The Basics


Lyme 101

Lyme disease is a bacterial infection transmitted when an infected tick bites a human or animal host. The main tick responsible for the disease is the blacklegged tick or deer tick (Ixodes scapularis). The primary pathogen causing the illness and making people sick is called Borrelia burgdorferi, a corkscrew-shaped (spirochete) bacterium and the most common Borrelia species in the United States.


In 1975, the first known cases of the illness showed up as arthritic symptoms in a cluster of people near the rural town of Lyme, Connecticut, the eventual namesake of the tick-borne disease. Though Borrelia burgdorferi takes center stage when it comes to Lyme, current data suggests there are upwards of 20 Borrelia species that are agents of tick-borne diseases. In Europe, Borrelia afzelii and Borrelia garinii are the two most prevalent species resulting in Lyme disease.

How Do You Get It?

The majority of people become infected with Lyme disease through tick bites, but there are a variety of other ways one can become infected. Project Lyme answers this important question to help minimize your risk of transmission.

Where Can You Get It?

Lyme is not specific to one area of the country, or even the world. Understand the surveillance data so you can be aware of the locations that pose a threat.

What Are the Symptoms?

The range of Lyme symptoms is expansive, and trying to figure out what’s wrong can be overwhelming.

Early-Stage Lyme Disease

In the early stages of Lyme disease, the illness may present as flu-like symptoms: fatigue, fever, enlarged lymph nodes, headaches, muscle aches, and joint pain. A neurological symptom known as Bell’s palsy or facial drooping may occur in certain people.

Persistent, Chronic Lyme Disease

When a Lyme disease diagnosis is missed or delayed, the illness can progress to late-stage Lyme, in which ongoing, widespread, multi-systemic symptoms are present.  As persistent or chronic Lyme disease arises, some of the symptoms of the early stage might remain. However, several new ones emerge because Lyme bacteria disseminates (spreads) through the body.

When symptoms resurface, they may affect a multitude of organ systems, joints, and tissues. Though it’s not always so clear-cut, symptoms may correspond to the body system that’s been impacted. For example, cognitive impairment, sleep problems, and mood changes like depression and anxiety could indicate brain and nervous system involvement. Shortness of breath, heart palpitations, or fluttering in the chest might suggest cardiac issues. Other affected systems include gastrointestinal, endocrine, musculoskeletal, reproductive, lymphatic, skin, and urinary.

How Do You Test For It?

It can be difficult to determine who has a tick-borne illness. Laboratories have varying levels of sensitivity, specificity, and cost. The CDC’s diagnostic criteria and recommended testing process miss approximately one-half of actual cases. We have compiled a variety of options so you can decide about what is best for you. Click the link below to learn more.

Funding Inequities in a Growing Health Crisis

Lyme is a common infectious disease. According to the CDC, there are 476,000 new cases of Lyme disease in the US each year. This number was updated in 2021, from the CDC’s previous estimate of 300,00 new cases per year, and does not reflect the numbers of people who remain sick or suffer false negatives due to inaccurate testing.

Yet since the last official numbers published in 2018, only $63 is allocated per patient in NIH NIAID research funding–less funding than for much rarer infectious diseases. For example, West Nile (2647 cases) allocations are $13,600 per patient, and Malaria (1700 cases) research affords $118,823 per patient. Estimated increases for 2021 bring the total closer to $111 per patient, but this is still not enough.