Mosquitoes to blame for childhood obesity?

4:10 PM, Jul 25, 2013   |    comments
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(Asbury Park Press) -- Are mosquitoes to blame for childhood obesity?

A new Rutgers University-led study suggests that may be the case. The report is one of a few that quantify just how much misery is caused by mosquitoes - especially the Asian tiger mosquito, a particularly vicious species that has been colonizing New Jersey and 29 other states since 1985.

At times they are so bad in northern Monmouth County and Trenton that the tiny pests may be keeping too many kids indoors and passive during the summer - and contributing to childhood obesity, a new Rutgers report claims.

Furthermore, people in Cliffwood Beach and Union Beach shell out nearly $90 a year on average to rid their yards of mosquitoes, and they lose nearly two hours a week of outdoor time because of the bugs.

Now in its homestretch, the five-year, $3.8 million investigation into the Asian tiger mosquito invasions of Union Beach, the Cliffwood Beach section of Aberdeen and Trenton shows that the pests seriously affect the quality of life in urban and suburban neighborhoods.

"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.

Asian tiger mosquitoes invading

Asian tiger mosquitoes - so called for their distinctive black-and-white-striped coloration - are an exotic species that have staked out a foothold in 30 states since first showing up in 1985.

They are not yet known to be what insect experts call vectors, or 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 transmits serious illnesses like dengue fever. In Southeast Asia, Asian tigers 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 Rutgers study is funded primarily by the U.S. Department of Agriculture, because it wants to find the best way to fight the insects before they become a disease vector here. The project's goal is a virtual manual for fighting the Asian tiger, with both suppression by mosquito-control agencies and public education that gets the whole community involved in stamping out the bugs.

Mosquitoes have always been an unpleasant fact of summer life in New Jersey, but the Asian species is something else: a "day biter" that unlike native mosquitoes preys on people in the daytime heat and light. The best guess among experts is the mosquitoes arrived in shipments of used autombile tires from Japan in the early 1980s; the first big breeding population was discovered at a Houston tire dump in 1985, and 10 years later they showed up in New Jersey.

Measuring time spent outside

The study is among a handful that try to quantify exactly how miserable mosquitoes make people feel. Researchers from Brandeis University, including Donald Shepard, a health economist who has studied the economic costs of dengue fever, led a survey of adults in Cliffwood and Union Beach.

That part of the study found that three-quarters of the population said their outdoor activity was limited by mosquitoes, 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 percent of residents are willing to pay more to be rid of mosquitoes - on average, $9.54. Not much, compared with desperate homeowners buying those $200 electric traps (which Fonseca says do not really work), but if that amount were applied across Monmouth and Mercer 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, they reported.

Seeking methods to control the bugs

The main focus of the USDA-sought project was to find the best ways to control mosquitoes in urban landscapes. The Asian tiger mosquito is a particularly challenging pest in city and suburban neighborhoods, because it can lay its eggs in tiny amounts of standing water like mop buckets or flowerpots. Mosquito-control workers say they even find the larvae in bottle caps on the ground.

At those levels of infestation, the researchers thought they could learn the real, everyday effects on people's lives.

"Of course, we'd never have even have contemplated such a study due to the immense expense of such a large effort, but by piggybacking it onto the mosquito suppression aspect of our project, we saw that it was feasible," said professor Randy Gaugler, the director of the Rutgers Center for Vector Biology and a project organizer. "So mosquito control in urban settings came first, and the children's physical activity idea was birthed from that."

Environmental causes of obesity

Joining the team was professor John Worobey of Rutgers' nutritional sciences department, who studies the relationships between children's diets and activities.

With childhood obesity an important topic for the university's recently launched Institute for Food, Nutrition and Health, the researchers saw a novel approach for measuring mosquitoes as an environmental health issue for children. Additional funding from the Robert Wood Johnson Foundation helped with this phase of the research.

In 2009 they recruited 12 children from Cliffwood Beach and Union Beach, and 26 during 2011, to record in activity logbooks 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 Worobey and his colleagues acknowledge that the children's playtime study, the first of its kind, was limited by the relatively small number of children who participated and the fact the scientists had to rely on the kids' self-reporting of their daily activity.

Still, the authors wrote, the results were clear: "Children residing in the community where effective abatement took place spent more time outdoors in play."

Genetics are a big part of childhood obesity risk, but there are environmental factors, too, 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.

Childhood obesity experts stress the need to remove neighborhood barriers to playing outside, so the team suggests targeting mosquito controls to create "Asian tiger mosquito-free environments may positively impact children's physical activity by encouraging daytime outdoor activities."

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