Ticks that carry pathogens like Borrelia afzelii and Borrelia garinii from Europe and Asia can be transported to the USA through various means, such as on migrating birds, imported animals, or via human travel. This is a public health concern about invasive species introduced into new regions.
Additionally, a person who acquired a tick-borne infection and traveled from Europe or Asia to the U.S., could potentially transmit the infection to another person indirectly (e.g., via blood transfusion, organ transplant, vertical transmission in pregnancy, sexual transmission).
While DNA from the Borrelia bacterium has been detected in human bodily fluids, including urine, saliva, and semen, the possible mechanisms responsible for indirect transmission remain a topic of research. However, the evidence for this is inconclusive, and indirect routes of transmission of Lyme disease have not been definitively established.
