Spatial distribution and seasonal profile of parasitic contamination in sewage water samples from the city of Santana do Ipanema, Northeast region of Brazil

Wastewater released into the environment without proper treatment contributes to the high prevalence of parasitic infections. We aimed to investigate the occurrence of parasites in sewage waters in both rainy and dry seasons in the city of Santana do Ipanema, Brazil. This is a descriptive cross-sectional study carried out between the months of June, July (rainy season) and October (dry season) of 2021. A total of 50 streets were selected by a sample calculation in the Epi Info™ program. From each street, two wastewater samples were collected in both climatic periods. In the laboratory, the water samples were submitted to the Bailenger method with some adaptations and analyzed under an optic microscope. In the rainy season, we detected Strongyloides stercoralis (87.6%; 134), Strongylus spp. (4.6%; 7), Ancylostomides (2.0%; 3) and Iodamoeba butschlii (62.5%; 5), and in the dry season, it was detected S. stercoralis (55.0%; 71), Metastrongylids (19.4%; 25), Ancylostomides (12.4%; 16) and I. butschlii (76.5%; 13). The spatial analysis has shown that most hotspots were associated with S. stercoralis, mainly during periods of intense rainfall and close to river areas. Thus, the city population is subject to infections, especially by helminths regardless of seasonality.