WHO Bioassay Cones Kit Includes Aspirator
The cone bioassay is a controlled test to measure insecticide effectiveness, particularly in mosquito nets. It uses specialized cones where mosquitoes are exposed to treated material or a control. After exposure, researchers monitor mortality rates to assess the insecticide's impact. This standardized procedure helps ensure mosquito nets remain potent weapons against malaria by evaluating their ability to kill or knock down these disease-carrying insects.
- Diameter: 12 cm
- Height: 9 cm
- Volume: 180 cm3
The cone bioassay is a standardized test used to assess the effectiveness of insecticides, especially those applied to mosquito nets. Here's a breakdown of the typical procedure:
Materials:
- WHO-specified bioassay cones (12 cm diameter, 9 cm height)
- Holding cages or cups for mosquitoes
- Aspirator for transferring mosquitoes
- Bungs for sealing cone openings
- Timer
- Insecticide-treated material (e.g., net sample)
- Control material (untreated net sample)
- Mortality recording sheet
Preparation:
- Mosquito Selection: Use healthy, non-blood fed, female mosquitoes of the target species (usually malaria-transmitting mosquitoes).
- Material Preparation: Cut appropriate test pieces from the insecticide-treated material and control material according to the specific protocol.
Test Procedure:
- Negative Control: Introduce a set number of mosquitoes (often 5) into a cone containing the untreated control material. Seal the cone with a bung and start the timer.
- Treatment Groups: Repeat step 1 for each cone containing a test piece of the insecticide-treated material. Ensure separate aspirators are used for treated and control groups to avoid contamination. Introduce mosquitoes into each cone sequentially, allowing a short interval (e.g., 1 minute) between each introduction.
- Exposure: After all mosquitoes are introduced, leave them exposed to the material for a specified duration (usually 30 minutes to 1 hour).
- Post-Exposure: Transfer the mosquitoes from each cone back to their designated holding cages and monitor them for mortality over a set period (typically 24 hours).
Data Collection:
- Record the number of knocked down (KD) mosquitoes at specific intervals during exposure (e.g., every 10 minutes).
- Record the number of dead mosquitoes after the monitoring period.
Analysis:
- Calculate the mortality rate for each treatment group and the control group.
- Compare the mortality rates between treated and untreated groups to assess the effectiveness of the insecticide.
Additional Considerations:
- Maintain consistent temperature and humidity throughout the experiment.
- Use proper handling techniques to minimize stress on the mosquitoes.
- Perform the bioassay with replicates for each treatment and control group to ensure statistical significance.
- Follow specific protocols and guidelines set by organizations like the WHO for accurate and reliable results.
By following this procedure, researchers can evaluate the efficacy of insecticides and ensure long-lasting insecticidal nets remain effective in controlling mosquito populations.