Risk Factors for Toxoplasma gondii Infection in Wild Rodents from Central Coastal California and a Review of T. gondii Prevalence in Rodents

Sera from 523 wild rodents were tested for Toxoplasma gondii antibodies using either an indirect fluorescent antibody test (IFAT) (rats and mice, with titer ≥80 considered positive) or a latex agglutination test (LAT) (voles, squirrels, and pocket mice, with titer ≥32 considered positive). Seventeen percent (88/523) of the rodents, including 26% (85/328) of the Peromyscus sp. and 8% (3/37) of Spermophilus beecheyi, were seropositive. Fourteen percent (23/161) of rodents captured in trap sites next to Morro Bay (California) and 15% (16/109) of rodents from sites adjacent to riparian habitats had antibodies to T. gondii, compared to 19% (49/253) of rodents captured in habitats not associated with water; this difference was not statistically significant (P = 0.32). Significantly fewer rodents were captured <200 m from residential housing compared to locations further away (11% vs. 30%, respectively). Factors associated with an increased risk for T. gondii seropositivity in rodents were capture location ≥200 m from residential housing and adult age.