PREVALENCE OF TOXOPLASMA-GONDII ANTIBODIES IN HUNTER-KILLED WHITE-TAILED DEER (ODOCOILEUS-VIRGINIANUS) IN 4 REGIONS OF MINNESOTA

Sera from 1,367 white-tailed deer (Odocoileus virginianus) from 4 geog raphic regions in Minnesota collected during 4 hunting seasons (1990-1 993) were tested for antibodies to Toxoplasma gondii using the modifie d direct agglutination test incorporating mercaptoethanol. Sera from 3 0% of the deer had antibody titers greater than or equal to 25; 8.6% w ere positive at a titer of 25, 11% at a titer of 50, and 10% at a tite r greater than or equal to 500. There was a significant increase in se ropositivity with age (P < 0.0001). Adult deer were twice as likely to be positive as yearlings; yearlings were 2.5 times as likely to be po sitive as fawns. There was no difference in prevalence by sex when adj usted for age (P = 0.316), nor was there age-sex interaction. Only mal es showed a slight increase in titer with age (P = 0.049). There were no significant differences in prevalence among the regions of northeas t pine/aspen forest, southwest tall-grass prairie, southeast mixed-har dwood forest, and aspen/oak suburban park land. There were no statisti cally significant differences by year of collection. The prevalence of T. gondii antibodies in white-tailed deer remains high and deer hunte rs and consumers should ensure that venison is well-cooked or frozen p rior to consumption.