Comparative Bionomics Of Haemonchus Contortus In Sheep And Goats Between Malaysia And Yemen And Its Respective Morphological And Molecular Characterization
| dc.contributor.author | Gharamah, Abdullah Abobakr Mohammed | |
| dc.date.accessioned | 2020-01-28T07:17:18Z | |
| dc.date.available | 2020-01-28T07:17:18Z | |
| dc.date.issued | 2011-12 | |
| dc.description.abstract | The bionomics of the parasitic nematode worm, Haemonchous contortus were compared between Malaysia and Yemen. The morphological and molecular characterizations of H. contortus isolates from the two countries were investigated. Samples were obtained from sheep and goats. Study sites comprised of two States in Malaysia (Perak and Kelantan) and two Governorates in Yemen (Sana'a and Al- Hudaydah). The sites were chosen based on their geographical isolation within each country. Records of total number of infected sheep and goats by H. contortus adult worms during 2007-2009 in Malaysia and Yemen were collected from the annual reports of veterinary service centers in each country. High prevalence rates of this nematode in both sheep and goats were reported in Yemen. Data for temperature, humidity and rainfall during those years were collected to show the climatic conditions in the study areas and to assess a possible relation between these climatic parameters and the percentages of infected animals. Abattoir investigations were also carried out in Yemen during the period from September 2008 till February 2009. The abomasa of 68 sheep and 33 goats were collected in Sana'a while 59 abomasa of sheep and 105 abomasa of goats were collected in Al-Hudaydah. The data obtained showed high monthly prevalences of this worm in sheep and goats with no significant difference between host species in prevalences and total worm burdens. In Malaysia, it was difficult to find adult worms in the abomasa of sheep and goats. Thus samples utilized in this study were collected from the Department of Veterinary Services in Perak and Kelantan. Taxonomic differences of H. contortus populations of sheep and goats from Malaysia and Yemen were investigated using morphological and molecular techniques. Statistical analysis revealed that there were several significant differences between H. contortus isolates from sheep and goats in the four study areas. Also, H. contortus isolates from the two countries showed significant differences in all morphological characters investigated except gubernacula lengths of male worms. This was also supported by the principal component analysis and discriminant function analysis plots, where H. contortus populations of sheep and goats from Malaysia and Yemen were separated into two distinctive groups with very slight overlapping between them. This was attributed mainly to the geographical isolation between the two countries and thus movement of animals between countries is totally absent . The mitochondrial nicotine amide dyhydrogenase subunit-4 (ND4) was used to explore and compare the population genetics of H. contortus of sheep and goats from Malaysia and Yemen. The results showed high numbers of haplotypes (113 among 120 individuals sequenced) and the base composition of ND4 was very ATrich (82.1%). The phylogenetic analysis showed a clear geographical pattern between isolates from Malaysia and Yemen, where populations of H. contortus formed distinct clusters, but with no host isolation. In general, this study showed low population structure within the same country in comparison with higher genetic structuring at a wider geographical scale. This was explained by the high gene flow within the same country due to the possibility of host movement while between the two countries, there was a strong geographical barrier to gene flow. The AMOVA results showed that the majority of genetic variance was within H. contortus populations, represented by 72.19% of the total genetic variance. Furthermore, the internal transcribed spacer-2 (ITS-2) which is a nuclear marker was used to confirm the species identity of H. contortus in sheep and goats from Malaysia and Yemen. Sequence alignment of the 216 base pair of the ITS-2 fragment in sheep and goats from Malaysia and Yemen and available GenBank sequences revealed high identity (98-100%) confirming the taxonomic status of these populations as a single species. This was further supported by comparing the ITS-2 sequences of the present study with the most closely related species of H. placei from GenBank, where three fixed nucleotides differences were observed between the two species (transitions between purines G/A in three different positions: 9, 190 and 204). | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/9466 | |
| dc.language.iso | en | en_US |
| dc.subject | Haemonchus contortus | en_US |
| dc.title | Comparative Bionomics Of Haemonchus Contortus In Sheep And Goats Between Malaysia And Yemen And Its Respective Morphological And Molecular Characterization | en_US |
| dc.type | Thesis | en_US |
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