The Asian tiger mosquito is an aggressive biter and has the ability to spread many viruses.
These invasive mosquitoes were first discovered in Michigan in 2017 in an industrial area of Livonia. They were found again in 2018, in an industrial area of Romulus. In 2020, they were found in an industrial area in Taylor.
These mosquitoes, the aedes albopictus, can transmit viruses such as dengue, chikungunya and Zika to people. They are not found naturally in Michigan because the winter weather is too harsh for them to survive.
Climate change is helping them move further North. Their populations are considered established in Ohio, Illinois, and Indiana. It is believed they travel to Michigan in products shipped from states where they are established.
Mosquito-borne illnesses (arboviruses)
Arboviruses are a group of viruses that are transmitted by mosquitoes, ticks or other arthropods.
Jamestown Canyon Virus (JVC)
There were 10 cases of JVC in Michigan between 2012 and 2021 that were reported to the CDC.
JCV sickened three Michigan residents in 2020. Most cases occur from late spring through mid-Fall. Illnesses can develop within a few days to two weeks after a bite from an infected mosquito. Most people do not become ill.
Symptoms include fever, headache and fatigue. In rare cases, JVC can cause severe disease in the brain and/or spinal cord including encephalitis and meningitis.
According to Michigan, there were 12 JVC-positive mosquito pools in 2022 and one human JCV case.
Eastern Equine Encephalitis (EEE)
According to Michigan officials, EEE is one of the most dangerous mosquito-borne diseases in the United States. It has a 30% fatality rate in people who become ill.
Most people who become infected do not develop any symptoms. However, the symptoms that people can experience include chills, fever, weakness, muscle and joint pain. The illness can last up to two weeks. Fatigue and weakness can last for weeks or months. Less than 1% of people who are infected will develop a serious neurological illness.
In 2020, there were four human EEE cases reported and 41 animal EEE cases reported. In 2022, there were only 4 animal EEE cases reported.
West Nile virus (WNV)
Most people who become infected with WNV do not develop any symptoms. When people do become ill symptoms include headache, body aches, joint pains, vomiting, diarrhea or rash. Most people with that type of WNV recover completely.
About 1 out of 150 people infected will develop a serious neurologic illness. Symptoms include, headache, high fever, neck stiffness, disorientation, coma, tremors, seizures or paralysis.
According to Michigan officials, there were 77 WNV-positive mosquito pools in 2022 and there were 12 human WNV cases.
Zika virus
Zika virus is not currently being transmitted within the United States. The last cases of local zika transmission happened in Florida and Texas in 2016 and 2017, according to the CDC.
The virus is spread through mosquitoes and can be passed through sex from a person who has zika to their partners, even if the person doesn’t have any symptoms. It can also be spread to a baby during pregnancy.
Most people who are infected with zika develop mild symptoms, or none at all. If zika is passed from a pregnant person to their baby, the baby can have severe brain defects and other nervous system defects.
Symptoms include fever, rash, joint pain, conjunctivitis, muscle pain, and headaches. Zika symptoms usually last several days to a week. People rarely die of zika.
Dengue
There have been no reported cases of dengue in Michigan. Almost all reported cases in the U.S. are associated with travel. Most people infected with dengue will develop mild symptoms or none at all, but severe forms of the disease can be fatal.
The symptoms include severe headache, eye pain, muscle pain, joint pain, bone pain, rash, and unusual bleeding. Symptoms usually begin four to seven days after the mosquito bite and last for about two to seven days.
Chikungunya
Cases of chikungunya in Michigan are linked to travel.
Most people infected with chikungunya develop some symptoms three to seven days after an infected mosquito bites them. The most common symptoms include fever and joint pain.
Other symptoms include headache, muscle pain, joint swelling, or rash. People rarely die from chikungunya.
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Preventing mosquito bites
Michigan officials suggest taking the following steps to prevent mosquito bites:
- When used as directed, Environmental Protection Agency (EPA)-registered insect repellents with one of the active ingredients below are proven safe and effective, even for pregnant and breastfeeding women: DEET, Picaridin (known as KBR 3023 and icaridin outside the US), IR3535, Oil of lemon eucalyptus (OLE), Para-menthane-diol (PMD), and 2-undecanone.
- Wear light-colored, 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, unused kiddie pools, old tires or similar sites where mosquitoes lay eggs.
- You could also hire a mosquito control business. Mosquito control businesses are required to be licensed to apply pesticides in Michigan. A list of Michigan firms licensed to apply pesticides is available online.
Mosquitoes lay eggs in or near standing water
Mosquitoes need standing water to reproduce. That’s why you should empty, scrub or cover any items that hold water.
Standing water is often found in old tires, buckets, planters, toys, pools, birdbaths, flower pot saucers or trash containers.
Mosquitoes can complete their life cycle in about a week. The CDC recommends using an outdoor insect spray made to kill adult mosquitoes. Mosquitoes are often found in dark, humid areas.
Can’t remove standing water? Larvicides are an option
If you’re unable to remove the standing water where you live then you’ve got one other option: Larvicides.
Larvicides work by killing mosquito larvae and pupae before they grow into pesky adults. According to the CDC, if you use larvicides correctly they do not harm people, pets or the environment.
Larvicides come in liquids, tablets, bits, pellets, granules and briquettes. You use them by applying them where mosquitoes lay eggs (that means anywhere that holds standing water). That can include buckets and rain barrels, fountains, gutters or downspouts, non-chlorinated swimming pools, pool covers that collect water, tires and tree holes.
Use larvicides to treat standing water that will not be used for drinking and cannot be covered, dumped or removed.
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