Municipal Slaughterhouses Waste Management as a Diver of Environmental Contamination of Surface Water by Gastrointestinal Parasites in the Vina Division, Adamawa (Cameroon)

Abstract

From August 2022 to January 2023, a study was conducted to assess the impact of animal waste management on the dispersion of gastrointestinal parasites in municipal slaughterhouses in the Vina Division. Faecal waste and water samples from riverside streams were analysed using coprological tests, as well as sedimentation, Mini-FLOTAC and Bailenger flotation techniques, respectively. For nematode parasites, the eggs were cultivated and the L1–L3 larvae were identified. The results indicate the absence of waste management and treatment systems, with open dumps being the norm. Thirteen taxa were present in faeces and water, with frequencies of 100% (13/13 parasites) at Baladji 2 in Ngaoundere Centre, 92.3% (13/13 parasites) at Dang, 69.23% (10/13 parasites) at Mbe and Nyambaka, and 53.85% (7/13 parasites) at Nganha. The most abundant parasites in faecal waste were Eimeria spp. (229.55 ± 128.28 eggs/gram), Paramphistomum daubneyi (167.44 ± 92.54 eggs/gram), Trichuris sp. (156.57 ± 120.27 eggs/gram) and Toxocara sp. (156.06 ± 78.63 eggs/gram) (Kruskal–Wallis H = 790.45, df = 12, p < 0.0001). The highest densities were observed in samples from Baladji 2 (124.39 ± 35.59 eggs/g) and Dang (110.47 ± 28.29 eggs/g) (Kruskal–Wallis H = 208.02, df = 4, p < 0.0001). The highest frequencies of water parasites were recorded at the 10 stations near the slaughterhouses in Nyambaka (61.54%), Mbe (92.31%), Dang (100%), Nganha (100%) and Baladji 2 (100%). Parasites were highly abundant at Site 1 near all slaughterhouses. Notably, Toxocara sp., Cooperia sp., Giardia spp. and Trichostrongylus sp. were found in Baladji 2; Giardia spp. and Haemonchus contortus in Dang; Eimeria spp., Dictyocaulus viviparus, Toxocara sp., Cooperia sp. and Moneizia expansa in Nyambaka; and Eimeria spp. in Nganha. These parasites were distributed up to distances greater than 500 metres (p < 0.05). These findings show that the water surrounding the slaughterhouses was heavily contaminated with parasite eggs and larvae, posing a significant risk to public health.