First detection of dengue and chikungunya viruses in natural populations of Aedes aegypti in Martinique during the 2013 - 2015 concomitant outbreak / Primera detección del virus del dengue y del chikungunya en poblaciones naturales de aedes aegypti en martinica durante el brote concomitante del 2013 al 2015

ABSTRACT Dengue and chikungunya viruses are transmitted by Aedes mosquitoes. In Martinique, an island of the French West Indies, Aedes aegypti is the suspected vector of both arboviruses; there is no Aedes albopictus on the island. During the concomitant outbreak of 2013 - 2015, the authors collected wild A. aegypti populations, and for the first time, detected dengue and chikungunya viruses in field-collected females. This paper demonstrates the mosquito's role in transmission of both dengue and chikungunya on the island, and also highlights a tool that public health authorities can use for preventing outbreaks.(AU)

RESUMEN Los virus del dengue y del chikungunya se transmiten a través de los mosquitos del género Aedes. Se da por supuesto que en Martinica, en las Antillas francesas, Aedes aegypti es el vector de ambos arbovirus, puesto que en la isla no hay Aedes albopictus. Durante el brote concomitante del 2013 al 2015, los autores recogieron muestras de poblaciones salvajes de A. aegypti y, por primera vez, detectaron virus del dengue y del chikungunya en las hembras obtenidas en el terreno. En el presente artículo se demuestra que el mosquito actúa en la isla como transmisor tanto del dengue como del chikungunya y se describe, además, una herramienta que las autoridades de salud pública pueden utilizar para prevenir los brotes.(AU)

Failure to demonstrate experimental vertical transmission of the epidemic strain of Chikungunya virus in Aedes albopictus from La Réunion Island, Indian Ocean

Aedes albopictus was responsible for transmission in the first outbreak of chikungunya (CHIK) on La Réunion Island, Indian Ocean, in 2005-2006. The magnitude of the outbreak on this island, which had been free of arboviral diseases for over 30 years, as well as the efficiency of Ae. albopictus as the main vector, raises questions about the maintenance of the CHIK virus (CHIKV) through vertical transmission mechanisms. Few specimens collected from the field as larvae were found to be infected. In this study, Ae. albopictus originating from La Réunion were orally infected with a blood-meal containing 10(8) pfu/mL of the CHIKV epidemic strain (CHIKV 06.21). Eggs from the first and second gonotrophic cycles were collected and raised to the adult stage. The infectious status of the progeny was checked (i) by immunofluorescence on head squashes of individual mosquitoes to detect the presence of viral particles or (ii) by quantitative RT-PCR on mosquito pools to detect viral RNA. We analysed a total of 1,675 specimens from the first gonotrophic cycle and 1,709 from the second gonotrophic cycle without detecting any viral particles or viral RNA. These laboratory results are compared to field records.