Gut expulsion of some mammalian nematodes requires IL-13 secreted by Th2 cells. Interleukin 13 enhances gut contractions and glycoprotein hyper-secretion that propel parasites to detach from the gut wall. Haemonchus contortus is a gastrointestinal blood sucking nematode of small ruminants. This study evaluated expression of IL-13 in selected parasite resistant Spanish and Myotonic goats. Whole blood, and abomasal and intestinal tissues were harvested from goats exhibiting susceptibility and resistance to Haemonchus contortus through standard and molecular detection methods. An indirect Enzyme Linked Immunosorbent Assay was performed to determine IL-13 expression. Results showed that IL-13 was expressed 70% more in intestinal than abomasal tissues. Parasite resistant goats expressed more IL-13 than susceptible goats. These data indicate that IL-13 expression may be useful as a biomarker for resistance to Haemonchus contortus infection in goats, allowing IL-13 based anthelmintic drug development and goat producers the ability to select parasite resistant animals.

Haemonchus contortus, a gastrointestinal parasite costs the global small ruminant industry massive production loss and drug costs per annum. In Haemonchus contortus, one of the single nucleotide polymorphisms (SNP) at codon 200 of the beta tubulin isotype-1 gene (TTC to TAC), renders this nematode resistant to benzimidazole based anthelmintics. Goats infected with such strains are resistant to benzimidazole based anthelmintics. We used this well established SNP as a diagnostic tool to detect and quantify resistant Haemonchus contortus in grazing goats. Spanish goats had 28% higher (P<0.05) amounts of both benzimidazole sensitive and resistant strains of Haemonchus contortus in stool than Myotonic goats. Bucks also had 25% higher (P<0.05) of both sensitive and resistant strains than Does. These data demonstrate that this SNP can be used as a diagnostic tool for detection and quantitation of Haemonchus contortus in the stool of grazing goats.