Testing Methods for Mosquito-Repellent Treated Textiles

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Figure 16.2: A human volunteer’s whole forearm was covered and wrapped by repellent

treated textiles or untreated textiles, and then exposed to the testing cage with 200 female

mosquitos.

The inner chamber with attached papers is carefully inserted into the outer chamber

and the front door is then attached to the chamber together with the front escape

funnel. A receiving box (6 x 6 x 6 cm) constructed of stiff paper carton material with

screen netting on top for observation of escaped mosquitos is attached to the exterior

exit portal of the chamber. Both of these tests provide a simple and easy experiment

for contact and excito repellency (Chareonviriyaphap et al. 2002; Kawada et al. 2014;

Obermayr 2015). However, on the other hand, they are less adopted as mosquito

repellent test for clothing.

4. Olfactometer and choice system test: In the laboratory, a pieces of repellent treated

textiles or clothing/fabrics is used to cover an attractant object or a human volun-

teer’s hand, then the covered attractant unit or human hand is placed or inserted to

one of the ports of the olfactometer and an untreated attractant object or a human

volunteer hand is placed or inserted into another port of the olfactometer for 5 min-

utes. The number of mosquitos to enter each port are observed and counted. If the

number of mosquitos in the repellent treated textile is significantly less than the num-

ber of mosquitos in the untreated control port, this means that the repellent treated

textile works. The mosquitos could be replaced every 4 hrs and the same testing be

conducted many times to figure out the persistence.

5. WHO bioassay: The World Health Organization (WHO) guidelines prescribe mainly

on the test methods for insecticide-treated bed nets (ITNs). Laboratory studies such

as the WHO cone bioassays and tunnel tests (phase I), small-scale field trials (phase

II), and large-scale field trials (phase III) are involved in the above guidelines.