Anthelmintic resistance of nematodes in communally grazed goats in a semi-arid area of South Africa

Abstract

A survey was conducted on the occurrence of anthelmintic resistance of nematodes in communally grazed goats in a semi-arid area in SouthAfrica. In herds belonging to 10 smallholder goat farmers, the efficacies of fenbendazole, levamisole and rafoxanide were tested by faecal egg count reduction (FECR) tests. Efficacies of 80 % were considered a threshold for anthelmintic resistance. The FECR tests showed that all drugs tested more than 80 % effective in most instances, but there were notable exceptions. In 1 case, rafoxanide was only 31 % effective and in another case fenbendazole was only 47 % effective. The occurrence of anthelmintic resistance in this farming sector is of concern. Steps should be taken to prevent its further spread and to avoid the development of a situation as onnumerous commercial sheep farms in South Africa where resistance is very common.

February-2021

“…The predominance of Haemonchus spp. both preand post-treatment in the sheep found in the present study is consistent with the results obtained from studies conducted in Mpumalanga and Limpopo Province [6], North West Province [9], and Gauteng [7] where the most prevalent species was H. contortus. The reduction of Trichostrongylus/Teladorsagia spp.…”

“…AR has been reported for all anthelmintic classes currently available, namely, benzimidazoles (BZ) (e.g., flubendazole, albendazole, and fenbendazole), imidazothiazoles (e.g., levamisole [LEV]), and macrocyclic lactones (ML) (e.g., ivermectin) [5]. In South Africa, AR has been reported in sheep [6,7] and goats [7][8][9] in both the commercial and resourcepoor farming systems. The overall prevalence of AR in South Africa and elsewhere in Africa has, however, not been extensively investigated.…”

Awareness of porcine helminthiasis and the prevalent farm management operations among smallholder pig farmers in the Free State

“…Figure 3 explains that 78% of the respondents were not aware of anthelmintic resistance in some porcine helminth species and other livestock nematodes. Reports on anthelmintic resistance in some livestock nematode species of economic importance have been documented in South Africa and other parts of the world (Bakunzi, 2003;Leathwick & Besier, 2014;Van Den Brom et al, 2015;Van Wyk et al, 1999). Furthermore, 17.4% of farmers indicated that they repeated or increased the dosage of worm expellers mostly because of anthelmintic failure.…”

“…This infection can lead to considerable loss of productivity, which in turn threatens food security, especially in subsistence farming systems. The intensive use of anthelmintics has resulted in a substantial anthelmintic failure due to increasing incidences of resistance in some worm species (Bakunzi, 2003;Coles et al, 2006;European Medicines Agency (EMA), 2017). A review of literature revealed that in the Free State Province, insufficient information is available regarding the predisposing factors, prevention, control, and consequences of porcine helminthiasis, zoonosis and anthelmintic administration.…”

Anthelmintic Resistance in Livestock

“…Underestimation of real weight has a potential to lead to underdosing, which can contribute to the development of AR [48]. The results of a South African study attributed AR observed in goats to underdosing caused by visual appraisal of an animal to estimate its weight as opposed to the actual weighing before dosing to determine the correct anthelmintic dosage [31]. In consideration of ensuring a correct dose, livestock farmers have to determine the weight as accurately as possible, preferably by individually weighing each animal [40].…”