Efficacy of Albendazole against gastrointestinal nematodes of pigs in the sub-humid savanna zone of southeastern Nigeria.

Albendazole is the most widely used anthelmintic in the Nigerian pig industry; however, its efficacy is increasingly compromised by emerging resistant strains of gastrointestinal nematodes (GINs). This study evaluated albendazole efficacy in pigs reared in the sub-humid savanna zone of southeastern Nigeria using a faecal egg count reduction test (FECRT) to assess anthelmintic resistance. Faecal samples were collected from 130 randomly selected pigs across 13 farms and screened for GIN infections. Six farms, with no anthelmintic treatment for at least three months, were selected for FECRT; ten infected pigs per farm were randomly chosen, with pre-treatment faecal egg counts (FEC) assessed prior to albendazole administration and post-treatment FEC recorded on day 10. Overall, GIN prevalence was 63.1 %, with mixed infections representing 74.6 % of cases. Results indicated resistance among GINs, particularly strongyles and trichurids. Albendazole-resistant GINs were detected in three farms, while two farms exhibited susceptibility and one yielded an inconclusive result. Specifically, albendazole-resistant strongyles were observed in one farm, with susceptible populations in four farms and inconclusive findings in one. Resistant trichurids were found in two farms, whereas ascarids remained susceptible across all farms. These findings demonstrate variable albendazole efficacy against GINs in pigs, with significant resistance among trichurids and strongyles. The detection of albendazole-resistant GIN strains in the sub-humid savanna zone of southeastern Nigeria underscores the need for regular monitoring and integrated parasite management strategies to mitigate the development of resistance.