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Forced Salivation As a Method to Analyze Vector Competence of Mosquitoes
Published on: August 7, 2018
Vector Competence of Peruvian Mosquitoes for Two Orthobunyaviruses Isolated From Mosquitoes Captured in Peru
M J Turell1, D J Dohm1, R Fernandez2
1Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD.
Abstract:
We evaluated the potential for mosquitoes collected in the Amazon Basin, near Iquitos, Peru, to become infected with and transmit Murutucu (MURV) and Itaqui viruses (ITQV) (Order Bunyavirales, Family: Peribunyaviridae, Genus: Orthobunyavirus). Viremia levels in Syrian hamsters peaked 2 d after infection with either virus, and both viruses were highly lethal in hamsters with virtually all hamsters dying prior to 3-d postinfection. For almost all of the mosquito species tested some individuals were susceptible to infection and some developed a disseminated infection after oral exposure to either MURV or ITQV. However, only the Culex species (Culex (Culex) coronator Dyar and Knab [Diptera, Culicidae], Culex (Melanoconian) gnomatos Sallum, Huchings, and Ferreira [Diptera, Culicidae], Culex (Mel.) pedroi Sirivanakarn and Belkin [Diptera, Culicidae], and Culex (Mel.) vomerifer Komp [Diptera, Culicidae]) successfully transmitted virus by bite. However, even among these species, only about 37% of the individuals with a disseminated infection successfully transmitted these viruses, indicating a significant salivary gland barrier. Although little is known about the medical or veterinary importance of many members of the genus Orthobunyavirus, we have demonstrated that Culex spp. (Diptera, Culicidae) could be potential vectors.
Insights
Culex mosquitoes in the Amazon Basin can become infected with Murutucu virus (MURV) and Itaqui virus (ITQV). However, only certain Culex species transmitted these potentially dangerous arboviruses, indicating a significant barrier to transmission.
Area of Science:
- Arthropod-borne viruses
- Medical entomology
- Viral pathogenesis
Background:
- Murutucu virus (MURV) and Itaqui virus (ITQV) belong to the genus Orthobunyavirus.
- The medical and veterinary importance of many Orthobunyavirus species remains largely unknown.
- Understanding potential arbovirus vectors is crucial for public health in endemic regions.
Purpose of the Study:
- To evaluate the susceptibility of Amazon Basin mosquitoes to MURV and ITQV infection.
- To determine the vector competence of these mosquitoes for transmitting MURV and ITQV.
- To identify potential mosquito vectors for these understudied arboviruses.
Main Methods:
- Mosquitoes collected near Iquitos, Peru, were orally exposed to MURV or ITQV.
- Infection, dissemination, and transmission rates were assessed in various mosquito species.
- Syrian hamsters were used to determine virus lethality and viremia levels.
Main Results:
- Both MURV and ITQV were highly lethal in hamsters.
- Several mosquito species were susceptible to infection and developed disseminated infections.
- Only Culex species (Cx. coronator, Cx. gnomatos, Cx. pedroi, Cx. vomerifer) transmitted the viruses by bite, with a significant salivary gland barrier observed (37% transmission efficiency).
Conclusions:
- Culex species in the Amazon Basin are potential vectors for MURV and ITQV.
- A significant salivary gland barrier limits efficient transmission, even in susceptible mosquito species.
- Further research is needed to assess the public health impact of these Orthobunyavirus infections.
