Clinical Evaluation of Mosquito Coils to Control Malaria in China

Mosquito coils are extremely widely used by households across the world and reportedly make up the largest single family expenditure on any health-related items in many developing Countries. Despite their widespread use there has been no robust clinical evaluation to determine whether they can provide protection from malaria. This study is designed to determine if using coils (and / or LLIN) each evening can reduce malaria at the household level.

The study will be a single-blind, randomised clinical evaluation clustered at the household level. There will be 4 treatment arms, Coils / Insecticide treated nets / Coils + ITN / No treatment. Each arm will include 400 households each with 5 people / household (total of 8000 people). A maximum of 20% of houses in any village will be enrolled to reduce any effects of diversion of mosquitoes by any treatment. Epidemiological factors and baseline malaria prevalence will be recorded during a pre-intervention baseline month by questionnaire and rapid diagnostic test (RDT) using species-specific dip sticks for malaria. Post intervention will be 5 further monthly visits during the malaria season to detect new cases by RDT, reported fevers and operational data (compliance, adverse effects etc). Primary outcome clinical measures will be incidence of malaria (P. falciparum / P. vivax) comparing new cases in each of the 3 treatment & non-treatment groups. All cases will be treated promptly according to local policy. At the end of the study, all households which did not have a treated bed net will be provided with one.

Secondary non-clinical outcome measures will include entomological data collected in houses using / non using coils in sentinel villages at baseline & during the study. CDC mosquito light traps will be used to record number / species / feeding status / parity (age) / sporozoite infection rates of mosquitoes in houses using / not-using coils following a randomised latin square design. Such entomological data can be used to determine reduction in vector species mosquitoes entering houses using coils and / or ITN.

Ethical approval for the study has been granted by the LSHTM University of London Ethics Committee and the Yunnan Bureau of Health, P.R.China.