Deadly feline coronavirus variant has been present in the U.S. for over a decade

Cornell researchers have discovered that a lethal variant of feline coronavirus, previously thought to be limited to a devastating 2023 outbreak in Cyprus that killed thousands of cats, has in fact appeared in the United States, raising concerns about future large-scale outbreaks in vulnerable cat populations. The findings were published in the March 6th issue of the Journal of Feline Medicine and Surgery by a cohort of researchers at Cornell University's College of Veterinary Medicine. "The findings are significant and are a result of our ongoing work in surveillance of pathogenic diseases of veterinary relevance in the U.S," said Ximena A. Olarte-Castillo, post-doctoral associate in the Goodman lab at the Baker Institute for Animal Health and first author on the paper.

Feline coronavirus is common in cats and typically causes mild or asymptomatic infections. However, in some cases, it can mutate within the cat's body and cause feline infectious peritonitis (FIP), a severe disease that is almost routinely fatal if not treated. The most common form of the virus, FCoV-1, tends to be relatively benign and highly transmissible or highly pathogenic but unable to spread easily. A less common variant, FCoV-2 - thought to be a hybrid of a feline and a canine coronavirus - accounts for only about 5 percent of FIP cases worldwide; the specific strain of FCoV-2 that impacted the cat population on Cyprus is known as FCoV-23, or Cyprus-23.

Whittaker and his team conducted a retrospective analysis of three archived samples of FCoV-2 from 2013 and 2016. Using whole-genome sequencing and viral analysis, the researchers examined 20 samples of tissue, feces, and abdominal fluid (ascites). They identified deletions in a region of the virus's spike protein - known as "domain zero" - in two of the cats that developed prolonged disease. The offspring of one of the cats, which had a shorter disease course, was found to have a long version of the spike protein.

Read the full story on the College of Veterinary Medicine site.