Abstract
INTRODUCTION: Strongyloidiasis is an important but underdiagnosed soil-transmitted helminthiasis, particularly in tropical areas and some vulnerable groups. OBJECTIVES: To assess the parasitological prevalence, seroprevalence and sociodemographic factors of Strongyloides stercoralis infection in patients living with human immunodeficiency virus (PLWH) in an endemic area. MATERIALS AND METHODS: We performed a cross-sectional study of strongyloidiasis in 537 PLWH in two hospitals in Iquitos, Peru, from 20 Oct 2023 to 20 May 2024. We tested patient sera using Strongyloides IgG enzyme-linked immunosorbent assay (ELISA) and stool via the modified Baermann technique and/or charcoal fecal culture as highly sensitive parasitological techniques. We used multivariable logistic regression to identify factors associated with S. stercoralis infection. RESULTS: Among the 339 PLWH whose stool samples were collected, 82 were positive for S. stercoralis (prevalence 24.2%; 95% confidence interval [CI] 20.0-29.1%). Among the 534 PLWH whose serum samples were collected, 227 were positive (seroprevalence: 42.5%; 95% CI 38.1-47.5%). The kappa value for charcoal culture and Baermann technique was 0.69. ELISA showed a sensitivity of 92.6% and a negative predictive value of 96.9%. Significant risk factors for stool positivity included living in a rural (unpaved) area (adjusted OR: 1.86), whereas significant risk factors for both stool and seropositivity included living in a poor house (made of wood/leaves) (adjusted odds ratio (ORs): 2.18 and 2.48, respectively), in the Loreto Regional Hospital catchment area (adjusted ORs: 5.66 and 5.37, respectively), or being infected by hookworms in stool (adjusted ORs: 23.88 and 9.78, respectively). Having a low level of studies was associated with seropositivity (adjusted OR 2.42). CONCLUSION: The prevalence of S. stercoralis is high among PLWH in Iquitos, especially among those living in conditions of socioeconomic vulnerability or co-infected with hookworms. The negative predictive value of the S. stercoralis ELISA was high, although this result should be taken with caution in severe immunosuppression.