Therapeutic effectiveness of treatment schemes for coronavirus infection in cats

Abstract

Feline coronavirus infection is dangerous due to the mutation of the virus leading to the development of fatal infectious peritonitis which was long considered incurable. The advent of nucleoside analogues (GS-441524, molnupiravir) has changed the prognosis; however, in clinical practice, there remains a need for a comparative evaluation of their efficacy and safety. The research goal was to comparatively evaluate the therapeutic efficacy and safety of three treatment regimens for feline coronavirus infection (based on GS-441524, Molnupiravir and symptomatic therapy) in a veterinary clinic. A retrospective observational study was conducted on 26 cats with confirmed coronavirus enteritis or infectious peritonitis observed at the Irbis clinic (the City of Kemerovo) from December 2023 to April 2025. The patients were divided into three groups: Group 1 (n = 12) - monotherapy with Coronacat subcutaneously, a course of 84 days; Group 2 (n = 8) - oral Molnupiravir (10–15 mg kg every 12 hours, 84 days); Group 3 (n = 6) - symptomatic diet therapy (for coronavirus enteritis that did not progress to infectious peritonitis). The dynamics of clinical and laboratory parameters, achievement of clinical remission, and side effects were assessed. In Group 1, remission was achieved in 11 of 12 cats (91.7%): for coronavirus enteritis - 100% (4/4), for the effusive form of infectious peritonitis - 100% (4/4), for the dry form - 75% (3/4). Side effects included local reactions at the injection site. In Group 2, the overall efficacy was 50% (4/8): for the effusive and dry forms of infectious peritonitis - 50% each (2/4). Transient increases in liver enzymes (2 cases), leukopenia (1), and skin itching (1) were noted. In Group 3 (symptomatic therapy for coronavirus enteritis), remission occurred in 5 of 6 cats (83.3%). Coronacat demonstrated high clinical efficacy (91.7% remission) against various forms of coronavirus infection, surpassing Molnupiravir (50%) in this indicator. Symptomatic dietary therapy was sufficient for most uncomplicated cases of coronavirus enteritis. Molnupiravir was associated with more frequent side effects. The obtained data is of practical value for veterinarians when choosing a therapeutic strategy.