Trans Species Transmission

It is rare that virions can go readily trans-species. But not impossible, rabies is a clear example of such a transmission. But recently Nature reported trans species transmissions with cats. They noted:

Cats can be infected with the coronavirus that causes COVID-19, and can spread it to other cats, but dogs are not really susceptible to the infection, say researchers in China. The team, at Harbin Veterinary Research Institute, also concludes that chickens, pigs and ducks are not likely to catch the virus. Other scientists say the findings are interesting, but cat owners should not be alarmed just yet. The results are based on lab experiments in which a small number of animals were deliberately given high doses of the virus, SARS-CoV-2, and do not represent real-life interactions between people and their pets, says virologist Linda Saif at the Ohio State University in Wooster. There is no direct evidence that the infected cats secreted enough coronavirus to pass it on to people, she says.

Well here we go. The Hill reports transmission to a  tiger in the Bronx Zoo. They note:

A tiger at the Bronx Zoo in New York City has tested positive for the coronavirus, while several other animals are being monitored for similar symptoms. In a press release, the Wildlife Conservation Society (WCS), which operates the zoo, said that the animals were likely infected by an asymptomatic carrier of the disease. It's the first known case of the virus being detected in an animal in the U.S. as well as the first confirmed case in a tiger anywhere in the world.

Now this should be a bigger concern. One is reminded of Camus and The Plague, first dead rats.... Thus if cats, why not mice, birds, fish, frankly any other species. Rabies has that potency. It is a stretch but after all we do a great amount of testing on mice. Most of our immune studies, cancer studies are done with murine models, genetically engineered mice.

At what point does one start to get nervous? I suggest that it is now perhaps. Trans species transmissions often enable dramatic mutations and retransmissions. The cycle is significant and deadly. Even with great immunizations one is always chasing one's tail.