Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand

Transmission of forest-related malaria was observed entomologically and epidemiologically for 2 transmission seasons in 1990 and 1991 in 5 villages of Mae Sariang district, Mae Hong Son Province, north-west Thailand. The entomological study included collections of mosquitos and determination of infe...

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Main Authors: Somboon P., Aramrattana A., Lines J., Webber R.
Format: Article
Language:English
Published: 2014
Online Access:http://www.ncbi.nlm.nih.gov/pubmed/3502482
http://cmuir.cmu.ac.th/handle/6653943832/3399
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Institution: Chiang Mai University
Language: English
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spelling th-cmuir.6653943832-33992014-08-30T02:26:05Z Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand Somboon P. Aramrattana A. Lines J. Webber R. Transmission of forest-related malaria was observed entomologically and epidemiologically for 2 transmission seasons in 1990 and 1991 in 5 villages of Mae Sariang district, Mae Hong Son Province, north-west Thailand. The entomological study included collections of mosquitos and determination of infection rate by using enzyme-linked immunosorbent assay in the residential villages and the farm huts. The epidemiological study included fortnightly visits to 30% of the households to interview and record movement activities and illness of villagers. Circumsporozoite proteins, in most cases of Plasmodium falciparum, were detected in Anopheles minimus species A, An. dirus s.l., An. maculatus s.s. and An. sawadwongporni in residential villages and/or farm huts, suggesting transmission could occur there. Movement of people away from their residences occurred throughout the year for several reasons with a sharp peak in July for agricultural activity, mainly ploughing and planting for rice cultivation. The relative risk of infection for people engaged in agricultural activity was 3 times that of people living in the residential villages. Although a higher biting density of vectors was generally evident at the farm huts, the estimated inoculation rates in the 2 settings were similar. Movement for forest activity increased after harvesting rice in the cool dry season and carried the highest malaria risk, suggesting different epidemiological and probably entomological conditions which need further investigation. The significance is discussed of discrepancies between the case classification system used by this study and that used by malaria sector staff. 2014-08-30T02:26:05Z 2014-08-30T02:26:05Z 1998 Journal Article 0125-1562 9740259 http://www.ncbi.nlm.nih.gov/pubmed/3502482 http://cmuir.cmu.ac.th/handle/6653943832/3399 eng
institution Chiang Mai University
building Chiang Mai University Library
country Thailand
collection CMU Intellectual Repository
language English
description Transmission of forest-related malaria was observed entomologically and epidemiologically for 2 transmission seasons in 1990 and 1991 in 5 villages of Mae Sariang district, Mae Hong Son Province, north-west Thailand. The entomological study included collections of mosquitos and determination of infection rate by using enzyme-linked immunosorbent assay in the residential villages and the farm huts. The epidemiological study included fortnightly visits to 30% of the households to interview and record movement activities and illness of villagers. Circumsporozoite proteins, in most cases of Plasmodium falciparum, were detected in Anopheles minimus species A, An. dirus s.l., An. maculatus s.s. and An. sawadwongporni in residential villages and/or farm huts, suggesting transmission could occur there. Movement of people away from their residences occurred throughout the year for several reasons with a sharp peak in July for agricultural activity, mainly ploughing and planting for rice cultivation. The relative risk of infection for people engaged in agricultural activity was 3 times that of people living in the residential villages. Although a higher biting density of vectors was generally evident at the farm huts, the estimated inoculation rates in the 2 settings were similar. Movement for forest activity increased after harvesting rice in the cool dry season and carried the highest malaria risk, suggesting different epidemiological and probably entomological conditions which need further investigation. The significance is discussed of discrepancies between the case classification system used by this study and that used by malaria sector staff.
format Article
author Somboon P.
Aramrattana A.
Lines J.
Webber R.
spellingShingle Somboon P.
Aramrattana A.
Lines J.
Webber R.
Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand
author_facet Somboon P.
Aramrattana A.
Lines J.
Webber R.
author_sort Somboon P.
title Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand
title_short Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand
title_full Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand
title_fullStr Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand
title_full_unstemmed Entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west Thailand
title_sort entomological and epidemiological investigations of malaria transmission in relation to population movements in forest areas of north-west thailand
publishDate 2014
url http://www.ncbi.nlm.nih.gov/pubmed/3502482
http://cmuir.cmu.ac.th/handle/6653943832/3399
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