Environmental Public Health Tracking: Lyme Disease

This page is for data users of the Wisconsin Environmental Public Health Tracking data portal.  You can find general Lyme disease information on the Bureau of Communicable Disease's page.

Lyme disease is spread by the bite of an infected black-legged tick and is becoming more common in Wisconsin.

Public health professionals track Lyme disease in order to educate their communities and plan prevention efforts.  View the video to the right to learn more about how we collect Lyme disease data.

The section below presents answers to frequently asked questions about Lyme disease and the data.

Access the Lyme disease data




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What is Lyme disease?

Lyme disease is an infection caused by the bacterium Borrelia burgdorferi.  The infection is spread by the bite of an infected black-legged tick (Ixodes scapularis), which are commonly called a deer tick.  Symptoms can vary depending on the stage of infection and may include a characteristic bullseye rash, fever, arthritis, headache, fatigue, and facial paralysis.  Lyme disease can be treated with antibiotics.¹  Lyme Disease Trends in Wisconsin, P-01295 (PDF) is a surveillance brief that offers more details on Lyme disease and its spread in Wisconsin.

The video below offers tips for preventing Lyme disease:

How can tracking Lyme disease improve public health?

Tracking Lyme disease gives public health professionals a better understanding of how often Lyme disease happens in their county. With Environmental Public Health Tracking, we can monitor how many cases of Lyme disease occur in a county over time and can use that information to educate our communities and plan prevention efforts.

What is the data source?

The source of the data is the Wisconsin Vectorborne Disease Program.  Healthcare providers are required to report cases of Lyme disease.  The Vectorborne Disease Program aggregates the cases and sends this information to Wisconsin Environmental Public Health Tracking Program. 

Which measures does Wisconsin Tracking provide for Lyme disease?

  • Cases of Lyme disease - The total number of Lyme disease cases in Wisconsin in a given year.
  • Incidence of Lyme disease -  The crude rate of new confirmed cases of Lyme disease in a given year, per 100,000 people.  See our glossary entry on incidence rate for more information.

What are some considerations for interpreting the data?

  • Cases are based on the county of residence; some infections may have been acquired during travel to other areas.

  • Data users should keep in mind that many factors contribute to illness. These factors should be considered when interpreting the data. Factors include:

    • Socioeconomic status

    • Demographics (age)

    • Geography (rural, urban)

    • Changes in the medical field (diagnosis patterns, reporting requirements)

    • Individual behavior (outdoor hobbies)

  • In 2008, the national surveillance case definition for Lyme disease introduced probable cases.  In 2012, the Wisconsin Department of Health Services implemented a system to estimate cases of Lyme disease.

Where can I learn more about Lyme disease?

Last Revised: September 14, 2020