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Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak

In Sarawak, Plasmodium knowlesi, which is commonly found in long-tailed and pig-tailed macaques, is the main cause for human malaria infections. Other simian malaria parasites from Southeast Asia that can infect humans are P. inui and P. cynomolgi. To date, epidemiological data on knowlesi malari...

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Main Author: Liew, Sze Tze
Format: Thesis
Language:English
Published: Universiti Malaysia Sarawak, (UNIMAS) 2017
Subjects:
R Medicine (General)
Online Access:http://ir.unimas.my/id/eprint/23910/1/Liew%20Sze.pdf
http://ir.unimas.my/id/eprint/23910/
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spelling my.unimas.ir.239102023-06-28T03:40:49Z http://ir.unimas.my/id/eprint/23910/ Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak Liew, Sze Tze R Medicine (General) In Sarawak, Plasmodium knowlesi, which is commonly found in long-tailed and pig-tailed macaques, is the main cause for human malaria infections. Other simian malaria parasites from Southeast Asia that can infect humans are P. inui and P. cynomolgi. To date, epidemiological data on knowlesi malaria in Sarawak has been derived solely from hospitalbased investigations and all of them were symptomatic malaria cases. A longitudinal study was therefore undertaken to determine asymptomatic Plasmodium infections including P. knowlesi and other simian malaria parasites infections in the Betong Division of Sarawak. A total of 555 people were recruited from 8 longhouses, which had individuals recently admitted to Betong Hospital with knowlesi malaria. Blood spots, collected bi-monthly over a period of 21 months, were examined using PCR assays. Pooled and non-pooled nested PCR strategies were used to screen DNA extracted from the blood spots for the presence of Plasmodium DNA. Next, each of the genus-positive DNA samples was screened using species-specific primers for P. falciparum, P. vivax, P. malariae, P. ovale, P. knowlesi, P. cynomolgi and P. inui. A subset of samples was also screened with real time PCR for the presence of P. knowlesi. Nine subjects were positive for malaria DNA by nested PCR -- seven P. knowlesi, one P. vivax and one sample that could only be identified as positive for Plasmodium DNA. For real time PCR, 21 samples were positive for P. knowlesi, including two samples that were positive for P. knowlesi by nested PCR. Only one subject, who was positive for both nested PCR and real time PCR for P. knowlesi, was symptomatic and admitted to Betong Hospital. None of the other PCR-positive subjects were febrile nor did any of them sought any medical treatment. Lastly, cloning and sequencing was only successful for 4 out of the 9 samples, in which phylogenetic analyses of these sequences confirmed that samples from three subjects were infected by P. knowlesi and one sample found to be co-infected by both P. knowlesi and P. coatneyi. Universiti Malaysia Sarawak, (UNIMAS) 2017 Thesis NonPeerReviewed text en http://ir.unimas.my/id/eprint/23910/1/Liew%20Sze.pdf Liew, Sze Tze (2017) Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak. Masters thesis, Universiti Malaysia Sarawak.
institution Universiti Malaysia Sarawak
building Centre for Academic Information Services (CAIS)
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Sarawak
content_source UNIMAS Institutional Repository
url_provider http://ir.unimas.my/
language English
topic R Medicine (General)
spellingShingle R Medicine (General)
Liew, Sze Tze
Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak
description In Sarawak, Plasmodium knowlesi, which is commonly found in long-tailed and pig-tailed macaques, is the main cause for human malaria infections. Other simian malaria parasites from Southeast Asia that can infect humans are P. inui and P. cynomolgi. To date, epidemiological data on knowlesi malaria in Sarawak has been derived solely from hospitalbased investigations and all of them were symptomatic malaria cases. A longitudinal study was therefore undertaken to determine asymptomatic Plasmodium infections including P. knowlesi and other simian malaria parasites infections in the Betong Division of Sarawak. A total of 555 people were recruited from 8 longhouses, which had individuals recently admitted to Betong Hospital with knowlesi malaria. Blood spots, collected bi-monthly over a period of 21 months, were examined using PCR assays. Pooled and non-pooled nested PCR strategies were used to screen DNA extracted from the blood spots for the presence of Plasmodium DNA. Next, each of the genus-positive DNA samples was screened using species-specific primers for P. falciparum, P. vivax, P. malariae, P. ovale, P. knowlesi, P. cynomolgi and P. inui. A subset of samples was also screened with real time PCR for the presence of P. knowlesi. Nine subjects were positive for malaria DNA by nested PCR -- seven P. knowlesi, one P. vivax and one sample that could only be identified as positive for Plasmodium DNA. For real time PCR, 21 samples were positive for P. knowlesi, including two samples that were positive for P. knowlesi by nested PCR. Only one subject, who was positive for both nested PCR and real time PCR for P. knowlesi, was symptomatic and admitted to Betong Hospital. None of the other PCR-positive subjects were febrile nor did any of them sought any medical treatment. Lastly, cloning and sequencing was only successful for 4 out of the 9 samples, in which phylogenetic analyses of these sequences confirmed that samples from three subjects were infected by P. knowlesi and one sample found to be co-infected by both P. knowlesi and P. coatneyi.
format Thesis
author Liew, Sze Tze
author_facet Liew, Sze Tze
author_sort Liew, Sze Tze
title Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak
title_short Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak
title_full Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak
title_fullStr Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak
title_full_unstemmed Epidemiology of Knowlesi and other Simian Malarias in Humans in the Betong Division of Sarawak
title_sort epidemiology of knowlesi and other simian malarias in humans in the betong division of sarawak
publisher Universiti Malaysia Sarawak, (UNIMAS)
publishDate 2017
url http://ir.unimas.my/id/eprint/23910/1/Liew%20Sze.pdf
http://ir.unimas.my/id/eprint/23910/
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score 13.211869

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