Keepers of asymptomatic animals at a personal zoo in South Africa transmitted the Delta variant of Covid-19 to captive lions, which were quarantined and developed symptoms such as respiratory problems, runny nose and dry cough, according to a recent study by a team of scientists. . University of Pretoria.
The study report, recently published in the journal “Virus”, also suggests the public be aware of the possibility of infecting their puppies, cats and dogs, if they have Covid-19.
The team was led by Professor Marietjie Venter, head of the zoonotic, arboreal and respiratory viruses program at the university’s Department of Medical Virology; and Professor Katja Koeppel, Associate Professor of Wildlife Health in the Faculty of Veterinary Sciences. They conducted a study of three sick lions at the zoo during the third wave of the Covid-19 pandemic in South Africa in late 2021.
“The team of transdisciplinary scientists found that reverse zoonotic transmission of Covid-19 from asymptomatic animal handlers at a private zoo in Gauteng (province) posed a risk to big cats kept in captivity,” the university said in a statement.
“Transmission of the Delta variant to these animals can lead to more severe disease. The animals tested positive on PCR up to seven weeks after becoming ill.
“This prolonged period of potential loss of the virus poses a risk of infection to nearby animals and likely humans. The animals were quarantined until they tested negative,” the scientists said.
Koeppel said the lions had respiratory disorders such as runny nose and dry cough for up to 15 days.
“Persistent cough was observed for five to 15 days, and two lions experienced shortness of breath. One lioness developed pneumonia that did not respond to antibiotics,” he added.
The staff and lions were monitored for SARS-CoV-2 in the weeks that followed, and within 15 to 25 days, all three lions fully recovered.
“(Other) tests showed that SARS-CoV-2 may have circulated among lions while they were sick, and suggest that those who were in direct contact with the animals were likely to blame for the opposite zoonotic transmission,” Venter said. .
A year earlier, two pumas at the zoo had also been tested for Covid-19.
Genome sequencing conducted on humans and three lions, and testing revealed that each of the infections is a Delta variant.
The two pumas and the 3 lions suffered from a respiratory illness due to Covid-19 in humans.
The animals did not respond to antibiotic treatment but recovered after treatment with anti-inflammatory medications and supportive care.
“The detection of viral RNA in the respiratory tract and feces, coupled with the fact that pumas and lions were showing symptoms, shows that this virus is capable of infecting those animals through an herbal pathway of infection,” Venter said.
Scientists said the timeline of lion infections through a Covid-positive human is difficult to estimate because all staff members were asymptomatic during the outbreak. They said the opposing zoonotic transmission of SARS-CoV-2 through caretakers of asymptomatic animals poses a threat to big cats kept in captivity. .
Scientists are under pressure to implement precautions in zoos such as vaccinating staff, wearing masks when entering cages and preparing food, controlling infections through the use of disinfectants and distancing barriers for the public.
“These are species potentially threatened with infection and death,” the scientists said.
“These measures are also due to the threat of new variants emerging if the virus becomes established in other animal reservoirs; These variants could simply be transmitted to humans,” they said.