EC25F-398: Test to treat: managing FIP in cats within the framework of antiviral therapy

Feline coronavirus (FCoV) is a widespread viral pathogen in domestic cats. Highly pathogenic FCoVs can cause feline infectious peritonitis (FIP), a systemic disease. Once regarded as a death sentence, FIP has become treatable with antivirals, including GS-441524 and molnupiravir (widely used in humans). Before its approval for use in the US, cat owners were obtaining unlicensed antivirals to treat their cats, which could have resulted in prolonged or subtherapeutic antiviral treatments. The uncontrolled at-home antiviral treatments without follow-up may promote the emergence of resistant FCoV variants. Concern is also growing because resistance has been observed in vitro. Therefore, it is essential to obtain data on the genetic basis of antiviral resistance in FCoV and to develop testing methods for the detection of emergent resistant variants. This study aims to conduct a longitudinal genetic investigation to determine if antiviral-induced mutations are emerging in FCoV. The genetic diversity of genes targeted by the antivirals in FCoVs circulating in the U.S in the past 10 years will be studied. Studying the genetic diversity of these genes will help detect if specific mutations have emerged and become common over the past six years, when antiviral use began to spread in the country.  Cases of domestic cats before and after treatment with antivirals will be studied to determine if they continue to shed the virus, and antiviral efficacy and resistance trends will also be monitored. The outcome of this research will raise awareness about the risks associated with unregulated antiviral use. (George Sydney and Phyllis Redmond Miller Trust Grant Awards)