An Epidemic of Dengue-1 in a Remote Village in Rural Laos

Abstract

In the Lao PDR (Laos), urban dengue is an increasingly recognised public health problem. We describe a dengue-1 virus outbreak in a rural northwestern Lao forest village during the cool season of 2008. The isolated strain was genotypically “endemic” and not “sylvatic,” belonging to the genotype 1, Asia 3 clade. Phylogenetic analyses of 37 other dengue-1 sequences from diverse areas of Laos between 2007 and 2010 showed that the geographic distribution of some strains remained focal overtime while others were dispersed throughout the country. Evidence that dengue viruses have broad circulation in the region, crossing country borders, was also obtained. Whether the outbreak arose from dengue importation from an urban centre into a dengue-naïve community or crossed into the village from a forest cycle is unknown. More epidemiological and entomological investigations are required to understand dengue epidemiology and the importance of rural and forest dengue dynamics in Laos.

Co-Circulation of Dengue Virus Type 3 Genotypes in Vientiane Capital, Lao PDR

“…In Vientiane capital, our network allowed following the proportions of dengue confirmed cases and of virus serotypes in real time. Initiatives of independent research groups started providing important information on dengue phylogeny [8] . Interestingly, these data obtained in a different context, (i.e.…”

“…The second putative contributing parameter could have been a very low incidence of DENV-3 circulation at least during the past three years [5] , [8] , hence a more immunologically permissive environment for DENV-3 expansion. Retrospectively, in 2010 dengue 1 was predominant [8] whereas the year 2011 was marked by a low dengue activity. Indeed, in 2011only one DENV-3 isolate was detected in Vientiane capital through our surveillance network.…”

“…Presently, there is no national biobank of isolates that could help establish the history of dengue serotypes and genotypes in Lao PDR. The identification of the co-circulation of multiple genotypes highlights the need to maintain efforts to understand the movement and dispersal of dengue strains throughout the Indochinese peninsula [3] , [4] , [5] , [8] , [9] , [10] , [11] .…”

Effects of socio-demographic characteristics and household water management on Aedes aegypti production in suburban and rural villages in Laos and Thailand

“…The transmission of this mosquito-borne disease is considered urban, but it also occurs in rural areas [3–8]. The disease is caused by four serotypes of the dengue virus and is transmitted by two main mosquito species, Aedes aegypti and Ae.…”

Temperature and the Field Stability of a Dengue Rapid Diagnostic Test in the Tropics

“…In the Lao PDR (Laos), urban areas such as the capital, Vientiane are particularly affected but there is also good evidence of dengue virus circulation in rural Laos. 3 – 5 Dengue fever can be difficult to clinically distinguish from other common sympatric causes of fever in Laos such as scrub typhus, murine typhus, leptospirosis, typhoid, and Japanese encephalitis virus and chikungunya virus infections. 5 , 6 Approximately one-third to two-thirds of patients clinically diagnosed with dengue do not have supportive laboratory etiological evidence.…”