Virus-infected lions worry South African researchers

Posted on 01/21/2022 16:32

(credit: AFP)

Researchers at the University of Pretoria in South Africa have raised new concerns about the novel coronavirus, which continues to break new records around the world. A study published last Tuesday (18/1) concluded that lions in a South African zoo were infected with the virus that causes covid-19 and developed severe symptoms of the disease, and recovery from which took up to 7 weeks – which raised an alarm about the risks of spreading the virus among people Animals in the wild and create new mutations.

Researchers began monitoring captive wild animals in South African zoos and sanctuaries after a tiger became ill at the Bronx Zoo in the United States in April 2020, according to Professor Maritje Venter, the study’s lead author. The team initially monitored two cougars who contracted the coronavirus at a private zoo in July 2020, during the country’s first pandemic wave. About a year later, in the same place, three lions began showing symptoms similar to those of Covid-19 in humans: breathing difficulties, a runny nose and cough. In addition to animals, a zoo keeper and an engineer also tested positive.

Using sequential samples from infected lions and humans, the researchers were able to determine that both the animals and the keepers of the nannies were infected with the delta variant.

The lions recovered after 25 days but were PCR positive for an additional three weeks. The data analyzed by the study indicated that the viral load the lions were carrying decreased during those weeks, but it was not clear how long they were able to transmit the disease.

The disease that lions developed, especially in older females, showed that animals, like humans, can display severe symptoms. An older lioness has pneumonia

In the case of cougars, which are not of their native habitat, symptoms included loss of appetite, diarrhea, runny nose and persistent cough. Both cats made a full recovery after 23 days.

In a captive environment, infected animals were kept in quarantine, the study said, but in parks across South Africa, where lions are a tourist magnet, outbreaks can be “extremely difficult” to control, especially if the virus is not detected. In certain locations, humans often feed on lions rather than hunting for themselves, which increases the chance of exposure to the virus.

While the study did not show how much viral load the lions had or whether they were able to transmit the virus for the duration of the period they tested positive for the virus, longer periods of infection in big cats will increase the risk of disease spreading in the wild. The researchers said it widely infects other species. This may eventually lead to the virus being colonized among wild animals and, in the worst case, the emergence of new variants that could return to humans.

“If you don’t know it’s Covid, there’s a risk it could spread to other animals and then back to humans,” said Venter, a professor of medical virology, who collaborated with a wildlife veterinarian to conduct the study. She said the animals had been infected long enough “that the virus could actually mutate.”

The transmission of viruses between animals and humans is a known fact to scientists. The coronavirus itself could have originated in bats and ended up “jumping” into humans, in what is known as “overflow” infection.

Scientists warn that human ‘reflux’ infections that infect animals – such as mink, deer and domestic cats – can destroy entire ecosystems in the wild. Infections that have reached nature can also increase the potential for the virus to spread unchecked and mutate in animals, potentially mutating into forms that are dangerous to humans.

A well-studied phenomenon involves infection among large numbers of captive mink. On a mink farm in Denmark, the virus mutated into a new strain while switching from human to animal, triggering mass culling across the country and Europe to prevent it from spreading back to humans.

In contrast, the South African study included small outbreaks, but Venter noted that the mink outbreak shows the potential risk of a larger outbreak in wildlife.

* With international agencies