JAKARTA: Indonesia is hoping a major trial in regions plagued by dengue fever will reduce the number of disease-carrying mosquitoes and lower the incidence of the viral illness in the country.

The trial involves the release of mosquitoes infected with the Wolbachia bacteria, which stops the insects from transmitting the dengue virus, a health ministry official said on Tuesday.

A similar experiment from 2017 to 2020 in Yogyakarta, a city of 3.6 million people on Java, led to a dramatic fall in the number of new dengue cases, with numbers falling by up to 77 percent.

The number of patients with mild dengue symptoms also fell by 86 percent in areas of the city where mosquitoes infected with Wolbachia were released.

The results of the study, conducted by the World Mosquito Program (WMP) at Monash University in Australia and Indonesia’s Gadjah Mada University, were published in the New England Journal of Medicine earlier this month.

However, Didik Budijanto, the health ministry’s director of zoonotic disease prevention, told Arab News that while the ministry welcomed the study, further tests will be needed before the strategy is adopted.

Denpasar in Bali is among locations where further tests are planned, he said.

According to the Bali health agency, 1,803 cases and three deaths were registered on the resort island from January to May.

Meanwhile, the provincial capital Denpasar is among the two most infected regions on the island, where 364 out of 962,900 residents were infected with the disease.

Trials were held in Yogyakarta to see how the Wolbachia-infected mosquitoes affected the incidence of dengue among 8,100 city residents, aged between three and 45, who took part.

According to the WMP, over 4,500 dengue patients were hospitalized in the city in the five years before the trial.

However, experts believe the number could be as high as 14,000, with 2,000 people needing hospital treatment every year.

Indonesia records an estimated 7-8 million dengue cases out of the more than 50 million that occur worldwide annually. As of May, the country reported 13,372 cases with 134 deaths.

Scott O’Neill, WMP’s program director, said that the test results proved that the strategy could significantly reduce dengue numbers.

Joint principal investigator Adi Utarini, from Gadjah Mada University, said that she is optimistic that cities across Indonesia can live without dengue in the future.

“The trial’s success allows us to expand our work across Yogyakarta and into neighboring urban areas,” she said.

However, Budijanto said that the government will carry out further checks before the trial is expanded.

“We just want to make sure science and technology do not outpace regulations and the people can still benefit from it,” he said.

Budijanto told a recent press conference to mark ASEAN Dengue Day, which is commemorated annually on June 15, that the government had set a target to reduce the national dengue incidence rate to below 37 per 100,000 population and the number of fatalities by 0.2 percent by 2030.

In 2018, the International Society for Neglected Tropical Diseases launched a petition demanding that the World Health Organization follow ASEAN’s move by declaring a World Dengue Day, focusing global efforts on tackling the disease which threatens up to half the world’s population. The petition has collected over 26,500 signatures.

“Growing population densities, unplanned urban development, poor water storage, and unsatisfactory sanitary conditions are all common factors that contribute to the worsening burden of this mosquito-borne disease — not just for ASEAN, but for many countries around the world,” the society said in its online petition.