Title |
Microgeography and molecular epidemiology of malaria at the Thailand-Myanmar border in the malaria pre-elimination phase
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Published in |
Malaria Journal, May 2015
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DOI | 10.1186/s12936-015-0712-5 |
Pubmed ID | |
Authors |
Daniel M. Parker, Stephen A. Matthews, Guiyun Yan, Guofa Zhou, Ming-Chieh Lee, Jeeraphat Sirichaisinthop, Kirakorn Kiattibutr, Qi Fan, Peipei Li, Jetsumon Sattabongkot, Liwang Cui |
Abstract |
Endemic malaria in Thailand continues to only exist along international borders. This pattern is frequently attributed to importation of malaria from surrounding nations. A microgeographical approach was used to investigate malaria cases in a study village along the Thailand-Myanmar border. Three mass blood surveys were conducted during the study period (July and December 2011, and May 2012) and were matched to a cohort-based demographic surveillance system. Blood slides and filter papers were taken from each participant. Slides were cross-verified by an expert microscopist and filter papers were analysed using nested PCR. Cases were then mapped to households and analysed using spatial statistics. A risk factor analysis was done using mixed effects logistic regression. In total, 55 Plasmodium vivax and 20 Plasmodium falciparum cases (out of 547 participants) were detected through PCR, compared to six and two (respectively) cases detected by field microscopy. The single largest risk factor for infection was citizenship. Many study participants were ethnic Karen people with no citizenship in either Thailand or Myanmar. This subpopulation had over eight times the odds of malaria infection when compared to Thai citizens. Cases also appeared to cluster near a major drainage system and year-round water source within the study village. This research indicates that many cases of malaria remain undiagnosed in the region. The spatial and demographic clustering of cases in a sub-group of the population indicates either transmission within the Thai village or shared exposure to malaria vectors outside of the village. While it is possible that malaria is imported to Thailand from Myanmar, the existence of undetected infections, coupled with an ecological setting that is conducive to malaria transmission, means that indigenous transmission could also occur on the Thai side of the border. Improved, timely, and active case detection is warranted. |
X Demographics
Geographical breakdown
Country | Count | As % |
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United States | 2 | 25% |
Australia | 1 | 13% |
Singapore | 1 | 13% |
France | 1 | 13% |
Unknown | 3 | 38% |
Demographic breakdown
Type | Count | As % |
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Members of the public | 6 | 75% |
Scientists | 2 | 25% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
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United Kingdom | 1 | 1% |
Thailand | 1 | 1% |
Unknown | 93 | 98% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Researcher | 21 | 22% |
Student > Master | 16 | 17% |
Student > Ph. D. Student | 10 | 11% |
Student > Bachelor | 7 | 7% |
Student > Doctoral Student | 4 | 4% |
Other | 19 | 20% |
Unknown | 18 | 19% |
Readers by discipline | Count | As % |
---|---|---|
Medicine and Dentistry | 22 | 23% |
Agricultural and Biological Sciences | 11 | 12% |
Nursing and Health Professions | 7 | 7% |
Social Sciences | 7 | 7% |
Biochemistry, Genetics and Molecular Biology | 4 | 4% |
Other | 21 | 22% |
Unknown | 23 | 24% |