Syphilis and HIV infection in indigenous Mbya Guarani communities of Puerto Iguazu (Argentina): diagnosis, contact tracking, and follow-up.

The aim of study was to assess the prevalence of Treponema pallidum and HIV infection in Amerindian people (Mbya Guarani) over the age of 11 in Puerto Iguazu (Argentina) and to describe the contact tracking of cases. The method was a cross-sectional study in the Mbya Guarani people living in three villages of Puerto Iguazu (community A, pop. 1,146; community B, pop. 369; and community C, pop. 149). Participants were randomly invited to participate in the survey and in blood testing. Of the 551 participants, 48 were infected by T. pallidum (8.71%; 95% confidence interval [CI] 7.38-10.04). The infection prevalence decreased with age, standing at 9.66% in the 11-19 age group, 8.42% in 20-39 age group and 4.54% in people aged 40 and older. We tracked 130 contacts for the 48 T. pallidum cases; 39/40 (97.5%) sexual contacts tested positive for syphilis. Among the 90 children born to infected mothers, 76 aged 18 months or older tested negative, while 8/14 younger children were still at risk for congenital syphilis. There were four cases of HIV infection (0.72%, 95% CI 0.31-1.13). Prevalence of T. pallidum infection and HIV infection are relevant in this indigenous community of Argentina, representing a public health concern.