High Hopes for Japan’s Abilities in Fight Against Dengue Fever; Japanese Companies Make Huge Contributions to Battle Against Dengue Fever

Takashi Itoda / The Yomiuri Shimbun
A demonstration of a spray to repel mosquitoes, developed by Kao Corp. and Earth Corp., is held in Bangkok in early May.

BANGKOK — Japanese pharmaceutical makers and other companies have been releasing pesticides, vaccines and other products to help in the fight against dengue fever, which is running rampant in Southeast Asia and South America.

Their efforts can partly be attributed to the increasingly grave situation on the ground, with the number dengue fever infections worldwide in 2023 hitting their highest ever. In countries where the disease has been spreading, expectations for Japanese products, research and development projects are rising.

Dengue fever is an infectious disease transmitted through such mosquitoes as the dengue mosquito. The disease is rampant mainly in tropical and subtropical regions. People contract the disease when they are bitten by a mosquito carrying the virus. There is no effective medicine to treat the disease. Symptoms, which include a fever and headache, occur three to seven days after infection. Severe case may result in death.

In Japan in 2023, 175 people were reportedly infected with the disease overseas and developed symptoms after returning to Japan. The Health, Labor and Welfare Ministry has issued warnings about the disease to people travelling to Southeast Asia and other regions.

Kao Corp. and Earth Corp. in July are scheduled to sell ARS Mos Shooter, a mosquito repellent spray jointly developed in Thailand. The new product prevents mosquitoes from flying by covering them with an interfacial active agent that blends water and oil.

According to the companies, the spray is not only free of chemically synthesized substances, it is also effective even against pesticide-resistant mosquitoes. The companies are also thinking about selling the product in Vietnam and Malaysia.

Takeda Pharmaceutical Co. shipped out 3.6 million shots of a vaccine against dengue fever in 2023. The shots were administered in Thailand, Indonesia, Brazil and other countries.

The company in February collaborated with Biological E. Ltd., an Indian pharmaceutical maker. Under the partnership, the company plans to increase the supply capacity of the vaccine to 100 million shots a year by 2030, equivalent to a supply for 50 million people.

Fujifilm Corp. has been selling antigen test kits, which can detect the dengue fever virus, to medical institutions in Thailand and the Philippines since summer last year. The kits can determine if a person is infected with the disease even if they only carry a small quantity of the virus.

According to the World Health Organization, dengue fever infections in 2023 numbered more than 6.5 million, the highest ever. The death toll from or related to the disease exceeded 7,300. Currently, the disease is rampant in more than 100 countries, and 70% of infections are concentrated in Asia.

The Yomiuri Shimbun
Rapid increase of dengue fever infections and death toll in Thailand after COVID-19 pandemic

According to the Thai government, in 2023 dengue fever infections rose four-fold and the death toll surged six-fold from the previous year. The increases were assumed to have been caused by such factors as the expansion of mosquito habitat zones, a result of global warming and urbanization, and increased human activity after COVID-19.

The Thai government makes concentrated efforts to eliminate mosquitoes and enact other disease prevention measures.

Chantana Padungtod, head of the Bureau of Occupational and Environmental Health in Thailand’s Department of Disease Control, said that though combatting dengue fever is a formidable task for public health and sanitation officials, the disease can be prevented. Knowledge gained from Japanese pharmaceutical makers will likely be increasingly utilized.

The increase of inbound tourism to Japan brings a rising risk that infectious diseases originating overseas may spread inside the country. Moving forward, it will be necessary to promote measures that deal with infectious diseases, including treatments.