US researchers have successfully treated cats with a severe coronavirus infection using a combination of stem cells and antiviral drugs, offering insights that could benefit both veterinary and human medicine. 

Feline infectious peritonitis (FIP) is a fatal disease in cats caused by a coronavirus. It leads to fever, inflammation, problems in multiple organs and a decrease in immune cells. Cats that survive the infection may suffer from long-term immune system problems, including enlarged lymph nodes, a sign of inflammation. This condition is similar to the immune dysregulation seen in some people with long COVID. 

Researchers at the University of California, Davis, treated cats recovering from FIP with either antiviral drugs alone or a combination of antivirals and stem cells. Cats that received the combined therapy had no serious side effects and showed reduced inflammation. They had fewer overly active immune cells and more regulatory T cells, a type of immune cell that helps calm the immune system. 

Because FIP shares several features with COVID-19, the study published in Stem Cells Translational Medicine may help improve treatments for coronavirus-related immune disorders in humans. 

“Many pets suffer from diseases that are similar to human diseases,” said Amir Kol, lead researcher at UC Davis. “Veterinary medicine is a wonderful platform to conduct translational science that helps both pets and humans.”