Prevalence of Parasitic Contamination in Spinach and Soil, and Its Relationship with Soil Physicochemical Properties, in Lafia, North-Central Nigeria

Abstract

Fresh leafy vegetables and their growing soils are recognised as vehicles for soil-transmitted helminths and intestinal protozoa in low- and middle-income countries, yet farm-level data linking soil quality to contamination remain scarce for North-Central Nigeria. This study determined the prevalence and diversity of parasitic contamination in spinach (leaf and root) and soil from three vegetable-growing/vending locations (Gandu, Emir Palace and Poly) in Lafia, Nasarawa State, Nigeria, in relation to soil physicochemical properties. Ninety samples (30 each of spinach leaf, spinach root and soil) were examined parasitologically, and soils were analysed for pH, organic carbon, nitrogen, available phosphorus, potassium, exchangeable acidity and particle size. Overall parasitic prevalence was 37.8% (34/90). Hookworm had the highest prevalence (15.6%), followed by Entamoeba histolytica and Strongyloides spp. (6.7% each), Giardia lamblia and Ascaris lumbricoides (3.3% each), and Fasciola hepatica (2.2%), with a significant difference among parasite taxa (χ² = 19.305, df = 5, p = 0.002). Soil was the most contaminated sample type (46.7%), followed by spinach leaf (40.0%) and spinach root (26.7%), though differences among sample types (p = 0.064) and locations (p = 0.924) were not significant. Organic carbon, organic matter, nitrogen and available phosphorus differed significantly among locations (p < 0.05); exchangeable acidity showed the strongest, non-significant, positive association with prevalence (r = 0.875, p = 0.322). These findings indicate a moderate, taxonomically diverse contamination burden across the Lafia spinach supply chain, with soil as an important reservoir, underscoring the need for integrated food-safety and soil-hygiene interventions in peri-urban Nigeria.