Anthelmintic resistance in livestock in Africa: review of the current status.

BACKGROUND

Livestock across the globe are frequently infected with multiple gastrointestinal nematode (GIN) species, and the use of anthelmintics remains a cornerstone of their control. However, anthelmintic resistance (AHR) poses a growing threat to sustainable livestock production, resulting in reduced productivity and compromised animal health and welfare. Reports of resistance in various helminth species against multiple anthelmintic classes exist in African livestock; however, studies summarising the extent and burden of this resistance are limited, and systematic monitoring or surveillance efforts are largely absent across the continent.

METHODS

We conducted a comprehensive scoping review to evaluate the current status of AHR in African livestock.

RESULTS

Our systematic search yielded 357 original studies, 28 met the eligibility criteria, covering nine countries and spanning from 1996 to 2024. All studies involved cattle and/or small ruminants, focusing primarily on two anthelmintic classes-benzimidazoles and macrocyclic lactones-and two gastrointestinal nematode genera: Haemonchus and Trichostrongylus. Resistance was reported across most of the studies, although reported prevalence rates were highly heterogeneous, varying considerably with anthelmintic class, livestock species, and geographic location. We observed variability in study methodologies, including differences in faecal egg count reduction test (FECRT) design, sampling intervals, dosage regimens, and reporting quality, which potentially limits comparability across countries and restricts epidemiological insight.

CONCLUSIONS

These findings highlight the urgent need to more accurately quantify the burden of AHR and to establish coordinated surveillance systems across Africa. Equally important is the development of sustainable parasite control strategies and the promotion of responsible anthelmintic use to preserve the efficacy of existing drugs.