Purpose

While there is strong evidence that permethrin treated clothing prevents insect bites there is insufficient evidence from trials to demonstrate a reduction in infections. The evidence that topical insect repellants prevent malaria is more robust, but studies in civilian suffer from poor compliance. It is not known if there is an added benefit from combining the two. The effectiveness of permethrin-treated uniforms with and without DEET lotion are compared in a 2x2 design in Mgambo Jeshi la Kujenga Taifa (JKT) military camp in Tanga region.

The four arms are: 1) combined intervention group receiving permethrin treated uniform (PTU) and 30% DEET (diethyl toluamide) liposome formula; 2) permethrin intervention group receiving PTU and placebo lotion; 3) DEET intervention group receiving untreated army combat uniform (ACU) and 30% DEET liposome formula; 4) placebo group receiving untreated ACU and placebo lotion. Both participants and investigators will be blinded to treatment allocation.

The outcome measure is the incidence of Plasmodium falciparum malaria infection measured by Polymerase Chain Reaction every month by active case detection.

The study is a prospective, cluster-randomised placebo controlled trial using a 4-arm non-inferiority design with 12 months of follow-up. Healthy recruits of the Tanzanian National Service Program JKT Mgambo Camp will be enrolled in the trial. The recruits come from all over Tanzania. The transmission in the camp is relatively high: the incidence of malaria infection in Mgambo camp among recruits in the last quarter of 2014 was 0.68 per person per year measured by RDT.

One thousand five hundred recruits will be enrolled in the trial. Randomisation will be based on combania (the company, comprising typically 30-50 recruits). Recruits in a combania perform all activities together as a group. The randomisation will be unequal since the investigators expect that the primary comparison requiring the greatest precision is that of adding DEET lotion to PTU. Investigators will randomise 500 recruits for each arm of the primary comparison (PTU plus DEET, PTU uniform only) and 250 recruits to each of DEET only and placebo.

Compliance will be maximised by requesting participants to use their uniforms and lotions only at night. Monitoring of uniform use will be conducted by random spot checks of participants in the evenings by study staff. In addition, bottles of lotion will be weighed on a monthly basis during active case detection as a direct measure of compliance with lotion use.

Artemether-lumefantrine (Co-Artem) will be given to any participant with a temperature of ≥37.5 degrees centigrade or a history of fever in the past 48h, and P. falciparum parasites detected by RDT in the absence of other detectable cause of fever.

The participants' activities for the previous two weeks will be recorded by questionnaire by study staff during active case detection. Time away from the camp or in the sick bay and prophylactic periods in the case of antimalarial treatment will be excluded from time at risk.

Soldiers are a vulnerable group because they have limited ability to protect their own interests. It is therefore, particularly important that they should be prevented from being involved in the research project because they feel it is their duty to do so or that they may be subject to penalty from senior members of the army. Therefore, in order to protect the soldiers from coercion the ethical review process for the research is conducted the same processes procedure as is required by a civilian Institutional Review Board (IRB). In addition, service members' commanders or supervisors may not be in the room during the consent process. It will be stressed to Tanzania People's Defence Force (TPDF) staff performing spot checks that they are merely to monitor compliance and should not coerce participants into wearing their uniforms when in the barracks

Inclusion Criteria:

Member of a platoon passes physical examination - no underlying health risks females that are not pregnant malaria negative at enrolment consents to participate

Exclusion Criteria:

Not assigned to a platoon underlying health risks - does not pass physical examination pregnant female (pregnant females are not recruited into the army) malaria positive at enrolment does not consent to participate

Placebo