Outcomes of treatment of cats with feline infectious peritonitis using parenterally administered remdesivir, with or without transition to orally administered GS-441524.

BACKGROUND: Nucleoside analog GS-441524 is effective in treating cats with feline infectious peritonitis (FIP). Investigation into the use of parent nucleotide analog remdesivir (GS-5734) is needed. OBJECTIVES: To assess efficacy and tolerability of remdesivir with or without transition to GS-441524 in cats with FIP and document clinical and clinicopathologic progression over 6 months. ANIMALS: Twenty-eight client-owned cats with FIP. METHODS: Cats were prospectively recruited between May 2021 and May 2022. An induction dosage of remdesivir 10 to 15 mg/kg intravenously or subcutaneously q24h was utilized for 4 doses, with a maintenance dosage of remdesivir (6-15 mg/kg SC) or GS-441524 (10-15 mg/kg per os) every 24 hours continued for at least 84 days. Laboratory testing, veterinary, and owner assessments were recorded. RESULTS: Twenty-four cats survived to 6 months (86%). Three cats died within 48 hours. Excluding these, survival from 48 hours to 6 months was 96% (24/25). Remission was achieved by day 84 in 56% (14/25). Three cats required secondary treatment for re-emergent FIP. Remission was achieved in all 3 after higher dosing (15-20 mg/kg). Adverse reactions were occasional site discomfort and skin irritation with remdesivir injection. Markers of treatment success included resolution of pyrexia, effusions, and presenting signs of FIP in the first half of treatment and normalization of globulin concentration, and continued body weight gains in the latter half of the treatment period. CONCLUSIONS AND CLINICAL IMPORTANCE: Parenteral administration of remdesivir and oral administration of GS-441524 are effective and well-tolerated treatments for FIP. Early emphasis on clinical, and later emphasis on clinicopathologic response, appears prudent when monitoring treatment efficacy.

Pig-hunting dogs are an at-risk population for canine heartworm (Dirofilaria immitis) infection in eastern Australia.

BACKGROUND: Canine heartworm disease, caused by Dirofilaria immitis, has global veterinary importance. In Australia, the prevalence of canine heartworm infection decreased markedly following the introduction of over-the-counter macrocyclic lactones. We aimed to estimate the prevalence of canine heartworm infection in at-risk populations of dogs in eastern Australia and analyse published prevalence data from Australia. METHODS: In total, 566 dogs from eastern Australia were tested for the presence of D. immitis antigen. Four cohorts were studied: pig-hunting dogs from Queensland (Cohort 1, n = 104), dogs from remote New South Wales (NSW) (Cohort 2, n = 332), urban pets from rural NSW (Cohort 3, n = 45) and ex-racing Greyhounds from Sydney, NSW (Cohort 4, n = 85). Serum samples were screened for D. immitis antigen using a reference laboratory microwell-based assay (DiroChek®) or a point-of-care immunochromatography test kit (Anigen Rapid®). Risk factors associated with the odds of D. immitis antigen seropositivity were identified using binary logistic regression models. Seropositive blood samples were tested for the presence and quantity of D. immitis DNA using a species specific real-time (q)PCR assay. A metanalysis of the Australian canine heartworm literature was conducted. RESULTS: The prevalence of dirofilariasis in pig-hunting dogs from Queensland (Cohort 1) was 12.5% (95% CI: 6.5-18.9%), with a subpopulation of dogs from Central Queensland having a prevalence of 21% (95% CI: 12.3-33.4%). Age was significantly associated with D. immitis antigen seropositivity (increased risk with increased age). The odds of being > 5 years versus ≤ 5 years was 3.7-times (95% CI: 1.1-12.5) greater in antigen positive versus antigen negative dogs. No D. immitis antigen positive dogs were detected in dogs from NSW (Cohorts 2-4). The Australian canine heartworm disease literature includes 98 peer-reviewed publications (1901-2019) with 30 studies reporting on D. immitis prevalence in dogs. Throughout the publication peak period (1980s), the primary antemortem diagnostic test was detection of microfilariae. CONCLUSIONS: Canine heartworm infection in dogs used for pig hunting is a previously unexplored topic in Australia. Pig-hunting dogs are infected with canine heartworm in Queensland, Australia, placing pet dogs and cats at increased risk of infection.