Update: Aerial spraying for mosquito-borne illness canceled in most counties due to weather

LANSING, MI — Spraying is scheduled to begin at 8 p.m., Sunday, Sept. 29 in 14 lower Michigan counties to combat the mosquito-borne illness that has been spreading across the state.

To date, there have been reported deaths of three people and 27 animals, and nine people total have been inflicted with Eastern equine encephalitis, according to the Michigan Department of Health and Human Services.

Dr. Joneigh Khaldun, chief medical executive and chief deputy director for health with MDHHS, said that the state is “experiencing it’s largest ever outbreak” of the disease.

It is the first time since 1980 that the state of Michigan has conducted aerial spraying to combat the disease, though individual communities have sprayed since that time, state officials announced at an afternoon press conference.

A total of 720,000 acres will be sprayed, state officials said. The cost of the spraying is estimated to be between $1.5 and $1.8 million.

“We believe that this is another tool that we can use to protect public health,” Khaldun said. “That is why we are moving forward at this instance.”

There have been 13 confirmed cases in horses and 11 in deer, according to the MDHHS. Two wolf pups at the Binder Zoo in Battle Creek, and a donkey have also died from the disease.

Cases have been confirmed in Barry, Berrien, Calhoun, Cass, Genesee, Jackson, Kalamazoo Kent, Lapeer, Montcalm, Newaygo, St. Joseph and Van Buren counties.

Spraying will occur in all of those counties with the exception of Genesee County. Spraying will also occur in Allegan and Branch counties. The ability to spray is weather-dependent, according to the MDHHS. Residents are encouraged to visit michigan.gov/eee for up-to-date information about the update and treatment plans.

Aerial spraying to combat the fast-spreading mosquito-borne illness will occur in 14 counties, beginning at 8 p.m. Sept. 29. The aerial treatment zones account for 720,000 acres in 14 lower Michigan counties. (Courtesy photo | MDHHS)

Aerial spraying will be conducted, in areas of concern, by low-flying aircraft, beginning Sunday evening and continuing up until 4:30 a.m. Monday morning, a news release from MDHHS states.

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

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

The pesticide that will be used is Merus 3.0, an organic pesticide containing 5% pyrethrin, the MDHHS states.

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, according to the MDHHS news release.

“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,” Khaldun said. “The continuing number of cases in both people and animals indicate an ongoing risk for EEE exposure.

The 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.

Only 4-5% of people will be become sick when infected with the virus, according to information provided by the MDHHS. Those infected usually do not show symptoms; however, those who do will develop chills, fever, weakness, muscle and joint pain.

Less than 1% of people who are infected will develop a serious neurological illness that causes inflammation of the brain or surrounding tissues, according to MDHHS. About 30% of people who develop neurological infection due to Eastern equine encephalitis will die.

Persons younger than age 15 and over age 50 are at greatest risk of severe disease following infection.

People in the affected areas are encouraged to:

Avoid being outdoors from dusk to dawn when mosquitoes that carry the EEE virus are most active.

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

Maintain window and door screening to help keep mosquitoes outside.

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

Use nets and/or fans over outdoor eating areas.

Wear long-sleeved shirts and pants.

Signs of EEE infection 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. Anyone who thinks they may be experiencing these symptoms should contact a medical provider.

In general, health risks are not expected during or after spraying, according to the MDHHS.

For those concerned about coming into contact with the spray, including those who have known sensitivities to pyrethrins, state officials urge them to remain indoors, close windows and doors, shut off fans and air conditioners, bring in laundry and children’s toys and cover items left outside.

Aerial spraying is not expected to have any impacts on surface water or drinking water and reservoirs will be excluded from the spray area.

The product can be toxic to honeybees or butterflies, but the state is applying the pesticide during a time in which bees are in their hives and butterflies are covered, said Laura McGowan, spokesperson for Clarke.

Neither bees nor butterflies are in danger from residual, day-after affects, she said. McGowan added that pets are not at risk from residual effects either, but it is recommended to keep pets indoors during the spraying.

McGowan said that the product is used with 85% efficacy.