Status of benzimidazole resistance in Haemonchus contortus of goats from different geographic regions of Uttar Pradesh, India

•A comprehensive survey has been done for BZ resistance in H. contortus by FECRT and AS-PCR.•FECRT showed BZ resistance prevalent in all regions; however, six farms harboured susceptible populations.•It revealed 55-85% of H. contortus were homozygous resistant and 5-24% heterozygous.•The allele frequencies were 67-87.5% for resistant and 12.5-33% for susceptible.•The survey indicated that the status of BZ resistance is in alarming conditions.

Present study was designed to survey the status of benzimidazole (BZ) resistance in goat flocks of different agro climatic regions of Uttar Pradesh (U.P.), India by faecal egg count reduction test (FECRT) and allele specific PCR (AS-PCR). Faecal egg counts and larval culture were made from representative samples of all regions. The results of the faecal culture and PCR-RFLP on beta tubulin isotype-1 gene showed Haemonchus contortus was predominant species. FECRT results showed BZ resistance prevalent in all regions. However, six farms of twenty screened, harboured susceptible populations of strongyles. Three hundred H. contortus infective larvae from all regions of the state were genotyped for BZ resistance. AS-PCR results revealed 55-85% of H. contortus homozygous resistant (rr), 10-21% homozygous susceptible (SS) and 5-24% heterozygous (rS) among different regions of U.P. The allele frequencies were 67-87.5% for resistant (TTC) and 12.5-33% for susceptible (TAC). The survey indicated that the status of BZ resistance is in alarming conditions in all the parts of the state.