Blood-thirsty insects nipping at our flesh are spreading Zika, West Nile, and other viruses. Rutgers entomologist Dina Fonseca tackles the public health crisis. 

By Ilene Dube

We’ve read all the studies: it’s healthier to be outdoors, where walking among the trees alleviates depression, lowers blood pressure and staves off Alzheimer’s disease. Children who play outside do better in school.

OK, but how to protect ourselves from ticks and mosquitoes that spread deadly diseases?

Among the most ferocious is the Asian tiger mosquito (Aedes albopictus). Native to both tropical and temperate climates, this insect with a penchant for international travel arrived in New Jersey in 1995. It can survive in urban, densely populated areas, and eggs of the species hitchhike on used tires that fill with rainwater, stimulating their eggs to hatch. Classified as an invasive species, the Asian tiger mosquito—thus named for its striped body and aggressive behavior—can transmit pathogens such as Zika, dengue and Chikungunya viruses. And unlike mosquitoes of yore, which limited their human feasting to dawn and dusk—those otherwise splendid hours for pulling weeds—the Asian tiger feasts all day. The stealth predators with a fondness for legs and ankles bite before even making their presence known.

Who better to chat with about these critters than Dina Fonseca, a professor of medical and veterinary entomology at Rutgers University. The Fonseca Labs, a mosquito research and control lab, is part of the Rutgers Center for Vector Biology, located in an unassuming building behind the New Brunswick Community Farmers Market on Jones Avenue. Surrounded by greenhouses and sunflowers growing 10 feet tall, a visitor is greeted by illustrations of mosquitoes on the glass entry doors.

Dr. Fonseca ended her summer with a visit to Montpellier, France, where she gave a talk on urban mosquitoes at the 2016 EcoSummit. The conference coincided with World Mosquito Day, August 20, commemorating Sir Ronald Ross, the British doctor who, in 1897, discovered that female mosquitoes transmit malaria between humans.

DETERMINED TO REPRODUCE

Female mosquitoes pierce mammal flesh with a hypodermic needle-like proboscis to draw in blood, which provides them with enough protein to develop eggs—and send more mosquitoes into the world! To the rescue: John Smith, an attorney with a passion for insects who went on to become the second professor of entomology at Rutgers, giving Rutgers the distinction of being the place where mosquito control was invented.

“If not for John Smith, we could not take vacations on the Jersey Shore,” Dr. Fonseca points out. His book Mosquitoes of New Jersey (1904) details practical control on a large scale. Smith led the effort to amend the New Jersey Health Act, leading to a bill signed by then Governor Woodrow Wilson authorizing the formation of mosquito control commissions in New Jersey.

“As a lawyer, Smith had the ability to talk to politicians and persuade them to fund the solution,” continues Dr. Fonseca. Each county is required to have a mosquito control program and allocate funding. “That’s how important mosquito control is to New Jersey and why I have the position I hold.” The model has been copied in Florida and California, three states with strong mosquito control programs, she adds.

In some quarters, biting insects are considered defenders of the wilderness. Because of the system of narrow trenches Smith developed to eliminate areas where larva develop, he is sometimes blamed for the erosion of salt marshes, now known to be beneficial. “But it was developers, who realized they could dry out the marsh and build houses on it, who are really responsible,” says Fonseca. “We have to be smart about it—the marsh is a habitat for fish. Scientists and engineers need to talk to each other and create incentives for restoring habitat.” And that’s exactly what happened at the EcoSummit in Montpellier.

Dina M. Fonseca, a professor of entomology at Rutgers University, warns that if temperatures continue to be higher than normal, it could be a banner year locally for Asian tiger mosquitoes. Fonseca worked with genetic markers of the insect at her lab in 2014, part of her study of the species’ rapid expansion in the United States. (Photo by Kristina Carle)

FROM AN INTEREST IN CONSERVATION

Interestingly, despite her vast knowledge of insects, and her ability to rattle off Latin names and research results, Fonseca didn’t start out as an entomologist but as an ecologist. She grew up in Coimbra, Portugal, an ancient city with a 13th-century university. “I always liked insects and experiments. We had frogs, chickens, fish and snakes—my parents were understanding.”

At the University of Coimbra, where Fonseca was the first member of her family to go to college, she studied biology and geology and proposed a course on biospeleology, or cave biology, to study organisms that live in caves. “In my 52 years, of the two moments that terrified me most, the first was spelunking in a cave so narrow I couldn’t fit my helmet on my head,” she recounts. “I had to push it ahead of me inch by inch. Of course you had to get out the same way. I suddenly had this urgent need to stand up.” Fonseca had to exercise mind over matter to calm herself and get over it.

And the second terrifying moment? “It was in 2001 when I came home from the hospital with my one-day-old baby and my husband said, ‘OK, I have to go to work now.’ I looked at my kid and said, ‘We can do this.’” Fonseca and her husband have two sons, 12 and 15. The youngest shares her interest in insects.

Insects are good indicators of water quality. Before she left Portugal, Fonseca, enamored of her country’s beautiful rivers, worked to establish metrics. After she taught high school health and biology, the University of Coimbra offered her an opportunity to get her doctorate and become a tenured professor. During the program she spent a summer at Central Michigan University Biological Station, taking classes on the Beaver Island archipelago, and fell in love with American education. Without any guarantees, she switched programs to get her master’s degree at Central Michigan, then to the University of Pennsylvania for a doctorate in ecology and evolutionary biology. The year was 1989, she was 25, and she met her future husband who was getting a doctorate in immunology.

The problem with being married to another researcher, Fonseca says, is that you don’t always get to work in the same state. There was a time when his work was in Philadelphia and hers was in Washington, D.C. The family lived in Bala Cynwyd, Pennsylvania, in an old stone farmhouse whose stone walls were a great place to capture the marmorated stink bugs she needed for research. Fonseca’s husband had been a professor at the University of Pennsylvania, but two years ago he became a senior researcher for the National Institutes of Health and the family moved to Bethesda, Maryland. Fonseca spends Wednesdays through Fridays in New Jersey. This leads to occasional confusion. During the day I visited, she received a phone call from the piano teacher, wondering who would be bringing the boys to their lesson.

IN THE RIGHT PLACE AT THE RIGHT TIME

In 1996, after completing her Ph.D., during which she studied how stream insects interact with the fast-flowing water they live in, Fonseca applied for a fellowship at the Smithsonian Institution. “I wanted to learn molecular biology and, surprisingly, when I applied for a postdoc at the National Zoo my soon-to-be advisor proposed I develop genetic tools to examine populations of mosquitoes that transmit bird malaria to endangered Hawaiian endemic birds.” As it turns out the vectors of bird malaria in Hawaii are also the vectors of West Nile Virus the pandemonium around which started in 1999. “I had the tools and it launched my career. I got into medical entomology through conservation.”

She then spent two years as a research associate at Walter Reed Army Hospital studying human malaria in Kenya, and in 2001 the Smithsonian hired her as a geneticist. In 2004 she became an assistant curator at the Academy of Natural Sciences in Philadelphia, and in 2007 she came to Rutgers, becoming tenured in 2010 and a full professor in 2014.

Fonseca’s primary field of research is documenting and understanding how mosquitoes adapt to the human environment, how they change our quality of life, and strategies to empower homeowners and communities to develop and support enlightened mosquito control. Among questions she’s explored when looking at the costs of not controlling mosquitoes have been whether fear of mosquitoes leads to childhood obesity because children are less likely to go outside. (Children are more likely to play outside when the mosquito population has been controlled.)

For every $1 spent on research, she says, $8 is saved on money not spent, for example, on  citronella torches and repellant bracelets, none of which work.

An important step, she says, is to improve elementary school education on insects and arachnids. Teachers often have a dislike for insects. “Kids who say they like insects, especially girls, are looked at in a funny way,” says Fonseca.

So, I ask, scratching mosquito bites on my arms, incurred a day earlier while snipping basil from the garden, is it safe to go outside?

Aedes albopictus

IT’S AN ODDS KIND OF THING

Chikungunya is debilitating but doesn’t kill, she points out. Victims recover and go on with their lives. Mosquitoes can spread EEE—Eastern Equine Encephalitis—that has a 30 percent chance of killing you, but getting the disease is rare. Since 1958 there have been 50 cases in New Jersey.

Age is another factor. EEE can kill people of all ages, and Zika virus is most problematic for women of childbearing age. Older people are more susceptible to West Nile Virus, but few of those infected get sick; millions have been infected in the U.S., but their immune systems take over and they may never notice an infection. “It’s unlikely to make you sick, and even less likely to kill you,” says Fonseca.

“It’s a perception thing and panic driven,” she adds. “Six or seven years ago we were talking about dengue and Chikungunya in Florida and Texas. Now it’s all about Zika. If it weren’t for microcephaly we wouldn’t be talking about Zika.”

Zika is already here in New Jersey, having arrived with travelers to the Caribbean or South America. “If you get bit by a mosquito, what’s the likelihood of local transmission? We don’t know the odds. We know the Asian tiger can transmit. It’s an odds kind of thing.”

When a mosquito bites an infected person it can then transmit to another person and lead to an avalanche of cases. For example, Fonseca recounts, a traveler from India infected with Chikungunya arrived in Italy in 2007. He visited friends in northeastern Italy, spending time at an outdoor café, and two weeks later cases of Chikungunya started occurring in the region. Eventually there were more than 260 reported cases. “You’re only infectious for a short time, and it takes two weeks to develop symptoms, but the more mosquitoes are infected, the more they infect,” says Fonseca.

The good news is, as temperatures fall, frost will kill the female mosquitoes and their eggs won’t hatch again until spring. “Winter is a good thing,” says Fonseca. “We need to make use of it.”

I put on my hiking boots and head out into the crisp fall air. I’m scratching just from thinking about the conversation with Fonseca. It’s never too late to slather on the lemon eucalyptus oil.