Haemonchus contortus load and anthelmintics resistance in Sheep and Goats in Chennai, Tamil Nadu, India

Sheep and goats are the small ruminants which have enormous potential to boost economy and this may be major source of income especially to marginal farmers and landless laborers. Gastrointestinal (GI) parasitism is a very common and economically important condition affecting domestic livestock species worldwide. Among the gastrointestinal parasites Haemonchus contortus, commonly known as barber’s pole worm, wire worm is an economically important parasite causing a great economic loss in small ruminants industry. The present study was conducted to infection load and anthelmintics resistance status of Haemonchus contortus in sheep and goat. A total of 6785 sheep/goats abomasum were examined, out of which 2645 abomasal samples were found to contain H. contortus worms. Egg hatch assay (EHA) and larval migration inhibition assay (LMIA) were carried out to assess the status of thiabendazole and ivermectin resistance. In EHA, 36% of the samples were benzimidazole resistant with a mean ED50 of 0.247 µg/ml and ED50 0.070 µg/ml in susceptible populations of H. contortus. Resistance factor for thiabendazole was 3.5. In LMIA, 42% of the samples were ivermectin resistant with LM50 value of 0.149.