A group of Sumatran tigers at the San Diego Zoo Safari Park is suspected to have been exposed to the virus that causes COVID-19, prompting the closure of that park's Tiger Trail habitat, zoo officials said Tuesday.
Some of the tigers have had a cough, and an in-house SARS-CoV2 PCR test yielded a positive test result from fecal samples. Zoo veterinarians are awaiting confirmation of the test results by the National Veterinary Services Laboratory.
Because of the animals' tight social grouping, the wildlife health and care teams are operating as if all six tigers who reside at the Safari Park are exposed. They are quarantined as a group in their usual, shared habitat.
The potentially affected tigers are not showing any concerning signs of illness other than intermittent cough, fatigue and occasionally decreased appetite, and have not required treatment. The zoo's veterinary team of specialists will continue to monitor them closely and treat symptoms as they may arise.
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"This suspected exposure of the tigers at the safari park, and snow leopards at the zoo, highlights the challenges of containing this virus and how important preventative vaccines are to protect the wildlife in our care," the statement read. "Wildlife health and care teams at both the safari park and zoo have been working as fast as they responsibly can to vaccinate the animals most at risk for contracting the virus."
In late July, a male snow leopard at the San Diego Zoo preliminarily tested positive for SARS-CoV-2. The leopard has fully recovered from his symptoms, but in an abundance of caution, snow leopards will remain quarantined in their habitat until further notice.
All susceptible species at the Safari Park and the San Diego Zoo are scheduled to have received their first vaccine within the coming days, a statement from the San Diego Zoo Wildlife Alliance read.
Some of the tigers have received their first dose of a recombinant purified spike protein vaccine, intended for use in protecting animals against SARS-CoV-2. Infection appears to have occurred before the first dose was able to convey any immunity. The full benefit of the vaccine is generally expected sometime after the second dose is received -- about three weeks after the first dose is administered.
Vaccinations used in some species include those designed to protect wildlife against rabies, West Nile virus, seasonal influenza, measles and canine distemper. Vaccinating wildlife is a common practice around the world and has helped to ensure that endangered and threatened species like black-footed ferrets, California condors, gorillas and cheetahs are protected, the statement read.
Wildlife receiving vaccines at the parks consist primarily of felids such as lions, tigers, leopards, cheetahs, jaguars, mountain lions, servals, ocelots, caracals, black-footed cats and sand cats; primates like vervet monkeys, hamadryas baboons, geladas, colobus monkeys and siamangs; mustelids like otters; carnivores like hyenas and dholes; and other animals, as veterinarians determine necessary.
"As the world is learning more about this virus, San Diego Zoo Wildlife Alliance is doing everything we can to prevent the spread of COVID-19," the statement read. "Our team members are wearing masks, are encouraged to get the vaccine if they haven't done so already, and we are vaccinating the animals most at risk to contracting the virus."
The origin of the possible tiger exposure is being investigated.
Early last year, as COVID-19 spread, San Diego Zoo Wildlife Alliance officials say they surveyed both parks to ensure that safe distance was maintained between known susceptible species and guests.
Following county and state guidelines, the zoo and the Safari Park recently lifted the mandate for all guests to wear masks at both parks, though officials continue to strongly recommend that unvaccinated guests wear masks. The parks have no plans to change biosecurity protocols at this time, officials said.