Acquired tick resistance
Conditions
Interventions
We will challenge the three groups of human volunteers with ten uninfected ticks once. The ticks will be placed under a dressing placed on the arm and checked daily for up to ten days. The used tick c
Sponsors
Amsterdam UMC
Eligibility
Age
18 Years to 99 Years
Inclusion criteria
Inclusion criteria: Naturally acquired self-reported tick resistant individuals:• Age: 18 - 70 years; • History of repeated tick bites • Local reaction (like redness or itch) at place of previous tick bites and/or signs of impaired tick feeding after bite (anamnestic)Individuals without previous tick exposure:• Age: 18 years – 70 years;• Negative Borrelia VlsE1/pepC10 ELISA.Experimentally acquired tick resistant individuals (previous TICK ME participants):• Previous participant in the TICK ME study that has completed all 4 challenges • Age: 18 years – 70 years;• Negative Borrelia VlsE1/pepC10 ELISA.• No (suspicion of) a tick-borne diseases since participating in the TICK ME study
Exclusion criteria
Exclusion criteria: A potential participant who meets any of the following criteria will be excluded from participation in this study:Current suspicion of any tick-borne diseaseDiagnosed with tick-borne disease within the last yearChronic skin condition affecting the skin of the arm;Inability to maintain the dressing for any reason;Known immunodeficiency or autoimmune disease;Use of systemic immunomodulating drugs or chemotherapy, current or in the past;Chronic use of antibiotics;Unable to give informed consent or do not have a thorough command of the Dutch language;Refusal to participate in specimen collection and storage for future study related use;Pregnant or breastfeeding women;Not willing to use adequate contraception during the study period;Red meat allergy (both medically confirmed and self-reported);Use of investigational therapy and devices during the time of the study;Any other condition that, in the opinion of the investigator, would make the patient unsuitable for enrolment or could interfere with the patient participating in and completing the study. Additional exclusion criteria for the individuals without previous tick exposure:Known history of tick bites;Positive Borrelia serology (VlsE1/PepC10 ELISA);Known history or current suspicion on any tick-borne disease
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Tick weight: measurement of the ticks’ weight after feeding; | — |
Secondary
| Measure | Time frame |
|---|---|
| Other tick feeding parameters: Attachment rate: amount of ticks able to attach;Days of attachment: number of days attached to the participant’s skin;Tick survival: percentage of ticks still alive at detachment;Molting success: the number of (to adult ticks) of the collected ticks.Tick scutal index (exploratory): the ratio of the idosoma length compared to scutal width of the tick to assess feeding duration by taking daily pictures with a digital dermatoscope Clinical signs:Itch: degree of itch at the site of the tick-exposed skin by using a visual analogue scale;Redness: size and intensity of redness of the skin by using a dermatological spectrometer to determine the erythema index once the tick has detached and at the end of the challenge and by taking standardized digital photographs daily that will be scored by medical specialists using a standardized clinical score;Host immune reponse: Humoral and cellular immune responses in blood;Inflammatory protein measurements in blood; Cellular immune responses in the skin using histological staining of biopsies and spatial transcriptomics;Identification of potential tick proteins using an innovative yeast surface display expressing tick salivary proteins to screen for anti-tick antibodies.Exploratory: The reactivity of the observed itch and redness in response to tick bites in our previously repeatedly experimentally tick-challenged volunteers upon a challenge 1-2 years later. | — |
Countries
Netherlands
Contacts
Public ContactJ.W.R. Hovius
Amsterdam UMC
Outcome results
None listed