Molecular Epidemiology and Genetic Characterization of Feline Panleukopenia Virus among Clinically Suspected Domestic Cats in Tamil Nadu, India

Feline panleukopenia virus (FPV) causes feline panleukopenia (FP), a highly contagious and often fatal disease in domestic cats. This study investigated FPV detection, associated epidemiological factors, and partial VP2 genetic characteristics among clinically suspected cats presented in Chennai, Tamil Nadu, India. Exploratory molecular docking was also performed to compare predicted VP2–transferrin receptor type-1 interactions in feline and canine systems. FPV DNA was detected in 83 of 180 clinically suspected cats (46.11%). Multivariable analysis revealed higher odds of FPV PCR positivity in female cats than in male cats (aOR: 2.65; 95% CI: 1.35–5.21) and lower odds in vaccinated cats than in unvaccinated cats (aOR: 0.41; 95% CI: 0.17–0.97). Compared with summer, higher odds were observed during the southwest monsoon (aOR: 3.59; 95% CI: 1.26–10.20) and northeast monsoon (aOR: 17.11; 95% CI: 3.86–75.80), whereas age group and breed were not significantly associated with PCR positivity. FPV was successfully isolated from four of the ten PCR-positive clinical samples inoculated onto CRFK cells. Partial VP2 sequencing of 13 PCR-positive samples showed 98.1–98.5% nucleotide identity with the vaccine reference strain and identified several nucleotide and amino acid substitutions. Most study sequences clustered with Indian FPV reference strains, whereas one sequence clustered separately within the carnivore parvovirus grouping. Molecular docking of the (TfR1-VP2 interaction identified differences in the predicted interaction patterns between feline and canine complexes, with the feline complex exhibiting a more favourable ZRANK score. However, these findings represent computational predictions and require experimental validation. Overall, the study highlights the circulation of genetically diverse FPV strains in southern India and underscores the importance of continued surveillance and molecular characterization to support disease monitoring and control strategies.