Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand
Abstract Background Cross-border malaria transmission is an important problem for national malaria control programmes. The epidemiology of cross-border malaria is further complicated in areas where Plasmodium falciparum and Plasmodium vivax are both endemic. By combining passive case detection data...
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doaj-046291ba00a94c9ebf71834292802c012020-11-24T21:45:40ZengBMCMalaria Journal1475-28752017-06-011611910.1186/s12936-017-1900-2Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern ThailandPatchara Sriwichai0Stephan Karl1Yudthana Samung2Kirakorn Kiattibutr3Jeeraphat Sirichaisinthop4Ivo Mueller5Liwang Cui6Jetsumon Sattabongkot7Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol UniversityPopulation Health and Immunity Division, Walter and Eliza Hall Institute of Medical ResearchDepartment of Medical Entomology, Faculty of Tropical Medicine, Mahidol UniversityDepartment of Medical Entomology, Faculty of Tropical Medicine, Mahidol UniversityBureau of Vector Borne Diseases, Pra PhuttabhatPopulation Health and Immunity Division, Walter and Eliza Hall Institute of Medical ResearchDepartment of Entomology, Pennsylvania State UniversityMahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol UniversityAbstract Background Cross-border malaria transmission is an important problem for national malaria control programmes. The epidemiology of cross-border malaria is further complicated in areas where Plasmodium falciparum and Plasmodium vivax are both endemic. By combining passive case detection data with entomological data, a transmission scenario on the northwestern Thai–Myanmar border where P. falciparum is likely driven by importation was described, whereas P. vivax is also locally transmitted. This study highlights the differences in the level of control required to eliminate P. falciparum and P. vivax from the same region. Methods Malaria case data were collected from malaria clinics in Suan Oi village, Tak Province, Thailand between 2011 and 2014. Infections were diagnosed by light microscopy. Demographic data, including migrant status, were correlated with concomitantly collected entomology data from 1330 mosquito trap nights using logistic regression. Malaria infection in the captured mosquitoes was detected by ELISA. Results Recent migrants were almost four times more likely to be infected with P. falciparum compared with Thai patients (OR 3.84, p < 0.001) and cases were significantly associated with seasonal migration. However, P. falciparum infection was not associated with the Anopheles mosquito capture rates, suggesting predominantly imported infections. In contrast, recent migrants were equally likely to present with P. vivax as mid-term migrants. Both migrant groups were twice as likely to be infected with P. vivax in comparison to the resident Thai population (OR 1.96, p < 0.001 and OR 1.94, p < 0.001, respectively). Plasmodium vivax cases were strongly correlated with age and local capture rates of two major vector species Anopheles minimus and Anopheles maculatus (OR 1.23, p = 0.020 and OR 1.33, p = 0.046, respectively), suggesting that a high level of local transmission might be causing these infections. Conclusions On the Thai–Myanmar border, P. falciparum infections occur mostly in the recent migrant population with a seasonality reflecting that of agricultural activity, rather than that of the local mosquito population. This suggests that P. falciparum was mostly imported. In contrast, P. vivax cases were significantly associated with mosquito capture rates and less with migrant status, indicating local transmission. This highlights the different timelines and requirements for P. falciparum and P. vivax elimination in the same region and underlines the importance of multinational, cross-border malaria control.http://link.springer.com/article/10.1186/s12936-017-1900-2Malaria transmissionBorder malariaMigrationMosquito infectionThailand |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Patchara Sriwichai Stephan Karl Yudthana Samung Kirakorn Kiattibutr Jeeraphat Sirichaisinthop Ivo Mueller Liwang Cui Jetsumon Sattabongkot |
spellingShingle |
Patchara Sriwichai Stephan Karl Yudthana Samung Kirakorn Kiattibutr Jeeraphat Sirichaisinthop Ivo Mueller Liwang Cui Jetsumon Sattabongkot Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand Malaria Journal Malaria transmission Border malaria Migration Mosquito infection Thailand |
author_facet |
Patchara Sriwichai Stephan Karl Yudthana Samung Kirakorn Kiattibutr Jeeraphat Sirichaisinthop Ivo Mueller Liwang Cui Jetsumon Sattabongkot |
author_sort |
Patchara Sriwichai |
title |
Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand |
title_short |
Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand |
title_full |
Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand |
title_fullStr |
Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand |
title_full_unstemmed |
Imported Plasmodium falciparum and locally transmitted Plasmodium vivax: cross-border malaria transmission scenario in northwestern Thailand |
title_sort |
imported plasmodium falciparum and locally transmitted plasmodium vivax: cross-border malaria transmission scenario in northwestern thailand |
publisher |
BMC |
series |
Malaria Journal |
issn |
1475-2875 |
publishDate |
2017-06-01 |
description |
Abstract Background Cross-border malaria transmission is an important problem for national malaria control programmes. The epidemiology of cross-border malaria is further complicated in areas where Plasmodium falciparum and Plasmodium vivax are both endemic. By combining passive case detection data with entomological data, a transmission scenario on the northwestern Thai–Myanmar border where P. falciparum is likely driven by importation was described, whereas P. vivax is also locally transmitted. This study highlights the differences in the level of control required to eliminate P. falciparum and P. vivax from the same region. Methods Malaria case data were collected from malaria clinics in Suan Oi village, Tak Province, Thailand between 2011 and 2014. Infections were diagnosed by light microscopy. Demographic data, including migrant status, were correlated with concomitantly collected entomology data from 1330 mosquito trap nights using logistic regression. Malaria infection in the captured mosquitoes was detected by ELISA. Results Recent migrants were almost four times more likely to be infected with P. falciparum compared with Thai patients (OR 3.84, p < 0.001) and cases were significantly associated with seasonal migration. However, P. falciparum infection was not associated with the Anopheles mosquito capture rates, suggesting predominantly imported infections. In contrast, recent migrants were equally likely to present with P. vivax as mid-term migrants. Both migrant groups were twice as likely to be infected with P. vivax in comparison to the resident Thai population (OR 1.96, p < 0.001 and OR 1.94, p < 0.001, respectively). Plasmodium vivax cases were strongly correlated with age and local capture rates of two major vector species Anopheles minimus and Anopheles maculatus (OR 1.23, p = 0.020 and OR 1.33, p = 0.046, respectively), suggesting that a high level of local transmission might be causing these infections. Conclusions On the Thai–Myanmar border, P. falciparum infections occur mostly in the recent migrant population with a seasonality reflecting that of agricultural activity, rather than that of the local mosquito population. This suggests that P. falciparum was mostly imported. In contrast, P. vivax cases were significantly associated with mosquito capture rates and less with migrant status, indicating local transmission. This highlights the different timelines and requirements for P. falciparum and P. vivax elimination in the same region and underlines the importance of multinational, cross-border malaria control. |
topic |
Malaria transmission Border malaria Migration Mosquito infection Thailand |
url |
http://link.springer.com/article/10.1186/s12936-017-1900-2 |
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