Genetic variability within and among Hypobiotic Haemonchuscontortus isolates from goats in Kenya
Siamba D.N1, Mulambalah C. S2
1 Department of Agriculture and Veterinary Sciences, Kibabii University, P.O Box 1699-50200, Bungoma
2Department of Medical Microbiology & Parasitology, School of Medicine, Moi University P.O Box 4606 -30100
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Citation: KIBU Conference (2017). Innovative Research and Knowledge for Global Competitiveness and Sustainable Development. Proceedings of 2nd Interdisciplinary International Scientific Conference 14 – 15 June 2017. Kibabii University Main campus, Bungoma Kenya ISBN: 978-9966-59-011-4
Haemonchuscontortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. Knowledge of genetic variation within and among H. contortus populations can provide a foundation for understanding the biology and transmission patterns and might contribute to the control of haemonchosis. Infective larvae of H. contortus were cultured from eggs collected from goats raised on six farms located in different geographical regions in Kenya. The second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA and mitochondrial nicotinamide dehydrogenase subunit 4 gene (nad4) were amplified by polymerase chain reaction (PCR) and sequenced directly. The sequence variations and population genetic diversities were determined. Nucleotide sequence analyses revealed 18 genotypes (ITS-2) and 142 haplotypes (nad4) among the 152 worms, with nucleotide diversities of 2.6% and 0.027, respectively, consistent with previous reports from other countries. Population genetic analyses revealed that 92.4% of nucleotide variation was partitioned within populations; there was no genetic differentiation but a high gene flow among Kenyan populations; some degree of genetic differentiation was inferred between some specimens from China and those from other countries. This is the first study of genetic variation within H. contortus in Kenya. The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus Kenya. The present results could have implications for studying the epidemiology and ecology of H. contortus in Kenya.
Key words:Haemonchuscontortus, Genetic variation