GENETIC VARIABILITY OF BETA-TUBULIN GENE IN BENZIMIDAZOLE-SUSCEPTIBLE AND-RESISTANT STRAINS OF Haemonchus Contortus AND EVALUATION OF ANTHELMINTIC POTENTIAL OF SOME Artemisia SPECIES

Abstract

Small ruminants are the important component of livestock sector in developing Pakistan. Gastrointestinal nematodes (GINs) are the major parasitic group inflicting heavy economic losses due to high morbidity and mortality rate. In past injudicious use of commercially available anthelmintics has resulted in wide spread anthelmintics resistance among nematodes. There have been reports on development of resistance and emergence of multi resistant strains all over the world. This demands the knowledge of anthelmintic resistance in population and development of alternative source of anthelmintics. Therefore, aim of the present study was to find out resistant allele in population by studying beta tubulin gene and to evaluate the anthelmintic activity of Artemisia spp. as alternative control against gastrointestinal nematodes by selecting Haemonchus contortus as a target nematode species. The DNA of individual nematode was analyzed for Beta-Tubulin by PCR using specific primers and sequenced to observe resistance/susceptible region and other possible variations. Plant extracts of Artemisia was prepared using standard procedure and their efficacy was evaluated according to the procedures described by World Association for Advancement of Veterinary Parasitology (WAAVP). In vitro investigation was carried out to observe the ovicidal, larvicidal and wormicidal activity of methanolic plant extracts. The results for in vitro assays indicated that selected plant species have maximum activity (100%). A. meritima and A. vulgaris proved to be most effective in reducing adult worms and infective larvae followed by A. vestita, A. perviflora and A. siversiana. In vivo study was carried out by forming three groups as positive control negative control and treated. Infection was tested by hematological profile, worm burden and fecal examination. The results for molecular evaluation showed presence of resistant allele in all selected populations as 43%, 40%, 33% and 47% in Rawalpindi, Attock, Jehlum and Chakwal, respectively and overall resistant allele to benzimidazole was 36%. While for in vivo assay the maximum mortality percentage for Fecal Egg Count (FEC) was 87%, 84%, 78% 89% and 75% for A. vestita, A. meritima, A. vulgaris, A. perviflora and A. siversiana respectively. While, phenotypic profiles like Pack Cell Volume (PCV) and FAMACHA scores also increased significantly. However, this research provided validated information regarding the trends in population about anthelmintic resistance and scientific knowledge about Artemisia having anthelmintic activity and can serve as basis for the development of new and cheaper biological compounds to be used as anthelmintics.