Coinfecção por Strongyloides stercoralis e pelo Vírus-T Linfotrópico Humano do Tipo 1, outras infecções parasitárias e infecções sexualmente transmissíveis, em indivíduos de área urbana e rural na Bahia, Brasil

Abstract

Introduction: Both intestinal parasites and Sexually Transmitted Infections (STIs) are a public health problem in the world, whose relationship with conditions of social vulnerability is evident. In this context, co-infections between these agents are frequent, such as S. stercoralis infection in individuals with human T-lymphotropic virus type 1 (HTLV-1), which is around 2.4 times higher than in the population general. Objective: To identify the presence of parasitic infections, emphasizing the co-infection of HTLV-1 and Strongyloides stercoralis in individuals attending at a referral center for HTLV in Salvador, Bahia, and parasitic and sexually transmitted infections in a rural community in Camamu-Bahia. Method: These are two epidemiological, descriptive and cross-sectional studies, carried out from Jan./2014 to Dec./2019, with individuals with HTLV-1 treated by the Multidisciplinary Integrative Center of the Bahia School of Medicine and Public Health (CHTLV /EBMSP) Salvador-Bahia (n=178; group 1), and residents of a Rural Community (RC), Camamu-Bahia (n=223; group 2). Information on socioeconomic, sanitary and educational conditions was obtained through a epidemiological questionnaire. The parasitological diagnosis was performed through spontaneous sedimentation, Baermann-Moraes and Agar Plate Culture (APC) methods. Serological diagnosis was performed for the detection of anti-S. stercoralis antibodies and other serological methods, standardized by the Brazilian Ministry of Health, were used for the diagnosis of STIs (HTLV-1/2, HIV-1/2, HBV, HCV and T. pallidum/Syphilis). Total serum IgE and cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, INF-γ and IL-17) of the supernatant of the culture of peripheral blood mononoclear cells (PBMC) were measured by flow cytometry in patients from rural areas positive for HTLV-1. Individuals in the rural area who needed treatment were referred for care by the Municipal Health Department of Camamu, Bahia. Health education activities were carried out, through workshops, for the prevention of parasites and STIs. Results: The HTLV-1 positive individuals treated at the CHTLV/EBMSP, despite having low socioeconomic conditions, were mostly residents of urban areas, whose sanitary conditions are relatively satisfactory and, consequently, had a lower frequency of infections by S. stercoralis (1.9 %) and by other intestinal parasites, while among individuals from rural areas attending to the CHTLV/EBMSP, the infection by S. stercoralis was about 9 times higher (17.6%). There was a higher prevalence of Syphilis (11.7%), followed by HTLV-1 infection (8.1%) among STIs in people from RC. The infection rate of enteroparasites in this community was 73.9% and the frequency of specific IgG4 anti-S. stercoralis was 22.9%, about three times higher than the identification of S. stercoralis larvae in feces (7.2%). The frequency of coinfection by S. stercoralis and HTLV-1 in the RC was 1.3% (3/223), considering only the parasitological diagnosis. When considering both the results of the S. stercoralis parasitological and serological diagnosis (detection of specific IgG4) it was observed a general frequency of 6.7% for strongyloidiasis and of 16.7% among HTLV-1 carriers. The transmission by S. stercoralis within the family nucleus in the RC showed that a total of 53.3% (119/223) of individuals with positive parasitological and/or serological tests were concentrated in 25 families. In families with 5 or more individuals, living in the same household, the prevalence of S. stercoralis was 2.45 times higher compared to individuals living in households less than 5 people (p=0.028). Of the 18 individuals infected by HTLV-1 in the RC, 17 were relatives, suggesting that the transmission occurred through the vertical route. Cytokine and total IgE dosages were performed in 13 of these individuals, 10 of whom were infected with HTLV-1 and three coinfected (HTLV-1 plus S. stercoralis hyperinfection), showing high levels of TNF-α (p=0.034) and IL-17 (p=0.011) and low levels of total IgE. In the process of territorial recognition and development of the research, the report of the experience of the researchers in the RC, emphasizes the situation of social vulnerability of the residents, the receptivity and trust towards the research team, the adherence to the treatment and the active participation in the workshops of prevention of parasitic infections and STIs. Conclusion: Parasitic infections and STIs have a high prevalence in the rural community studied. Coinfected individuals with HTLV-1 and S. stercoralis living in precarious sanitary conditions are more predisposed to develop severe forms of strongyloidiasis. Public policies investments to prevent health problems can contribute to improving the quality of life of populations living in poverty.