Seroconversion and seroreversion rates of anti- Strongyloides IgG in rural areas of the Amazon: a population-based panel study

Author(s)

de Paula, Fabiana Martins ; Gomes, Bruna Barroso ; Meisel, Dirce Mary Correia Lima ; Roldan, William Henry ; Nunes, Monica da Silva ; Ferreira, Marcelo Urbano ; Gryschek, Ronaldo Cesar Borges

• Document type: Journal article
• Source: Revista do Instituto de Medicina Tropical de São Paulo; v. 66, p. 9-pg., 2024-01-01.

Abstract

Using a panel study design, we aimed to estimate the seroconversion and seroreversion rates of anti- Strongyloides IgG antibodies from surveys carried out 11 months apart in a rural community in the Amazon Basin in Brazil. We used enzyme immunoassays to measure anti- Strongyloides IgG antibodies in 325 baseline plasma samples and 224 others that were collected 11 months later from residents in the agricultural settlement of Granada, Acre State. We observed anti- Strongyloides IgG antibodies in 21.8% of the baseline samples (which showed that 3.4% of participants had larvae in their stool) and in 23.7% of the follow-up samples. The seroconversion rate estimated at 9.7 episodes/100 person-years at risk agrees with ongoing transmission. Specific antibodies were relatively short-lived and nine (25.0%) of 36 seropositive participants at baseline were seronegative when retested 11 months later. Fecal surveys can severely underestimate the prevalence of S. stercoralis infection in rural Amazonians. Serology provides a field-deployable diagnostic tool to find high-prevalence populations, identify associated risk factors, and monitor intervention programs. (AU)

• FAPESP's process: 13/04236-9 - Immunoproteomics applied to the diagnosis human strongyloidiasis used antigen Strongyloides venezuelensis
• Grantee: Ronaldo Cesar Borges Cryschek
• Support Opportunities: Regular Research Grants
• FAPESP's process: 22/02401-1 - Evaluation of Strongyloides venezuelensis heterologous antigen in the immunodiagnosis of human Strongyloidiasis: a study between Brazil, Peru and Portugal
• Grantee: Fabiana Martins de Paula
• Support Opportunities: Regular Research Grants