Secondary vectors of Zika Virus, a systematic review of laboratory vector competence studies

Abstract

Background: After the unprecedented Zika virus (ZIKV) outbreak in the western hemisphere from 2015-2018, Aedes aegypti and Ae. albopictus are now well established primary and secondary ZIKV vectors, respectively. Consensus about identification and importance of other secondary ZIKV vectors remain. This systematic review aims to provide a list of vector species capable of transmitting ZIKV by reviewing evidence from laboratory vector competence (VC) studies and to identify key knowledge gaps and issues within the ZIKV VC literature.

Methods: A search was performed until 15th March 2022 on the Cochrane Library, Lilacs, PubMed, Web of Science, WHOLIS and Google Scholar. The search strings included three general categories: 1) "ZIKA"; 2) "vector"; 3) "competence", "transmission", "isolation", or "feeding behavior" and their combinations. Inclusion and exclusion criteria has been predefined and quality of included articles was assessed by STROBE and STROME-ID criteria.

Findings: From 8,986 articles retrieved, 2,349 non-duplicates were screened by title and abstracts,103 evaluated using the full text, and 45 included in this analysis. Main findings are 1) secondary vectors of interest include Ae. japonicus, Ae. detritus, and Ae. vexans at higher temperature 2) Culex quinquefasciatus was not found to be a competent vector of ZIKV, 3) considerable heterogeneity in VC, depending on the local mosquito strain and virus used in testing was observed. Critical issues or gaps identified included 1) inconsistent definitions of VC parameters across the literature; 2) equivalency of using different mosquito body parts to evaluate VC parameters for infection (mosquito bodies versus midguts), dissemination (heads, legs or wings versus salivary glands), and transmission (detection or virus amplification in saliva, FTA cards, transmission to neonatal mice); 3) articles that fail to use infectious virus assays to confirm the presence of live virus; 4) need for more studies using murine models with immunocompromised mice to infect mosquitoes.

Conclusion: Recent, large collaborative multi-country projects to conduct large scale evaluations of specific mosquito species represent the most appropriate approach to establish VC of mosquito species.

Fig 1. PRISMA flow diagram (adapted from Page et al. [33]) describing identification of articles examining vector competence of mosquito species other than Aedes aegypti and Aedes albopictus for Zika virus transmission.

The electronic search started on 10 November 2021 and article selection was finalized on 15 March 2022.

Fig 2. Geographic and temporal distribution of 45 vector competence studies of mosquito species other than Aedes aegypti and Aedes albopictus for Zika virus transmission included from an electronic search finalized on 15 March 2022 [78].

Figure created in ARCGIS using the following map which the information in the links claim is open source. https://www.arcgis.com/home/item.html?id=30e5fe3149c34df1ba922e6f5bbf808f https://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer/0 https://www.arcgis.com/apps/mapviewer/index.html?layers=30e5fe3149c34df1ba922e6f5bbf808f.