Environmental contamination by soil-transmitted helminths ova and subsequent infection in school-age children in Calabar, Nigeria

Abstract

The prevalence of soil-transmitted helminths (STHs) is linked to poverty, poor environmental hygiene, and poor sanitation. A cross-sectional study was conducted between July and September 2021 targeting school-age children (7–15 years) in Calabar South Local Government Area, Cross River State, Nigeria. Two hundred and forty-four (244) school-age children participated in the study and 240 soil samples were collected from the selected schools. Faecal and soil samples collected were analysed following standard methods. One hundred and thirty-two [132/244; 54.1%] of 244 faecal samples analysed were positive for STHs. Three STHs were present in faecal samples examined; Ascaris lumbricoides (31.6%), Trichuris trichiura (11.9%) and hookworm (8.2%). The prevalence of STHs was highest amongst the 13–15 years age-group (57.4%) and least in the 7–9 years age group (40.7%) (p = 0.319). Females had the highest prevalence rate (55.6%) while 52.3% was recorded in males (p = 0.164). The overall intensity of Ascaris lumbricoides (68.82±3.605 epg) infection was higher than that recorded for hookworm (58.80±7.279 epg) and T. trichiura (55.71±4.460 epg). There was no significant gender and age-related difference in infection intensities (P>0.05). Out of 240 soil samples examined, 156 (65%) were positive for STHs which included Ascaris lumbricoides (23.3%), hookworm (17.5%), Trichuris trichiura (16.3%) and Strongyloides stercoralis (15.8%). Dumpsites recorded the highest prevalence of STHs (72.5%). Ascaris lumbricoides had the highest mean parasite intensity in soil (148.78±12.28). Overall intensity of STHs in soil was significantly higher in dumpsites areas (164.32±20.58) compared to playground and toilet areas (p = 0.030). Our findings reveal that soil-transmitted helminthiases remains a burden amongst school-age children. Furthermore, the high level of contamination of soil with ova/larvae of parasites is a serious public health concern pointing to the need for proper sanitation and health education within the study area. Data present will aid policy makers in establishing measures to reduce the burden of soil-transmitted helminthiases in children as well as the level of contamination in the environment.