Everyone is at risk of mosquito bites during mosquito season. According to the Centers for Disease Control and Prevention, no vaccines or medications are available for most viruses spread by mosquitoes. The CDC described how disease epidemics are happening more often, including the recent Zika (2015-2017) and chikungunya (2013-2014) epidemics. West Nile virus in the most common virus spread my mosquitoes in the continental United States.
Researchers at the University of Missouri are trying to stop the spread of mosquito viruses by studying the molecular interactions of arthropod-borne (arbo)viruses, such as chikungunya and Zika viruses. The work is being done in the lab of Alexander Franz, an assistant professor in the Department of Veterinary Pathobiology in the MU College of Veterinary Medicine. The goal is to understand the molecular basis of mosquito vector competence for arboviruses and to develop novel strategies for interrupting the viral disease cycle in the insect.
Franz and his research team hope to one day take the virus out of the mosquito’s bite by inhibiting the genes involved with the release of the virus from within the mosquito’s stomach. This would prevent future transmission of mosquito-borne diseases.
With the help of state-of-the-art technology, they can see how a virus moves within a mosquito’s body, which could lead to the prevention of mosquitoes transmitting diseases. Three separate electron microscopes are used to view the virus traveling through the mosquito, beginning with its midgut, or stomach. The first two microscopes provided different two-dimensional views of a single layer of tissue in the mosquito’s stomach. The third, a focused ion beam electron microscope, allowed researchers to see multiple layers of tissue.
“Previously, the common understanding was that when a mosquito has picked up a virus, it first needs some time to build up inside the midgut, or stomach, before infecting other tissues in the mosquito,” said Franz. “However, our observations show that this process occurs at a much faster pace; in fact, there is only a narrow window of 32 to 48 hours between the initial infection and the virus leaving the mosquito’s stomach. For this field of research, that revelation is eye opening.”
The study, “Ultrastructural analysis of chikungunya virus dissemination from the midgut of the yellow fever mosquito, Aedes aegypti,” was published in “Viruses”.
Funding was provided by grants from the National Institutes of Health-National Institute of Allergy and Infectious Diseases and the University of Missouri award for “Excellence in Electron Microscopy.”