Tickborne Diseases

Tickborne diseases are caused by infectious agents transmitted by tick bites. Because individuals who have been bitten by a tick may not feel it, it is important to check yourself for ticks after spending time outdoors. If you find a tick attached to your skin, it may have fed and transmitted an infectious agent. If you find a tick attached to your skin, you should remove it and tell your healthcare provider about your recent tick bite.

How to remove a tick: Tick Removal and Testing (CDC)

  • Use tweezers to grasp the tick as close to the skin’s surface as possible
  • Pull upward without twisting the tick
  • Clean the bite area and your hands with rubbing alcohol or soap and water

Do not crush a tick with your fingers. Dispose of a live tick by

  • Putting it in rubbing alcohol
  • Placing it in a sealed bag or container
  • Wrapping it in tape, or
  • Flushing it down the toilet

TickThe Pennsylvania Department of Environmental Protection’s Tick Surveillance and Testing Program conducts statewide tick surveillance to determine the distribution, prevalence and expansion of tick populations throughout the state. The Program tests ticks for pathogens that can impact human health. Ixodes scapularis (Blacklegged or Deer Tick), ticks can transmit Lyme disease as well as other tickborne illnesses, the Program focuses mainly on this species, pictured below. Other ticks that are frequently collected include Dermacentor variabilis (American Dog tick), Amblyomma americanum (Lonestar tick), Haemaphysalis longicornis (Asian Longhorned tick) and Amblyomma maculatum (Gulf Coast tick).

The Allegheny County Health Department Vector Control Program offers tick identification services to county residents. To receive more information, please call the ACHD Housing and Community Environment Program at 412-350-4046.

Lyme Disease

Lyme disease is the most common tickborne disease in Pennsylvania. It is caused by the bacterium Borrelia burgdorferi and is transmitted by the blacklegged tick Ixodes scapularis in the Eastern and Midwestern parts of the United States. Transmission generally occurs when an infected tick has been attached for more than 36 hours. Symptoms include fever, headache, fatigue, and a skin rash called erythema migrans. This rash, pictured below, is sometimes referred to as a bulls-eye rash. If left untreated, the infection can spread to joints, the heart, and the nervous system. Early antibiotic treatment can help to prevent these complications.

Bulls-eye rash

Positive test results for Lyme disease are reported to the Health Department by laboratories. The number of reports of Lyme disease received by the Allegheny County Health Department (ACHD) has increased over the past 10 years (Figure 1). In addition to positive laboratory results, reports may include some physician diagnosed cases with no laboratory testing. Some people receive treatment from their healthcare provider without a lab test, there are likely more cases occurring in the county than are reported to the Health Department.

Figure 1. Lyme disease reports received by ACHD, 2013-2022
Figure 1 - Lyme disease reports 2013-2022

Between 2013-2022, there were 3,049 (2497 confirmed and 552 probable) cases of Lyme disease identified by the ACHD in Allegheny County. The age distribution of cases reported between 2013-2022 was bimodal with peaks in the 5-14 year old and 55-64 year old age groups (Figure 2). Of cases, 60% were male.

Figure 2. Lyme disease cases by age group and sex, Allegheny County, 2013-2022
Figure 2 - Lyme disease by age group 13-22

Lyme disease cases occurred throughout the county. Confirmed and probable cases identified between 2020-2022 are shown below by place of residence (Figure 3).

Figure 3. Reported Lyme disease cases by place of residence, 2020-2022
Figure 3 - Map of reported Lyme disease cases by place of residence


Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum and is transmitted by the blacklegged tick Ixodes scapularis. Anaplasmosis is most frequently reported from the upper midwestern and northeastern United States. Signs and symptoms of anaplasmosis include fever, chills, headache, muscle aches, fatigue, nausea, vomiting and abdominal pain. If left untreated, anaplasmosis can cause severe illness including bleeding problems, respiratory failure and organ failure.

Reported anaplasmosis cases have been increasing in Allegheny County during the past few years but are still relatively rare (Figure 4). Similar to Lyme disease, positive test results are reported to the Health Department by laboratories.

Figure 4. Anaplasmosis cases by year, 2013-2022
Figure 4 - Anaplasmosis 13-22

Other Tickborne Diseases

Other tickborne diseases reported in Pennsylvania include babesiosis, ehrlichiosis, spotted fever rickettsiosis and Powassan virus disease. In Allegheny County, two cases of babesiosis and one case of ehrlichiosis were reported in 2022. No cases of Powassan virus or Rocky Mountain Spotted Fever were reported in Allegheny County in 2022.

Tickborne Disease Prevention

While ticks are most active in warmer months (April through October), they can emerge any time temperatures are above freezing. Prevention measures include avoiding wooded and brushy areas, using repellants with DEET for skin or permethrin for clothing and shoes, showering after being outdoors, checking for ticks and removing ticks as soon as possible.

For additional information on Lyme disease and other tickborne diseases, see the resources listed below.



Pennsylvania Department of Health (includes information for schools and camps)

Pennsylvania Department of Environmental Protection

Allegheny County Health Department Vector Control Program