- Thor, an 11-year-old lion at Sri Lanka’s national zoo, has been isolated after PCR tests showed he was infected with COVID-19.
- Several lions at zoos in neighboring India have also reportedly contracted the virus, with at least two dying.
- In the case of Thor, zoo authorities in Sri Lanka suspect the lion contracted the virus from a zookeeper; subsequent tests showed a gardener at the zoo had COVID-19.
- With the increasing threat of COVID-19 impacting both wild and farm animal populations, Sri Lanka is monitoring suspected cases of animal deaths.
COLOMBO — Thor is an 11-year-old, well-built male lion at Sri Lanka’s National Zoological Gardens in the Colombo suburb of Dehiwala. He’s something of an icon at the zoo, famed for his regal appearance. Thor should have been enjoying a hassle-free period with his partner, Sheena, and their two cubs in their special den as the COVID-19 lockdown kept visitors away for weeks. But in early June, Thor fell ill, going off food and showing breathing difficulties.
In neighboring India, zoos had reported some of their lions contracting COVID-19 around the same time, so the veterinarians at Dehiwala feared the worst. They took samples of urine and saliva from their lion and carried out PCR tests. The results, released June 15, confirmed that Thor had contracted the coronavirus. Zookeepers took measures to keep him isolated from his family and started him on a medical regime to alleviate his symptoms.
“We are constantly monitoring his condition,” said Ishini Wickremesinghe, the zoo’s director general. Authorities also placed the lion’s keepers under self-quarantine and carried out PCR tests on zoo employees; a gardener tested positive for COVID-19.
“We believe the lion may have got COVID from a zookeeper. We have taken measures to safeguard our employees and animals running the risk of contracting SARS-CoV-2,” Wikremesinghe told Mongabay.
Animal patients
It is important to get saliva samples to carry out a PCR test, but sticking one’s hand inside a lion’s mouth to get a sample is a daunting mission. Vets would usually tranquilize an animal before taking a sample of their body fluids, but as Thor was weak, the Dehiwala zoo vets chose not to sedate him. Instead, they used bait coated with cotton wool, then retrieved the discarded and saliva-soaked cotton wool after Thor was done eating the bait.
The saliva samples were then sent to the molecular, nutrition biochemistry laboratory at the Faculty of Veterinary Medicine and Animal Science of the University of Peradeniya, which can perform PCR tests for animal samples.
“The COVID-19 PCR test performed on animals is similar to the human PCR test, but mainly focuses on tracing the virus family,” said lab supervisor Dilan Satharasinghe, a senior lecturer with the animal science department at Peradeniya. Samples of the virus have been sent to Hong Kong University for further analysis, Satharasinghe said.
The SARS-CoV-2 virus that causes COVID-19 impacts the respiratory system, and the symptoms can be deadly. It’s considered a zoonotic disease that jumped from animals to humans, but there have been confirmed cases where humans have transmitted it to animals, mostly pet dogs and cats.
Virus vulnerability
“Not all animal species are susceptible to SARS-CoV-2” said Malik Peiris, a Sri Lankan virologist with the University of Hong Kong who is credited with isolating the original SARS virus. Peiris’s lab was also the first to show reverse zoonosis of SARS-CoV-2 from humans to animals in Hong Kong, identifying infections among dogs in households with COVID-19 patients. However, it’s important to note that there’s no evidence that infected animals can transmit the virus back to humans, Peiris told Mongabay.
Other domesticated animals, such as poultry and pigs, aren’t susceptible to SARS-CoV-2 infection, but mink bred for the fur industry are extremely sensitive to infection, leading to major outbreaks in mink farms in Europe and the U.S., Peiris said.
The first confirmed case of a zoo animal contracting COVID-19 was reported from Bronx Zoo in New York in April 2020, when a tigress named Nadia tested positive. Subsequently three more tigers and three African lions at the Bronx Zoo also tested positive for COVID-19, but all have since recovered. Animals at other zoos have also contracted the virus, including at Arignar Anna Zoological Park in Chennai, India, where nine lions tested positive and two died.
Sri Lanka continues to monitor its urban wildlife and farm animals against COVID-19 through the Department of Animal Production and Health (DAPH), the state organization responsible for providing technical leadership to the livestock industry and stakeholders. DAPH together with the Department of Wildlife Conservation and Peradeniya’s veterinary faculty initiated a wildlife disease surveillance program in 2018, to which the COVID-19 monitoring program was added in 2020, said DAPH vet Ganga Wijesinghe.
“When there are suspected cases or when an animal dies while showing signs of respiratory issues, we analyze such samples in order to rule out COVID-19 infection to animals,” Wijesinghe said.
“We have to be alert to prevent animals from contracting COVID from the Dehiwala zoo,” Peiris said. “There could be some adverse impacts on wildlife. It will also help us establish new viral reservoirs in other animal species where the virus may continue to evolve.”
Banner image of Thor, an 11-year-old lion at the Dehiwala zoo in Colombo, Sri Lanka, who has contracted COVID-19. Image courtesy of the National Zoological Gardens of Sri Lanka.
