Low Transmission of Chikungunya Virus by Aedes aegypti from Vientiane Capital, Lao PDR

Abstract

In 2012–2013, chikungunya virus (CHIKV) was the cause of a major outbreak in the southern part of Lao People’s Democratic Republic (Lao PDR). Since then, only a few imported cases, with isolates belonging to different lineages, were recorded between 2014 and 2020 in Vientiane capital and few autochthonous cases of ECSA-IOL lineage were detected in the south of the country in 2020. The CHIKV epidemiological profile contrasts with the continuous and intensive circulation of dengue virus in the country, especially in Vientiane capital. The study’s aim was to investigate the ability of the local field-derived Aedes aegypti population from Vientiane capital to transmit the Asian and ECSA-IOL lineages of CHIKV. Our results revealed that, for both CHIKV lineages, infection rates were low and dissemination rates were high. The transmission rates and efficiencies evidenced a low vector competence for the CHIKV tested. Although this population of Ae. aegypti showed a relatively modest vector competence for these two CHIKV lineages, several other factors could influence arbovirus emergence such as the longevity and density of female mosquitoes. Due to the active circulation of CHIKV in Southeast Asia, investigations on these factors should be done to prevent the risk of CHIKV emergence and spread in Lao PDR and neighboring countries.

The High Capacity of Brazilian Aedes aegypti Populations to Transmit a Locally Circulating Lineage of Chikungunya Virus

“…In Brazil, the main vectors associated with the transmission of these CHIKV lineages are the mosquitoes Aedes aegypti and Aedes albopictus , both of which are widely distributed across the country [ 7 ]. Previous studies have shown that these two Aedes species are competent vectors for both the ECSA and Asian lineages across different regions of the world [ 13 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. However, in Brazil, the impact of locally circulating CHIKV genotypes and specific combinations of local Aedes aegypti populations on the vector competence has not been thoroughly examined.…”

High capacity of BrazilianAedes aegyptipopulations to transmit a locally circulating lineage of Chikungunya virus

“…In Brazil, the main vectors associated with the transmission of these CHIKV lineages are the mosquitoes Aedes aegypti and Aedes albopictus, both of which are widely distributed across the country [14,18,20,29]. Previous studies have shown that these two Aedes species are competent vectors for both the ECSA and Asian lineages across different world regions [15,[29][30][31][32][33][34][35][36].…”

Biology, Control and Zoonotic Role of Disease Vectors

“…However, they had no effect on egg numbers but did significantly reduce the survival time and hatching rate. Claver et al [ 8 ] reported relatively modest vector competence for Aedes aegypti in Vientiane, Lao PDR, to transmit the Asian and ECSA-IOL lineages of chikungunya virus, which may be influenced by the longevity and density of female mosquitoes. Leandro et al [ 9 ] evaluated the spatial and temporal association between vector infestation and the occurrence of dengue cases and reported a dynamic pattern indicating significant risks in certain areas of Foz do Iguaçu, Brazil, based on the entomological–virological index, while entomological indices were not effective in measuring dengue risk.…”