Abstract:

In Uganda, anthelmintics are widely used in the control of gastrointestinal nematode (GIN) parasites. However, control is not based on knowledge of the parasite epidemiology and status of Anthelmintic efficacies. This has led to their indiscriminate use and spreading of resistant nematodes in the ecosystem. This study hence identified the common GIN parasites, risk factors to anthelmintic resistance and evaluated the efficacies of albendazole (Alb), Levamisole (Lev) and Ivermectin (Tver) against natural GIN infections in goats in Gomba district. Fecal samples were collected on day 0 (N=470) before treatment. Parasite eggs were identified using the floatation technique, while worm burden (epg) was determined using the McMaster technique. Fecal samples were pooled and cultured for 7 days at 27° C. L3 were extracted using Bearmann’s technique and were identified using their morphological features. Goats with epg counts > 200epg were randomly set into 4 treatment groups: Alb, Lev, Iver and controls/placebo (n= 93). Fecal samples were collected on days 7, 14 and 21 post-treatment and fecal egg count reduction (FECR) test used to determine the efficacy for each treatment group. Risk factors for anthelmintic resistances were identified using questionnaire interviews on 62 farms (15- 300) goats/farm. Results: overall prevalence of GIN was 43%. Common GIN parasites were Flaemonchus (56%), Oesophagostomum (33%) and Stronyloides (11%). Drug efficacies were Alb: (82, 80 and 61) % at days 7, 14 and 21, Lev: (95, 91 and 69) % and Iver: (85, 84 and 81) % on the same days post treatment, respectively. Mean efficacies were Lev (85%), Iver (83%) and Alb (77.3%). Only Haemonchus were recovered in copro-cultures in Alb treated goats at day 21. Major risk factors for reduced efficacy were prolonged use of one drug type (97% Alb), weight determination by visual appraisal (94%), self-medication (67%) and grazing animals on communal pastures (80%). In conclusion, level of GIN infections in goats in Gomba was low probably due to heavy anthelmintic application. Haemonchus was the predominant GIN parasite. Albendazole, levamisole and ivermectin were still effective against common GIN parasites in Gomba but, (<90% efficacies) post-treatments was suggestive of possible parasite resistance against these drugs. Prolonged use of one anthelmintic and visual estimation of animal weight during treatment were the major risk factors for anthelmintic resistance. Specific reasons for the low GIN parasite prevalence needed further investigation. Farmer education was recommended to ensure judicious use of these drugs so as to maintain their current efficacies while alternative approaches to complement chemotherapy are sought.