [[dyspnea]].&lt;ref name=&quot;PM Belser models&quot; /&gt; There have even been recorded cases where a cat has neurological symptoms such as circling or [[ataxia]].&lt;ref name=&quot;SD Belak Boucraut-Baralon&quot; /&gt; 
In a case in February 2004, a 2-year-old male cat that had eaten a pigeon was panting and convulsing on top of having a fever two days prior to death. This cat also had lesions that were identified as renal congestion, pulmonary congestion, [[edema]], and [[pneumonia]]. Upon inspection, the cat also had {{Sic|cerebral congestion|hide=y}}&lt;!--Cerebral congestion is an obsolete term for stroke &amp; similar brain maladies, don't link--&gt;, [[conjunctivitis]], and [[bleeding|hemorrhaging]] in the [[Serous membrane|serosae of the intestines]].&lt;ref name=&quot;PM Carol Influenza&quot;&gt;{{cite journal |vauthors=Cardona CJ, Xing Z, Sandrock CE, Davis CE |title=Avian influenza in birds and mammals |journal=Comp. Immunol. Microbiol. Infect. Dis. |volume=32 |issue=4 |pages=255–73 |date=July 2009 |pmid=18485480 |doi=10.1016/j.cimid.2008.01.001 }}&lt;/ref&gt;

However, a cat that is infected with a low dose of the virus may not necessarily show symptoms. Though they may be asymptomatic, they can still transfer small amounts of the virus.&lt;ref name=&quot;PM Harder Vahlenkamp&quot; /&gt;

==Treatment and prevention==
There is currently no commercial vaccine to prevent or treat H5N1 in cats.&lt;ref name=&quot;PM Thiry Zicola&quot; /&gt;

If a cat is exhibiting symptoms, they should be put into isolation and kept indoors. Then they should be taken to a vet to get tested for the presence of H5N1. If there is a possibility that the cat has avian influenza, then there should be extra care when handling the cat.&lt;ref name=&quot;SD Belak Boucraut-Baralon&quot; /&gt; Some of the precautions include avoiding all direct contact with the cat by wearing gloves, masks, and goggles. Whatever surfaces the cat comes in contact with should be disinfected with standard household cleaners.&lt;ref name=&quot;PM Thiry Zicola&quot; /&gt;

Researchers have given tigers an antiviral treatment of [[oseltamivir]] with a dose of 75&amp;nbsp;mg/60&amp;nbsp;kg two times a day. The specific dosage was extrapolated from human data, but no data exist to suggest protection. As with many antiviral treatments, the dosage depends on the species.&lt;ref name=&quot;PM Thiry Zicola&quot; /&gt;

==References==
{{reflist}}

[[Category:Cat diseases]]
[[Category:Avian influenza]]