Human Immune Response to Ixodes Scapularis Tick Bites

Background: Each year, the number of cases of tick-borne diseases increases. The deer tick (Ixodes scapularis) is the vector of at least 7 pathogens that cause human diseases, including Lyme disease. Researchers want to learn more to help them develop vaccines against ticks in the future. Objective: To learn how people s bodies, particularly the skin, respond to tick bites. Eligibility: Healthy adults aged 18 years and older who have no known history of a tick-borne disease or tick bite exposure. Design: Participants will be screened with a medical history, physical exam, and blood tests. Participants will have 2 skin punch biopsies of healthy skin. For this, a sharp instrument will be used to remove a round plug of skin about the size of a pencil eraser. Participants will then have 10 clean laboratory-bred ticks placed at 2 different sites on their skin (20 ticks total). The ticks will be removed from the first site 1 day after placement and from the second site 2-4 days after placement. Participants will complete symptom diary cards. They will answer questions about itching at the tick feeding sites. They will give blood samples. Photos will be taken of the tick feeding sites. Skin punch biopsies will be collected at the sites of the tick bites. Participants will repeat the tick feeding procedures 2 times, each 2-8 weeks apart. For the 2nd and 3rd procedures, 10 clean laboratory-bred ticks will be placed at 1 site. The ticks will be removed 2-3 days after tick placement. They will have telephone follow-up visits after each procedure. After the final tick removal, participants will have follow-up visits in 4-6 weeks and again in 3 months. They will give blood samples and discuss how they are feeling. Participation will last about 5-7 months.