Room Test for Mosquito Repellents

Room Test Procedure

The room test for mosquito repellents can be performed in two ways: 

• With volunteers 
• Without volunteers

Test procedure for room test with volunteers:

• This test method involves the use of human volunteers to evaluate the effectiveness of the product against specific mosquito species. The number of volunteers and the number of species to be analyzed will vary depending on the guidelines specific to the concerned region/country and the manufacturer’s instructions.
• A known number of female mosquitoes are released into the controlled environment where the test is conducted.
• For mosquito repellent products such as creams, lotions and sprays, the mosquito repellents are applied to the participant’s forearms as per the manufacturer’s instructions. The rest of the body is covered with protective equipment before entering the room. 
• Participants monitor the number of mosquitos landing on the treated areas and the number of bites (if any) for a specified duration, as per the manufacturer’s instructions.
• A second set of volunteers repeats the same activity without applying any repellent.
• The biting activity and the mosquito-landing rates on the treated arms are compared with the untreated arms to evaluate the efficacy of the repellent.
• For repellent products such as incense sticks, candles, and other similar products, the products are lit and placed at a defined distance from the walls and the volunteers, as stated by the standard guidelines followed and the manufacturer’s instructions. 
• The biting activity and the mosquito-landing rates on the uncovered arms of volunteers in the room having lighted incense sticks, candles, and other similar products are compared with biting and landing rates in the room without the repellent products.  

Test procedure for room test without volunteers

• In this method, the test product is placed in the room.
• A known number of mosquitoes are released into the room for a specified time duration. (The duration of the test depends on the particular guidelines being followed and the manufacturer’s instructions)
• Within the exposure time, the knockdown effect of the repellent is recorded.
• The number of mosquitoes knocked down (unable to fly or move normally) is counted at regular intervals. 
• After the exposure period, the mosquitoes are transferred to a clean environment and are provided with 10% sucrose solution. The mortality rate is determined after 24 hours.

Note: The R&D team at Microbe Investigations Switzerland ensures that all precautionary measures are taken to prevent the transmission of diseases by the vectors during testing.

Passing criteria

For products like creams, lotions, sprays, etc., the efficacy of the repellent product is determined by measuring the Complete Protection Time (CPT)—the duration between application and the first confirmed mosquito bite. According to ECHA (European Chemicals Agency) Transitional Guidance, CPT is either the occurrence of two or more bites on the treated arm or one bite followed by another within 30 minutes. A longer CPT indicates greater repellent effectiveness.

For products like candles, incense sticks, aerosols and vaporizers, the efficacy of the repellent product (tested without volunteers) is determined by the knockdown effect. The level of knockdown efficacy should be >80% and the mortality after 24 hours should be >90% as per BPR (Biocidal Product Regulation) guidelines. 

(Note: These efficacy values may vary depending on the specific guidelines and regulatory standards followed in a particular region.)