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Updated: Mar 13, 2026
Vector Competence Analyses on Aedes aegypti Mosquitoes using Zika Virus
Published on: May 31, 2020
Vector Competence of American Mosquitoes for Three Strains of Zika Virus
James Weger-Lucarelli1, Claudia Rückert1, Nunya Chotiwan1
1Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado.
Abstract:
In 2015, Zika virus (ZIKV; Flaviviridae; Flavivirus) emerged in the Americas, causing millions of infections in dozens of countries. The rapid spread of the virus and the association with disease outcomes such as Guillain-Barré syndrome and microcephaly make understanding transmission dynamics essential. Currently, there are no reports of vector competence (VC) of American mosquitoes for ZIKV isolates from the Americas. Further, it is not clear whether ZIKV strains from other genetic lineages can be transmitted by American Aedes aegypti populations, and whether the scope of the current epidemic is in part facilitated by viral factors such as enhanced replicative fitness or increased vector competence. Therefore, we characterized replication of three ZIKV strains, one from each of the three phylogenetic clades in several cell lines and assessed their abilities to be transmitted by Ae. aegypti mosquitoes. Additionally, laboratory colonies of different Culex spp. were infected with an American outbreak strain of ZIKV to assess VC. Replication rates were variable and depended on virus strain, cell line and MOI. African strains used in this study outcompeted the American strain in vitro in both mammalian and mosquito cell culture. West and East African strains of ZIKV tested here were more efficiently transmitted by Ae. aegypti from Mexico than was the currently circulating American strain of the Asian lineage. Long-established laboratory colonies of Culex mosquitoes were not efficient ZIKV vectors. These data demonstrate the capacity for additional ZIKV strains to infect and replicate in American Aedes mosquitoes and suggest that neither enhanced virus replicative fitness nor virus adaptation to local vector mosquitoes seems likely to explain the extent and intensity of ZIKV transmission in the Americas.
Insights
African Zika virus (ZIKV) strains replicated well in American mosquitoes, but did not explain the epidemic
Area of Science:
- Virology
- Medical Entomology
- Epidemiology
Background:
- Zika virus (ZIKV) emerged in the Americas in 2015, leading to millions of infections and severe health outcomes.
- Understanding ZIKV transmission dynamics is crucial, yet vector competence of American mosquitoes for local ZIKV strains remains uncharacterized.
- The role of viral factors, such as enhanced replicative fitness or vector competence, in the epidemic's scope is unclear.
Purpose of the Study:
- To characterize ZIKV replication in various cell lines.
- To assess the vector competence of American Aedes aegypti mosquitoes for different ZIKV strains.
- To evaluate the potential of Culex mosquitoes as ZIKV vectors.
Main Methods:
- Replication of three ZIKV strains (from different phylogenetic clades) was assessed in mammalian and mosquito cell lines.
- Vector competence of Ae. aegypti from Mexico was tested using ZIKV isolates.
- Laboratory colonies of Culex spp. were infected with an American ZIKV strain to assess vector competence.
Main Results:
- ZIKV replication varied by virus strain, cell line, and multiplicity of infection (MOI).
- African ZIKV strains demonstrated superior in vitro replication compared to the American strain.
- West and East African ZIKV strains showed higher transmission rates by Mexican Ae. aegypti than the American strain.
- Culex mosquitoes were inefficient ZIKV vectors.
Conclusions:
- American Ae. aegypti mosquitoes can be infected and support replication of diverse ZIKV strains.
- Enhanced viral replicative fitness or adaptation to local vectors does not fully explain the extensive ZIKV transmission in the Americas.
- Further research into other factors influencing ZIKV epidemiology is warranted.
