Abstract
BackgroundThe natural history and potential impact of mosquito-specific flaviviruses on the transmission efficiency of West Nile virus (WNV) is unknown. The objective of this study was to determine whether or not prior infection with Culex flavivirus (CxFV) Izabal altered the vector competence of Cx. quinquefasciatus Say for transmission of a co-circulating strain of West Nile virus (WNV) from Guatemala.Methods and FindingsCxFV-negative Culex quinquefasciatus and those infected with CxFV Izabal by intrathoracic inoculation were administered WNV-infectious blood meals. Infection, dissemination, and transmission of WNV were measured by plaque titration on Vero cells of individual mosquito bodies, legs, or saliva, respectively, two weeks following WNV exposure. Additional groups of Cx. quinquefasciatus were intrathoracically inoculated with WNV alone or WNV+CxFV Izabal simultaneously, and saliva collected nine days post inoculation. Growth of WNV in Aedes albopictus C6/36 cells or Cx. quinquefasciatus was not inhibited by prior infection with CxFV Izabal. There was no significant difference in the vector competence of Cx. quinquefasciatus for WNV between mosquitoes uninfected or infected with CxFV Izabal across multiple WNV blood meal titers and two colonies of Cx. quinquefasciatus (p>0.05). However, significantly more Cx. quinquefasciatus from Honduras that were co-inoculated simultaneously with both viruses transmitted WNV than those inoculated with WNV alone (p = 0.0014). Co-inoculated mosquitoes that transmitted WNV also contained CxFV in their saliva, whereas mosquitoes inoculated with CxFV alone did not contain virus in their saliva.ConclusionsIn the sequential infection experiments, prior infection with CxFV Izabal had no significant impact on WNV replication, infection, dissemination, or transmission by Cx. quinquefasciatus, however WNV transmission was enhanced in the Honduras colony when mosquitoes were inoculated simultaneously with both viruses.
Highlights
The majority of the .70 recognized flaviviruses are arthropod-borne, and include some of the world’s most historically- and medically-important viruses including Yellow fever (YFV) and the Dengue (DENV) viruses
In the sequential infection experiments, prior infection with Culex flavivirus (CxFV) Izabal had no significant impact on West Nile virus (WNV) replication, infection, dissemination, or transmission by Cx. quinquefasciatus, WNV transmission was enhanced in the Honduras colony when mosquitoes were inoculated simultaneously with both viruses
Many strains of Culex flavivirus (CxFV) have been isolated from Culex pipiens L. in Japan [10], and North America [11], Culex tarsalis Coquillett throughout the western United States and Canada [11,12] (Bolling et al, unpublished data), Cx. restuans Theobald from Texas [13], and Cx. quinquefasciatus Say from Guatemala [14], the Yucatan Peninsula [15], Texas and Trinidad [13]
Summary
The majority of the .70 recognized flaviviruses (family Flaviviridae, genus Flavivirus) are arthropod-borne, and include some of the world’s most historically- and medically-important viruses including Yellow fever (YFV) and the Dengue (DENV) viruses. A number of novel flaviviruses which cluster phylogenetically with CFAV have been isolated and identified from a diversity of field-collected mosquitoes and ticks around the world, including known arbovirus vectors. These arthropodspecific viruses collectively represent a unique clade of flaviviruses and include Ngoye virus from Rhipicephalus ticks in Senegal [3], Kamiti River virus (KRV), isolated from Aedes mcintoshi Huang in. While there has been extensive genetic characterization of these viruses, the natural history and potential impact of mosquito-specific flaviviruses on the transmission efficiency of arboviruses of public health importance such as West Nile virus (WNV) remains unclear. The objective of this study was to determine whether or not prior infection with Culex flavivirus (CxFV) Izabal altered the vector competence of Cx. quinquefasciatus Say for transmission of a co-circulating strain of West Nile virus (WNV) from Guatemala
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
