How is Lyme disease most commonly transmitted to humans?

Lyme disease is primarily transmitted to humans through the bite of infected Ixodes ticks, commonly known as deer ticks or black-legged ticks. These ticks are often found in wooded and grassy areas, where they attach to passing animals and, by extension, humans. The transmission occurs when a tick that has been feeding on an infected animal, typically a small rodent or deer, bites a human and transfers the Borrelia burgdorferi bacteria, which causes Lyme disease.

Understanding the lifecycle of the Ixodes tick is crucial because the ticks go through several stages (larva, nymph, and adult), with the nymph stage being the most likely to transmit the bacteria due to its smaller size and increased likelihood of feeding on humans. The risk of infection increases significantly when ticks are attached for more than 24 hours, which emphasizes the importance of prompt tick removal.

Other transmission methods, such as direct contact with infected animals, aerosol transmission, or contamination of food or water, do not play a significant role in the spread of Lyme disease. The natural habitat of ticks and their life cycle is critical for understanding how Lyme disease is contracted.