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| Credit J. Patrick Fischer - Wikipedia |
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We used to think of birds, pigs and humans and horses as the principal hosts of flu viruses, but over the past 20 years our understanding of the host range of influenza A has expanded considerably.
We now know that dogs and cats are susceptible, that marine mammals can be infected, and that even bats have their own proprietary (HA17 & HA18) influenza A subtypes.To this growing list we've added camels, mink, rodents, raccoons, and even cotton-tailed rabbits and other peridomestic animals (see HPAI H5Nx Clade 2.3.4.4. Shedding In Cottontail Rabbits). While novel (mostly avian) flu viruses were the first to garner our attention, in recent years seasonal flu has turned up in a number of non-traditional hosts as well.
In December of 2009 in a blog called USDA Listing Of Animals With H1N1 we looked at some early reports of pandemic H1N1 infecting a variety of animals. Along with swine the USDA listed ferrets (5), cats(3), turkeys (5), and a Cheetah (1) as having contracted the virus.
A year later, the 2009 H1N1 virus was detected in California's Elephant seal population (see The 2009 H1N1 Virus Expands Its Host Range (Again)).
China documented at least one Giant Panda infected with H1N1 during the 2009 pandemic - and more recently a sloth bear was reportedly infected with H1N1 at a US Zoo in 2014.While no longer as surprising as it once was, today we've a new report out of Hong Kong describing the 2018 infection of a Giant Panda with the H1N1 virus.
Volume 25, Number 12—December 2019
Dispatch
Influenza A(H1N1)pdm09 Virus Infection in a Captive Giant Panda, Hong Kong
Paolo Martelli1, Jade L.L. Teng1, Foo-Khong Lee, Kai-Yan Yeong, Jordan Y.H.
Abstract
We report influenza A(H1N1)pdm09 virus infection in a captive giant panda in Hong Kong. The viral load peaked on day 1 and became undetectable on day 5, and an antibody response developed. Genome analysis showed 99.3%–99.9% nucleotide identity between the virus and influenza A(H1N1)pdm09 virus circulating in Hong Kong.
Conclusions
We documented a case of influenza infection caused by pH1N1 virus in a captive giant panda in Hong Kong. The viral load was >6 × 105 copies/mL during the first 2 days of the illness and decreased to an undetectable level on day 5. The decrease in viral load was coupled with development of antibody response. Complete genome sequencing and phylogenetic analysis showed that the pH1N1 virus from the giant panda differed from the influenza virus circulating in Hong Kong at that time by only 2–24 bases.
In 2014, pH1N1 infection was reported in giant pandas at the Conservation and Research Center for the Giant Panda in Sichuan (1). That pH1N1 virus, A/giant panda/01/Ya’an/2009, was also closely related to the pH1N1 strains circulating in humans during 2009 (1).
These findings show that influenza A virus infection in this giant panda was not an isolated case and that these infections have happened not only in mainland China. Our findings indicate that the influenza virus in giant pandas was most likely directly or indirectly from humans with seasonal influenza. Of interest, respiratory infection in a sloth bear due to pH1N1 has also been observed in a zoo in the United States in 2014, indicating that pH1N1 can probably infect a variety of bears (2).
Better strategies for prevention of influenza in giant pandas in captivity should be considered. In animal species with no preexisting immunity against an infectious agent, a new intrusion of the pathogen may result in high fatalities. Transmission of a new strain of influenza from birds and poultry to humans has resulted in many epidemics (10–15). Because the inactivated vaccine against pH1N1 has been widely used in humans and is effective in mice, pigs, and ferrets, it might be worthwhile to test its immunogenicity in giant pandas.
Moreover, caretakers working at these parks who are infected with influenza, even with mild illness or in recovery, should not work near the animals.
Dr. Martelli, a zoological veterinarian, is currently Director of Veterinary Services at Hong Kong Ocean Park.
(Continue. . . )
While the health risks from human-to-panda transmission (aka `reverse zoonosis') of seasonal influenza fall almost exclusively on the panda, when humans transmit flu to more capable`mixing vessel' species - like pigs - it can lead to the creation of new, potentially dangerous, flu strains.
Which is why the CDC has created guidance and vaccine recommendations for those who work with pigs.
