July 2025: Researchers from the Roslin Institute and Royal (Dick) School of Veterinary Studies have discovered that a harmful strain of coronavirus causes a fast-spreading outbreak of a feline disease know as feline infectious peritonitis (FIP) which originated in Cyprus. Cat in Cyprus, image credit: Kyriacos Georgiou A new type of coronavirus is responsible for a severe outbreak of disease which has spread among an island population of cats.The virus has been linked to a recent occurrence of Feline Infectious Peritonitis (FIP) cases in Cyprus, which is believed to have killed thousands of cats.A handful of cases were confirmed in the UK and are likely to have originated in Cyprus, although experts estimate the numbers may be much higher owing to undetected illness.The virus responsible for the disease has been shown to be a hybrid of a cat coronavirus combined with a dog coronavirus, resulting in a recombinant virus named FCoV-23, according to a study led by the Roslin Institute and Royal (Dick) School of Veterinary Studies. Harmful infection The newly developed coronavirus behaves in an unusual way. Typically, feline coronaviruses can occasionally mutate within a cat’s system to cause FIP, a severe disease which once established does not usually spread.In this outbreak, however, a protein acquired from the canine virus enables FCoV-23 to avoid existing immunity and mutate frequently within individual cats of all ages, causing cases of FIP on a scale not seen before. This ability of the virus to evolve and spread among cat populations indicates a critical need for international cooperation to monitor and control its transmission, researchers suggest. This includes strict guidelines for moving pets across borders and heightened awareness among pet owners and vets.Cyprus has likely emerged as a hotspot owing to its large population of cats, researchers suggest. Introduction of a more successful, spreading variant to a dense population, such as the cats in Cyprus, may be sufficient to allow this virus to cause an outbreak.More research is needed to better understand this virus, and this type of coronaviruses more widely. The development of new vaccines and optimisation of antiviral treatment regimes could help mitigate the consequences of this devastating disease. For the future, we must consider how we could intervene earlier and prevent disease spread. Dr Christine Tait-Burkard The Roslin Institute Viral details A separate study, led by the University of Washington, looked at the virus in detail, and how its newly acquired protein influences its behaviour.The team found that the mutation occurring in individual cats enabled the virus to quickly enter cells and cause infections. In addition, the protein virus was shown to pose limited risks to people.The studies, published in Nature, carried out in collaboration with colleagues in Cyprus and the US, highlight the necessity of continuing to study animal coronaviruses as potential threats to human health, considering the close contact between pets and people. Read the full study here Related links The Roslin InstituteRoyal (Dick) School of Veterinary Studies Publication date 15 Jul, 2025
