Population genetic structure of ixodid ticks and phylogenetic analysis of rickettsia in Chongwe and Chisamba districts of Zambia.
| dc.contributor.author | Khumalo, Cynthia Sipho | |
| dc.date.accessioned | 2025-01-17T09:52:28Z | |
| dc.date.available | 2025-01-17T09:52:28Z | |
| dc.date.issued | 2024 | |
| dc.description | Thesis of Master of Science degree in Infectious Diseases. | |
| dc.description.abstract | Ticks are known vectors of various disease-causing pathogens worldwide. The distribution of ticks, their genetic makeup and relations has not been fully explored. This study focused on the population genetics of Ixodid ticks and the molecular epidemiology of Rickettsia species infecting them. Population genetics is vital to understanding the vectorial capacity of the ubiquitous Amblyomma, Hyalomma, and Rhipicephalus tick species that can transmit various disease-causing organisms including Rickettsia which cause a group of re-emerging diseases known as Rickettsioses. This study was conducted on ticks that were collected from Chongwe and Chisamba districts of Zambia in November 2020 and June 2021 respectively. Ticks collected were morphologically identified, homogenised, DNA extracted and polymerase chain reaction (PCR) run using primers to amplify the cytochrome subunit I (CO1), 12SrDNA and 16SmRNA for tick species verification and population genetics as well as ompA, ompB and gltA genes for Rickettsia molecular epidemiology followed by sequencing. Sequences obtained were blasted then edited using ATGC plug in Genetyx ver.12 and aligned using clustalw. For Rickettsia, phylogeny was established using Mega version XI. Comparison of population genetics was by MEGA XI, DnaSP, Arlequin (Fst), NETWORK and GENAlex (to measure diversity). It was found that tick populations in Chongwe and Chisamba district were identified as belonging to Amblyomma, Hyalomma and Rhipicephalus genus. These tick populations were high in genetic diversity and low in genetic differentiation. The tick populations were observed to carry Rickettsia species with Amblyomma and Hyalomma carrying over 95% of the Rickettsia detected. Rickettsia species detected were R. africae and R. aeschlimannii-like are both zoonotic known to cause febrile diseases of varying morbidities and mortalities. The study accounts for the low genetic differentiation to the free movement of animals that act as carriers for the ticks across the two districts. Due to this effective vector control methods can be extrapolated between the two districts. The high genetic diversity is an indication of an expanding population and hence potential occurrence of diseases carried by the ticks such as Rickettsia. The Rickettsia species detected are all zoonotic species and hence pose a risk of the outbreak of Rickettsioses in the areas the vectors are expanding to. This warrants surveillance of Rickettsioses and further research on vector populations, factors attributed to their expansion and the pathogens they carry around the country. | |
| dc.identifier.uri | https://dspace.unza.zm/handle/123456789/9107 | |
| dc.language.iso | en | |
| dc.publisher | The University of Zambia | |
| dc.title | Population genetic structure of ixodid ticks and phylogenetic analysis of rickettsia in Chongwe and Chisamba districts of Zambia. | |
| dc.type | Thesis |