Soil-transmitted helminths contamination of carrots and cucumbers, and molecular identification of Ascaris lumbricoides in Jos Plateau State, Nigeria

Abstract

Background: Soil-transmitted helminths (STHs) are group of parasitic nematodes transmitted through ingestion of eggs in contaminated food and water or through active skin penetration by an infective larva. Aim: This study determined the prevalence of STHs and molecular identification of Ascaris lumbricoides in fresh carrots and cucumbers in Jos Plateau State, Nigeria. Materials and Method: This was a cross-sectional study of carrots and cucumbers obtained from two vegetable markets and streets of Jos metropolis. About 200 g of each sample was weighed and washed separately in a sterile container using 200 ml of normal saline. This was allowed to sediment overnight, and the sediment was examined microscopically for eggs or larvae of parasites using ×10 and ×40 objectives of the light microscope. The positive samples for eggs of A. lumbricoides were subjected to molecular identification. The data obtained were computed using IBM SPSS software version 26. Results: The overall prevalence of STHs was 38.3% (138/360). The rate of contamination was higher in carrots with 45.0% (81/180) compared to 31.7% (57/180) of the total cucumbers examined. This was statistically significant (P = 0.009). The vegetables from the Farin-Gada market were the most contaminated, having a prevalence of 63 (52.5%), followed by the building Materials Market 50 (41.7%) and street traders 25 (20.8%). Strongyloides stercoralis was the most identified parasite totaling 69 (50.0%), followed by hookworm 51 (37.0%), A. lumbricoides 10 (7.2%), and Trichuris trichiura 8 (5.8%) being the least. Conclusions: There was a high contamination of carrots and cucumber studied in this research by STHs. Hence, there is a need for proper washing and possible decontamination before consumption to prevent food-borne infections.