The occurrence of antibodies to Naegleria species in wild mammals.

Individuals from 13 wild mammalian species collected in southwestern Tennessee were serologically positive for anti-Naegleria spp. antibodies (ANA). This is the first report of ANA in wild mammals. Interspecific differences in the occurrence of ANA and titers indicate that wild mammals have differing degrees of contact with Naegleria spp. based on ecological or behavioral adaptations, and possibly the innate ability of a species to produce ANA. Intraspecifically, it appears that if a mammal is exposed to Naegleria spp. in the environment, titers of ANA will not significantly differ, regardless of age or sex. Adults of many species had significantly higher occurrences of ANA. Populations of juvenile wild mammals are probably at higher risk than adults to naeglerial infection in the environment, not because of lower titers, but because their chance of having ANA is less than adults. Differences in the occurrence of ANA in wild mammals may also reflect how humans are exposed to Naegleria spp. in the environment.