Soil-transmitted helminth infections: prevalence, incidence, post-treatment infection rate, and associated factors among children and young adults living in rural areas of Gabon

Abstract

Abstract Background Soil-transmitted helminth (STH) infections are of public health concern in endemic areas. For efficient control, the epidemiology of the disease needs to be updated. This report assesses the prevalence, incidence, post-treatment infection (PTI) rate, and risk factors of STH infections in two rural areas of Gabon. Method In this longitudinal and prospective study, participants aged six to 30 years from Lambaréné and vicinity were included and followed in two consecutive periods of six and nine months. Stool samples were obtained at the beginning and at the end of each follow-up phase (FUP). The Kato Katz technique was used for the detection of STH eggs while harada-mori technique and coproculture were used for the detection of larvae. Prevalence was determined at the three main time points of the study, incidence was assessed during the two study phases, and PTI was defined as an infection detected nine months post-treatment. Results A total of 262 participants were included. The overall prevalence of STH infections was 42% (95%CI: 34–50) and 44% (95%CI: 37–51) at baseline of both FUPs, respectively. Trichuris trichiura was the most prevalent species at each time point of assessment. The cumulative incidence at six- and nine-months follow-up of STH was 18% (95%CI: 12–27) and 35% (95%CI: 27–43), respectively, while the incidence rate was 41 (95%CI: 28–55) and 56 (95%CI: 46–67) per 100 person-years, respectively. The PTI rate at nine-months follow-up for T. trichiura, hookworm, and Ascaris lumbricoides was 58% (95%CI: 41–74), 31% (95%CI: 11–59) and 18% (95%CI: 5–40), respectively. The STH infection intensity was generally light. Conclusion The prevalence level of STH infection is moderate in the vicinity of Lambaréné, with T. trichiura being the most prevalent species. Our results reveal a rapid spread of the disease in the population mainly following intervention and particularly for trichuriasis, and therefore call for the full implementation of the World Health Organisation’s recommendations in the area, particularly adequate sanitation and hygiene activities. Trial registration: clinicaltrials.gov Identifier NCT02769013. Registered 21 April 2016, https://clinicaltrials.gov/study/NCT02769013