Study: Viral Infection May Prompt Mosquitoes to Fly Even Farther
Madison, Wisconsin - Mosquitoes carrying diseases like West Nile virus and dengue appear more likely than uninfected insects to fly around more, increasing their ability to spread the disease to humans and other animals.
The finding, based on an unusual study using microphones to measure the insects’ flight, suggests another way to control a variety of illnesses transmitted by mosquitoes.
Research by the University of Wisconsin School of Medicine and Public Health looked at two species of mosquito to see if there were changes in their flight activity based on their infection status.
“We used microphones that measure how often the mosquitoes beat their wings and lasers that detect movement,” said Dr. Rob Striker, associate professor of medicine at the UW School of Medicine and Public Health and a researcher at the UW Hospital infectious disease clinic. “These lab measurements are proxies for mosquito flight in the real world, and how often and far they can spread the viruses that they carry.”
Another recent study showed these types of viruses do change mosquito behavior, but this study is the first to address how the behavior is changed.
Results of the study were published this month in the journal Vector-Borne and Zoonotic Diseases.
The mosquitoes were exposed to protein kinase G (PKG), a substance that activates a particular behavioral pathway in mosquitoes. Striker and his research group had earlier shown this pathway was activated by insect-borne viruses such as dengue and West Nile. The pathway was known to regulate the behavior of non-disease carrying insects, but had never been used in experiments with mosquitoes.
The results showed increased wing and flight activity in mosquitoes that were given the PKG activator.
Striker said these findings could help in efforts to control mosquito-transmitted illnesses and ultimately curtail the number of West Nile virus and dengue cases that are diagnosed.
“It means that infected mosquitoes may behave differently than uninfected, flying farther and perhaps changing where mosquito-control measures are applied,” he said. “This research describes some of the steps needed for viruses to be efficiently transmitted by mosquitoes, and by knowing these steps we can better intervene to stop them.”
Striker added this pathway occurs in two different types of mosquitoes, and both carry viruses such as dengue, West Nile and malaria.
Many people infected with West Nile virus develop very mild symptoms and not even know they have an illness. However, in severe cases, the virus may cause high fever, headaches, chills, excessive sweating, fatigue, swollen lymph nodes, drowsiness and gastrointestinal problems such as nausea, vomiting, loss of appetite and diarrhea. Nationally, nearly 5,700 people were diagnosed with West Nile virus in 2012, resulting in 286 deaths.
Globally, infections from dengue, a tropical disease that may cause a high fever, severe pain in the joints, muscles and eyes, headaches, and bleeding, are increasing. It is thought at least 100 million dengue infections occur annually, resulting in 12,000 deaths, most of them women and children.
There are no vaccines to prevent West Nile virus or dengue.
Date Published: 08/15/2013