Thursday, March 15, 2012

Israel: Cats Infected With H5N1



UPDATED:  The Jerusalem Post is now carrying this story with advice to their readers to avoid contract with stray cats in the area.


Three stray cats die of avian flu in Eilat


LAST UPDATED: 03/15/2012 18:58

Three stray cats found by the Veterinary Service and Health Ministry inspectors at Shalva and Holit in southwest Israel were confirmed as having died from eating poultry infected with avian flu.


 # 6225



Last week Israel reported to the OIE a couple of bird flu outbreaks (H5N1) in turkeys in Hadarom.  Israel has seen limited outbreaks in poultry in the past, and so this was not exactly a huge story. 

But today the story takes a bit of a turn as we learn from a fresh OIE report that several cats have died after ingesting infected turkey carcasses (a hat tip goes to Giuseppe Michieli on FluTrackers for posting this report.)


While we’ve seen reports of cats infected with the H5N1 virus in the past, it is a fairly uncommon occurrence, particularly over the past few years.


First some details from today’s report, then I’ll return with more.



H5N1 was diagnosed in turkeys on 8 March 2012. On 9 March 2012, just before the culling of the birds, cats were seen eating carcasses. On 14 March 2012, 4 cats were found dead around the affected pen and some showed clinical signs such as respiratory signs and weakness. On 15 March 2012, the authorities succeeded to catch 16 cats roaming around the infected pen and euthanized them.



We’ve a number of reports over the years of cats infected with the H5N1 virus after consuming infected meat, the most famous being the deaths of scores of tigers kept in zoos in Thailand.


The following comes from a World Health Organization GAR report from 2006.


H5N1 avian influenza in domestic cats

28 February 2006


Several published studies have demonstrated H5N1 infection in large cats kept in captivity. In December 2003, two tigers and two leopards, fed on fresh chicken carcasses, died unexpectedly at a zoo in Thailand. Subsequent investigation identified H5N1 in tissue samples.


In February 2004, the virus was detected in a clouded leopard that died at a zoo near Bangkok. A white tiger died from infection with the virus at the same zoo in March 2004.


In October 2004, captive tigers fed on fresh chicken carcasses began dying in large numbers at a zoo in Thailand. Altogether 147 tigers out of 441 died of infection or were euthanized. Subsequent investigation determined that at least some tiger-to-tiger transmission of the virus occurred.


In 2006, Dr. C.A. Nidom demonstrated that of 500 cats he tested in and around Jakarta, 20% had antibodies for the bird flu virus.  


In 2007 the FAO warned that:


Avian influenza in cats should be closely monitored

So far no sustained virus transmission in cats or from cats to humans


For an overview of a number of other cases involving cats, see Apparently They Didn't Get The Memo.  But reports such as these have become less common over the past couple of years.


Last November we saw a study in the Journal of Virology that looked at an unusual route of infection  - and resultant pathogenesis – of the H5N1 virus in cats.


The study is called:

Marked endotheliotropism of highly pathogenic avian influenza virus H5N1 following intestinal inoculation in cats.

November 2011, doi: 10.1128/​JVI.06375-11

Reperant LA, van de Bildt MW, van Amerongen G, Leijten LM, Watson S, Palser A, Kellam P, Eissens AC, Frijlink HW, Osterhaus AD, Kuiken T.


Endotheliotropism is simply a 12-dollar word meaning an affinity for endothelial cells which are the cells that line the interior surface of blood vessels throughout the body.


From the abstract (the entire study is behind a pay wall), we learn that researchers gave cats enteric coated capsules containing H5N1 infected chicken liver in order to deliver the virus directly to the intestine.



Intestinal inoculation of HPAIV H5N1 resulted in fatal systemic disease. The spread of HPAIV H5N1 from the lumen of the intestine to other organs took place via the blood and lymphatic vascular systems but not via neuronal transmission.


Remarkably, the systemic spread of the virus via the vascular system was associated with massive infection of endothelial and lymphendothelial cells, resulting in widespread hemorrhages.


As the abstract points out, this resulted in a disease process similar to what is seen in terrestrial poultry, and differs greatly from the pathogenesis normally seen from respiratory tract infection.


The authors conclude that:


The marked endotheliotropism of the virus following intestinal inoculation indicates that the pathogenesis of systemic influenza virus infection in mammals may differ according to the portal of entry.


The surprise here isn’t that cats (and other mammals) can acquire the H5N1 virus via a non-respiratory route (we’ve known that for some time), it is the discovery of the manner in which the virus spread systemically; via massive infection of endothelial and lymph endothelial cells.


Another example of how H5N1 behaves in unexpected ways, and further evidence that we are just scratching the surface in our exploration and understanding of this remarkable virus.

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