Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR
Abstract Background In the Lao PDR, malaria morbidity and mortality have remarkably decreased over the past decade. However, asymptomatic infections in rural villages contribute to the on-going local transmission. The primary objective of this study was to explore the characteristics of infections i...
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doaj-f08ce8726d9444afb0704983040a97b52020-11-24T21:41:37ZengBMCMalaria Journal1475-28752016-10-0115111110.1186/s12936-016-1552-7Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDRTiengkham Pongvongsa0Daisuke Nonaka1Moritoshi Iwagami2Masami Nakatsu3Panom Phongmany4Futoshi Nishimoto5Jun Kobayashi6Bouasy Hongvanthon7Paul T. Brey8Kazuhiko Moji9Toshihiro Mita10Shigeyuki Kano11Savannakhet Provincial Health DepartmentSATREPS Project for Parasitic DiseasesSATREPS Project for Parasitic DiseasesSATREPS Project for Parasitic DiseasesSavannakhet Provincial Health DepartmentGraduate School of Tropical Medicine and Global Health, Nagasaki UniversitySATREPS Project for Parasitic DiseasesSATREPS Project for Parasitic DiseasesSATREPS Project for Parasitic DiseasesGraduate School of Tropical Medicine and Global Health, Nagasaki UniversityDepartment of Molecular and Cellular Parasitology, School of Medicine, Juntendo UniversitySATREPS Project for Parasitic DiseasesAbstract Background In the Lao PDR, malaria morbidity and mortality have remarkably decreased over the past decade. However, asymptomatic infections in rural villages contribute to the on-going local transmission. The primary objective of this study was to explore the characteristics of infections in a malaria-endemic district of the Lao PDR. The specific objectives were to investigate the prevalence and species of malaria parasites using molecular methods and to assess individual and household parasite levels and the characteristics associated with malaria infection. Methods The study population included 870 participants from 236 households in 10 villages of the Xepon district. Interviews, blood examinations and body temperature measurements were conducted between August and September 2013. A multilevel logistic regression model, with adjustment for clustering effects, was used to assess the association between predictor variables and an outcome variable (malaria infection status as principally determined by PCR). The predictive factors included individual-level factors (age, gender, past fever episode, and forest activity during night time) and household-level factors (household member size, household bed net usage/density and a household with one other malaria-infected member). Results Fifty-two participants (including 26 children) tested positive (positive rate: 6.0 %): Plasmodium falciparum mono-infection was the most common infection (n = 41, 78.8 %), followed by P. falciparum and Plasmodium vivax mixed infections (n = 9, 17.3 %). The majority of infected participants (n = 42, 80.8 %) had no fever episodes in the two previous weeks or a measurable fever (>37 °C) at the time of survey. Living in a household with one other malaria-infected member significantly increased the odds of infection (odds ratio 24.33, 95 % confidence interval 10.15–58.32). Among the 40 households that had at least one infected member, nine households were responsible for 40.4 % of the total infections. Conclusions Plasmodium vivax was detected more frequently than it was reported from the district hospital. Most infections were asymptomatic and sub-microscopic and were highly clustered within households. To further eliminate malaria in Xepon and other similar settings in the country, the National Malaria Control Programme should consider household-based strategies, including reactive case detection targeting the household members of index cases.http://link.springer.com/article/10.1186/s12936-016-1552-7Asymptomatic infectionsSub-microscopic infectionsMalaria eliminationActive case detectionLaos |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Tiengkham Pongvongsa Daisuke Nonaka Moritoshi Iwagami Masami Nakatsu Panom Phongmany Futoshi Nishimoto Jun Kobayashi Bouasy Hongvanthon Paul T. Brey Kazuhiko Moji Toshihiro Mita Shigeyuki Kano |
spellingShingle |
Tiengkham Pongvongsa Daisuke Nonaka Moritoshi Iwagami Masami Nakatsu Panom Phongmany Futoshi Nishimoto Jun Kobayashi Bouasy Hongvanthon Paul T. Brey Kazuhiko Moji Toshihiro Mita Shigeyuki Kano Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR Malaria Journal Asymptomatic infections Sub-microscopic infections Malaria elimination Active case detection Laos |
author_facet |
Tiengkham Pongvongsa Daisuke Nonaka Moritoshi Iwagami Masami Nakatsu Panom Phongmany Futoshi Nishimoto Jun Kobayashi Bouasy Hongvanthon Paul T. Brey Kazuhiko Moji Toshihiro Mita Shigeyuki Kano |
author_sort |
Tiengkham Pongvongsa |
title |
Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR |
title_short |
Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR |
title_full |
Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR |
title_fullStr |
Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR |
title_full_unstemmed |
Household clustering of asymptomatic malaria infections in Xepon district, Savannakhet province, Lao PDR |
title_sort |
household clustering of asymptomatic malaria infections in xepon district, savannakhet province, lao pdr |
publisher |
BMC |
series |
Malaria Journal |
issn |
1475-2875 |
publishDate |
2016-10-01 |
description |
Abstract Background In the Lao PDR, malaria morbidity and mortality have remarkably decreased over the past decade. However, asymptomatic infections in rural villages contribute to the on-going local transmission. The primary objective of this study was to explore the characteristics of infections in a malaria-endemic district of the Lao PDR. The specific objectives were to investigate the prevalence and species of malaria parasites using molecular methods and to assess individual and household parasite levels and the characteristics associated with malaria infection. Methods The study population included 870 participants from 236 households in 10 villages of the Xepon district. Interviews, blood examinations and body temperature measurements were conducted between August and September 2013. A multilevel logistic regression model, with adjustment for clustering effects, was used to assess the association between predictor variables and an outcome variable (malaria infection status as principally determined by PCR). The predictive factors included individual-level factors (age, gender, past fever episode, and forest activity during night time) and household-level factors (household member size, household bed net usage/density and a household with one other malaria-infected member). Results Fifty-two participants (including 26 children) tested positive (positive rate: 6.0 %): Plasmodium falciparum mono-infection was the most common infection (n = 41, 78.8 %), followed by P. falciparum and Plasmodium vivax mixed infections (n = 9, 17.3 %). The majority of infected participants (n = 42, 80.8 %) had no fever episodes in the two previous weeks or a measurable fever (>37 °C) at the time of survey. Living in a household with one other malaria-infected member significantly increased the odds of infection (odds ratio 24.33, 95 % confidence interval 10.15–58.32). Among the 40 households that had at least one infected member, nine households were responsible for 40.4 % of the total infections. Conclusions Plasmodium vivax was detected more frequently than it was reported from the district hospital. Most infections were asymptomatic and sub-microscopic and were highly clustered within households. To further eliminate malaria in Xepon and other similar settings in the country, the National Malaria Control Programme should consider household-based strategies, including reactive case detection targeting the household members of index cases. |
topic |
Asymptomatic infections Sub-microscopic infections Malaria elimination Active case detection Laos |
url |
http://link.springer.com/article/10.1186/s12936-016-1552-7 |
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