Identification of Zika virus in immature phases of Aedes aegypti and Aedes albopictus: a surveillance strategy for outbreak anticipation

Abstract

A progressive increase in the circulation of arboviruses in tropical countries has been observed, accounting for 700,000 yearly deaths in the world. The main objective of this article was to identify the presence of Zika (ZIKV), dengue (DENV), and Chikungunya (CHIKV) viruses in immature stages of Aedes aegypti and Ae. albopictus. Household collections of immature phases of the vectors were carried out in the years 2015 and 2016. A total of 2902 dwellings were visited and the rate of infestation with larvae and pupae of Aedes mosquitoes was 283/1462 (19.4%) in March 2015 and 55/1440 (3.8%) in June 2015. In March 2015, 907 larvae/pupae were collected (583 or 64.3% of Ae. aegypti and 324 or 35.7% of Ae. albopictus) while in June 2015 there was a reduction in the number of immature forms found: 197 larvae/pupae (121 or 61.4% of Ae. aegypti and 76 or 38.6% of Ae. albopictus). This reduction was accompanied by a decrease in suspected human ZIKV cases from March to June 2015. The RT-qPCR performed in 18 pools identified that three (two of Ae. aegypti and one of Ae. albopictus) were positive for ZIKV, and none were positive for DENV or CHIKV. Our findings demonstrated that ZIKV was present in immature stages of insect vectors in the study region at least five months prior to the peak of ZIKV associated cases. Xenomonitoring of immature phases of the vectors may prove useful for predicting outbreaks.

Highly Efficient Vertical Transmission for Zika Virus in Aedes aegypti after Long Extrinsic Incubation Time

“…aegypti [12][13][14]. ZIKV was also repeatedly detected in eggs and larvae collected in urban and forested environments [15][16][17][18]. However, a few other studies report an absence of VT in the laboratory or lack of detection in immature stages in the field [19,20].…”

An Updated Review Of the Invasive Aedes Albopictus in the Americas; The Minimum Infection Rate Suggests That Is More Efficient in the Vertical Than Horizontal Transmission of Arboviruses

“…The dispersal of eggs and larvae of Ae. albopictus infected with dengue and Zika viruses can cause the emergence and re-emergence of arboviruses and modify the local epidemiological pattern [23,24,[27][28][29][30]32]. Transovarial transmission ensures the presence of arboviruses in Ae.…”

“…Studies carried out in North and South America have found the dengue (all serotypes), Zika and La Crosse viruses in larvae and males of Ae. albopictus [20,[23][24][25][26][27][28][29][30][31][32][33]. Evidence suggests that the mosquito may have a reservoir role for the dengue virus by keeping it silent in nature [21].…”

An Updated Review of the Invasive <em>Aedes albopictus</em> in the Americas; Geographical Distribution, Host Feeding Patterns, Arbovirus Infection, and the Potential for Vertical Transmission of Dengue Virus

“…On the other hand, the Zika virus was identified in Ae. albopictus in six studies carried out in Brazil (n = 4) and Mexico (n = 2) [14,47,53,54,57,59].…”