Molecular epidemiology of malaria in the interior division of Sabah, Malaysia

Malaria is one of the important parasite transmitted diseases in Sabah, Malaysian Borneo that is covered by tropical rainforest. The objectives of this six months cross-sectional study were to accurately identify the human malaria parasites, to determine the rate of misidentification and to characte...

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Bibliographic Details
Main Author: Neoh, Joveen Wan Fen
Format: Thesis
Language:English
Published: 2011
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Online Access:https://eprints.ums.edu.my/id/eprint/6667/1/mt0000000210.pdf
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Summary:Malaria is one of the important parasite transmitted diseases in Sabah, Malaysian Borneo that is covered by tropical rainforest. The objectives of this six months cross-sectional study were to accurately identify the human malaria parasites, to determine the rate of misidentification and to characterize P. knowlesi isolates in the interior division of Sabah based on ssrRNA gene using nested PCR. A total of 243 blood spot samples from patients who had requested for Blood Film for Malaria Parasite (BFMP) test were collected from four study sites namely Keningau, Tenom, Tambunan and Nabawan. There were 16.1% P. malariae, 10.3% P. vivax, 7% P. falciparum, 1.2% mixed infection and 65.4% negative cases based on microscopic examination. However, the result of PCR indicated that P. knowlesi (58.9%), P. falciparum (18.7%), P. vivax (18.7%), mixed infection (3.7%) and no P. malariae infection were detected in these samples. There were only 35% of 243 samples gave consistent PCR and microscopic results. The highest malaria cases found in Keningau were P. falciparum (36.1%) whereas the prevalence of P. knowlesi was higher in Tambunan (85.7%) and Tenom (77.8%). Moreover, six positive samples for P. falciparum and P. knowlesi each were detected in Nabawan. Alignment analysis between P. knowlesi isolates from this study and P. knowlesi isolates from other geographical region showed two single nucleotide polymorphisms unique to P. knowlesi isolates from the interior division of Sabah. Besides, isolate KN048/2010 showing significant genetic variation among P. knowlesi isolates from this region. Phylogenetic analysis showed that P. knowlesi from this study clustered with naturally-acquired P. knowlesiisolates in human. This study provides further evidence of the actual transmission of different Plasmodium species in the interior regions of Sabah.