Tickborne Diseases

Maine has high rates of tickborne diseases. Lyme disease, anaplasmosis, and babesiosis are the most commonly reported tickborne diseases in Maine. Tracking the spread of tickborne diseases allows communities, state officials, and healthcare providers to prepare strategies to prevent the spread of these diseases. This data helps individuals educate residents about the need for early detection and treatment to prevent the progression to the debilitating late-stage of these diseases.

What data are available?

Maine tracks the following measures associated with tickborne diseases:

Near real-time data
- Year-to-date case counts
- Daily emergency department visits
Historical cases (annual summaries)
- Anaplasmosis incidence (caused by the Anaplasma phagocytophila bacteria)
- Babesiosis incidence (caused by the Babesia microti parasite)
- Lyme disease incidence (caused by the Borrelia burgdorferi bacteria)

Tickborne Disease Totals and Tick-related Emergency Department Visits

These displays provide year-to-date case counts of the most common tickborne diseases and the number of emergency department (ED) visits for suspected tick exposure. Preliminary case counts are updated at noon on the 1st and 3rd Wednesday of the month. Tick exposure visits are updated daily.

Tickborne Diseases: Historical Cases

This display shows the number and incidence rate per 100,000 population of confirmed and probable tickborne disease cases in Maine. These data can tell us which counties have a higher number and incidence rate of tickborne diseases and if an incidence rate is going up or down over time. To add a county to the trend chart, click a county on the map. To unselect a county, click the same county again.

Tickborne Diseases Trends

This display shows trends over the years in confirmed and probable tickborne disease cases. These data can tell you if a segment of a population (by sex or age) is at higher risk for a tickborne disease and how tickborne diseases compare year to year.

Tickborne Diseases Town Data

This map shows the number and incidence rate per 100,000 population of tickborne disease cases.

Tickborne Diseases Tables

Create a custom table of data about anaplasmosis, babesiosis, or Lyme disease.

Measure Definitions

Near Real-Time and Historical Cases of Lyme Disease, Anaplasmosis, and Babesiosis
- Tickborne disease case data are from Maine’s electronic surveillance system for notifiable conditions. Cases are classified based on surveillance definitions determined by the Council of State and Territorial Epidemiologists (CSTE), using lab results and clinical information collected by Maine CDC epidemiologists.
- Each case is classified by the case definition in the year the case was reported.

Tick-related emergency department (ED) visits
- Near real-time tick exposure data are from Maine’s syndromic surveillance system, which gathers and aggregates data from emergency department visits from hospitals in Maine.
- Visits are counted as tick-related based on a syndrome definition that uses a combination of keyword searches of a patient’s chief complaint along with relevant diagnosis codes.

Data Limitations

Near Real-time and Historical Cases of Lyme Disease, Anaplasmosis, and Babesiosis
- CSTE surveillance definitions change over time, and year-to-year changes in case counts may be partially due to changes in definitions.
- Only Maine residents are included in disease case counts. Out-of-state residents who acquired a tickborne disease in Maine are not counted in Maine’s data.
- Current year case counts are not complete or final and should not be compared to historical case counts which represent finalized data from complete years.

Tick-related emergency department (ED) visits
- Syndrome definitions using key words are imperfect, and occasionally include non-tick-related visits and mistakenly exclude some tick-related visits.
- ED visit data do not include visits to the Veteran’s Affairs hospital in Maine or the Indian Health Service.

Additional Details

In order to protect privacy as per the Maine CDC Privacy Policy, data may have been suppressed. For locations where data must be suppressed a range (e.g. 1-5) is provided for the number of events and an asterisk (*) for the rate. Data may be secondarily suppressed to prevent indirect identification and displayed as not reported (NR).
Combined year population data are the sum of individual years (e.g., 2010-2014 is the sum of populations in 2010, 2011, 2012, 2013, and 2014). Combined year rates are annualized across all included years.
For more information on case classifications, see CDC’s surveillance definitions: https://ndc.services.cdc.gov/

Environmental Public Health