Researchers pin hopes on Wolbachia to tackle dengue in Bangladesh

A group of international researchers believes Wolbachia bacteria could offer an effective solution to controlling dengue in Bangladesh, raising hopes for curbing Aedes-borne infections.

The team has successfully introduced a strain of Wolbachia into Aedes aegypti mosquitoes that can adapt to Dhaka’s environment.

As a result, the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) is optimistic that this safe, biological method will prove effective in controlling dengue and other mosquito-borne diseases in the country.

On Wednesday, icddr,b announced that scientists from Australia’s QIMR Berghofer Medical Research Institute, icddr,b, and the United States Centers for Disease Control and Prevention (CDC) have jointly conducted the research.

The findings were recently published in the scientific journal “Scientific Reports”, a publication of Nature.

Wolbachia is a genus of bacteria naturally found in fruit flies and some mosquito species—but not in Aedes mosquitoes.

This bacteria cannot infect humans or animals, yet it prevents Aedes mosquitoes from transmitting dengue, chikungunya, and Zika viruses.

According to icddr,b, two approaches are being used to prevent mosquito-borne viral infections through the introduction of Wolbachia into Aedes mosquitoes.

These males mate with wild female mosquitoes, but the resulting eggs do not hatch—leading to a reduction in the overall mosquito population.

In the second approach, both male and female mosquitoes are released into the wild. The Wolbachia-carrying female Aedes aegypti mosquitoes spread the bacteria to other mosquitoes of the same species.

Whether they mate with Wolbachia-carrying males or not, the offspring of these mosquitoes will carry the Wolbachia bacteria.

HOW THE TRIAL WAS CONDUCTED

The icddr,b said their research utilised a strain of Wolbachia bacteria known as wAlbB, which is suitable for Dhaka’s warm and humid climate.

Researchers first crossbred Wolbachia-carrying Aedes aegypti mosquitoes, originally preserved at Australia’s QIMR Berghofer Research Centre, with mosquitoes collected from Dhaka.

Through several generations of breeding, they developed a strain called wAlbB2-Dhaka.

This strain is capable of transmitting the Wolbachia bacteria to its offspring via eggs.

The research team assessed the ability of wAlbB2-Dhaka Aedes aegypti mosquitoes to block dengue virus transmission.

Results showed that, compared with non-Wolbachia mosquitoes, these infected mosquitoes reduced the capacity for dengue transmission by 92.7 percent.

In controlled lab conditions, the team also monitored the breeding ability, fertility, and survival of these mosquitoes.

They found that the “good mosquitoes”, adapted to Dhaka’s environment, were just as capable of reproducing and surviving as the local mosquito population.

Mohammad Shafiul Alam, a scientist at icddr,b, noted that there may be concerns about releasing mosquitoes into the environment, but emphasised that these are not genetically modified.

“These are good mosquitoes,” he said.

“They naturally carry bacteria that are proven to be harmless and, in fact, beneficial,” he added.

“Wolbachia has been used safely in many countries and could open up a new path for Bangladesh in the fight against dengue and similar viruses.”

Lead author of the study, Hasan Mohammad Al-Amin, said: “This research lays the groundwork for conducting field-level trials in Bangladesh.

“While the laboratory results are promising, cautious planning and testing are essential before implementing it on a larger scale.”

icddr,b Executive Director Tahmeed Ahmed said the organisation is ready to support the government in the necessary trials to ensure the successful implementation of this promising approach using Wolbachia-carrying mosquitoes.

He added, “Only after successful field trials should wide-scale release into the environment be considered. We have also made significant progress in dengue vaccine research.

“We’re hopeful about working with the government to accelerate local access to vaccines—something that could offer an integrated solution to the country’s dengue crisis.”

In recent years, Bangladesh has seen a sharp rise in dengue cases. In 2024, 101,214 patients were hospitalised due to dengue while in 2023, the number reached 321,179.

Last year, 575 people died from dengue, and in 2023, the death toll was 1,705.

As of Wednesday this year, 2,858 patients have been admitted to hospitals across the country, with 20 reported deaths.