Mosquitoes
A. Mosquitoes
About Culex quinquefasciatus
Commonly known as the southern house mosquito Culex quinquefasciatus is a medium-sized brown mosquito found widely in tropical regions and subtropical areas. This species is found throughout Florida and as far north as Virginia and Iowa and as far west as California. C. quinquefasciatus also breeds with the common house mosquito, C. pipiens. This hybridization results in a far larger range of territory. C. quinquefasciatus is an opportunistic blood feeder and a vector of many of pathogens, several of which affect humans.
The Insect Laboratory of Poseidon Sciences (Philippines) maintains a breeding facility for C. quinquefasciatus for research and development. Because this species is ubiquitous throughout the world, Poseidon Sciences have chosen this species as the primary model to study the effects of insect repellents.
World distribution of the southern house mosquito, Culex quinquefasciatus Say. Illustration by Stephanie Hill, University of Florida.
1. Arm-in-Cage Repellent Test
Most economical test is to run a conventional arm-in-cage test. Here the product is applied on the arm and then inserted into a cage containing unfed mosquitoes. We normally use Culex quinquefasciatus, which is a universal nuisance mosquito. Our Insect Control Station is located in Panay Island, Philippines. Studies using malarial mosquitoes are normally undertaken at our Tanzanian facility.
We follow the US EPA Guidelines for product evaluation of repellent products (see the References Section below). However, we are not an EPA certified lab and only support the product substantiation of experimental formulations by companies during the product development / testing phase.
We normally conduct the following testing paradigm. Here you may add up to 2 more test groups using the same positive and negative controls.
1. CONTROL (untreated or vehicle with no repellent)
2. EXPERIMENTAL PRODUCT (You may add up to 2 other additional products to test using the same negative control and positive control)
3. POSITIVE CONTROL (commercially comparable product at project sponsor’s choice as test reference; provided by the project sponsor)
OBSERVATION CRITERIA:
Determination of the Protection Time, i.e., the period of time elapsed after exposure of the arm in the cage and the first confirmed bite of the mosquito. The Protection time signals that the product had already reached its maximum period of protection against mosquito bites.
The timeline to completion is 3 weeks from receipt of samples and pre-payment of the study. You can ship your samples when you are ready and will send you the shipping instructions
2. Field Testing of Mosquito Repellents
All field test protocols follow the US EPA and ASTM Guidelines.
Poseidon Sciences R&D Station maintains areas with high densities of daytime biting mosquitoes (Aedes aegyptii) and nighttime biting mosquitoes or the common house mosquito (Culex quinquefasciatus).
Lotions and creams, sprays and area wide protection repellents (such as patches) can be tested. Because of safety concerns due to dengue fever carried by Aedes, all field tests are conducted beginning at 4:00 PM so that subjects are exposed only to Culex mosquitoes.
Typically, human volunteers are spaced at least two (2) meters apart in the testing area and allowed to move around provided they maintain distance of 2 meters from the next subject. Walking, sitting, reading and other activities actually enhance attraction of female mosquitoes.
Protection time is calculated from the time the subject uses the repellent product to the time of the first confirmed bite. Further confirmation is by noting the time of the second bite. A research technician monitors the field testing at all times and records the data.
Field tests tend to be difficult since environmental conditions, such as wind velocity, temperature, rainfall and other factors may affect biting activity. While field conditions tend to vary from time to time, all field trials are conducted only during optimum conditions of no rain and moderate wind.
Both sides of the freshwater creek have a high density of Culex mosquitoes.
3. Insect Repellent Candles
There has been a proliferation of candles with claims of mosquito protection. However, objective data on the performance of such products are often lacking. Human tests conducted during the biting period of mosquitoes in an outdoor setting are the most objective method of testing candle-repellent performance. But, when in the process of developing optimum formulation, human testing can be expensive and time-consuming. For this reason, scientists at Poseidon have developed a convenient screening method to show the performance of experimental candle formulations.
This same method may also be used in area-wide protection products, such as repellent patches.
To learn more about this testing paradigm, please read our Technical Insights
Candle_test_method_repellents_mosquitoes_Culex.pdf (poseidonsciences.com)
Type of results in a candle test
4. Tests on repellent-impregnated fabrics
Impregnating textile materials with repellents is a growing market for military and outdoor activities where mosquitoes and other biting insects are often encountered. Validation of the efficacy and estimation of the performance life of repellents impregnated into textile materials can be validated through arm-in-cage testing or actual field testing.
References
The following Guidelines are used in the performance of our testing operations.
EPA Guidelines on-Insect Repellent TestingDownload
ASTM Mosquito – E951Download
ASTM Mosquito Field Test – E939Download
Military specs for wash resistance of repellent clothing-GL-PD-07-14ADownload
If you might have questions or need additional information, please send email to:poseidonnova@aol.com
