Contamination of vegetables sold in markets with helminth eggs in Zaria metropolis, Kaduna State, Nigeria

Abstract

The increasing use of waste waters from human and animal wastes for irrigation of Agricultural produce as well as the indiscriminate defecation by both humans and animals in the environment has led to contamination of vegetables and salad crops with helminth eggs. The extent of contamination of vegetables sold in markets in Zaria metropolis, Kaduna state of Nigeria was determined in 199 vegetables using sucrose flotation medium of 1.21 specific gravity. Helminth eggs were found in 57.8% of the vegetables and the distribution was as follows: Toxocara spp. 48.3%, Strongyloides spp. 19.2%, Taenia spp./Echinococcus spp. 18.3%, Ancylostoma spp. 10.0%, Trichuris spp. 3.3 and Enterobius spp. 0.8%. Spinach (Spinacia oleracea) had the highest contamination rate (84.6%), followed by Waterleaf (Talinum triangulare) 84.0%, Carrot (Daucus carota var sativa) 76.9, Lettuce (Lactuca sativa) 56.5%, Jute mallow (Conchorus olitorius) 54.5%, Tomato (Lycopersicon esculentum) 48.0%, Fluted pumpkin (Telferia occidentalis) 38.5% and Cabbage (Brassica oleracea var capitata) 19.2%. Of the three markets examined, Sabo market had the highest contamination rate (65.5%) followed by Ahmadu Bello University community market (58.8%) and Samaru market (50.0%). Sixty eight (59.1%) of the vegetables examined were contaminated with helminth eggs in the pre-rainy period while 47 (56.0%) were contaminated in the rainy period. There was significant association (χ2 = 39.53; p = 0.0000) between helminth eggs and types of vegetables examined. On the other hand there were no statistical associations (p > 0.05) between prevalence of helminth eggs, markets sampled and the periods of study. This study has shown that vegetables sold in markets in Zaria metropolis are contaminated with helminth eggs. This is of public health significance. Hence there is need to compost human and animal wastes before they are used as manure. Thorough washing of vegetables is also recommended prior to consumption.