Research overview: FIV subtypes and global epidemiology

FIV strains cluster into several genetic subtypes (clades) distributed unevenly across continents, reflecting local transmission histories among free-roaming and owned cat populations. Surveys consistently find higher seroprevalence in adult, male, outdoor, and aggressive cats, matching a virus spread mainly through bite wounds. Regional studies document differing dominant clades in North America, Europe, Asia, Australia, and South America, with implications for diagnostic test sensitivity and vaccine cross-protection. This overview compiles general patterns from the epidemiological literature rather than one citation, describing why prevalence estimates vary by sampling method, how genetic diversity complicates universal vaccines, and why veterinarians weigh lifestyle and behavior when assessing an individual cat's infection risk and recommending preventive management.