Daiwa Chemical Industries Co., Ltd.
Anti-mosquito finishing agent "Aninsen CLC-3600"

Anti-mosquito finishing agent on textile products enables prevention of attack of West Nile fever virus

Because of global warming the distribution of mosquitoes has expanded from tropical regions to northern latitudes, and that leads to a spread in sources of viral infection from mosquitoes. Especially, the West Nile fever virus, which has infected many people around the world recently, has become a big issue.

West Nile fever is on the increase on a global scale (Red parts indicate areas infected. Data by National Center for Infectious Diseases (America)). Green parts are the areas infected with Japanese encephalitis.

West Nile fever occurs routinely in Africa as its virus was first recognized in humans at the West Nile District of Uganda in 1937, and then infections were confirmed in Israel, France and South Africa and it is now showing signs of spreading further all over the world. The first outbreak occurred in New York City in 1999, which spread rapidly to over 4000 people all over the U.S. and killed over 240 people.

It is likely that the virus arrived via wild birds imported as pets and via plane or boat in an infected mosquito.Persons diagnosed with the disease have recently even been confirmed in the island country of Japan with the wave of globalization, and the Ministry of Health, Labour and Welfare requires cases be reported to prefectural governors under regulations for disease control and prevention.

Symptoms of West Nile fever include sudden high fever over 39 degrees, headache, muscle ache, and a rash after an incubation period of 2 days to 2 weeks, and have some similarity to atypical pneumonia. About 20 % of infected people have a chance of developing the diseace, and 1 % become desperately ill causing brain fever which leads to eventual death.

Thus, West Nile fever is a terrifying disease after being exposed to it.

However, anti-mosquito finishing with an agent from Daiwa Chemical, “Aninsen CLC-3600,” on textile products can suppress mosquito-transmitted diseases such as West Nile fever, malaria and Japanese encephalitis.

Daiwa Chemical was the first in Japan to introduce a mosquito repellent called “Kaknock,” a medicated cosmetic agent which repels mosquitoes by direct application on the skin in 1947.

After this experience, Daiwa Chemical put “Aninsen CLC-3600,” an anti-mosquito finishing agent which is capable of being used on textiles without spoiling their characteristics and has good washing fastness, onto the market a few years ago and it has been used for some outdoor textile products.

Daiwa Chemical hopes that it could be of some help in introducing “Aninsen CLC-3600” for finishing textile products to protect against mosquito-transmitted viral infections such as West Nile fever and Japanese encephalitis.

Finishing textiles with “Aninsen CLC-3600”
keeps mosquitoes away from the processed surface before blood sucking behavior

▽Mechanism of repellent action

Action of repellent agent for blood-sucking insects including mosquitoes can be broadly divided into two types which are actions to repel insects by acting on the olfactory and tactile senses.

Action of repellent on sense of smell is called transpiration repelling, and this has the effect of keeping insects away without them touching a surface processed with the repellent agent.How it works is that repellent molecules block insects’ humidity sensory holes, which makes humans inaccessible to insects by inhibiting the function of sensing moisture, while insects usually use warm and humid convection rising from the human body as a guide for contacting humans sensing an increase in atmospheric carbon dioxide concentrations.

Action of repellent stimulating sense of touch is called direct-contact repelling, and this drives insects off the processed surface before blood sucking even after touching the surface.

It is believed that repellent substances work on insects’ peripheral nervous systems when contact is made, causing a collaterally-expressed confusional state and inhibition under sublethal doses before knockdown and lethal action.

Daiwa Chemical’s anti-mosquito finishing agent, “Aninsen CLC-3600,” has excellent effects based on the mechanism of the direct-contact repelling type.

This agent can be effective mainly in outdoor-related textile products, promoted for garments/tents for mountain climbing and trekking and fishing wear for outdoors, bedroom curtains, towel blankets, pajamas, bedding, garments/gloves for gardening, and work clothes for farming.

Anti-mosquito finishing agent “Aninsen CLC-3600”
Excellent washing fastness with microencapsulation

With realization of microencapsulation, Aninsen CLC-3600 makes possible anti-mosquito finishing on textiles which require washing fastness.

The following table shows characteristics of Aninsen CLC-3600 and Ficoat SE.

Anti-mosquito effects

▽	Testing method for anti-mosquito effects
	Release 30 mosquitoes in a 30×30×30cm mosquito-rearing cage (25°C±2°C、humidity 60~70%). Testing monitor keeps arm wrapped with rolled fabric in the cage for 2 minutes. Measure anti-mosquito effectiveness by counting the number of mosquitoes alighting on the arm during 2 minutes.
	・	Insect under test: Female tiger mosquito (OT74 series shared by Osaka Prefectual Institute of Public Health, which are bred for reproduction by Daiwa Chemical. About 7 days passed after emerging, and mating has been completed. )
	・	Name of monitors: A(Male), B (Male)

Unprocessed: Mosquitoes swarmed and sucked blood	Processed: No mosquitoes approach
Actual photo of the test (differs from results indicated above)