The mosquito that most commonly carries the Zika virus is not very common in North Carolina, according to a study by university researchers this summer.
Researchers collected 17,000 mosquito eggs at 16 sites across the state to determine the mosquito species that live in North Carolina and failed to turn up any Aedes aegypti, the yellow fever mosquito that is considered the dominant carrier of the Zika virus.
“Seventeen thousand may not sound like a lot, but it is a large sample set,” said Dr. Carl Williams, the Public Health Veterinarian at the state Department of Health and Human Services. “Not finding any Aedes aegypti shows they are not very common.”
DHHS enlisted entomology professors from N.C. State University, East Carolina University and Western Carolina University to conduct the mosquito study. While they didn’t find the most common carrier of Zika, they did find a significant number of eggs for Aedes albopictus or the Asian Tiger mosquito, a species that infects people with the Zika virus less frequently than Aedes aegypti.
Surveillance by the universities was funded by the U.S. Centers for Disease Control and Prevention and will continue until the end of mosquito season in October. The state hopes to secure more CDC funding for additional surveillance projects and a mosquito control protocol funded by the Federal Emergency Management Authority or FEMA.
Zika became a global concern in December, after the World Health Organization advised expecting mothers to cancel travel plans to Central and South America. The warning came after a quick rise in microcephaly, a condition marked by proportionally small heads and limited brain function, in children born to mothers in Brazil who were sick with Zika. Only about one in five people infected with Zika actually get sick, according to the CDC, and then the symptoms most commonly resemble the flu, including fever, rash, joint pain and conjunctivitis or red eyes.
There have been 18 confirmed cases of Zika in North Carolina as of July 20, all of them thought to have been contracted outside the continental United States, according to the CDC. State and federal officials are investigating two cases in southern Florida that may have been transmitted locally, but otherwise all cases in the continental U.S. so far are considered travel related.
The threat of Zika prompted the state to hire two entomologists to oversee mosquito surveillance and a control program. DHHS began seeking two entomologists in March, and Williams says the positions should be filled soon. He said “the project led by university entomologists was tremendously helpful to get surveillance done,” but that the department needs to recruit its own.
Scientists are working on a vaccine for Zika. Among them is Dr. Sallie Permar, a Duke pediatrician specializing in illnesses contracted by children before birth. Last month, Permar said her vaccine had protected pregnant apes and their babies from Zika.
On June 21, the U.S. Food and Drug Administration approved the first human clinical trials for a Zika vaccine developed by a joint research team from the University of Pennsylvania and Université Laval in Quebec, Canada. Dr. David Weiner, lead researcher in the University of Pennsylvania group, said late last week that dosing of human subjects will begin “pretty quickly.” The vaccine has been tested on several animal species but not on pregnant animals.
Until a Zika vaccine is perfected, the state DHHS recommends following guidelines to remove breeding grounds for mosquitoes. They include keeping doors and windows closed, because Aedes aegypti commonly lays eggs indoors, and removing standing water from your home and backyard. Further guidelines can be found in the Zika toolkit on the CDC website, www.cdc.gov.
Williams emphasizes that mosquitoes carrying Zika are not the most likely danger from insects. He says “tick-borne diseases are literally orders of magnitude more common in North Carolina” than mosquito-borne ones. He says preventative measures such as bug spray are an easy and effective way to keep yourself safe from Zika and more common diseases like Lyme disease carried by ticks.
Stephen Ginley: 919-829-4520