A map released by the Michigan Department of Health and Human Services showing Lyme disease risks by county for 2018. Livingston County was added to the red zone, which shows counties with known risks, and several others were added to the list of counties with potential risks.(
ANN ARBOR, MI – The risk of getting Lyme disease from ticks has increased in several Michigan counties, according to a new map from the Michigan Department of Health and Human Services.
Livingston County, just north of Washtenaw County, is now considered in the red zone, moving from being a county with a potential risk to a county with a known risk of Lyme disease.
The red zone includes counties with at least two confirmed cases of local exposure and/or ticks/animals with Lyme bacteria. Washtenaw and Ingham counties were added to the red zone in 2016.
The latest map shows Alpena, Bay, Genesee, Huron and St. Clair counties have been added to the list of counties with a potential risk of Lyme disease, meaning they’re either adjacent to a county with confirmed cases or blacklegged ticks are present.
The Humane Society of Huron Valley near Ann Arbor shared the new map on Facebook this week with a warning to pet owners.
"The emergence of warmer weather in Michigan brings with it spring flowers, green leaves, and TICKS," the HSHV post states.
"Our beautiful great lakes have long provided us a moat of protection from these little invaders in the Lower Peninsula. However, since the first population of blacklegged ticks carrying Lyme disease were detected in 2002 along the coast of Lake Michigan, they have continued to spread across several portions of the Lower Peninsula. The Upper Peninsula has had known infected populations longer due to their close association with Wisconsin."
The Human Society warns that both humans and pets are at risk for exposure.
"While ticks most commonly reside in wooded or rural areas, they are quickly spreading into more suburban areas," the HSHV wrote. "Pet owners should regularly check their furred family members for intruders and consult their veterinarian to discuss safe and effective preventatives that can be used to help protect them."
Lyme disease is caused by the bacterium Borrelia burgdorferi and is spread by the bite of an infected blacklegged tick, also known as a deer tick. The more common dog tick does not carry Lyme disease.
Typical symptoms include fever, headache, fatigue, aching muscles or joints and a skin rash at the site of the tick bite that may look like a bull’s eye or target.
Untreated infections can spread to the joints, heart and nervous system. Most cases of Lyme disease can be treated successfully with antibiotics.
Infections are diagnosed based on symptoms and the possibility of contact with infected ticks.
Health care providers must be ready to diagnose cases and provide early, appropriate treatment, public health officials advise.
Washtenaw County public health officials have been tracking cases as Lyme disease has spread into the region in recent years.
For at least the past decade or more, there have been known cases of Lyme disease in Washtenaw County residents every year. But until the summer of 2016, all local cases were considered likely to be related to travel to western Michigan or other states where infested tick populations are present.
But in summer 2016, a resident in a rural area in the western part of Washtenaw County contracted Lyme disease, apparently without leaving the county, Washtenaw County Public Health reported.
Overall, there were 17 total cases of Lyme disease in Washtenaw County residents in 2016, and four were likely exposed within the county, according to the health department.
WCPH spokeswoman Susan Cerniglia said there were 10 more confirmed cases of Lyme disease among Washtenaw County residents in 2017, two of which were likely exposed here.
Transmission season for Lyme disease in Michigan typically occurs from May through August, with a peak in June, according to the county. Frequent tick checks are important during this time of year, as prompt removal of ticks can prevent infection, the county advises.
Cerniglia said one of the four residents believed to have contracted Lyme disease in Washtenaw County in 2016 was infected in the western part of the county. She said blacklegged ticks were found and tested in and around the Waterloo and Pinckney state recreation areas and some tested positive for Lyme.
Washtenaw County Public Health continues to warn that there are infected tick populations in the western part of the county, specifically around the Waterloo Recreation Area near Chelsea.
"Helping to identify where infected tick populations might be is one of the reasons that we recommend residents use a test kit to submit ticks to the state for identification and testing," Cerniglia said. "This helps us know where the populations may be within the county."
More information about Lyme disease and tick-borne disease prevention is available on the WCPH website.
The state also has a program to identify ticks, and if it is a live blacklegged tick, test for Lyme disease. Information is available on the state’s website.
See images and read key facts about Michigan five most common ticks, including the blacklegged tick.