Haemonchus contortus is blood sucking nematode and causal pathogen of intestinal infection. Such type of infection causes serious constraint to goat production. Toll-like receptors (TLRs) are known to induce immune response predominantly through activate different signaling pathways that produce natural resistance against pathogens. Toll-like receptors are thought to be a critical ‘‘bridge’’ between innate and adaptive immunity to diverse pathogens. The current study was performed to investigate the association between polymorphisms of the TLRs gene and susceptibility to H. contortus infection in goat. Preliminary, 31 single nucleotide polymorphisms were identified in the TRLs gene using both pooled DNA and randomly selected DNA sequencing. The identified single nucleotide polymorphisms (SNPs) were genotyped by MALDI-TOF MS (Matrix-assisted laser desorption/ionization time of flight mass spectrometry) methods from 245 individuals. Out of 31, nine SNPs individually showed statistical significance association with H. contortus infection, of which, three were non synonymous resulted to amino acid replacement. Seven haplotype blocks were observed in this study and of those, four blocks are found to be significantly associated with H. contortus infection. Among the blocks, block 6 containing haplotypes GAGCATC, GAACATC, TGGGGGT, GGGGGGC and GGGGGTC were associated (P<0.002) with a higher risk of H. contortus infection in goat. Our results indicate polymorphisms detected in TLRs might have an impact on the structure and/or function of TLRs; goat TLRs are predicted to be associated with responses to gastrointestinal nematode infection including H. contortus and hence affect the immune response to pathogens.

Key words: Gastrointestinal nematode, Goat, Haemonchus, Single nucleotide Polymorphism, Toll-like receptor