Clinical Trials Logo

Clinical Trial Summary

Isolated minority communities in China use traditional plant-based methods of mosquito control. This study is evaluating 4 plants used in this way by monitoring mosquitoes entering houses on nights when the plants are being used in this way. A blind, placebo controlled study design will monitor plant use and record mosquito species / numbers caught in CDC light traps indoors over 3 months.


Clinical Trial Description

Introduction

One of the greatest challenges to those planning vector control programmes in developing Countries is the provision of cover to those populations in remote or isolated areas. Commonly, it is these communities which bear the greatest burden of disease due to location and inaccessibility to local health care. Yunnan Province is a good example of such problems. The border region with Laos, Myanmar and Vietnam contributes a high proportion of all malaria cases in the whole of China, yet few if any disease control initiatives cover the rural minority peoples and migrant workers who inhabit the region. Comprehensive ethnobotanical surveys in the area have shown many of the 25 minority peoples living in isolated communities already use traditional herbal forms of mosquito control utilising several of the abundant species in the particularly diverse local environment. Having identified a number of potentially useful plant species being used, in terms of their availability, sustainability, low cost (free) and known chemical constituents, the investigators and the local Chinese malaria control officials consider a phase II evaluation of the most promising candidates is justified. In particular, 4 widely used plants are traditionally used as fumigants to reduce / prevent mosquitoes entering houses, either by burning dried or fresh material on the indoor cooking fires each evening, or by spraying tinctures around entry sites like eaves & windows. Due to the method of use, it would be very difficult to simulate this in the laboratory, so a simple means of field evaluation has been chosen.

Materials

The ethnobotanical survey revealed the following plant species as candidates for further study; Artemesia argyi, Eucalyptus robusta, Eupatorium odoratum, Cinnamomum glanduliferum

Each of these plant species occurs naturally in abundance in the region and collection will have no significant environmental impact. Moderate amounts (approx 1 Kg) sufficient for each study will be collected locally in each field site prior to (if used dried) or at the start of each experiment (fresh).

Methods

Plants will be evaluated under natural user conditions in a randomised and controlled manner in villages in Xishuangbanna Region, Yunnan, PR China. Village- based studies of several other mosquito control methods have already been successfully undertaken in this region by the LSHTM and YIPD team. Villages belonging to one of the ethnic groups using each traditional method will be selected according to agreement between local health workers from YIPD and the village elders, availability of plant species, and preliminary survey of vector species collected indoors with CDC traps. A different village will be selected for each plant being evaluated. After collecting background entomological data, 6 houses matched for baseline parameters (such as occupancy level, location, construction & animal proximity) and being evenly spaced among others in the village (to reduce diversion effects) will be enrolled into the study. On any one night, 2 will be allocated treatment (use of plant), 2 will be allocated hay (used for cattle bedding) as a negative control, and 2 will be left unused (to reduce any residual effects). In each case the treatment or control group will be instructed to place pre-prepared batches of plant material (weighed fresh or dry depending upon type) onto their cooking fire in the traditional manner in the early evening. Commercial CDC traps (BioQuip Inc., USA) will be used in / beside the sleeping areas of each house from 1 hour before sunset to early morning. Catches will be identified by local vector experts each day to record species and number. House treatment will be rotated each night using latin square principles to achieve a minimum of 12 replicates of each treatment in every house (36 nights duration, 216 trap/nights), and will take place during the rainy (malaria) season (July - Nov 2005) when both plants and vector levels are highest.

In the case of C. glanduliferum, the plant extract (or hay extract) will be sprayed at a predetermined rate onto eaves & doors / windows in the traditional manner following the same principles. Efficacy will be determined by comparing mosquito species / numbers caught in control & treatment houses using appropriate statistical analysis & ANOVA methodologies. ;


Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind, Primary Purpose: Prevention


Related Conditions & MeSH terms


NCT number NCT00116766
Study type Interventional
Source London School of Hygiene and Tropical Medicine
Contact
Status Completed
Phase Phase 2
Start date July 2005
Completion date September 2006

See also
  Status Clinical Trial Phase
Completed NCT04601714 - Baseline Cohort Malaria Morbidity Study
Withdrawn NCT04020653 - A Study to Assess the Safety and Efficacy of 5-aminolevulinic Acid Hydrochloride (5-ALA HCl) and Sodium Ferrous Citrate (SFC) Added on Artemisinin-based Combination Therapy (ACT) in Adult Patients With Uncomplicated Malaria Phase 2
Terminated NCT04368910 - Safety and Efficacy of Pyronaridine Artesunate Vs Chloroquine in Children and Adult Patients With Acute Vivax Malaria Phase 3
Completed NCT03641339 - Defining Skin Immunity of a Bite of Key Insect Vectors in Humans N/A
Completed NCT02544048 - Markers of T Cell Suppression: Antimalarial Treatment and Vaccine Responses in Healthy Malian Adults
Completed NCT00527163 - Role of Nitric Oxide in Malaria
Not yet recruiting NCT05934318 - L-ArGinine to pRevent advErse prEgnancy Outcomes (AGREE) N/A
Active, not recruiting NCT04704674 - Community Dynamics of Malaria Transmission in Humans and Mosquitoes in Fleh-la and Marshansue, Salala District, Bong County, Liberia
Completed NCT03276962 - Efficacy, Safety and Immunogenicity Study of GSK Biologicals' Candidate Malaria Vaccine (SB257049) Evaluating Schedules With or Without Fractional Doses, Early Dose 4 and Yearly Doses, in Children 5-17 Months of Age Phase 2
Completed NCT04966871 - Safety, Tolerability and Efficacy of PfSPZ Vaccine Against Heterologous CHMI in US Malaria naïve Adults Phase 1
Completed NCT00289185 - Study of Safety, Immunogenicity and Efficacy of a Candidate Malaria Vaccine in Tanzanian Infants Phase 2
Recruiting NCT03937817 - Collection of Human Biospecimens for Basic and Clinical Research Into Globin Variants
Active, not recruiting NCT06153862 - Africa Ready Malaria Screening N/A
Completed NCT04545905 - Antenatal Care as a Platform for Malaria Surveillance: Utilizing Community Prevalence Measures From the New Nets Project to Validate ANC Surveillance of Malaria in Burkina Faso
Recruiting NCT06278181 - Diabetes, Metabolic Syndrome and Risk of Malaria in Cameroon
Withdrawn NCT02793414 - Diagnostic Utility of Volatile Organic Compounds in Human Breath for Acute Clinical Malaria in Ethiopia
Completed NCT02793622 - Prevention of Malaria in HIV-uninfected Pregnant Women and Infants Phase 3
Completed NCT02909712 - Cardiac Safety of Dihydroartemisinin-Piperaquine Amongst Pregnant Women in Tanzania Phase 2
Withdrawn NCT02793388 - A Trial on Supervised Primaquine Use in Ethiopia Phase 4
Completed NCT02605720 - Cardiac Safety of Repeated Doses of Dihydroartemisinin-Piperaquine for the Use in Mass Treatment Campaigns Phase 3