Newswise — Researchers at New Mexico State University have received a second contract from the New Mexico Department of Health to expand last summer’s project to map the geographic distribution of mosquitoes that can carry the Zika virus in the state.
In May, the new study determined the species that transmits the Zika virus –Aedes aegypti – is in Doña Ana County. Last year, New Mexico had 10 reported cases of Zika virus disease imported by travelers. There have been no reports of Zika virus disease so far this year.
“The state was extremely pleased with our previous work,” said Kathryn Hanley, NMSU biology professor in the College of Arts and Sciences. “Consequently when there was more money issued to study these vectors for Zika virus, they asked us to come on board again and this time they asked if we could do a more detailed study within cities.”
Hanley and NMSU geography professor Michaela Buenemann’s investigations last summer demonstrated the Aedes aegypti and Aedes albopictus mosquitoes are only found in the southern third of the state.
“All we know right now is that the species occur in urban and built-up environments in the southern counties of New Mexico,” said Buenemann. “We don’t know where the species occur within cities. For example, we don’t know if they are more prevalent in vegetated or built-up areas, in open spaces or densely populated parts, or in neighborhoods with higher or lower incomes. Both human and environmental factors likely shape the distributions of those mosquitoes but at this point we really don’t know.”
The new contract will allow the researchers to uncover specifics about what kinds of conditions attract the mosquitoes that can potentially transmit Zika virus.
“We’re going to do a detailed study of the 11 largest cities in southern New Mexico,” said Hanley. “So we’ll be doing extensive trapping in urban areas. We’re knocking on doors in urban areas to ask people if we can access their backyards to put our mosquito traps down. That will also lend itself to modeling which environmental factors in cities shape the distribution and abundance of these mosquitoes.”
Graduate students working with Buenemann and Hanley have already made one discovery this summer. They started trapping in the spring expecting to see the first mosquitoes in July. Instead they caught mosquitoes in early May, which indicates the insects have been active since March, a much longer period of disease risk than initially predicted.
“We will continue to trap at least until we get a hard frost,” said Hanley. “We assume once we get a hard frost we’ll stop collecting Aedes aegypti but it’s not inconceivable that we’ll be trapping all year long and into next summer.”
“We’re not only interested in how these mosquitoes vary across space and through time but also in what kinds of human-environmental interactions might explain these distributions,” said Buenemann.
This new study will include two additional areas of research conducted by Immo Hansen and Jiannong Xu, both associate professors of biology at NMSU.
The Hansen lab is going to test how resistant the New Mexican mosquitoes are against commonly used insecticides.
“Resistance levels are important to know when there is an outbreak because it helps the mosquito control professionals choose the right type of insecticide to get the biggest bang for the buck,” Hansen said.
Xu will lead research about the New Mexico mosquitoes’ microbiome, the bacteria and fungi that live together with the mosquito. Manipulating the mosquito microbiome also can help mosquito control efforts.
“The mosquito associated microbes have co-evolved with the mosquito host,” Xu said. “They have significant contributions to various mosquito life traits including development, fecundity and vector competence. Understanding the microbe-mosquito interactions will facilitate development of novel strategies for mosquito control.”
The goal for the NMDOH is to inform southern New Mexico communities of the risk of Zika and other mosquito-borne diseases.
“Your relative risk is going to be determined by how many Aedes aegypti mosquitoes you are likely to encounter at your home,” Hanley said. “If you live way out on a farm, our research suggests you are unlikely to encounter them. If you live in Las Cruces proper, our study should allow us to tell you whether you work, live or play in an area of very high or low mosquito density.”