Mosquito Invasion: Tips from Maryland's Bug Guy

As temperatures warm, mosquitoes will hatch and Maryland residents need to take steps now to ward off the disease-carrying insects.

A University of Maryland expert says that the type of mosquitos that carry yellow fever could also carry the Zika virus – which can cause severe birth defects – and those insects spend the winter underground in the DC area. Contrary to the early reports that the insects with the virus are mostly in the Caribbean and South America, Maryland’s Bug Guy says mosquitoes that carry yellow fever spend the winter in Prince George’s County.

Michael J. Raupp, Ph.D., professor of entomology at the University of Maryland, wrote in a recent blog that yellow fever mosquitoes overwinter in the Capital Hill neighborhood of Washington, DC, somewhere beneath the city.

“This clever human-loving species spends winter snug underground and then bubbles up in late spring to breed in the warmth of the Washington summer and dine on humans and likely other mammals in the heart of DC,” Raupp wrote.

Most people may never know they have the Zika virus, which is typically mild, say doctors. The exception, of course, is the risk it poses to pregnant women and their children. Babies exposed to the virus before birth can be develop abnormally small heads and suffer from seizures, developmental delays, impaired balance, hearing and vision, and reduced intellectual capacity.

Raupp told “Good Morning America” Wednesday that mosquito-repellent clothing can ward off bites and can reduce the incidence of mosquito-borne diseases.

Homeowners should get rid of mosquito-breeding sites now, before the insects can lay eggs. That means emptying anything that holds standing water: an old paint can, a bucket or other containers.

“If it can hold water for a week or two, it can breed mosquitoes,” Raupp said.

Other tips from Raupp’s blog to avoid mosquito bites:

• Apply mosquito repellent to exposed skin before you go outdoors. He recommends any brand that contains up to 30 percent DEET.
• Place a small fan on your patio if you eat outdoors. The light breeze created by the fan will greatly reduce the number of mosquitoes flying and biting.
• Eliminate standing water by cleaning your gutters, dumping your birdbath twice a week, turning over your wheelbarrow, emptying the wading pool, and getting rid of water-filled containers.
• Add a soil microbe known as Bacillus thuringiensis israelensis, a.k.a. Bti to an aquatic water garden or standing water on your property that could breed mosquitoes. The microbe comes in doughnut-shaped tablets that can be placed in water to kill mosquito larvae.

And in the past week the Centers for Disease Control said that Zika is very likely to spread from mosquitoes to people across the country this summer.

The CDC has these tips to control mosquitoes inside your home:

• Install or repair and use window and door screens. Do not leave doors propped open.
• Keep windows and doors shut and use air conditioning when possible.
• Keep mosquitoes from laying eggs inside your home. Once a week, empty and scrub, turn over, cover, or throw out any items that hold water like vases and flowerpot saucers.
• Kill mosquitoes inside your home. Use an indoor flying insect fogger* or indoor insect spray* to kill mosquitoes and treat areas where they rest. These products work immediately, but may need to be reapplied. Always follow label directions. Only using insecticide will not keep your home free of mosquitoes.
  • Mosquitoes rest in dark, humid places like under the sink, in closets, under furniture, or in the laundry room.
  • Use an indoor fogger* or indoor insect spray* to reach and treat areas were mosquitos rest inside the home.

There have been no locally transmitted cases in the continental U.S. as of yet, but there have been over 400 travel-related cases. And there have been close to 700 cases in Puerto Rico, with 65 pregnant women having been infected.

The U.S. Centers for Disease Control and Prevention has confirmed that the virus is responsible for causing severe defects in unborn children, including microcephaly, which leaves babies with abnormally small heads and often with brains that do not develop properly.

Zika is a mosquito-borne illness that is characterized by a fever, rash and joint pain. According to the state, only about one out of five people infected with Zika are symptomatic. While the illness typically resolves within a week, some severe cases may require hospitalization.

Aside from mosquitoes, Zika can be spread through sexual contact in some cases, the CDC notes. A Florida case originated through sexual contact, state officials said. The patient in the case contracted the virus while traveling outside of the country.

Image via Shutterstock; screenshot from "Good Morning America"