Intestinal parasite infections associated with sociodemographic and seasonal factors in the Western Amazon

Intestinal parasites are a constant public health problem in the Amazon region, with a high prevalence of cases related to poor sanitary conditions. We investigated the sociodemographic and seasonal factors associated with human intestinal parasite infections in an area of the Western Amazon, Brazil, from September 2017 to August 2019. Data were collected using a database available at the Diagnostic Support Centre (Centro de Apoio ao Diagnóstico, CAD) of the Municipality of Rio Branco, on positive diagnoses for intestinal parasites. Among the 53,200 samples analysed, 18.3% (n = 9712) were positive. Of these, 96.4% (n = 9363) and 3.6% (n = 349) were protozoan and helminthic infections, respectively. Males showed higher odds ratio (OR) for Enterobius vermicularis infection (OR: 2.3) and giardiasis (OR: 1.9) and lower OR for Endolimax nana (OR: 0.9) and Entamoeba coli (OR: 0.9) infections. Individuals aged ≥ 15 presented higher OR for Strongyloides stercoralis (OR: 3.4), hookworms (OR: 2.3), and almost all protozoan infections than younger individuals. In the dry season, the OR for hookworms (OR: 1.5), Iodamoeba butschlii (OR: 1.4), and Endolimax nana (OR: 1.3) infections was higher than that in the rainy season, including a high chance of polyparasitism (OR: 1.6). We concluded that there was a significant difference between the different types of intestinal parasites, particularly protozoa, with high OR in the dry season and for certain groups.