Virology J: Human-like H3N2 Influenza Viruses In Dogs - Guangxi, China

 

# 9674

 

Influenza viruses are constantly evolving, and do so via two well established routes; Antigenic drift & Antigenic Shift (reassortment).

 

Antigenic drift causes small, incremental changes in the virus over time. Drift is the standard evolutionary process of influenza viruses, and often come about due to replication errors that are common with single-strand RNA viruses (see NIAID Video: Antigenic Drift).

 

Shift occurs when one virus swap out chunks of their genetic code with gene segments from another virus.  This is known as reassortment. While far less common than drift, shift can produce abrupt, dramatic, and sometimes pandemic inducing changes to the virus (see NIAID Video: How Influenza Pandemics Occur).

While most reassortant viruses fail to thrive, every once in a while a viable, and competitive new subtype will emerge.  As any virologist will tell you, while rare  – Shift Happens.

 

It has only been in the past few years that dogs have been viewed as potential important `mixing vessels’  for influenza – an evolutionary process that has traditionally been associated with birds and swine. 

 

But as we learn more about the host range (which includes humans, equines, swine, birds, bats, camels, and marine mammals) and the genetic diversity of influenza viruses (currently 18 hemagglutinin & 11 neuraminidase subtypes identified), we find a far more complex and intermingled ecology than previously envisioned. 

 

In years past we’ve looked at a number of species with at least theoretical potential to act as mixing vessels, including in  Mixing Vessels For Influenza & A Host Of Reservoirs.

 

Last summer, and particularly apropos for today’s blog -  in Study: Dogs As Potential `Mixing Vessels’ For Influenza - we looked at the ability of different influenza strains (canine, equine and human)  to infect, and replicate in, canine tracheal tissues. 

Last November, In A Dog & Cat Flu Review, we looked at (among other things) the emergence and evolution of avian H3N2 and equine H3N8 viruses in dogs, and just last week we saw reports that Korea has continued to find evidence of avian H5N8 infection in dogs.

 

So it isn’t a huge surprise that we find a study, published yesterday in the Virology Journal, that has isolated and identified what appears to be a human/swine combination H3N2 influenza virus in pet dogs from Guangxi, China.

 

Emergence of human-like H3N2 influenza viruses in pet dogs in Guangxi, China

Ying Chen^1*, Yan-Ning Mo¹, Hua-Bo Zhou², Zu-Zhang Wei¹, Guo-Jun Wang³, Qing-Xiong Yu¹, Xiong Xiao¹, Wen-Juan Yang¹ and Wei-Jian Huang¹ 

Virology Journal 2015, 12:10  doi:10.1186/s12985-015-0243-2

Published: 3 February 2015

Abstract (provisional)

Background After the 1968 H3N2 pandemic emerged in humans, H3N2 influenza viruses continuously circulated and evolved in nature. An H3N2 variant was circulating in humans in the 1990s and subsequently introduced into the pig population in the 2000s. This virus gradually became the main subtype of swine influenza virus worldwide. However, there were no reports of infections in dogs with this virus.

Findings  In 2013, 35 nasal swabs from pet dogs were positive for Influenza A virus by RT-PCR. Two viruses were isolated and genetically characterized. In the phylogenetic trees of all gene segments, two H3N2 canine isolates clustered with Moscow/10/99 and most H3N2 swine influenza viruses.

These results indicated that two H3N2 CIVs possessed high homology with human/swine influenza viruses, which at the same time exhibited some amino acid substitutions in NA, polymerase basic protein 1 (PB1), and nucleoprotein (NP), which probably were related to the interspecies transmission

.Conclusions These two viruses share the highest homology with swine H3N2, Moscow/99-like viruses, which indicated that these viruses might originate from swine viruses.

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.

While it doesn’t appear that these reassortant viruses have become well established in canine hosts, this adds to the growing body of evidence that dogs could serve as intermediate hosts – and potential mixing vessels – for a variety of non-canine influenza viruses.

Swine and poultry undoubtedly pose far larger reassortment risks, simply because they are natural hosts for influenza viruses, are often raised in large numbers and in close proximity with one another, and are often shipped long distances.

 

But as we’ve discussed previously, in China: Avian-Origin Canine H3N2 Prevalence In Farmed Dogs, in some parts of the world dogs are regarded as food  - not pets - and are raised under pretty much the same type of crowded conditions as other livestock, but apparently with even less oversight. 

China’s MOH introduced new regulations in 2013 requiring vaccinations and certificates of health for farmed dogs, but local reporting suggests widespread fraud or blatant disregard for these rules (see Yulin market dog safety not guaranteed - Reporter survey found that no regulations exist blank slaughter procedures).

While likely a minor player, all of this makes dogs a `wild card’ in the evolution and spread of new influenza reassortant viruses, and a host species worth keeping one eye on.

MAFRA: H5N8 Antibodies Detected In South Korean Dogs (Again)

Spread of H5N8 in Korea – Credit Japan’s MAFF 

 

*** UPDATED ***

 

Although it certainly wasn’t clear from the kludgy machine translation of MAFRA’s statement, or the Xinhua News report cited in this blog, this English language report from the Korea Herald  suggests that this latest case may have been detected using rt-PCR (or other viral test method), not through serum antibodies.  

Hopefully we’ll get something a bit more authoritative to clarify matters. Until then, Caveat Lector. 

Avian influenza detected in dog

Published : 2015-02-02 21:47

Avian influenza was found in a dog on a farm in South Gyeongsang Province amid growing concerns that the disease could spread to other animals, officials said Monday.

The dog ― one of three at a duck farm in Goseong-gun, South Gyeongsang Province ― had antigens for the highly pathogenic H5N8 strain of bird flu, the Ministry of Agriculture, Food and Rural Affairs said. The farm was affected by the disease on Jan. 23.

This is the first time bird flu has been found in a dog in Korea through the detection of antigens, but antibodies for the virus were found in a dozen dogs at virus-affected farms in March last year. The detection of antibodies suggests an immune response to the virus, the ministry said.

(Continue . . . )

 

 

# 9660

 

Different viruses have an affinity for binding to, and infecting, different types of cells.  That is why most viruses are fairly selective as to what organ systems they attack, or even what species they can infect.  This explains why a virus might affect a dog, or a cat, or a bird, yet not affect humans. 

 

This species selectivity is known as its `host range'.

 

Most viruses generally have a fairly narrow host range (there are exceptions, of course.  Like rabies).  All of which means that avian influenza viruses tend to infect birds, and swine influenza viruses usually infect pigs, and that we pay special attention when ever we see one of these viruses `break the rules’.

 

The HPAI H5N8 virus, which came to prominence just over a year ago in South Korean poultry and wild birds, has spread remarkably well, now plaguing poultry operations on 3 continents. Although highly destructive in birds, this virus’s one saving grace has been its apparent inability to sicken humans.

 

I say `apparent inability’ because there has been precious little published on human seroprevalence studies among cullers, poultry workers, and others since the virus emerged last year. 

 

You may recall that during Korea’s H5N1 outbreaks early in the last decade they found 9 cullers (who received prophylactic Tamiflu ®)  that  went on to develope antibodies to the virus, even though none were symptomatic (see Avian Influenza A (H5N1) Virus Antibodies in Poultry Cullers, South Korea, 2003–2004).

 

We do know that dogs are susceptible to mild or subclinical infection with H5N8, something we saw reported twice last spring (see Korea Detects H5N8 Antibodies In Farm Dog & Korea Finds More Dogs With H5N8 Antibodies), and that is being reported once again today

 

First the slightly syntax-challenged translation of South Korea’s MAFRA  announcement, followed by a more easily read Xinhua report, after which I’ll return with a bit more.

 

 

Quarantine Division, AI in the dog (H5N8) virus detected confirmation

Added
2015-02-02 10:05:00

 

Agriculture, Forestry, Livestock Quarantine Division (Head of State otolith) said that the H5N8 virus is released from the two nasal passages are raised in the AI occurred last January 23, Gyeongnam Goseong material broiler duck farms.

Factory farms that slaughter for broiler ducks January 23 AI virus has been identified in the previous inspection, and thus farm AI virus was detected in one of my test result breeding dogs are three sampling time were all three had clinical symptoms, the other two antigens, antibodies

No contact is not being propagated as determined by between two dogs that are breeding farm inspection results generated AI * 2014 23 55 two farms in the confirmation H5 antibodies ** 2015 August 24, two tests both farms antibody not detected Agriculture, Forestry, Livestock Quarantine Division was urged to give careful not therefore believe that it is the AI virus has been confirmed in poultry contamination from infected dogs in the dog is not used to our chickens and ducks from the farm to feed.

 

S. Korea confirms dog infected with avian flu

Source: Xinhua | February 2, 2015, Monday | Online Edition

SOUTH Korea's agriculture ministry on Monday confirmed a dog at a duck farm has been infected with avian influenza.

The bird flu virus was found in a dog among three dogs at a duck farm in southeastern South Korea where the highly pathogenic H5N8 strain of virus was confirmed on Jan. 23, the Ministry of Agriculture, Food and Rural Affairs said at a briefing.

There have been no antigens nor antibodies found in two other dogs, reflecting no dog-to-dog transmission of the virus, the ministry said.

The three dogs, which the ministry estimated may have had infected ducks, were culled.

Since the first case of a dog being infected with the poultry virus in March 2014, there have been 55 dogs found with antibodies to the bird flu virus. The antibody means the immune system of the dogs eliminated the virus.

More than 1.8 million ducks and chicken have been culled since the latest outbreak of the bird flu was reported in September 2014.

 

 

H5N8 infection is believed to have been contracted through the consumption of infected birds, something we’ve seen before with both dogs and cats (see A Dog & Cat Flu Review).  New with this report is the announcement that at least 55 dogs in South Korea have now shown evidence of H5N8 antibodies, a four-fold increase over the number revealed last spring.

 

While it’s still a major leap from sparking antibodies in dogs to posing a human health threat, the ability for an avian flu virus to affect any mammalian species is considered a bit of a red flag.

 

This isn’t the first time we’ve seen a novel influenza virus jump to dogs from another species.

• In 2004, the H3N8 equine influenza – a strain that has been around nearly a half century – suddenly jumped, and adapted to dogs, creating a new dog-specific (canine) lineage of H3N8.  Since then, H3N8 has continued to spread  among dogs, although it has never been known to infect humans.
• And again from Korea, in 2008 the CDC’s EID Journal carried a report on a newly emerging canine flu jumping from an avian source (see Transmission of Avian Influenza Virus (H3N2) to Dogs). In 2011, we saw the plot thicken yet again, when it was announced that this canine H3N2 had jumped to cats (see Korea: Interspecies Transmission of Canine H3N2). 
• And during the 2009 H1N1 pandemic, we saw cases of reverse zoonosis, where dogs (and cats) contracted the `humanized’ H1N1 virus from their human contacts (see US: Dog Tests Positive For H1N1)

 

This ability to be infected by more than one type of influenza virus also opens the door to the possibility that dogs could serve as a `mixing vessel’ for influenza viruses, through a process called Reassortment. 

 

Reassortment, or `Shift’ occurs when a single host is simultaneously infected with two different influenza viruses.   When that happens, it is possible for viruses to swap parts of their genetic sequence, and create a new, hybrid virus.

 

While most of the time, this leads to an evolutionary failure, every once in awhile this process produces a viable, even highly competitive, new flu strain. 

 

Although pigs and birds are vastly better `mixing vessels’ for influenza than dogs or cats will ever be, companion animals are of particular concern because of how closely humans interact with them.  

 

Of course, if there is some – as yet unidentified - `species barrier’ that prevents H5 viruses from adapting well enough to humans to pose a serious threat, then all of this concern may be moot.  

 

Some scientists believe that may be a possibility (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?), but few are willing to gamble on our being that lucky. 

 

On Friday, because of the recent arrival of HPAI H5 (H5N8, H5N2 & a `new’ H5N1) into North American birds, the CDC prudently issued two pieces of interim guidance (see links below), that have this to say about the risks posed by HPAI H5 viruses:

 

The appearance of newly detected avian influenza A H5 viruses in North America may increase the likelihood of human infection with these viruses in the United States. Because these newly identified avian influenza A H5 viruses are related to avian influenza A viruses associated with severe disease in humans (e.g., highly pathogenic Asian-lineage avian influenza A (H5N1) virus), they should be regarded as having the potential to cause severe disease in humans until shown otherwise.

An acknowledgment that not only do viruses change over time, so can our understanding of their abilities and threats. 

 

For more, see:

CDC Interim Guidance For Testing For Novel Flu

CDC Interim Guidance On Antiviral Chemoprophylaxis For Persons With Exposure To Avian Flu

A Dog & Cat Flu Review

 

# 9382

 

Until about a decade ago, it was widely (and erroneously) believed that dogs and cats were not generally susceptible to influenza A infections. 

 

That perception began to change in 2004 with two unrelated events; the jump of equine H3N8 influenza from horses to Florida greyhounds, and the infection by avian H5N1 of tigers fed infected chickens in Thailand.

 

While not considered major players (yet) in the spread of human or novel influenza viruses, their role as companion animals make dogs and cats of particular interest to influenza researchers.

 

First a look back at some of the evidence on dogs & cats susceptibility to influenza – then I’ll have a couple of new studies that shed additional light on their ability to contract, and spread, certain subtypes of flu.

 

In 2004, the H3N8 equine influenza – a strain that has been around in horses nearly a half century – was discovered to have jumped, and adapted to dogs, creating a new dog-specific (canine) lineage of H3N8. 

 

Since then, H3N8 has continued to spread among dogs both in North America and around the globe.

While we’ve yet to see any evidence that this equine/canine H3N8 virus can infect humans, there are a number of different H3N8 lineages out there, including the equine, canine, avian, and even a recently discovered Mammalian Adapted H3N8 In Seals.

And a related H3N8 virus is thought to have sparked the 1900 influenza pandemic, giving it a track record in humans, and is considered likely to return someday (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).

Added to this mix, in 2008 the CDC’s EID Journal carried the following report on a newly emerging canine flu in Korea.

 

Transmission of Avian Influenza Virus (H3N2) to Dogs

Daesub Song, Bokyu Kang, Chulseung Lee, Kwonil Jung, Gunwoo Ha, Dongseok Kang, Seongjun Park, Bongkyun Park, and Jinsik Oh

Abstract

In South Korea, where avian influenza virus subtypes H3N2, H5N1, H6N1, and H9N2 circulate or have been detected, 3 genetically similar canine influenza virus (H3N2) strains of avian origin (A/canine/Korea/01/2007, A/canine/Korea/02/2007, and A/canine/Korea/03/2007) were isolated from dogs exhibiting severe respiratory disease.

 

In late 2012, in China: Avian-Origin Canine H3N2 Prevalence In Farmed Dogs, we saw a study that found more than 12% of farmed dogs tested in Guangdong province carried a strain of canine H3N2 similar to that seen in Korea.

 

During the 2009 H1N1 pandemic we saw reports of dogs infected, and in the middle of the last decade we saw several reports indicating that dogs were susceptible to the H5N1 bird flu virus (see Study: Dogs And H5N1).

Cats, too, were infected during the 2009 H1N1 pandemic (see Companion Animals And Novel H1N1 & EID Journal: Pandemic H1N1 Infection In Cats), and In 2011, it was announced that Korea’s canine H3N2 had jumped to cats (see Korea: Interspecies Transmission of Canine H3N2).

 

Previously we’d seen reports of cats infected with the H5N1 virus after consuming infected birds.  The following comes from a World Health Organization GAR report from 2006.

H5N1 avian influenza in domestic cats

28 February 2006

(EXCERPTS)

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, and in 2012 the OIE reported on Cats Infected With H5N1 in Israel, although so far no sustained virus transmission in cats or from cats to humans has been observed.

 

Contrary to the prevailing scientific opinion until the early 2000’s, dogs and cats are obviously both susceptible to a variety of influenza A viruses. All of which proves that you never know what you are apt to find until you actually start looking for it. 

 

Which brings us to a pair of recently published studies.  The first being on the virulence (or lack, thereof) of H5N1 in dogs and cats, and what that might portend as far as transmission is concerned.

 

Arch Virol. 2014 Nov 22. 

Greater virulence of highly pathogenic H5N1 influenza virus in cats than in dogs.

Kim HM¹, Park EH, Yum J, Kim HS, Seo SH.

Author information

Abstract

Highly pathogenic H5N1 influenza virus continues to infect animals and humans. We compared the infectivity and pathogenesis of H5N1 virus in domestic cats and dogs to find out which animal is more susceptible to H5N1 influenza virus. When cats and dogs were infected with the H5N1 virus, cats suffered from severe outcomes including death, whereas dogs did not show any mortality.

Viruses were shed in the nose and rectum of cats and in the nose of dogs. Viruses were detected in brain, lung, kidney, intestine, liver, and serum in the infected cats, but only in the lung in the infected dogs. Genes encoding inflammatory cytokines and chemokines, Toll-like receptors, and apoptotic factors were more highly expressed in the lungs of cats than in those of dogs.

Our results suggest that the intensive monitoring of dogs is necessary to prevent human infection by H5N1 influenza virus, since infected dogs may not show clear clinical signs, in contrast to infected cats.

An interesting result, considering that last spring  Korea Detected H5N8 Antibodies In asymptomatic Farm Dogs.

The second study, which appears in the December issue of the EID Journal, looks at the ability of cats to contract, and spread a contemporary strain of the equine/canine H3N8 virus.

 

Equine Influenza A(H3N8) Virus Infection in Cats

Shuo Su¹, Lifang Wang¹, Xinliang Fu, Shuyi He, Malin Hong, Pei Zhou, Alexander Lai , Gregory Gray, and Shoujun Li

Abstract

Interspecies transmission of equine influenza A(H3N8) virus has resulted in establishment of a canine influenza virus. To determine if something similar could happen with cats, we experimentally infected 14 cats with the equine influenza A(H3N8) virus. All showed clinical signs, shed virus, and transmitted the virus to a contact cohort.

Conclusions

That cats are susceptible to EIV by direct inoculation is not surprising because infection of cats with various influenza A viruses has been reported. Feline respiratory tract epithelial cells contain sialic acid α-2,3-galactose β-1,3-N-acetyl galactosamine (SA α2,3 gal) receptors for avian and equine influenza viruses and SA α2,6 gal receptors for mammalian influenza virus (13).

However, our finding of horizontal transmission of EIV among cats is significant. If transmission occurs outside the laboratory, and if the basic reproduction rate is higher than 1.0, then EIV could potentially establish itself and circulate in this new host species. Why it has not yet happened naturally, as it did for canine influenza virus (H3N8), remains to be determined. Possibilities include lower transmission efficiency, lower probability of horse–cat contact, less virus shedding in a laboratory, or feline behavior (less social contact than dogs).

 

These researchers repeated this experiment with an older strain of the equine H3N8 virus, and while some of the cats seroconverted, they all remained asymptomatic. Illustrating the variance of virulence one often finds between clades or strains of the same influenza A subtype.

.

In just over a decade we’ve gone from believing that dogs and cats aren’t really susceptible to flu to viewing them as Potential `Mixing Vessels’ For Influenza. 

 

Last summer, in Canine H3N2 Reassortant With pH1N1 Matrix Gene, we looked at this precise scenario. At roughly the same time the American Society for Microbiology issued this warning:

 

Evolution of Equine Influenza Led to Canine Offshoot Which Could Mix With Human Influenza

WASHINGTON, DC – June 19, 2014 – Equine influenza viruses from the early 2000s can easily infect the respiratory tracts of dogs, while those from the 1960s are only barely able to, according to research published ahead of print in the Journal of Virology. The research also suggests that canine and human influenza viruses can mix, and generate new influenza viruses.

(Continue . . . )

 

Although  it’s true that pigs and birds are considered  far superior biological `flu factories’,  any jump of a novel flu virus to a new species is viewed with concern, because it affords the virus new opportunities to acquire host adaptations – or reassort with other viruses – and thereby increases its chances of becoming a human health threat.

While the future role of dogs and cats in the evolution of influenza is subject to debate, for now, your pet is at far greater risk of catching the flu from you, than you are from it (see Companion Animals & Reverse Zoonosis).

Research: Ferret H5N1 Infection Via Consumption Of Infected Chicken

Photo Credit Wikipedia

 

 

# 8704

 

Although we’ve seen numerous warnings from public health agencies about the dangers of consuming undercooked poultry products in those areas of Asia and the Middle East where H5N1 is endemic, most of the evidence for that risk has been anecdotal.   We’ve seen a relatively small number of human H5N1 infections where consumption of undercooked poultry, or raw duck blood pudding, was been strongly suspected as the route of infection. 

 

Poultry and eggs are considered safe if handled and cooked properly.  Consumption of raw blood pudding (duck or pig), a delicacy in Asia, is probably never a good idea as it carries other additional risks, including Strep Suis infection (see A Streptococcus suis Round Up).

.

 

In 2010, we saw a study (see H5N1 Can Replicate In Human Gut) that provided additional evidence that the bird flu virus can thrive in the human gastrointestinal system. Researchers found that Avian Influenza A(H5N1) Viruses Can Directly Infect and Replicate in Human Gut Tissues.

 

We’ve also seen numerous reports over the years of cats infected with the H5N1 virus after consuming infected birds.  The following comes from a World Health Organization GAR report from 2006.

H5N1 avian influenza in domestic cats

28 February 2006

(EXCERPTS)

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.  And in 2007 the FAO warned that: Avian influenza in cats should be closely monitored, although so far no sustained virus transmission in cats or from cats to humans has been observed.

 

Dogs are not exempt, as in 2006 the EID Journal published a Dispatch Fatal Avian Influenza A H5N1 in a Dog that documented a a fatal outcome following ingestion of an H5N1-infected duck in Thailand in 2004.

 

In 2011 we looked at a study that examined Gastrointestinal Bird Flu Infection In Cats, and as recently as 2012 the OIE reported on Cats Infected With H5N1 in Israel.

 

All of which brings us to a new short report that appears in Veterinary Research, that attempts to quantify the viral dose needed to infect ferrets through ingestion of infected meat.   First the link and abstract (the entire study is available), and an excerpt from the Discussion, then I’ll be back with a little more.

 

High doses of highly pathogenic avian influenza virus in chicken meat are required to infect ferrets

Kateri Bertran and David E Swayne

Author Affiliations

For all author emails, please log on.

Veterinary Research 2014, 45:60  doi:10.1186/1297-9716-45-60

Published: 3 June 2014

Abstract (provisional)

High pathogenicity avian influenza viruses (HPAIV) have caused fatal infections in mammals through consumption of infected bird carcasses or meat, but scarce information exists on the dose of virus required and the diversity of HPAIV subtypes involved. Ferrets were exposed to different HPAIV (H5 and H7 subtypes) through consumption of infected chicken meat.

The dose of virus needed to infect ferrets through consumption was much higher than via respiratory exposure and varied with the virus strain. In addition, H5N1 HPAIV produced higher titers in the meat of infected chickens and more easily infected ferrets than the H7N3 or H7N7 HPAIV.

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.

Discussion

In  conclusion,  relatively  high  concentrations  of  H5N1  HPAIV  are  required  to  produce infection  and  death  by  consumption  of  infected  meat  in  ferrets  as  compared  to  respiratory exposure.  Ingestion  of  HPAIV-infected  meat  can  produce  infection  that  primarily  involves  the respiratory tract but can also spread systemically depending on both the virus strain and virus dose received. Although human infections by HPAIV through direct oral contact have  been occasionally reported [12,13], airborne virus or contact with fomites is still considered the main route of exposure in human species [1].

 

Essentially researchers used 9 ferrets per virus tested, dividing them into three groups; low dose, medium dose, and high dose. They then compared morbidity, and mortality, seroconversion rates, and finally necropsy and histopathology test results to determine which viruses were able to infect via the oral consumption route, their effects, and how much of a viral load was required.

 

H5N1 viruses tended to replicate to higher titers in poultry meat than did the H7 viruses tested, and therefore were more infectious. 

 

Interestingly (but not surprisingly), there was a good deal of variability in the ferret outcomes between the two HPAI H5N1 strains (Mong/05 & VN/04) tested. None of the Mong/05 infected ferrets died, and most showed little or no signs of illness. Seven of nine seroconverted. Two of the VN/04 infected ferrets died, while two other seroconverted.

 

As this study illustrates, different clades of the H5N1 virus often demonstrate different degrees of virulence, something we looked at back in 2012 in Differences In Virulence Between Closely Related H5N1 Strains.

 

With the caveat that it is always a bit perilous to transpose animal study results to humans, this study supports the notion that consumption of improperly cooked avian-flu-infected poultry products could be reasonably assumed to pose a health risk.  

 

The good news, at least for ferrets, is that it takes a fairly large helping, and  the `right’ strain of virus, to prove fatal.

Korea Finds More Dogs With H5N8 Antibodies

 

# 8396

 

Ten days ago in Korea Detects H5N8 Antibodies In Farm Dog we learned of a single dog at a farm in Chungcheongnam-do province that had tested positive for antibodies to the H5N8 avian flu virus, which emerged in that country’s poultry flocks last January (see South Korea: 30 Days Into Their H5N8 Outbreak).

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Antibodies to a virus generally rise a couple of weeks after exposure, and are considered a solid indicator of past infection (either symptomatic or sub-clinical).

 

While not terribly common, we’ve seen dogs (and other non-avian species) infected with novel avian influenzas in the past.  In late 2012, in China: Avian-Origin Canine H3N2 Prevalence In Farmed Dogs, we looked at a study that found a newly emergent avian origin H3N2 virus prevalent in pet and farmed dog populations in southern China.

 

Although we’d seen reports of a handful of similar infections with the avian H5N1 virus during the last decade (see Study: Dogs And H5N1), canines were not generally believed very susceptible to `humanized’  flu strains.  That is, until we began seeing dogs infected with the 2009 pandemic H1N1 virus (see Companion Animals And Novel H1N1).

 

The concern is that  viruses are given new opportunities to evolve, adapt and mutate when they jump species, which led the author of a 2008 EID study - Transmission of Avian Influenza Virus (H3N2) to Dogs - to write:

 

Transmission of avian influenza A virus to a new mammalian species is of great concern, because it potentially allows the virus to adapt to a new mammalian host, cross new species barriers, and acquire pandemic potential.

 

All of which serves as prelude to a new status report from Korea’s Ministry of Food, Agriculture and Rural Affairs  that now raises to 11 the number of  dogs, from two farms, that have tested positive for the H5N8 virus. First a somewhat cryptic (machine translated) snippet from that report (h/t Sharon Sanders @FluTrackers for the link), then some excerpts from a Yonhap News report.

 

( One pig inspection situation ) the current test results were all negative pigs , dogs , today (3:24 days) 2 farms (Cheonan one , give one ) in addition to antibodies (H5 type) have been identified.

So far, research results, this time in addition to detection of antibodies to the last two farms ( one 3:11 ) antibodies such as those listed in the case of dogs , as - Dogs are AI antibody was confirmed to be without symptoms, which detects antibodies to the virus has been exposed to the disease state is determined not to be caused by infection

 

S. Korea reports additional infection of bird flu in dogs

2014/03/24 02:46

SEJONG, March 24 (Yonhap) -- South Korea reported additional cases of avian influenza (AI) in dogs Monday, further confirming the spread of the bird flu to different species.

The cases also marked the first time in the world in which infected dogs survived, according to officials from the Ministry of Agriculture, Food and Rural Affairs.

The ministry said antibodies to AI have been detected in 11 dogs at two separate farms in Cheonan, 80 kilometers south of Seoul, and Buyeo, located 195 kilometers south of the capital.

The detection of antibodies against bird flu confirms that the canines have at least once been infected with the virus that mostly affects poultry. The first case of a dog being infected with the virus was reported March 11 at a different farm in Cheonan.

(Continue . . . )

 

In addition to incrementing the number of birds culled since January over the H5N8 virus to more than 11 million, this article also makes mention of the first known H5N1 infection in dogs ( in Thailand in 2004) which was described in this 2006 Dispatch to the CDC’s EID Journal.

Dispatch

Volume 12, Number 11–November 2006

Fatal Avian Influenza A H5N1 in a Dog

Thaweesak Songserm,* Alongkorn Amonsin,† Rungroj Jam-on,* Namdee Sae-Heng,* Nuananong Pariyothorn,† Sunchai Payungporn,† Apiradee Theamboonlers,† Salin Chutinimitkul,† Roongroje

Abstract
Avian influenza H5N1 virus is known to cross the species barrier and infect humans and felines.

We report a fatal H5N1 infection in a dog following ingestion of an H5N1-infected duck during an outbreak in Thailand in 2004. With new reports of H5N1 virus continuing across Asia, Europe, and Africa, this finding highlights the need for monitoring of domestic animals during outbreaks.

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The list of zoonotic diseases (those shared between humans and animals) is long and continually expanding, and includes: SARS, Babesiosis, Borrelia (Lyme), Nipah, Hendra, Malaria, Hantavirus, Ebola, Bartonella, Leptospirosis, Q-Fever, bird flu and many, many others.

 

So understandably, anytime we see a virus – particularly a flu virus – jump species, it gets our attention.

 

And when they infect companion animals, such as dogs and cats, it becomes of even greater concern, because of how closely we humans interact with them.  For now, the H5N8 virus is only known to be pathogenic in avian species, and we’ve seen no evidence that it can infect humans.  And admittedly, that may never happen.

 

But as we learned earlier this month in EID Journal: Describing 3 Distinct H5N8 Reassortants In Korea, this emergent virus is a work in progress, and we can expect to see new variants and/or clades of the virus emerge over time.

 

New variants can behave differently, and so enhanced surveillance and vigilance is required, else we get blindsided by a virus coming out of left field. 

 

The ability of novel influenza viruses to evolve, mutate, or reassort in a variety of hosts has been a frequent topic of discussion in this blog.  For more on this, you may wish to revisit:

 

H3N2v: When Pigs Flu

mBio: Characterizing A Novel Influenza C Virus In Bovines & Swine

PLoS Pathogens: New World Bats Harbor Diverse Flu Strains

mBio: A Mammalian Adapted H3N8 In Seals

The (Swine) Influenza Reassortment Puzzle

Korea Detects H5N8 Antibodies In Farm Dog

 

 

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In addition to announcing that the number of domestic birds culled in South Korea’s 2 month-old H5N8 outbreak has now exceeded 10 million (see Reuters South Korea culls over six percent of poultry to curb bird flu), Korea’s Ministry of Agriculture announced today that a dog from a bird flu affected farm in Chungcheongnam-do province has tested positive for antibodies to the H5N8 virus.

 

This marks the first time that evidence of an H5N8 infection has been found in a non-avian species, although the dog was reportedly asymptomatic. 

 

Antibodies are generally detectable a couple of weeks after exposure, and are considered an indicator of past infection. First a report from Arirang News, then I’ll have more on the expanding host range of influenza viruses.

 

Dog infected with Avian Influenza

Updated: 2014-03-14 PM 4:30:10 (KST)

Authorities have confirmed that a dog at a farm in Korea's Chungcheongnam-do province has been infected with the H5N8 strain of avian influenza.

Korea's agriculture ministry said Friday that the dog had tested positive for having antibodies against the H5 strain, meaning its immune system is battling the virus.

It's the first time in Korea that a mammal has come down with the AI virus.

Authorities say the dog became infected after eating an infected chicken at the farm.

Prior to this case, it was believed that the AI virus could only be transmitted among the same species.

It's raising concerns that humans could be susceptible to the H5N8 strain, but health authorities say that's very unlikely, although the farm's workers are being tested.

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Despite the tendency of officials to make reassuring blanket statements whenever a new disease threat appears, one of the oft mentioned caveats in this blog is that viruses constantly evolve, as does our understanding of them.  What might be reasonably stated as `true’  last week could easily require revision and amendment tomorrow.

 

And one of those areas of knowledge that seems to constantly evolve centers around the host range of various influenza viruses.

 

So the detection of H5N8 antibodies in canines, while potentially significant, isn’t completely unexpected. Over the past decade we’ve seen plenty of evidence of influenza’s cross-species promiscuity.

• Five years ago, few scientists would have put money on bats being a host species for influenza, yet in 2012 CDC researchers discovered a new flu strain in Guatemalan bats (see A New Flu Comes Up To Bat) and last year we saw in  PLoS Pathogens: New World Bats Harbor Diverse Flu Strains.
• One of the surprises with the H5N1 avian flu virus was how readily it infected dogs and cats (see Study: Dogs And H5N1 and Israel: Cats Infected With H5N1 for background), when previously neither species had been consider particularly susceptible to influenza.
• The (formerly) pandemic H1N1 2009 flu virus was documented in  turkeys, skunks, ferrets, cats, elephant seals and dogs.
• While in That Touch Of Mink Flu I wrote about 11 farms in Holstebro, Denmark that were reported to be infected with a variant of the human H3N2 virus.
• In 2012 we also saw mBio: A Mammalian Adapted H3N8 In Seals
• And just last week, we learned of a previously unknown subtype of Influenza C (see mBio: Characterizing A Novel Influenza C Virus In Bovines & Swine) prevalent in cows. 

 

Today’s announcement simply means that scientists now have a little better understanding of this emerging H5N8 virus.  We’ve moved beyond saying it can `only infect birds’, but the role or importance of mammals in the ecology of this virus is far from established.   

 

What can be said, two months into this outbreak, is that in its present incarnation, the H5N8 virus is primarily a threat to avian species, as it doesn’t appear to readily sicken or infect mammals.

 

But as we learned yesterday (see EID Journal: Describing 3 Distinct H5N8 Reassortants In Korea) there are at least three genetically distinct versions of the virus in play on the Korean peninsula, and these will inevitably change, evolve, or reassort over time.

 

And as we know all too well . . . as viruses evolve, so can the threat they pose.   

Australia: Dog Tests Positive For Hendra Virus

 

 

 

Nipah/Hendra Virus & Fruit Bat Home Range – WHO

 

 

 

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Over the past month more than a dozen horses in and around Queensland Australia have died from the Hendra Virus – a pathogen normally carried by flying foxes (bats), but that can be transmitted to horses and, on rare occasions, to humans as well.

 

The virus was first isolated in 1994 after the deaths of 13 horses and a trainer in Hendra, a suburb of Brisbane, Australia. A stable hand, who also cared for the horses, was hospitalized, but survived.

 

Another outbreak took place in MacKay, 1000 km to the north of Brisbane, the previous month. Two horses died, and the owner was hospitalized several weeks later with meningitis. 

 

He recovered, but developed neurological symptoms and died 14 months later.

Subsequent studies have showed a high prevalence of the newly identified Hendra virus in Pteropid fruit bats (flying foxes) in the region.

 

In 1999, a very similar virus emerged at a Malaysian pig farm, resulting in 105 human deaths and the culling of one million pigs.  Exported pigs caused another outbreak at an abattoir in Singapore, resulting in 11 infections and 1 additional death.

This virus was designated Nipah, named after the place where it was first isolated in humans. It too, is believed to be carried by the fruit bat.

 

 

Since then, there have been scattered outbreaks of both viruses in Australia (Hendra virus) and in Bangladesh and adjacent parts of India (Nipah).  Of the two, the Nipah virus has infected and killed the most humans.

 

For more background on these two rare viruses, the CDC’s Special Pathogens Branch maintains a fact sheet:

 

Hendra Virus Disease and Nipah Virus Encephalitis

 

The World Health Organization maintains a website on the Hendra Virus (Hendra Virus (HeV) Infection) and Nipah Virus (Nipah Virus (NiV) Infection) on their Global Alert And Response (GAR) site.

 

Today, we’ve news of an unusual discovery out of Australia.  

 

A dog on one of the quarantined ranches in Queensland has tested positive for antibodies to the Hendra Virus.  Although the dog appears healthy, this indicates a previous exposure to the virus.

 

And this marks the first known infection of a dog by the virus in the wild.

 

The following notice appears on the Queensland Government Primary Industry & Fisheries website:

 

Current situation as at 26 July 2011

The Australian Animal Health Laboratory (AAHL) in Geelong has confirmed that a dog has tested positive for Hendra virus.

 

This is an unprecedented situation, and the first time outside a laboratory that an animal other than a flying fox or horse, or a human has been confirmed with Hendra virus infection.

 

Biosecurity Queensland´s policy is to test cats and dogs on properties where there are infected horses.

 

The remaining horses and dogs on this property are still being monitored daily and show no signs of illness.

 

We recommend that people keep dogs and cats away from sick horses to reduce the risk of such an infection happening.

 

 

While it is too soon to gauge the impact of this particular discovery, anytime a virus jumps species we tend to pay close attention.

 

Many of the common illnesses we think of as `human’ diseases actually began in other species, and only later migrated to humans.

 

Tuberculosis probably jumped to humans when man began to domesticate goats and cattle. Measles appears to have evolved from canine distemper and/or the Rinderpest virus of cattle.   And Influenza, as most of you know, is native to aquatic birds.

 

The list of zoonotic diseases (those shared between humans and animals) is long and continually expanding, and includes: SARS, Babesiosis, Borrelia (Lyme), Nipah, Hendra, Malaria, Hantavirus, Ebola, Bartonella, Leptospirosis, Q-Fever, bird flu and many, many others.

 

When a virus adapts to a new host, it not only gives it fresh opportunities to mutate and evolve, it provides another potential vector to spread the pathogen.

 

And when that host is a dog or a cat – animals with whom humans closely interact – the risks of spreading to humans are even greater.

 

As the following article from the Sydney Morning Herald tells us, in light of this latest discovery scientists are now tasked with determining what – if any – changes may have occurred in the Hendra virus.

 

 

Scientists guessing over Hendra dog

Kym Agius, Jessica Marszalek and Petrina Berry

July 26, 2011 - 5:49PM

AAP

The first dog to contract the Hendra virus has scientists guessing whether the virus is being transmitted differently or if humans can now catch the disease from canines.

(Continue . . . )

 

 

For now, there are far more questions than answers.

 

 

 

Korea: Interspecies Transmission of Canine H3N2

 

 

 

# 5669

 

Many of the common illnesses we think of as `human’ diseases actually began in other species, and only later migrated to humans. The age of emerging infectious diseases in humans really began in earnest about 10,000 years ago when man began to domesticate – and live in close proximity to – other animals.   

 

• The scourge of Tuberculosis, which now infects 1/3rd of humanity, probably jumped to humans when man began to coral and raise its traditional hosts; goats and cattle.
• Measles appears to have evolved from canine distemper and/or the Rinderpest virus of cattle.  
• Influenza, as most of you know, is native to aquatic birds – but jumped species thousands of years ago and many strains have adapted to humans, pigs, and other species.

 

The list of zoonotic diseases (those shared between humans and animals) is long and continually expanding, and includes: SARS, Babesiosis, Borrelia (Lyme), Nipah, Hendra, Malaria, Hantavirus, Ebola, Bartonella, Leptospirosis, Q-Fever, bird flu and many, many others.

 

Yet despite these disease overlaps, viruses generally adapt to a fairly narrow range of species. 

 

Horse viruses generally attack equines, and not say, cats and dogs.   Cat viruses tend to attack felines, and not birds.  Bird viruses usually only infect avian species.

 

The species that a virus will infect is known as its host range.  And while usually limited, it isn't always the case.

 

Rabies is a good example of a virus that can infect an extraordinarily wide range of species.

 

 

 

We know that every once in awhile, viruses will suddenly jump to a new species. A couple of recent examples include:

 

The H5N1 bird flu virus, which has been unusually promiscuous: showing up in cats (including tigers), dogs, martens, civets, and of course humans. Researchers have successfully infected cattle with the H5N1 virus, along with ferrets and mice for testing.

 

H3N8 Canine influenza, which only showed up in dogs in 2004, had been known to infect horses for the past 40 years.

 

 

All of which serves as prelude to a report that appears in the latest edition of the Journal of General Virology, that finds a recently emerged canine H3N2 influenza virus common in Korea has now adapted to infect domestic cats.

 

 

Interspecies transmission of the canine influenza H3N2 virus to domestic cats in South Korea, 2010

D.S. Song, D.J. An, H.J. Moon, M.J. Yeom, H.Y. Jung, W.S. Jung, S.J. Park, H.K. Kim, S.Y. Han, J.S. Oh, B.K. Park, J.K. Kim, H. Poo, R.G. Webster, K. Jung and B.K. Kang

Abstract

In the last 4 years, incidences of endemic or epidemic respiratory diseases associated with canine influenza H3N2 virus in Asian dogs have been reported in countries such as South Korea and China. Canine species were considered to be the new natural hosts for this virus.

However, at the beginning of 2010, influenza-like respiratory signs, such as dyspnea, were also observed among cats as well as in dogs in an animal shelter located at Seoul, South Korea. The affected cats showed 100% morbidity and 40% mortality.

We were able to isolate a virus from the lung specimen of a dead cat that had suffered from the respiratory disease, in embryonated chicken eggs. The 8 viral genes isolated were almost identical to those of the canine influenza H3N2 virus suggesting interspecies transmission of canine influenza H3N2 virus to the cat.

Moreover, 3 domestic cats infected with intranasal canine/Korea/GCVP01/07 (H3N2) all showed elevated rectal temperatures, nasal virus shedding, and severe pulmonary lesions, such as suppurative bronchopneumonia.

Our study for the first time shows that cats are susceptible to canine influenza H3N2 infection, suggesting that cats may play an intermediate host role in transmitting the H3N2 virus among feline and canine species, which could lead to the endemic establishment of the virus in companion animals.

Such a scenario raises a public health concern, as the possibility of the emergence of new recombinant feline or canine influenza viruses in companion animals with the potential to act as zoonotic infection cannot be excluded.

 

 

The canine H3N2 virus only just appeared in Korea in 2007, and unlike the canine H3N8 virus seen in the United States, appears to have jumped directly from an avian source.

 

In 2008 the CDC’s EID Journal carried the following report on this newly emerging canine flu.

 

Transmission of Avian Influenza Virus (H3N2) to Dogs

Daesub Song, Bokyu Kang, Chulseung Lee, Kwonil Jung, Gunwoo Ha, Dongseok Kang, Seongjun Park, Bongkyun Park, and Jinsik Oh

Abstract

In South Korea, where avian influenza virus subtypes H3N2, H5N1, H6N1, and H9N2 circulate or have been detected, 3 genetically similar canine influenza virus (H3N2) strains of avian origin (A/canine/Korea/01/2007, A/canine/Korea/02/2007, and A/canine/Korea/03/2007) were isolated from dogs exhibiting severe respiratory disease.

 

To determine whether the novel canine influenza virus of avian origin was transmitted among dogs, we experimentally infected beagles with this influenza virus (H3N2) isolate. The beagles shed virus through nasal excretion, seroconverted, and became ill with severe necrotizing tracheobronchitis and bronchioalveolitis with accompanying clinical signs (e.g., high fever).

Consistent with histologic observation of lung lesions, large amounts of avian influenza virus binding receptor (SAα 2,3-gal) were identified in canine tracheal, bronchial, and bronchiolar epithelial cells, which suggests potential for direct transmission of avian influenza virus (H3N2) from poultry to dogs.

Our data provide evidence that dogs may play a role in interspecies transmission and spread of influenza virus.

 

 

The good news is that so far, these new canine viruses haven’t shown the ability to infect humans. 

 

But as the author’s of the EID study above point out:

 

Transmission of avian influenza A virus to a new mammalian species is of great concern, because it potentially allows the virus to adapt to a new mammalian host, cross new species barriers, and acquire pandemic potential.

 

Companion animals, such as dogs and cats, are of particular concern because of how closely humans interact with them.

 

While pigs might be biologically better suited as a `mixing vessel’ for influenza (see The (Swine) Influenza Reassortment Puzzle), there are far more opportunities for transmission between humans and their pets.

 

In terms of their potential to spread rapidly among humans, and cause significant morbidity and mortality, few viruses can compete with influenza. As we saw in 2009, a new influenza virus can jump species and spread around the globe in a matter of months.

 

A recurring theme in this blog is that nature’s bio lab is open 24/7, and that it is constantly trying out new genetic combinations looking for an evolutionary advantage. 

 

And for a virus, jumping to a new, immunologically naive species is like hitting the jackpot; a fresh supply of hosts and an opportunity to adapt further.

 

Which is why we watch these species jumps with more than a passing interest.

Companion Animals And Novel H1N1

 

 

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Colorized transmission electron micrograph (TEM) of HN1 virus – Credit CDC PHIL) 

 

Unlike `normal’ strains of human-adapted seasonal influenza - which are thought to rarely (if ever) infect dogs, cats, and other companion animals - the 2009 H1N1 virus has been observed a number of times in pets over the past 18 months.

 

Given that relatively few companion animals get tested for the H1N1 virus, and the likelihood that some animals only experience mild or sub-clinical symptoms of infection, the true prevalence of H1N1 infection among household pets is unknown. 

 

Yesterday, another veterinary industry alert was issued by IDEXX Laboratories - a company that produces a veterinary influenza test kit - regarding the first known H1N1 infection of 2011 in a domestic cat.

 

First some excerpts from the press release, then I’ll be back with more on pets and influenza.

 

 

First confirmed 2011 case of H1N1 influenza virus infection reported in a domestic cat

February 14, 2011

One cat with severe respiratory disease from Wisconsin has tested positive for the H1N1 influenza virus with the IDEXX H1N1 Influenza Virus RealPCR™ Test.

 

Two cats from the same household presented to a veterinary emergency hospital in respiratory distress. The owners reported to have been suffering from the flu themselves at the time the cats developed severe respiratory signs.

 

After intensive supportive care that included ventilator support, the 6-year-old male domestic shorthair (DSH) was euthanized. The IDEXX Feline Upper Respiratory Disease (URD) RealPCR™ Panel was performed using fluid obtained at the time of intubation for ventilation and was positive for the H1N1 influenza virus. The second cat, a 10-year-old female DSH, originally responded to supportive therapy but relapsed and was euthanized 8 days after presentation.

 

An oropharyngeal swab was obtained at the time of euthanasia for testing, but it was negative for H1N1 influenza virus. Given the strong-positive quantitative real-time PCR result in the first cat, the H1N1 influenza virus is still the presumptive cause of respiratory disease in the second cat. The shedding period of influenza viruses is short, which may have been responsible for the negative PCR result.

(Continue . . .)

 

The AVMA (American Veterinary Medical Association), which represents 80,000 Veterinarians around the nation, understandably keeps track of these cases.

 

They also maintain several  FAQs on H1N1 and pets.

 

» Veterinarians 2009 H1N1 FAQs

» Pet owners 2009 H1N1 FAQs

» General 2009 H1N1 FAQs

» Pandemic preparedness for veterinarians

 

 

Over the past year or so, we’ve seen ample evidence of non-human infection by the novel H1N1 virus (e.g.  turkeys, swine, ferrets, dogs, cats . . . even a cheetah).

 

This influenza’s propensity to cross species has also been observed with the H5N1 bird flu virus as well.

 

A few past blogs on the unusually promiscuous nature of the swine H1N1 influenza strain include:

 

US: Dog Tests Positive For H1N1

US: Turkey Farm Reports H1N1

Study: H1N1 And Birds

Cat Got Your Virus?

 

Cats seem to be more severely affected than dogs, at least based on the limited number of cases detected. Of eleven known feline cases, only 4 have recovered.

 

Last October we saw a study (see  EID Journal: Pandemic H1N1 Infection In Cats) that looked at the pathogenesis of novel H1N1 in domestic felines.

 

Experimental Pandemic (H1N1) 2009 Virus Infection of Cats

DOI: 10.3201/eid1611.100845
van den Brand JMA, Stittelaar KJ, van Amerongen G, van de Bildt M, Leijten LL, Kuiken T, et al. Experimental pandemic (H1N1) 2009 virus infection of cats. Emerg Infect Dis. 2010 Nov; [Epub ahead of print]

Conclusions

Intratracheal infection of domestic cats with pandemic (H1N1) 2009 virus resulted in mild-to-moderate clinical signs and virus replication throughout the respiratory tract that caused diffuse alveolar damage.

 

Pathogenic changes in the respiratory tract in cats were similar to those that occur in humans, macaques, and ferrets (7,11–13). Seroconversion of sentinel cats indicated cat-to-cat transmission.

 

The full study runs about 4 pages, with heavy emphasis on the necropsy and histological examination of these laboratory cats several days post infection.

 

Those discomforted by such details might want to skip the full paper.

 

While usually producing less dramatic symptoms, cats infected with the pandemic H1N1 virus showed similar pathogenic processes to cats infected with the HPAI H5N1 bird flu virus.

 

None of this is to suggest that your pet presents a serious H1N1 infection risk to you or your family.  Quite the opposite, in fact.

 

Your pet is far more likely to contract the virus from  you or other members of your household.

 

But promiscuous flu viruses - those capable of expanding their host range to other species - are a bit more worrisome because they have more opportunities to mutate, reassort, or evolve.

 

So we watch for signs of species jumping of any influenza with considerable interest.