Telling the biters apart: WCU lab helps researcher with mosquito project
Don’t swat at that mosquito.
Swedish entomologist Anders Lindström is sitting in a Western Carolina University lab, patiently waiting for the insect to stay put on a leaf cutting long enough to take its photo. When the mosquito takes flight, Lindström captures it in a vial and puts it back on the leaf.
Lindström visited Cullowhee from the Swedish National Veterinary Institute the week after Thanksgiving. He was working in WCU’s Mosquito and Vector-Borne Infectious Disease Facility, which specializes in research and education about mosquito-borne diseases in Western North Carolina.
Lindström traveled to the facility to photograph two local mosquito species for a guidebook he’s creating, a project for the European Centre for Disease Control and Prevention. The publication aims to be a tool for non-entomologists to identify and report invasive mosquito species in Europe and help stop their spread across that continent.
The mosquito flies off again. And again. Lindström says he often has to offer the bloodthirsty insects a sacrificial finger as a perch to help them pose long enough for a photo.
“Usually, it’s a good way to make them sit still. But these are too young, I think. They don’t seem interested in me,” Lindström says of the American rock pool mosquito, Aedes atropalpus, he’s trying to photograph. The other mosquito species, the eastern tree hole mosquito, Aedes triseriatus, later proves more than happy to take a bite of Lindström’s finger.
The WCU facility maintains collections of many of North Carolina’s mosquito species and can make them available to researchers. Shipping the two requested mosquito species to Sweden proved impossible, so the lab hatched some for Lindström to come photograph in person. The WCU facility started its mosquito collection in 2008 and has since preserved more than 4,000 specimens representing more than 100 mosquito species from North America.
Both species are native to North Carolina and much of Eastern North America. They grow in small water pools on trees and among rocks — and in countless items that can hold a bit of water and are commonly found outside homes and businesses. They’re not native to Europe, so they will go into the guidebook as invasive species of concern.
The American rock pool mosquito has already been reported in parts of Europe, though the eastern tree hole mosquito has not. It was, however, found in a batch of used tires shipped to the continent from North America.
“They have been exterminated, at least that’s what we think,” said Lindström. “Whole tire yards were sprayed and they have been doing captures afterwards, and they have not been found again.”
Through human trade and travel, mosquitoes can be transported from continent to continent and create problems for quality of life, public health and the environment, Lindström said. He points to the Asian tiger mosquito, Aedes albopictus, and the Asian bush mosquito, Aedes japonicus, as two examples. Both were transported from Asia to North America and to Europe, where they now bite aggressively and transmit diseases.
Anders Lindström photographs a mosquito in Western Carolina University’s Mosquito and Vector-Borne Infectious Disease Facility. Tom Lotshaw/WCU photo
The tiger mosquito “is all around the Mediterranean now, and it’s spreading,” Lindström said. “It’s a really annoying mosquito that lives close to people, and we have had outbreaks of dengue, chikungunya, Zika, all the associated viruses.”
The European Centre for Disease Prevention and Control will make the mosquito guidebook available for free online and translate it into all the various European languages. The guide will include identification tips, photos and detailed illustrations. The goal, Lindström says, is to help more people observe and report invasive mosquitoes for control measures before they become well-established, problematic and more difficult, if not impossible, to eradicate from the landscape.
As in Europe, the tiger mosquito and the bush mosquito are disease-spreading invasives in North Carolina. In the United States, they’re known to transmit La Crosse Encephalitis, which most severely impacts children.
Addressing regional needs related to La Crosse Encephalitis — including education, prevention and response — is the primary mission of the Mosquito and Vector-Borne Infectious Disease Facility. The viral disease is the most common mosquito-borne disease in North Carolina and is most problematic in the western counties. According to the Centers for Disease Control and Prevention, between 2010 and 2019, 683 cases were reported in the United States — of which 180 were in North Carolina. Nearly all of those occurred in the western region.
While many infected people have no apparent symptoms, others develop severe disease affecting the nervous system, often involving inflammation of the brain and sometimes including seizures, coma and paralysis, according to the CDC. Severe disease most often affects children under the age of 16.
“We are happy to help Anders as he develops this important surveillance tool,” says Brian Byrd, an environmental health sciences professor at WCU and supervisor of WCU’s Mosquito and Vector-Borne Infectious Disease Facility. “We also understand the impacts of invasive mosquitoes, as there are two invasive Aedes species here in Western North Carolina that are known to transmit La Crosse virus — our most common mosquito-borne disease in North Carolina.”
Tom Lotshaw is a multimedia journalist within WCU’s University Communications and Marketing Office.