Occurrence of Soil-transmitted Helminths from Selected Dumpsites and Farmlands in Calabar, Nigeria

Aims: The present study investigated the prevalence and intensity of soil-transmitted helminth contamination in dumpsite and farmland soils in Calabar, Cross River State, Nigeria.

Methodology: Soil samples were randomly collected from selected dumpsites and farmlands from July to December 2019. 200 soil samples (100 samples each from dumpsites and farmland) were collected. Soil samples were analysed using Zinc sulphate flotation technique whereas soil nematode extraction for hookworm and Strongyloides larvae was carried out using the modified Baermann technique.

Results: Of the 200 soil samples examined, 131 (65.5%) were positive for ova/larvae of one or more parasites. Dumpsite soils were highly contaminated with ova/larvae of soil-transmitted helminths than farmland soils with a prevalence of 79% (n=79) and 52% (n=52) respectively (P=.02). Farmlands had the highest mean intensity (6.75±1.88) of contamination with ova/larvae of soil-transmitted helminths compared to dumpsite soils (1.68±0.14). Ascaris lumbricoides recorded the highest occurrence (35.5%) (P=.003) in soil samples examined. A. lumbricoides (40%) and Trichuris trichiura (6%) contamination was higher in dumpsite soils, while Strongyloides stercoralis larvae (34%) and hookworm (10%) contamination was higher in farmland soils. Dumpsite soils recorded the highest number of parasites (84%) in the wet season, while farmland soils recorded the highest number of parasites (92%) in the dry season (P=.11). Generally, parasitic ova/larvae were more prevalent in the dry season (91%) than in the wet season (73%) (P=.33). S. stercoralis (33%) was more prevalent in the wet season followed while A. lumbricoides (43%) recorded highest occurrence in the dry season.

Conclusion: This study revealed the potential health risk of contracting soil-transmitted helminth parasites in soils around farmlands and dumpsites in Calabar, Nigeria. It is therefore important that a combination of sanitation and health education be put in place for effective control of soil-transmitted helminths.