FeLV & FIV Statistics by State

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are two of the most common serious viral infections in cats, and both are almost always tested for together in a single combo test at the vet. Unlike heartworm or Lyme disease, neither spreads through a mosquito or tick bite — both pass cat-to-cat, mainly through bite wounds, which gives their state-by-state map a very different shape than our other CAPC-sourced pages.

The figures below come from CAPC's live Parasite Prevalence Maps: more than 1.24 million real FeLV/FIV combo test results from US veterinary clinics and labs, year-to-date 2026.

FeLV & FIV Positivity Rates by State

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are almost always tested together in a single combo snap test, which is why the Companion Animal Parasite Council's (CAPC) sample sizes for the two are nearly identical — over 1.24 million tests each, year-to-date 2026. Nationally, FIV positivity (4.44%) runs more than double FeLV positivity (1.91%).

Why These Maps Look Different From Heartworm and Lyme

Unlike heartworm (mosquito-borne) or Lyme disease (tick-borne), FeLV and FIV spread cat-to-cat — primarily through bite wounds, which is why FIV in particular is closely tied to outdoor and feral cat populations where fighting between unneutered males is common. That's a fundamentally different transmission route than a vector-borne disease tied to climate and mosquito or tick range, and it shows in the map: Hawaii has the single highest FIV rate in the country (7.67%) despite having essentially no heartworm or Lyme risk, almost certainly reflecting its large free-roaming and feral cat population rather than any climate factor.

Arkansas leads for FeLV specifically at 3.39%, with Arizona, Mississippi, Kentucky, and Missouri rounding out the top five. For FIV, Hawaii, Mississippi, Kentucky, Louisiana, and Delaware lead. Both viruses run consistently lowest in New England and the northern Midwest — Massachusetts, Maine, New Hampshire, Minnesota, and Alaska sit near the bottom of both lists.

What This Data Does and Doesn't Show

These are positivity rates among tested cats, not the infection rate across each state's full cat population. Testing is more common for cats with outdoor access, cats being introduced to a new household, or cats showing signs of illness, so these figures likely skew somewhat toward at-risk cats rather than a random population sample. Still, this is real diagnostic test data rather than a modeled estimate, and the geographic pattern — concentrated in the South and notably elevated in Hawaii — is consistent with what's known about outdoor/feral cat population density in those regions.

For our other CAPC-sourced cat health page, see feline heartworm statistics by state, and for general national cat statistics, see our cat ownership statistics page.

The Big Picture

FIV runs more than twice as common as FeLV nationally, and both viruses concentrate in the South and in Hawaii rather than following a climate-driven pattern like heartworm or Lyme. Because these are bite-transmitted rather than vector-transmitted diseases, the map reflects outdoor and feral cat population dynamics as much as anything else — a reminder that not every regional pattern in pet health data comes down to weather.