The prevalence and avidity of Toxoplasma gondii IgG antibodies in pigs from Brazil and Peru

Raw or inadequately cooked pork is an important source of Toxoplasma gondii infection, and the infection rate in animals used as human food, is an imp ortant risk predictor. The prevalence of this infection was estimated in 39 6 sera from 5-month old pigs obtained at abattoirs in Sao Paulo, Brazil (30 0) and Lime, Peru (96). The seroprevalence was higher in pigs from Pem (32. 3%) as compared to Brazil (9.6%), as detected by ELISA and Western blot. He magglutination gave poor resolution which was not useful for the diagnosis of T. gondii infection. Specific antibody avidity is correlated with infect ion time, as shown in experimentally infected piglets. Using an arbitrary c ut-off of 50% avidity index, Brazilian pigs were found to be more recently infected than Peruvian pigs. Pork should be considered a significant source of human T. gondii infection both in Brazil and Peru, Avidity assays could help in the detection of the time of T. gondii infection in pigs, allowing preventive management. (C) 2000 Elsevier Science B.V. All rights reserved.