A Within-subject Laboratory and Field Trial to Test the Use of Commercially Available Insect Repellents Against Contact From Musca Sorbens, the Putative Vector of Trachoma
试验速览
- 阶段
- 2 期
- 状态
- 已完成
- 入组人数
- 64
- 试验地点
- 2
- 主要终点
- Protective Efficacy (PE)
研究概览
简要总结
Musca sorbens, a fly that feeds from ocular and nasal discharge on humans, is thought to be the vector of trachoma. We are developing methods of fly control that specifically target this species, in the hope of interrupting Ct transmission. To our knowledge, the use of commercially available insect repellents has never been tested for prevention of Musca sorbens fly-eye contact (i.e. nuisance and landing in the peri-ocular area). Given the likely necessity for prolonged and/or high frequency fly-eye contact for Ct transmission, the reduction of these contacts through the use of fly repellents presents an exciting opportunity for disease control. Here we propose a within-subject, non-masked, trial of the use of commercially available insect repellents against Musca sorbens, with two consecutive participant groups in the laboratory and in the field, and a primary endpoint of measuring the protective efficacy of each repellent product. Repellent products will be chosen from: DEET (N,N-diethyl-3-methylbenzamide), IR3535 (3-[N-butyl-N-acetyl]-aminopropionic acid ethyl ester), Picaridin (2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester); PMD (para-Menthane-3,8-diol) or permethrin (m-Phenoxybenzyl)-cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate). Products tested will be either (1) topical repellents, or (2) in long-lasting, plastic formulations of repellents that can be worn on the body (wearable repellent technologies). The insect repellent synergist Vanillin (4-Hydroxy-3-methoxybenzaldehyde) may be added to the long-lasting plastic formulations, to improve the duration of protection.
详细描述
Introduction
Trachoma
Trachoma, a Neglected Tropical Disease (NTD), is the commonest infectious cause of blindness globally, affecting some of the world's poorest communities. Trachoma is caused by repeated ocular infection with the bacterium Chlamydia trachomatis (Ct). Active trachoma begins in childhood with recurrent episodes of follicular conjunctivitis (TF). Chronic inflammation results in immunologically mediated conjunctival scarring and in-turned eyelashes scratching the eye: trichiasis. Eventually sight is lost from irreversible corneal opacification.
Trachoma is currently endemic in 42 countries. The latest estimates from the Global Trachoma Mapping Programme (GTMP) suggest that 180 million people live in trachoma endemic areas and 3.2 million people have trachomatous trichiasis. Around 2.2 million people are visually impaired, of whom 1.2 million are blind. More than 80% of the burden of active trachoma is concentrated in 14 countries, mainly in the Sahel of West Africa and savannahs of East and Central Africa, where water supplies are often scarce.
Trachoma in Ethiopia
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 主要目的
- Prevention
- 盲法
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 3 Years 至 65 Years（Child, Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Laboratory trial eligibility criteria
- •Participant is aged > 18 years and < 65 years and in good health
- •Participant has a good understanding of the procedures of the study and agrees to abide to these procedures
- •Participant is able to communicate well with the investigator, and attend the laboratory for all aspects of the laboratory studies
- •Participant has no known adverse reactions, or evidence at screening of adverse reactions, to the commercially available repellents DEET, PMD, IR3535, Picaridin or Permethrin, or to Vanilla
- •Participant has no known history of skin allergies or hypersensitivity to topical creams
- •Participant agrees to a pre-trial skin reactivity test for all the repellents that will be used in the trial
- •If in the event of the participant experiencing an adverse reaction to a repellent during the trial, the participant agrees to inform his/her general practitioner and seek appropriate treatment if necessary
- •Participant is willing to allow laboratory-reared Musca sorbens flies to land and crawl on their arm, during the modified arm-in-cage assay, for periods of up to ten minutes at a time
- •Participant agrees not to use any perfumed or scented product, including bathing products, for a 24-hour period before each laboratory session
- •Participant has signed informed consent
- •Participant is not a smoker, and will agree to refraining from smoking for the 12 hours before each laboratory trial
- •Field trial eligibility criteria
- •Participant lives in the designated study site
- •Participating households must be within a one-hour drive of Feya General Hospital
- •Participant considers themselves to be in good health, as does the parent or guardian
- •Participant is aged > 3 years and < 12 years
- •Participant has a good understanding of the procedures of the study and agrees to abide to these procedures
- •The parent or guardian of the participant has a good understanding of the procedures of the study and agrees to abide to these procedures
- •Participant is able to communicate well with the investigator or fieldworker who is conducting the study
- •Participant has no known adverse reactions to the commercially available repellents DEET, PMD, IR3535, Picaridin or Permethrin, or to Vanilla
- •Participant has no known history of skin allergies or hypersensitivity to topical creams
- •Participant agrees to a pre-trial skin reactivity test for all the repellents that will be used in the trial
- •If in the event of the participant experiencing an adverse reaction to a repellent during the trial, the participant can request medical advice from the Stronger-SAFE field team nurses if they wish
- •Participant is willing to sit still on a chair outside their house, for sequential periods of up to ten minutes, allowing wild fly contact and landing on the body and face, as much as possible without disturbing fly behaviour
- •Participant agrees not to use any perfumed or scented product, including bathing products, for a 24-hour period before each laboratory session
- •Able and willing to give fully informed assent
- •The parent or guardian has signed informed consent
排除标准
- 未提供
研究组 & 干预措施
Field study: IR3535
干预措施: IR3535 (Other)
Field study: Permethrin lower dose
干预措施: Permethrin lower dose (Other)
Field study: Permethrin higher dose
干预措施: Permethrin higher dose (Other)
Field study: control arm
Laboratory study
干预措施: IR3535 (Other)
Laboratory study
干预措施: Permethrin lower dose (Other)
Laboratory study
干预措施: Permethrin higher dose (Other)
结局指标
主要结局
Protective Efficacy (PE)
时间窗: 2 months
The protection (protective efficacy, p) afforded by a repellent product will be presented as a percentage. p will be estimated by comparing fly-arm contact duration and fly-eye contact frequency, in laboratory and field trials respectively, after application (or wearing) of the repellent product to that during the control period.
Complete Protection Time (CPT)
时间窗: 3 months
Median CPT will be estimated in stage two ('persistence') laboratory trials only, for those repellents that demonstrated more than 30 % PE. The complete protection time for a specific dose will be estimated as the time elapsed until the first fly landing on the arm in each replicate, and based on repeat estimates of CPT, the mCPT will be estimated using a Kaplan-Meier function.
次要结局
未报告次要终点