Prevalence of Gastrointestinal Parasites, Anthelmintic Use and Resistance in Selected Sheep Farms in Kasarani, Nairobi County.

Abstract

The adverse effects of gastrointestinal parasitic infection have resulted in low productivity of sheep in Kenya. As a result, farmers relied on anthelmintic therapy that may lead to occurrence of anthelmintic resistance. The occurrence of clinical and sub-clinical cases despite treatment, enhanced the need to determine prevalence and intensity of gastrointestinal parasites infection in sheep, assess knowledge, practice and attitudes towards treatment and control of helminthes infection in sheep and test for anthelmintic resistance. A cross-sectional study was conducted in 30 selected sheep farms in Kasarani to determine the prevalence and intensity of gastrointestinal parasites in different breeds of sheep. One thousand six hundred and forty-two (1642) faecal samples were subjected to coprological examination to determine the egg per gram (EPG), oocyst per gram (OPG) of faeces with a detection level of 100 EPG/OPG and for the presence of cestode and trematode eggs. The overall prevalence of gastrointestinal parasites was 99.6 %. The prevalence of strongyle eggs was 72%, coccidial oocyst 49% and 7% for tapeworm eggs. There was no significant difference in prevalence of strongyle between adults and lambs (P-value 0.7), males and females (P value 0.4) and coccidial infection between adults and lambs (P value 0.2) and male and female (P value 0.3). Prevalence of tapeworm infection in between adults and lambs (P-value 0.000) and male and female (P value 0.0001). The overall intensity of strongyle (480 mean egg count (MEC) and coccidial (330 mean oocyst count (MOC) infection in sheep were low. At farm level the intensity of strongyle (32-1561 MEC) and coccidia (7-2034 MOC) ranged from mild to severe (MEC, 2034 MOC). Helminthes spectrum showed 90% Haemonchus species, 5% Trichostrongylus species and 5% Oesophagostomum species. There was no evidence of trematode infection in the sampled sheep. xiv Survey on knowledge, practice and attitude towards treatment and control of gastrointestinal parasites showed that all the respondents 77(100%) were aware about helminthes infection in sheep. Classes of anthelmintics available in veterinary drugs stores were benzimidazole, imidazothiazole and macrocyclic lactones. The proportions of farmers using these anthelmintics were 43%, 30% and 27% respectively. The ease of administration (70%) and price (30%) greatly influenced the choice of anthelmintics to use. Veterinary consultation was rare (13%) in suspected case of sheep helminthosis. Dose determination was based on visual estimation of the sheep’s weight (67%) and weight of individual sheep (33%). Deworming was done every three months (67%) and whenever there was sign of helminthes infection (33%). In every subsequent treatment a different class of anthelmintics was used (73%). Faecal egg count reduction test (FECRT) detected multiple anthelmintic resistance whereby resistance to albendazole, levamisole and ivermectin was confirmed in one farm with FECR% of 11.1%, 59.3%, 59.3% respectively. More farms (60%) showed resistance to albendazole than to levamisole (40%) and ivermectin (40%). Haemonchus contortus and Trichostrongylus species were resistant to the three anthelmintics while Oesophagostomum species were resistant to levamisole and ivermectin. This study demonstrated high prevalence of 99.6% of gastrointestinal parasites infection in sheep. The inappropriate dosing, frequent deworming and short alternation period might have resulted in occurrence of multiple and multi-generic anthelmintic resistance (AR) in sheep in Kasarani Sub-County. Therefore, there is need to educate farmers on proper use of anthelmintics, the risk of anthelmintic resistance occurrence and its consequences on production.