NEW BRUNSWICK, N.J. - A small study suggests that mosquitoes should get some of the blame for childhood obesity.
The Rutgers University report is one of a few that quantify just how much misery mosquitoes cause - especially the Asian tiger mosquito, a particularly vicious species that has colonized more than half the states since 1985.
At times these mosquitoes are so numerous that the pests keep too many kids indoors and passive during the summer, a new Rutgers report claims. Furthermore, people in Cliffwood Beach and nearby Union Beach, N.J., two of the areas studied, shell out an average of almost $90 a year to rid their yards of mosquitoes, and they lose nearly two hours a week of outdoor time because of the bugs.
"We're looking at the costs, not of controlling the mosquitoes, but what's the cost of not controlling them?" said Dina Fonseca, a population geneticist and associate professor with the Rutgers Center for Vector Biology.
Now in its home stretch, the five-year, $3.8 million investigation into tiger mosquito invasions of the two areas and the state capital of Trenton shows that the pests affect the quality of life in urban and suburban neighborhoods.
Asian tiger mosquitoes - so called for their distinctive black-and-white-striped coloration - are an exotic species that invaded 30 states since first showing up in in the continental U.S. in 1985. Experts believe they arrived in shipments of used automobile tires from Japan in the early 1980s. The first big breeding population was discovered at a Houston tire dump.
They are not known yet as major disease carriers in North America in the way native mosquitoes can carry West Nile virus.
But in other parts of the world, the Asian tiger mosquito transmits serious illnesses such as dengue fever. In Southeast Asia, the mosquitoes have spread dengue and chikungunya, a virus that causes a debilitating, arthritis-like inflammatory disease.
With a changing climate, the new mosquito makes American public health planners worry. The U.S. Department of Agriculture is giving most of the money for the Rutgers study because it wants to find the best way to fight the insects before they become a disease carriers.
The main focus of the project was to find the best ways to control mosquitoes in urban landscapes. The Asian tiger mosquito is particularly challenging because it lays eggs in tiny amounts of standing water such as mop buckets or flowerpots. Mosquito-control workers say they even find the larvae in bottle caps on the ground.
"Mosquito control in urban settings came first, and the children's physical activity idea was birthed from that," said professor Randy Gaugler, the director of the Rutgers Center for Vector Biology and a project organizer.
The project's goal is a virtual manual for fighting the Asian tiger mosquito with both suppression from public agencies and an education campaign to get communities involved.
What makes the Asian tiger mosquito worse than some others: It likes to bite all day long. Most other species are active at dawn and dusk.
The study is among a handful trying to quantify exactly how miserable mosquitoes make people feel. Researchers from Brandeis University in Waltham, Mass., led a survey of adults in Cliffwood and Union Beach.
That part of the study found that three-quarters of the population said mosquitoes limited their outdoor activity, and that households spent an average of $86 a year on their own controls: bug sprays, screens, electronic traps and the like. Researchers even averaged out how much more time people spent outdoors when the mosquitoes were kept under control: 113 minutes a week, nearly two hours.
The study also showed that 41% of residents are willing to pay more to be rid of mosquitoes, $9.54 on average. Not much, compared with homeowners buying those $200 electric traps, which Fonseca says do not work. But if that amount were applied across two northern New Jersey counties, it would add up to $9.6 million a year - more than three times the current annual budgets of the counties' mosquito-control agencies, researchers reported.
In 2009, researchers recruited 12 children from Cliffwood Beach and Union Beach and 26 during 2011 to log their time spent outdoors. During those seasons, treatment to kill mosquitoes was alternated between the two places to see the difference between controlled and uncontrolled areas.
In a paper published in the Journal of the American Mosquito Control Association, lead author John Worobey of Rutgers' nutritional sciences department and his colleagues acknowledge that the children's playtime study, the first of its kind, was limited because of the small number who participated and the fact the scientists had to rely on the kids' self-reporting.
Still, the results were clear: "Children residing in the community where effective abatement took place spent more time outdoors in play," the authors wrote.
Genetics are a big part of childhood obesity risk, but environment also is a factor, and now mosquitoes can be added to that list, the paper concludes.
"Because obesity is difficult to treat, public health efforts need to be directed toward prevention, which could include mosquito abatement since physical activity protects against obesity," the researchers wrote.
U.S. distribution of Asian tiger mosquito
The Centers for Disease Control and Prevention most recently mapped Asian tiger mosquito infestations in 2000. Since then, the pest has spread to additional counties.
By the numbers
• 229. Average minutes of daily outdoor playtime for children where mosquitoes were controlled.
• 113. Increase minutes people spent outdoors each week where mosquitoes were controlled.
• 99. Average minutes of daily outdoor playtime for children where mosquitoes were not controlled.
• 88. Percentage of adults who reported being bitten at least once a week.
• 74. Percentage who reported spending less time in infested neighborhoods.
• 66. Percentage who say they use insect repellent all or most of the time.
Sources: Rutgers and Brandeis universities research papers in the Journal of the American Mosquito Control Association, 2012-13
Kirk Moore, Asbury Park (N.J.) Press