Intestinal parasites and sexually transmitted infections in a socially vulnerable rural community in southern Bahia, Brazil.

Introduction: Intestinal parasites and sexually transmitted infections (STI) are frequent among people living in conditions of social vulnerability. The aim of this study was to investigate the prevalence of parasitic infections, STIs (human T lymphotropic virus (HTLV), human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and T. pallidum/syphilis) in the residents of a rural community in southern Bahia, Brazil.

Methodology: The study was conducted from March 2018 to September 2019, and 88.8% of residents of the rural community (n = 223/251) participated. Diagnosis was performed by parasitological examination and by detection of specific antibodies in sera. Data on socioeconomic and health conditions were obtained with a questionnaire.

Results: The prevalence of parasitic infection was 73.9%. Trichuris trichiura (26.9%) and Ascaris lumbricoides (25.6%) were the most frequent, with a higher occurrence in children and adolescents (p < 0.05%). The prevalence of anti-Strongyloides stercoralis antibodies (22.9%) was about 3 times higher than the presence of larvae in feces (7.2%; p < 0.05%). Seroprevalence for STI was 19.3%, mostly syphilis (11.7%) in the elderly participants (p < 0.05%), followed by HTLV-1 (8.1%; 18/223). The co-infection rate of S. stercoralis and HTLV-1 was 1.3% (3/223), based on parasitological diagnosis alone, but when the detection of IgG4 anti-S. stercoralis was considered, it increased to 6.7% (15/223).

Conclusions: Illnesses associated with poverty, such as intestinal parasite infections and STI, trigger a vicious cycle of socioeconomic exclusion and persistent poverty. Therefore, it is essential to break the social determinants that perpetuate both poverty and diseases.