#18,329
Two decades ago a number of Southeast Asian zoos found to their dismay what happens when you feed bird flu infected chicken carcasses to tigers and leopards.
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 the 20 years since then, we've seen this pattern repeated a number of times, including 2016's Fatal H5N1 Infection In Tigers By Different Reassortant Viruses - China.
The more recent subclades of HPAI H5N1 have proved - if anything - to be even more pathogenic in felines, and we've seen record setting outbreaks among domestic felines in Europe, Asia, and the United States over the past couple of years.
Today, several Vietnamese media outlets are reporting on the deaths of multiple tigers (and other large cats) at at least two zoos/nature preserves in Vietnam. According to these reports (FluTrackers already has a thread on these reports), at least one cat has tested positive for H5N1.
I've been unable to find anything `official' on any of the government websites, and as of this writing nothing has been posted by WOAH. However, Vietnamese media are licensed by the government, and tend to be pretty reliable.
Typical of the reporting are the following excerpts from a translated report from the INTECH Technology Observer, which is licensed by the Hanoi Department of Information and Communications.
Investigate and identify people in close contact with dead tigers at the zoo infected with A/H5N1 flu
Manh Thang • 01/10/2024 20:41
Many tigers raised at a zoo in Long An province died and tested positive for the A/H5N1 flu virus, including 3 newly imported from the Mango Garden Eco-tourism Company Limited (Dong Nai).
On October 1, the Dong Nai Province Center for Disease Control is coordinating with relevant agencies to clarify the details related to the case of several tigers at the Mango Garden Eco-tourism Area (Phuoc Tan Ward, Bien Hoa City, Dong Nai) dying of suspected pneumonia.
According to information exchanged from the Veterinary Department of Region VI, at the Mango Garden Eco-tourism Area, 11 Bengal tigers (Panthera tigris) and 1 black panther (Panthera pardus) died. Animal Husbandry and Veterinary staff of Bien Hoa City conducted clinical examinations and random autopsies on the 2 dead tigers. Initial diagnosis of the 2 Bengal tigers' deaths was suspected to be due to pneumonia. The results of the test results on the cause are not yet available.
(SNIP)
Previously, on September 30, the Pasteur Institute of Ho Chi Minh City reported to the Department of Preventive Medicine (Ministry of Health) about the recording of wild animals infected with influenza A/H5N1.
(SNIP)
Specifically, from August 2024 to September 16, 2024 at My Quynh Zoo, 27 tigers and 3 lions died, including 3 newly imported tigers from Vuon Xoai Eco-tourism Company Limited (Dong Nai) on September 6, 2024. The remaining individuals originated from My Quynh Zoo. In Long An province, 3 My Quynh Zoo staff members were identified as having direct contact with tigers. In Dong Nai province, about 30 people had contact with tigers. Currently, no people in close contact with tigers have been recorded to have symptoms of respiratory infection.
(Continue . . . )
At this point, we don't know what version (clade and/or genotype) of HPAI H5N1 is involved in these feline deaths, but Southeast Asia has reported an uptick in human infections since early 2023, and is increasingly on our radar.
Last April in - FAO Statement On Reassortment Between H5N1 Clade 2.3.4.4b & Clade 2.3.2.1c Viruses In Mekong Delta Region - we learned that a new genotype - made up of an older clade and the current 2.3.4.4b clade of H5N1 - had emerged in Southeast Asia.
In Asia, several clades continue to circulate, including A(H5N1) 2.3.4.4b, 2.3.2.1c and others, which can lead to reassortment and the appearance of viruses with new characteristics. A novel reassortant influenza A(H5N1) virus has been detected across the Greater Mekong Subregion (GMS), causing infections in both humans and poultry since mid- 2022.
This virus has recently caused human outbreaks in Cambodia early this year. This virus contains the surface proteins from clade 2.3.2.1c that has circulated locally, but internal genes from a more recent clade 2.3.4.4b virus.
The introduction and widespread circulation of this reassortant influenza A(H5N1) virus into the GMS poses a significant risk to both animal and human health, given the historical impact of HPAI outbreaks in the region. Further, this reassortment event indicates not only the adaptive capacity of the virus but also the ever-present risk of the emergence of new, potentially more virulent strains.
A reminder that H5N1 continues to spread, and evolve, around the globe and that we should not focus entirely what it is doing in North America.
With novel influenza, a threat anywhere can quickly become a threat everywhere.
