The α-gal Syndrome - Investigating Immune Reactions to Tick Bites

Tick bites can transmit pathogens, but they can also induce a food allergy to mammalian meat. The goal of this clinical trial is to follow immune response and antibody build-up in individuals bitten by a tick. Participants are invited to enroll within 48 hours after the tick removal and donate some blood. The tick is also collected and analysed. Researchers will then try to answer the following questions:

* Was the tick infected with parasites? * Did the participant make antibodies against tick proteins or tick-borne parasites? * Did the participant develop IgE antibodies against the alpha-Gal sugar? The alpha-Gal sugar is present on mammalian meat, and ticks can transmit the alpha-Gal sugar to the host during their blood meal. Humans recognize the alpha-Gal sugar as foreign and some individuals will build IgE antibodies in response. These IgE antibodies against alpha-Gal can lead to a food allergy to red meat, also known as alpha-Gal syndrome.

Researchers will compare a group of participants that develop IgE against the alpha-Gal sugar with participants that will not. They want to find out if there are specific immune features that differentiate the 2 groups.

Participants will:

* Enroll after a recent tick bite within 48 hours after tick removal: they will be asked to donate some blood and fill out a questionnaire. * Visit the clinic 4 to 6 weeks later for a follow-up sample and questionnaire. * Visit the clinic 3 months after the tick bite for allergy tests if they have been selected for this 3rd visit.