RALEIGH — With state officials reporting the second case of a mosquito-borne tropical virus in North Carolina in less than a month, researchers at N.C. State University are working hard to stomp out such illnesses.
The state’s second case of chikungunya (chik-en-GOON-ya) was confirmed in Alamance County on Wednesday. The first was in Forsyth County on June 12.
In both cases, the victims, neither of whom were named, had returned to the state from the Caribbean.
Chikunguna – first found in East Africa, India and the Western Pacific – has erupted across the Caribbean and South America in recent months, with more than 180,000 cases reported. In the United States, 88 cases have been reported in 22 states, Puerto Rico and the U.S. Virgin Islands combined.
Cases within the United States so far have been linked to returning travelers. The disease has not been locally transmitted.
Keeping that from happening is part of ongoing research at NCSU.
Michael Reiskind, assistant professor of entomology at NCSU, is looking into why mosquitoes become abundant in certain areas, such as North Carolina. His team is working on tracking and understanding why the Asian tiger mosquito has invaded and replaced the yellow fever mosquito here.
“The importance of this research keeps coming up because there is an emergence of new pathogens that weren’t in the United States recently,” Reiskind said. “From a public health perspective, it determines the likelihood of people getting sick and the best vector of a disease.”
North Carolina recently played host to a battleground between the Asian tiger mosquito and the yellow fever mosquito. The former, which came to the United States by laying eggs in used tires from Asia, eventually displaced most yellow fever mosquitoes along the East Coast.
In the initial Caribbean islands that saw chikungunya cases, the yellow fever mosquito was the dominant vector. But in later outbreaks, such as in Haiti, the Asian tiger mosquito acted as the primary distributor.
“If the virus becomes very well adapted to the Asian tiger mosquito, the entire East Coast could become at risk, not just Florida, where the yellow fever mosquito is still prominent,” Reiskind said.
Other NCSU research
Elsewhere at NCSU, Charles Apperson, a professor of entomology, is researching the behavior and control of mosquitoes and ticks for public health importance.
“Viruses have to incubate within mosquitoes, and they have to bite a person susceptible to the disease,” Apperson said. “The bulk of mosquitoes don’t live long enough to develop a disease.”
Apperson is working to develop a baited trap that would lure mosquitoes with dark colors and odors produced by a bacteria. Egg-laying females would rest on the sides of the trap and be exposed to an insecticide that kills them.
“We live in a ... world where we have disposable containers that make ideal habitats for mosquitoes to lay eggs in,” Apperson said. “So if we intercept them before they lay their eggs and kill them, we can prevent them from passing the disease on.”
Meanwhile, Max Scott, also a professor of entomology at NCSU, is making “transgenic insects” – insects with new gene sequences inserted into their own DNA – who will then mate and cause the female bug to die so the population cannot be maintained. Scott’s lab had worked on blowflies and is now working on transgenic mosquitoes.
About 20 years ago, most funding for this type of research came from the federal government. Today, donors and organizations such as the Bill and Melinda Gates Foundation are putting money toward research to prevent the outbreak of viral diseases.
“A lot of it is driven by the Gates Foundation in their interest in neglected tropical diseases,” Scott said. “One way you can control these diseases is by controlling the mosquitoes.”
Chikungunya can only be transmitted from a mosquito to a person, not from person to person.
“It’s moderately important that if a person comes back from the Caribbean and they have a high fever within a week to go to the doctor,” Reiskind said.
And if a person thinks he or she might be infected, precautions should be taken to avoid getting bitten by another mosquito here that could then transmit the disease to other insects and people.
“At the very least, don’t let yourself get bitten by a mosquito,” Reiskind said.
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