Veterinary Parasitology 91 (2000) 23–32 The prevalence and avidity of Toxoplasma gondii IgG antibodies in pigs from Brazil and Peru F. Suaréz-Aranda a , A.J. Galisteo Jr. b , R.M. Hiramoto c , R.P.A. Cardoso b , L.R. Meireles b , O. Miguel a , H.F. Andrade Jr. b,∗ a Dept. Pratica de Saúde Pública/FSP, São Paulo, SP, Brazil b Laboratório de Protozoologia, Instituto de Medicina Tropical de São Paulo, FMUSP, Av. Dr. E.C. Aguiar, 470,05403-000 São Paulo,SP, Brazil c S. Radiobiologia, IPEN/CNEN, São Paulo, SP, Brazil Received 17 December 1999; accepted 17 March 2000 Abstract 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 important risk predictor. The prevalence of this infection was estimated in 396 sera from 5-month old pigs obtained at abattoirs in São Paulo, Brazil (300) and Lima, Peru (96). The seroprevalence was higher in pigs from Peru (32.3%) as compared to Brazil (9.6%), as detected by ELISA and Western blot. Hemagglutination gave poor resolution which was not useful for the diagnosis of T. gondii infection. Specific antibody avidity is correlated with infection time, as shown in experimentally infected piglets. Using an arbitrary cut-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. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Toxoplasma gondii; Pigs; Prevalence; Avidity; Brazil; Peru 1. Introduction Toxoplasma gondii, an Apicomplexa protozoan parasite, infects man and other warm-blooded animals (Dubey, 1993). Human toxoplasmosis is generally asymptomatic in immunocompetent individuals, with occasional eye involvement, but causes devastating disease resulting in immune system immaturity or deficiency (Beaman et al., 1995). This ∗ Corresponding author. Tel.: +55-11-3066-7010; fax: +55-11-2805-237. E-mail address: hfandrad@usp.br (H.F. Andrade Jr.) 0304-4017/00/$ – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0304-4017(00)00249-1