Toxoplasma gondii prevalence in cats from Lisbon and in pigs from centre and south of Portugal.

Toxoplasmosis is an important zoonosis worldwide. Here we determined the presence of Toxoplasma gondii antibodies in sera and T. gondii DNA in faeces of 215 domestic cats from veterinary clinics in the Lisbon area; 44 (20.5%) had anti-T. gondii IgG antibodies by the modified agglutination test (cut-off 1:40) and DNA was detected in 16 (35.6%) of 45 cat faeces tested. Risk factor analysis indicated increase of seroprevalence with age of the cats. Sera and tissues of 381 pigs from a slaughterhouse were also tested for T. gondii infection; 27 (7.1%) of the 381 pigs were seropositive. T. gondii DNA was demonstrated in diaphragms and/or brains of seven (35.0%) of 20 anti-T. gondii seropositive pigs tested by the B1 nested-PCR. Results indicate very high prevalence of T. gondii DNA in the faeces (oocysts) of definitive hosts and relatively low, but still worrying, seroprevalence of T. gondii antibodies in pigs destined for human consumption.