Vientiane, Laos
Vientiane, Laos

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Hiscox A.,Wageningen University | Kaye A.,London School of Hygiene and Tropical Medicine | Vongphayloth K.,Institute Pasteur du Laos | Banks I.,London School of Hygiene and Tropical Medicine | And 5 more authors.
American Journal of Tropical Medicine and Hygiene | Year: 2013

We assessed risk factors for vectors of dengue and chikungunya viruses near a new hydroelectric project, Nam Theun 2, in Laos. Immature stages of Aedes aegypti were found only in sites within 40 km of the urban provincial capital, but Aedes albopictus was found throughout. Aedes aegypti pupae were most common in water storage jars (odds ratio [OR] = 4.72) and tires (OR = 2.99), and Ae. albopictus pupae were associated with tires in 2009 (OR = 10.87) and drums, tires, and jars in 2010 (drums OR = 3.05; tires OR = 3.45, jars OR = 6.59). Compared with water storage vessels, containers used for hygiene, cooking, and drinking were 80%less likely to harbor Ae. albopictus pupae in 2010 (OR = 0.20), and discarded waste was associated with a 3.64 increased odds of infestation. Vector control efforts should focus on source reduction of water storage containers, particularly concrete jars and tires. Copyright © 2013 by The American Society of Tropical Medicine and Hygiene.


Hiscox A.,Institute Pasteur du Laos | Hiscox A.,London School of Hygiene and Tropical Medicine | Khammanithong P.,Khammouane Provincial Health Office | Kaul S.,Nam Theun 2 Power Company | And 5 more authors.
PLoS ONE | Year: 2013

Background:Construction of the Nam Theun 2 hydroelectric project and flooding of a 450 km2 area of mountain plateau in south-central Lao PDR resulted in the resettlement of 6,300 people to newly built homes. We examined whether new houses would have altered risk of house entry by mosquitoes compared with traditional homes built from poorer construction materials.Methodology/Principal Findings:Surveys were carried out in the Nam Theun 2 resettlement area and a nearby traditional rice farming area in 2010. Mosquitoes were sampled in bedrooms using CDC light traps in 96 resettlement houses and 96 traditional houses and potential risk factors for mosquito house entry were recorded. Risk of mosquito house entry was more than twice as high in traditional bamboo houses compared with those newly constructed from wood (Putative Japanese Encephalitis (JE) vector incidence rate ratio (IRR) = 2.26, 95% CI 1.38-3.70, P = 0.001; Anopheline IRR = 2.35, 95% CI: 1.30-4.23, P = 0.005). Anophelines were more common in homes with cattle compared against those without (IRR = 2.32, 95% CI: 1.29-4.17, P = 0.005).Wood smoke from cooking fires located under the house or indoors was found to be protective against house entry by both groups of mosquito, compared with cooking in a separate room beside the house (Putative JE vector IRR = 0.43, 95% CI: 0.26-0.73, P = 0.002; Anopheline IRR = 0.22, 95% CI: 0.10-0.51, P<0.001).Conclusions/Significance:Construction of modern wooden homes should help reduce human-mosquito contact in the Lao PDR. Reduced mosquito contact rates could lead to reduced transmission of diseases such as JE and malaria. Cattle ownership was associated with increased anopheline house entry, so zooprophylaxis for malaria control is not recommended in this area. Whilst wood smoke was protective against putative JE vector and anopheline house entry we do not recommend indoor cooking since smoke inhalation can enhance respiratory disease. © 2013 Hiscox et al.


Hiscox A.,London School of Hygiene and Tropical Medicine | Hiscox A.,Institute Pasteur du Laos | Winter C.H.,National Center for Laboratory and Epidemiology | Vongphrachanh P.,National Center for Laboratory and Epidemiology | And 11 more authors.
American Journal of Tropical Medicine and Hygiene | Year: 2010

A large-scale cross-sectional seroprevalence study of dengue (DEN) and Japanese encephalitis (JE) was conducted in Khammouane province, Lao PDR, as part of the initial baseline health impact assessment of the Nam Theun 2 hydroelectric dam construction project. Health surveys were performed between May 2007 and February 2008 with serum samples collected from healthy individuals involved in the resettlement program of 16 villages (total surveyed population 4,369). Hemagglutination inhibition assay using flavivirus antigens (DENV1, DENV3, and JEV) performed on 1,708 plasma specimens revealed 30.4% (519) cross-reactive positives, and 10% (172) and 1.3% (22) positives to JEV or DENV, respectively. Entomological surveys conducted during the rainy season of 2008 indicated the presence of competent flavivirus vectors (Culex vishnui group and Aedes albopictus), although Aedes aegypti was not found. Continued surveillance and investigation is warranted to assess the clinical disease burden of flaviviruses in this area that is undergoing rapid ecological and demographic change. Copyright © 2010 by The American Society of Tropical Medicine and Hygiene.


Visser T.A.M.,Nam Theun 2 Power Company | Ovenden M.,Nam Theun 2 Power Company | Wongwai N.,Nam Theun 2 Power Company
Hydroecologie Appliquee | Year: 2016

The approach of Fish Catch Monitoring of the Nam Theun 2 hydro power project area is documented and describes the fish catch monitoring methodologies implemented for the period from 2006-2014 with special emphasis on changes in the methods and how data collection has evolved in the Xe Bangfai basin.The collected data aimed at documenting changes in the fisheries (e.g. habitat use, daily household catch, gear use and effort) before and after commencement of electricity generation. The methods used rely on social research methods, i.e. recall surveys and household catch logbooks that are provided and maintained by fishermen. The panel survey has demonstrated is appropriateness to monitor and document changes in the fisheries over time with a high level of confidence at relatively low cost. The households participating in the panel remained relatively stable throughout the survey period. The method tends to overestimate fish catches and under estimate the collection of other aquatic animals. The level of effort (fishing days) is consistent between different surveys. The monitoring results provide a good understanding of trends and changes in the fisheries. © EDF, 2014.

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