Chikungunya virus emergence in the Lao PDR, 2012–2013

Somlor, Somphavanh; Vongpayloth, Khamsing; Diancourt, Laure; Buchy, Philippe; Duong, Veasna; Phonekeo, Darouny; Ketmayoon, Pakapak; Vongphrachanh, Phengta; Brey, Paul T.; Caro, Valérie; Buisson, Y.; Grandadam, Marc

doi:10.1371/journal.pone.0189879

Cited by 15 publications

(35 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This study is a first step in filling this gap by providing genetic and epidemiologic information on the first DENV-4 epidemic recorded in Lao PDR. The progressive increase of DENV-4 burden occurred in a context of the co-circulation of different DENV serotypes previously described and maintained over the eight years of surveillance (i.e., 2012–2019) [ 29 , 30 , 31 ]. Since 2009, DENV-4 circulated sporadically in the country [ 29 , 30 ].…”

Section: Discussionmentioning

confidence: 99%

“…Only sporadic cases have been detected in villages located around Vientiane Capital in 2006–2007 [ 30 ]. In 2012, an integrated arbovirus surveillance system, involving virologists and medical entomologists, was set up in Vientiane Capital by the Institut Pasteur du Laos and was gradually extended to different provinces in Lao PDR for the detection and monitoring of arbovirus epidemics [ 19 , 20 , 31 ]. This surveillance system detected DENV-4 transmission in 2013 in Vientiane Capital’s suburban areas and subsequently its spread into the different districts of the city and then throughout the country.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Trends of the Dengue Serotype-4 Circulation with Epidemiological, Phylogenetic, and Entomological Insights in Lao PDR between 2015 and 2019

Calvez¹,

Pommelet²,

Somlor³

et al. 2020

Pathogens

Self Cite

View full text Add to dashboard Cite

Dengue outbreaks have regularly been recorded in Lao People’s Democratic Republic (PDR) since the first detection of the disease in 1979. In 2012, an integrated arbovirus surveillance network was set up in Lao PDR and an entomological surveillance has been implemented since 2016 in Vientiane Capital. Here, we report a study combining epidemiological, phylogenetic, and entomological analyzes during the largest DENV-4 epidemic ever recorded in Lao PDR (2015–2019). Strikingly, from 2015 to 2019, we reported the DENV-4 emergence and spread at the country level after two large epidemics predominated by DENV-3 and DENV-1, respectively, in 2012–2013 and 2015. Our data revealed a significant difference in the median age of the patient infected by DENV-4 compared to the other serotypes. Phylogenetic analysis demonstrated the circulation of DENV-4 Genotype I at the country level since at least 2013. The entomological surveillance showed a predominance of Aedesaegypti compared to Aedesalbopictus and high abundance of these vectors in dry and rainy seasons between 2016 and 2019, in Vientiane Capital. Overall, these results emphasized the importance of an integrated approach to evaluate factors, which could impact the circulation and the epidemiological profile of dengue viruses, especially in endemic countries like Lao PDR.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Trends of the Dengue Serotype-4 Circulation with Epidemiological, Phylogenetic, and Entomological Insights in Lao PDR between 2015 and 2019

Calvez¹,

Pommelet²,

Somlor³

et al. 2020

Pathogens

Self Cite

View full text Add to dashboard Cite

show abstract

“…The incidence of DENV and CHIKV are becoming more common in Lao PDR with active circulation of dengue within SEA [ 48 ], highlighting that favourable conditions for their transmission exists. These diseases will continue to be important health concern for the region [ 38 , 45 , 48 – 50 ]. The control of arboviral diseases in Lao PDR depends on vaccines for Japanese encephalitis, early alert systems using appropriate diagnosis, and mostly on the use of insecticides in areas where people live.…”

Section: Introductionmentioning

confidence: 99%

Bionomics and insecticide resistance of the arboviral vector Aedes albopictus in northern Lao PDR

et al. 2018

Self Cite

View full text Add to dashboard Cite

In the last four decades there has been a staggering increase in the geographical range of the arboviral vector Aedes albopictus (Skuse, 1894). This species is now found in every continent except Antarctica, increasing the distribution of arboviral diseases such as dengue and chikungunya. In Lao PDR dengue epidemics occur regularly, with cases of chikungunya also reported. As treatment methods for arboviral diseases is limited, the control of the vector mosquitoes are essential. There is a paucity of information on the bionomics and resistance status of this mosquito for successful vector control efforts. Here we describe the bionomics and insecticide resistance status of Ae. albopictus in Laos to identify opportunities for control. Adult Ae. albopictus were collected using human-baited double bed net (HDN) traps in forests, villages and rubber plantations and tested for alpha- and flaviviruses with RT-PCR. Surveys were also conducted to identify larval habitats. Seven adult and larval populations originating from Vientiane Capital and Luang Prabang province were tested against DDT, malathion, permethrin, deltamethrin and, temephos following WHO protocols. Aedes albopictus were found throughout the year, but were six-fold greater in the rainy season than the dry season. Adult females were active for 24 hours, with peak of behaviour at 18.00 h. The secondary forest and rubber plantation samples showed evidence of Pan-flaviviruses, while samples from the villages did not. More than half of the emerged Ae. albopictus were collected from mature rubber plantations (53.9%; 1,533/2,845). Most Ae. albopictus mosquitoes emerged from latex collection cups (19.7%; 562/2,845), small water containers (19.7%; 562/2,845) and tyres (17.4%; 495/2,845). Adult mosquitoes were susceptible to pyrethroids, apart from one population in Vientiane city. All populations were resistant to DDT (between 27–90% mortality) and all except one were resistant to malathion (20–86%). Three of the seven larval populations were resistant to temephos (42–87%), with suspected resistance found in three other populations (92–98%).This study demonstrates that rural areas in northern Laos are potential hot spots for arboviral disease transmission. Multiple-insecticide resistance was found. Aedes albopictus control efforts in villages need to expand to include secondary forests and rubber plantations, with larval source management and limited use of insecticides.

show abstract

“…In 2012, an arbovirus laboratory surveillance system was set up in the capital city of Vientiane to improve arboviral diagnosis and prevention in the country [5,9,10]. Since 2012, the Vientiane Capital Province has experienced two major DENV epidemics, first with a predominance of DENV-3 in 2012-2013 and then DENV-4 from the end of 2014 to end of 2018 [4,5,9,11].…”

Section: Introductionmentioning

confidence: 99%

Rapid genotyping protocol to improve dengue virus serotype 2 survey in Lao PDR

Calvez¹,

Somlor²,

Viengphouthong³

et al. 2020

PLoS ONE

Self Cite

View full text Add to dashboard Cite

Dengue fever is one of the major public health problems in Lao PDR. Over the last decade, dengue virus (DENV) epidemics were characterized by a novel predominant serotype accompanied by at least two other serotypes. Since 2008, DENV-2 circulated at a low level in Lao PDR but its epidemiologic profile changed at the end of 2018. Indeed, the number of confirmed DENV-2 cases suddenly increased in October 2018 and DENV-2 became predominant at the country level in early 2019. We developed a Genotype Screening Protocol (GSP) to determine the origin(s) of the Lao DENV-2 and study their genetic polymorphism. With a good correlation with full envelope gene sequencing data, this molecular epidemiology tool evidence the co-circulation of two highly polymorphic DENV-2 genotypes, i.e. Asian I and Cosmopolitan genotypes, over the last five years, suggesting multiple introductions of DENV-2 in the country. GSP approach provides relevant first line information that may help countries with limited laboratory resources to reinforce their capabilities to DENV-2 and to follow the epidemics progresses and assess situations at the regional level.

show abstract

Chikungunya virus emergence in the Lao PDR, 2012–2013

Cited by 15 publications

References 40 publications

Trends of the Dengue Serotype-4 Circulation with Epidemiological, Phylogenetic, and Entomological Insights in Lao PDR between 2015 and 2019

Trends of the Dengue Serotype-4 Circulation with Epidemiological, Phylogenetic, and Entomological Insights in Lao PDR between 2015 and 2019

Bionomics and insecticide resistance of the arboviral vector Aedes albopictus in northern Lao PDR

Rapid genotyping protocol to improve dengue virus serotype 2 survey in Lao PDR

Contact Info

Product

Resources

About