Following the confirmation of COVID-19 in a tiger in Bronx Zoo, New York, USA we asked Dr John Lewis, WVI Founder, WVI Senior Veterinary Partner and big cat specialist what this meant for other felid (cat) species and wild tigers in particular.

Which cat species are susceptible? 

“The Bronx Zoo case demonstrates that tigers(and probably other large cats) can become infected with COVID-19 from close contact with infected people, and develop relatively mild clinical signs of respiratory disease. (in this case dry cough, sometimes wheezing and decreased appetite). Until other cases are reported we do not know whether more severe clinical disease may develop in other infected individuals. Both lions and tigers were clinically affected in the Bronx Zoo, but COVID-19 was only isolated from one Malaysian tiger – the others were not tested, but the clinical picture was similar and occurred during the same period. Applying precautionary principles we should assume at this stage that all felids may be susceptible."

Can we get infected from our cats?

"Recent unpublished research indicates that the COVID 19 virus can replicate in domestic cats, that some domestic cats develop respiratory disease, and that domestic cats may be able to infect other domestic cats. We do not know to what extent infected tigers can infect other tigers yet, but in close contact it seems likely.  We do not yet have proof that cats can pass COVID 19 to people."

What is the threat of this pandemic to wild tigers?

"Whether the virus poses a major threat to wild tiger populations has yet to be determined, but given our current understanding of how this virus spreads, its’ environmental persistence, its’ clinical impact on tigers, their solitary nature and their natural tendency to “socially distance” themselves from humans, it seems unlikely.

Tigers involved in human-tiger conflict situations could be at slightly greater risk as contact rates with humans and infected material is presumably somewhat greater. However, tigers at the greatest risk of infection would be those handled for conflict resolution or research radio-collaring etc. Staff undertaking these activities will have close contact with the cats, and there is clearly a risk of infection from human to tiger in these circumstances. It should be remembered that in the Bronx Zoo case transmission of virus was likely to have been from a non-symptomatic person in the early stages of infection.

"In situations that bring people into close contact with tigers it will be prudent for everyone involved to apply rigorous bio security measures such as limiting the number of people coming within 2 – 3 metres of the cat to the absolute minimum; excluding anyone with a fever or a cough (or people that have been in contact with others that have symptoms of COVID-19); thorough washing of hands before and after handling tigers; the wearing of such personal protective equipment as is available such as disposable gloves, face masks etc. In other words we should apply all those measures that are being implemented to prevent spread between people. It may be prudent to suspend research activities that require the handling of tigers for a period. In India the NTCA and the Central Zoo Authority have already issued guidelines that address some of these points.

"In some of the tourism areas in India tigers habituated to vehicles come very close to people who are in the open vehicles. Once the current bans have been lifted it may also be prudent to prevent people who are sick from going on these wildlife tours.

Having said all that, it seems to me that the greatest impact on wild tiger populations will be the effect COVID-19 could have on protected area & National Park staff, anti-poaching personnel etc.Where staff numbers are depleted, tigers will be more vulnerable than ever to poaching."

However....

"RNA viruses can evolve rapidly in terms of virulence and species affected, and our knowledge of COVID-19 even in humans can only be described as provisional, with knowledge changing day by day. Today’s COVID “truths” often turn out to be tomorrow’s “ignorant history”!

Therefore, the comments offered above are at best only provisional.”

John Lewis MA, VetMB, PhD, MRCVS - Partner, International Zoo Veterinary Group (IZVG)

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To find out more about Dr Lewis's work preventing disease in wild tigers, please see the Wild Tiger Health Centre and Tiger Health Programme. Please donate to support this crucial work helping conservationists, vets and tigers throughout their rage.

Information on best practice during the pandemic for IZVG clients can be found here.

For further details on COVID-19 and zoo animals please see "Science-based facts and knowledge about wild animals, zoos and SARS-CoV-2 virus" of the EAZWV Transmissible Diseases Handbook written by the EAZWV Infectious Diseases Working Group (last updated 6th April).

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