Zaisen Wang

Gastrointestinal nematodes (GINs), particularly Haemonchus contortus (H. contortus), pose significant challenges to small ruminant health and productivity, with increasing resistance to commercial anthelmintics. Conventional diagnostic techniques, such as fecal egg counts (FEC) and larval cultures (LC), are labor-intensive, time-consuming, and require technical expertise, limiting their practicality in field settings.

1. Introduction Gastrointestinal parasitism poses major challenges to small ruminant production, especially in tropical, sub-tropical, and temperate regions worldwide, often resulting in substantial stock losses and economic hardship [1] [2]. Chemical anthelmintics, the current standard for parasite control, have led to widespread anthelmintic resistance due to overuse, and drug residues in food products pose additional public health concerns [3]-[5].