This archive report was first published on 19 August 2019.
Published on August 19, 2019, a key aspect of Lyme disease diagnosis is the presence of the signature rash, erythema migrans, which appears in about 80 percent of patients.
According to Dr. Meissner, blood testing is not recommended when the rash is present, as only a third of people will have detectable antibodies. Instead, a clinical diagnosis is made based on factors such as the season, the quality of the rash, and the patient's history of tick exposure.
The highest risk season for Lyme disease is late spring and summer, when young nymphal stage ticks are active. Adult ticks also play a role, transmitting the disease during the spring and fall.
When a tick is found attached to a person, testing the tick is not recommended. However, the length of time the tick was attached is relevant, and an engorged tick may indicate a longer attachment time, increasing the risk of transmission.
The transmission process is complex, involving the migration of the spirochete bacteria from the tick's midgut to its salivary glands. If the tick is attached for less than 36 to 48 hours, the spirochete may not have enough time to activate and be transmitted.
