Active clinical trials for "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.

An innovative way to prevent multiple tick-borne diseases is an anti-tick vaccine, i.e. targeting the vector to prevent transmission of pathogens from the tick to the host. The rationale for an anti-tick vaccine stems from a phenomenon coined tick immunity. This study aims to show proof of concept that humans indeed develop immunity to ticks. Therefore subjects will be challenged three to four times with ticks reared in colony from a designated laboratory and that are exhaustively tested negative for various known tick-borne pathogens. Several tick feeding parameters will be evaluated to assess the development of tick immunity in the subjects. To this end, a total amount of ten ticks per challenge will be placed under a dressing placed on the forearm. The primary study endpoint is the tick feeding phenotype. Secondary parameters are signs of an immune response in the host; itch, redness, or other signs of a (local) immune response (blood and skin biopsies). All parameters, except for the skin biopsies, will be collected/evaluated after each tick challenge.

The high risk of acquiring tick-borne diseases by outdoor workers is well documented. Workers most at risk include, foresters, park rangers, land surveyors and other outdoor workers have frequent exposure to tick-infested habitats. Many North Carolina state employees with outdoor occupations report multiple tick bites each year, which indicates that existing tick preventive strategies may be ineffective. The principal goal of this study is to assess whether the use of long-lasting permethrin impregnated uniforms can reduce the number of tick bites sustained by North Carolina outdoor workers.

Lyme and other tick-borne diseases pose a significant health threat to outdoor workers. This study is a double-blind randomized controlled trial of outdoor workers in Rhode Island and the surrounding area that will address the following study aims: 1) Evaluate the effectiveness of LLPI clothing in preventing tick bites among outdoor workers in Lyme endemic areas; 2) Measure the urine levels of permethrin metabolites in study subjects; and 3) Measure the loss over time of knockdown activity against ticks and of permethrin in LLPI clothing.

This study evaluates the length of time an insect repellent product can protect against three species of ticks. Participants will have one arm treated with the repellent, and throughout the next 10 hours, ticks will be given the opportunity to crawl up the treated arm. The test will stop after 10 hours or when the repellent stops working whichever occurs sooner.

The proposed study is a collaboration between Microbiology, SU/Sahlgrenska and the Infectious Diseases clinic at SU/Östra as well as several Infectious Diseases clinics throughout Sweden aiming at improving microbiological diagnostic assays regarding the early identification of tick-borne microorganisms (including as of yet unidentified pathogens) capable of causing human disease using modern diagnostic tools. At the initial study visit (day 0) plasma, serum, urine, saliva, and PBMCs (and tick, if available) will be collected from patients developing fever within two weeks after a tick bite. Additional follow-up samples will be obtained after 9 and 30 days as well as after 6 months. The initial samples will be analyzed using (a) directed multiplex PCR analysis for Tick-Borne Encephalitis (TBE), Borrelia, Anaplasma, Neoerlichia, Rickettsia, Coxiella, Tularemia, and Babesiosis in plasma, whole blood and urine, (b) conventional IgM and IgG serology for TBE, (c) "Next Generation Sequencing" (NGS) for the detection of bacterial 16s rRNA as well as unknown viruses, (d) potential biomarkers, and (e) host genetic factors. Among patients where initial sampling indicates the presence of a potential pathogen or in patients developing neurological symptoms, a lumbar puncture will be performed and CSF will be further analyzed. Samples will also be evaluated regarding potential microbiological factors predisposing for severity of infection. The primary objective of the study is to improve diagnostic tools in the initial early phase of infections caused by tick-borne pathogens, especially TBE prior to the affliction of the central nervous system, and to attempt to identify which factors impact the course of infection as it is believed that approximately 75% of infected individuals resolve their infection in this first phase whereas others develop meningoencephalitis with significant subsequent neurological sequelae. Secondary objectives of the study include investigating for the presence of and treating other tick-borne pathogens, setting the stage for coming clinical trials evaluating novel anti-viral therapies for TBE.

Febrile syndromes after tick bites can be caused by different microorganisms: bacteria (B. miyamotoi, A. phagocytophilum, R. helvetica…), parasites (Babesia spp) and viruses (TBE virus). The clinical picture is not specific but complications may appear depending on the microorganism identified (thrombosis with N. mikurensis, meningoencephalitis with B. miyamotoi and the TBE virus). Thus, in order to provide appropriate treatment and monitoring, the infection should be documented.