(WWJ) Michigan's most high-risk areas are getting a boost in the battle against a deadly mosquito-borne virus.

Due to the large geographic distribution and number of Eastern Equine Encephalitis cases in humans and animals, coupled with warm weather projections, officials at the Michigan Department of Health and Human Services, working with 12 local health departments, have decided to conduct aerial spraying to combat further spread of EEE.

The spraying, by low-flying aircraft, will occur in the following 14 counties, according to MDHHS: Allegan, Barry, Berrien, Branch, Calhoun, Cass, Jackson, Kalamazoo, Kent, Lapeer, Montcalm, Newaygo, St. Joseph and Van Buren.

Spraying is scheduled take place starting Sunday, Sept. 29 starting at 8 p.m. and continuing up until 4:30 a.m. the next morning. However, officials say the ability to spray is weather dependent and the schedule may change.

Mosquito control professionals will apply approved pesticides as an ultra-low volume (ULV) spray -- very fine aerosol droplets that stay suspended in the air and kill adult mosquitoes on contact.

This is a tactic other states, including Massachusetts and Rhode Island, have recently employed to combat EEE.

“We are taking this step to help protect the health and safety of Michiganders in areas of the state that are being affected by this dangerous mosquito-borne disease,” said Dr. Joneigh Khaldun, MDHHS chief medical executive and chief deputy for health. "The continuing number of cases in both people and animals indicate an ongoing risk for EEE exposure. We continue to urge residents to protect themselves against mosquito bites until a hard frost.”

The pesticide being used is Merus 3.0 which is an organic pesticide containing 5 percent pyrethrin. Pyrethrins are chemicals found naturally in some chrysanthemum flowers. They are a mixture of six chemicals that are toxic to insects. Pyrethrins are commonly used to control mosquitoes, fleas, flies, moths, ants and many other pests. Pyrethrins have been registered for use in pesticides since the 1950s.

In general, health risks are not expected during or after spraying. No special precautions are recommended; however, residents and individuals who have known sensitivities to pyrethrins can reduce potential for exposure by staying indoors during spraying. Aerial spraying is not expected to have any impacts on surface water or drinking water.

Aerial spraying will be conducted in the nighttime hours as this is when mosquitos are more active. It is also when fish are less likely to be at the surface feeding and honeybees are most likely to be in their hives. However, owners should cover small ornamental fishponds during the night of spraying. While it is not necessary to bring animals indoors during spraying, concerned pet owners can bring animals inside during spraying.

As of Sept. 27, EEE has been confirmed in nine people in Barry, Berrien, Calhoun, Cass, Kalamazoo and Van Buren counties. Three of those people have died.

In addition, cases have occurred in 27 animals from 13 counties: Barry, Berrien, Calhoun, Cass, Genesee, Jackson, Kalamazoo, Kent, Lapeer, Montcalm, Newaygo, St. Joseph and Van Buren.

MDHHS is continuing to encourage local officials in the affected counties to consider postponing, rescheduling or cancelling outdoor activities occurring at or after dusk, particularly activities that involve children. This would include events such as late evening sports practices or games or outdoor music practices. The MDHHS recommendation is being made out of an abundance of caution to protect the public health and applies until the first hard frost of the year.

EEE is one of the most dangerous mosquito-borne diseases in the U.S., with a 33 percent fatality rate in people who become ill. People can be infected with EEE from the bite of a mosquito carrying the viruses. Persons younger than age 15 and over age 50 are at greatest risk of severe disease following infection.

Although the aerial spray is considered necessary to reduce human risk, it will not eliminate it.

As there is an EEE vaccine available for horses, but not for people, residents are urged to continue to protect themselves by:

Apply insect repellents that contain the active ingredient DEET, or other U.S. Environmental Protection Agency-registered product to exposed skin or clothing, and always follow the manufacturer’s directions for use.

Wear long-sleeved shirts and long pants when outdoors. Apply insect repellent to clothing to help prevent bites.

Maintain window and door screening to help keep mosquitoes outside.

Empty water from mosquito breeding sites around the home, such as buckets, kiddie pools, old tires or similar sites where mosquitoes may lay eggs.

Use nets and/or fans over outdoor eating areas.

Signs of EEE include the sudden onset of fever, chills, body and joint aches which can progress to a severe encephalitis, resulting in headache, disorientation, tremors, seizures and paralysis. Permanent brain damage, coma and death may also occur in some cases. Anyone experiencing these symptoms should see a doctor.

Those sickened but not killed by the virus include a Kalamazoo-area teen who suffered severe brain swelling. She is fighting with all her might, according to her mother on Facebook, and is making progress in her therapy at a rehab hospital.

Residents are encouraged to visit Michigan.gov/EEE for the very latest information.