While the rest of the world is keeping its distance from the mosquito that carries the Zika virus, two New Mexico State University professors are seeking out this mosquito, which carries not only Zika but also a host of other diseases as well.
Thanks to a grant through the New Mexico Department of Health, NMSU biology professor Kathryn Hanley and NMSU geography professor Michaela Buenemann, both in the College of Arts and Sciences, and their graduate students will begin a project to trap mosquitos in different locations around New Mexico and generate a species distribution model that health officials can use to identify where the disease-carrying insects are most likely to be.
"We know these mosquitoes occur in New Mexico," said Buenemann. "We know these mosquitoes have been detected, but we don't know their geographic distribution. We will collect samples at selected sites across the state and collect information about temperature, precipitation, land cover and other explanatory variables. We will then link these data in spatial models to map the distribution of mosquito vectors across the state."
Hanley has been studying the Zika virus for 10 years. She and Buenemann previously mapped mosquitoes carrying the virus in Senegal, West Africa.
"Until people appreciated that it could cause birth defects, no one was interested in Zika," said Hanley. "The reason no one paid much attention to Zika virus besides us is that it causes very mild disease in adults. Fever, a little rash, that's about it.
"It's only in 2015 that people noticed the association between Zika virus, pregnant women and microcephaly in the babies born to those women. What we found in 2015 is that not only is the virus transmitted by mosquitoes, but also it is sexually transmitted." Hanley explained those who should worry most about Zika are women who might get pregnant or men carrying the virus who have sex with pregnant women.
"We don't know the distribution of that vector in New Mexico. That's critically important. If we want to assess our risk, if we want to know 'Am I at risk of Zika infection from a mosquito bite?' we need to know where that mosquito is."
Stephanie Mundis, an NMSU graduate student with a double major in geography and biology, will spend the summer trapping mosquitoes in specific locations around the state as far north as southern Bernalillo County. Creating a map of mosquitoes that carry the Zika virus in New Mexico will be her thesis project. She expects to have mosquito collection data in the fall and to complete modeling next spring.
"We're going to be basing our sampling on land cover, so we're going to be sampling urban areas, agricultural, forest, barren, rangeland and wetlands," Mundis said. "We're trying to get a good sample for each of those land cover types so we know we've covered the types in the area.
"My thesis is based on modeling the potential distribution of these species throughout New Mexico," said Mundis, while unfolding one of three types of traps she and another graduate student, Clara Hansen, will use to capture mosquitos in the wild.
The white fabric cylinder contains a lactic acid lure that attracts mosquitoes by mimicking the scent of human skin. The mosquitoes follow the scent into a cone in the cylinder and a fan sucks them into a net where they are captured.
"Once we catch them, we will be freezing them or putting them in coolers, keeping them as cool as possible. We will be using morphological keys to identify them. Just by looking at certain traits and patterns on their thorax, we can easily identify these mosquitoes."
The Aedes aegypti mosquito, which carries the Zika virus, has noticeable white markings in the shape of a Greek lyre on its thorax and white banding on its legs.
Once the mosquitoes are captured and identified, layers of geographic data will be used to create a computer model to provide information for health officials and the general public.
"The problem with mosquitoes of course is that they are really, really tiny. We cannot see them from aerial or satellite imagery," said Buenemann. "There is no quick fix to figure out where they actually occur. We'll be tracking how the abundance of mosquitoes changes across space and through time, so we will have spatially and temporally somewhat explicit information that can be used to inform the public about when they are most likely be bitten by a potentially infected mosquito and where."
Hanley hears two questions from most people about the Zika virus: Is Zika coming to my area, and what can I do to minimize my risk?
"Here in New Mexico, the answer is yes. We have the vector for Zika virus. Zika will come to our area," Hanley said. "As for the risk, it depends on whether you are a reproductive age adult and interested in getting pregnant or you might have sex with someone who is pregnant or may get pregnant. If you're outside that range, you don't have to worry much."
After mapping New Mexico for the mosquitoes that carry the Zika virus, Hanley and Buenemann will begin another project to map Zika virus transmission in Borneo to find out which animal species are transmitting the virus.
"We know that the virus occurs in monkeys in Africa and Asia," Hanley said. "We're worried it is going to get into monkeys in the Americas, because if it does that, we'll never be able to eradicate Zika virus from the Americas."
How mosquito spit could help develop therapies for arboviral diseases