Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia
Abstract Background Malaria transmission is highly heterogeneous, especially in low endemic countries, such as Cambodia. This results in geographical clusters of residual transmission in the dry, low transmission season, which can fuel the transmission to wider areas or populations during the wet se...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2016-10-01
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| Series: | Malaria Journal |
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| Online Access: | http://link.springer.com/article/10.1186/s12936-016-1558-1 |
| _version_ | 1818836400338894848 |
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| author | Karen Kerkhof Vincent Sluydts Somony Heng Saorin Kim Myrthe Pareyn Laura Willen Lydie Canier Siv Sovannaroth Didier Ménard Tho Sochantha Marc Coosemans Lies Durnez |
| author_facet | Karen Kerkhof Vincent Sluydts Somony Heng Saorin Kim Myrthe Pareyn Laura Willen Lydie Canier Siv Sovannaroth Didier Ménard Tho Sochantha Marc Coosemans Lies Durnez |
| author_sort | Karen Kerkhof |
| collection | DOAJ |
| description | Abstract Background Malaria transmission is highly heterogeneous, especially in low endemic countries, such as Cambodia. This results in geographical clusters of residual transmission in the dry, low transmission season, which can fuel the transmission to wider areas or populations during the wet season. A better understanding of spatial clustering of malaria can lead to a more efficient, targeted strategy to reduce malaria transmission. This study aims to evaluate the potential of the use of serological markers to define spatial patterns in malaria exposure. Methods Blood samples collected in a community-based randomized trial performed in 98 high endemic communities in Ratanakiri province, north-eastern Cambodia, were screened with a multiplex serological assay for five serological markers (three Plasmodium falciparum and two Plasmodium vivax). The antibody half-lives range from approximately six months until more than two years. Geographical heterogeneity in malaria transmission was examined using a spatial scan statistic on serology, PCR prevalence and malaria incidence rate data. Furthermore, to identify behavioural patterns or intrinsic factors associated with malaria exposure (antibody levels), risk factor analyses were performed by using multivariable random effect logistic regression models. The serological outcomes were then compared to PCR prevalence and malaria incidence data. Results A total of 6502 samples from two surveys were screened in an area where the average parasite prevalence estimated by PCR among the selected villages is 3.4 %. High-risk malaria pockets were observed adjacent to the ‘Tonle San River’ and neighbouring Vietnam for all three sets of data (serology, PCR prevalence and malaria incidence rates). The main risk factors for all P. falciparum antigens and P. vivax MSP1.19 are age, ethnicity and staying overnight at the plot hut. Conclusion It is possible to identify similar malaria pockets of higher malaria transmission together with the potential risk factors by using serology instead of PCR prevalence or malaria incidence data. In north-eastern Cambodia, the serological markers show that malaria transmission occurs mainly in adults staying overnight in plot huts in the field. Pf.GLURP.R2 showed a shrinking pocket of malaria transmission over time, and Pf.MSP1.19, CSP, PvAMA1 were also informative for current infection to a lesser extent. Therefore, serology could contribute in future research. However, further in-depth research in selecting the best combination of antigens is required. |
| first_indexed | 2024-12-19T03:06:00Z |
| format | Article |
| id | doaj.art-430e63a1e826484281cc02a786a7e1f6 |
| institution | Directory Open Access Journal |
| issn | 1475-2875 |
| language | English |
| last_indexed | 2024-12-19T03:06:00Z |
| publishDate | 2016-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Malaria Journal |
| spelling | doaj.art-430e63a1e826484281cc02a786a7e1f62022-12-21T20:38:06ZengBMCMalaria Journal1475-28752016-10-0115111510.1186/s12936-016-1558-1Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, CambodiaKaren Kerkhof0Vincent Sluydts1Somony Heng2Saorin Kim3Myrthe Pareyn4Laura Willen5Lydie Canier6Siv Sovannaroth7Didier Ménard8Tho Sochantha9Marc Coosemans10Lies Durnez11Department of Biomedical Sciences, Institute of Tropical MedicineDepartment of Biomedical Sciences, Institute of Tropical MedicineNational Centre for Parasitology, Entomology and Malaria ControlMolecular Epidemiology Unit, Institut Pasteur du CambodgeDepartment of Biomedical Sciences, Institute of Tropical MedicineDepartment of Biomedical Sciences, Institute of Tropical MedicineMolecular Epidemiology Unit, Institut Pasteur du CambodgeNational Centre for Parasitology, Entomology and Malaria ControlMolecular Epidemiology Unit, Institut Pasteur du CambodgeNational Centre for Parasitology, Entomology and Malaria ControlDepartment of Biomedical Sciences, Institute of Tropical MedicineDepartment of Biomedical Sciences, Institute of Tropical MedicineAbstract Background Malaria transmission is highly heterogeneous, especially in low endemic countries, such as Cambodia. This results in geographical clusters of residual transmission in the dry, low transmission season, which can fuel the transmission to wider areas or populations during the wet season. A better understanding of spatial clustering of malaria can lead to a more efficient, targeted strategy to reduce malaria transmission. This study aims to evaluate the potential of the use of serological markers to define spatial patterns in malaria exposure. Methods Blood samples collected in a community-based randomized trial performed in 98 high endemic communities in Ratanakiri province, north-eastern Cambodia, were screened with a multiplex serological assay for five serological markers (three Plasmodium falciparum and two Plasmodium vivax). The antibody half-lives range from approximately six months until more than two years. Geographical heterogeneity in malaria transmission was examined using a spatial scan statistic on serology, PCR prevalence and malaria incidence rate data. Furthermore, to identify behavioural patterns or intrinsic factors associated with malaria exposure (antibody levels), risk factor analyses were performed by using multivariable random effect logistic regression models. The serological outcomes were then compared to PCR prevalence and malaria incidence data. Results A total of 6502 samples from two surveys were screened in an area where the average parasite prevalence estimated by PCR among the selected villages is 3.4 %. High-risk malaria pockets were observed adjacent to the ‘Tonle San River’ and neighbouring Vietnam for all three sets of data (serology, PCR prevalence and malaria incidence rates). The main risk factors for all P. falciparum antigens and P. vivax MSP1.19 are age, ethnicity and staying overnight at the plot hut. Conclusion It is possible to identify similar malaria pockets of higher malaria transmission together with the potential risk factors by using serology instead of PCR prevalence or malaria incidence data. In north-eastern Cambodia, the serological markers show that malaria transmission occurs mainly in adults staying overnight in plot huts in the field. Pf.GLURP.R2 showed a shrinking pocket of malaria transmission over time, and Pf.MSP1.19, CSP, PvAMA1 were also informative for current infection to a lesser extent. Therefore, serology could contribute in future research. However, further in-depth research in selecting the best combination of antigens is required.http://link.springer.com/article/10.1186/s12936-016-1558-1MalariaSerological markersGeographical patternsMalaria pocketsHeterogeneous transmissionCambodia |
| spellingShingle | Karen Kerkhof Vincent Sluydts Somony Heng Saorin Kim Myrthe Pareyn Laura Willen Lydie Canier Siv Sovannaroth Didier Ménard Tho Sochantha Marc Coosemans Lies Durnez Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia Malaria Journal Malaria Serological markers Geographical patterns Malaria pockets Heterogeneous transmission Cambodia |
| title | Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia |
| title_full | Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia |
| title_fullStr | Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia |
| title_full_unstemmed | Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia |
| title_short | Geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in Ratanakiri, Cambodia |
| title_sort | geographical patterns of malaria transmission based on serological markers for falciparum and vivax malaria in ratanakiri cambodia |
| topic | Malaria Serological markers Geographical patterns Malaria pockets Heterogeneous transmission Cambodia |
| url | http://link.springer.com/article/10.1186/s12936-016-1558-1 |
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