Lyme disease causes
The disease is caused by the bacteria Borrelia burgdorferi, which has an infectious cycle that involves ticks of the genus Ixodes and mammalian animals. Only tick females need blood meals, and only nymphs and adults transmit the disease. Every adult female lays new eggs during springtime, and they hatch on summer days. Larvae feed on mice, blood, and other animals and become nymphs the next spring and become adults the following fall.
Throughout their life cycle, ticks usually get infected with Borrelia burgdorferi when feeding on an infected animal in one of the three stages in their life cycle. The most common carrier of the disease is a type of mice known as white-footed mice. They do not develop the disease and only carry the bacteria in their midgut. Then, and only when the tick is infected and bites humans, they are at risk, but do not always get the disease.
Impressively, nymphs are more likely to transmit the disease as compared to adults. Being bitten by an adult tick is more noticeable. Nymphs sneak around easier due to their smaller size, and they are not easily detected before they are done feeding and transmitting the disease. Ticks can take hours to attach to the skin, and they should stay in place for 48 hours (nymphs) and up to 72 hours (adults) to transmit the disease.
Even when the spirochete is transmitted to a human host, there’s no 100% chance of getting the disease. Sometimes the bacteria are caught by the immune system and eliminated before infecting the patient. In other cases, the spirochete stays in the skin and starts causing the disease with a skin rash. But sometimes, it is disseminated in the blood or lymph instead of staying in the skin. Depending on what happens, the patient gets different clinical manifestations.
The bacteria have a preference for the skin tissue, the nervous system, the heart, joints, and the patient’s eyes. These organs are the most commonly affected, but the disease can spread anywhere, including the testes, liver, lymph nodes, and more.