Breadcrumbs

Lyme disease

Number of Lyme disease cases in Minnesota by year

 
 
Data source - MDH Vectorborne Disease Program surveillance data. Chart represents the number of cases of Lyme disease per year meeting the CSTE Surveillance Case Definition for confirmed cases of disease.

Although case counts vary from year to year, the overall trend for Lyme disease in Minnesota is an increase in cases. The highest number of cases were reported in 2013, with 1,431 confirmed cases. In 2017, Minnesota had a rate of 25.2 cases per 100,000 people compared to the national rate of 9.1 cases per 100,000 people. 

Many factors may explain this increase, including increasing awareness by doctors, increasing infection rates in ticks, and expanding tick distribution.

Distribution of Lyme disease cases in Minnesota over time

 
Source: MDH Vectorborne Disease Program Map is based on cumulative incidence per 100,000 people of Lyme disease cases during the 3 time periods. Click here to download these data.

Lyme disease is becoming even more common in Minnesota. There are more cases reported and the cases are being found in more counties. Since 1996, Lyme disease seems to be expanding to the north and west of the traditional risk areas in north central Minnesota.

Number of cases of Lyme disease in Minnesota by month of illness onset, 2000-2017

 
 
Data source - MDH Vectorborne Disease Program surveillance data. Chart represents the month of symptom onset for confirmed cases of Lyme disease from 2000-2017. Onset is not known for all cases.

Blacklegged ticks (also called deer ticks) are active and feeding in late May through June, with a smaller peak in the fall. Signs and symptoms of Lyme disease appear between 3 and 30 days after a bite from an infected tick, so most people who develop Lyme disease in Minnesota first experience symptoms in the summer. 

Number of cases of Lyme disease in Minnesota by age and sex, 2000-2017

 
 
Data source - MDH Vectorborne Disease Program surveillance data, 2000-2017.

There are more reports of Lyme disease in males than females for all age groups, except those over age 85. Most reports of Lyme disease cases are in males age 10 to 14 years. There are likely more reports in males and children due to their greater levels of outdoor activity.

Despite the differences in the number of cases between males and females, the overall trend is the same for both sexes: there is a peak in children age 5 to 14 and another peak in adulthood. This secondary peak in cases comes from age 45 to 54 in men and from age 55 to 59 for women.

Symptom presentation of Lyme disease patients in Minnesota, 2000-2017

 
 
Data source - MDH Vectorborne Disease Program surveillance data. Chart includes manifestations for all confirmed Lyme disease patients in Minnesota from 2000-2017. Patients may present with more than one clinical manifestation.

Most people with Lyme disease have erythema migrans - the "bull's eye rash." Other possible manifestations of Lyme disease include arthritis, neurological issues, heart issues,and brain inflammation, but these are less common. Occasionally, people experience more than one manifestation of Lyme disease.

Forested areas present a risk for tick-borne disease

In order to have a significant risk of getting Lyme disease - and other tick-borne diseases, somebody must be in areas where ticks live. For more information about the risk of tick-borne diseases, see this Tick-Borne Disease Risk Map.