Wolbachia-infected mosquitoes could transform dengue control in Bangladesh: Study

A new scientific research offers fresh hope for controlling dengue in Bangladesh, as researchers develop a strain of Wolbachia-infected Aedes aegypti mosquitoes adapted to local conditions in Dhaka.

Wolbachia-infected mosquitoes, dubbed "good mosquitoes," carry a natural bacterium that blocks viruses like dengue, zika, and chikungunya from multiplying, significantly reducing their ability to transmit these diseases to humans.

icddr,b said in a press release on Wednesday (7 May) that the development brings Bangladesh closer to deploying a safe, biological tool to combat arboviral diseases.

The international team behind the research includes scientists from Australia's QIMR Berghofer Medical Research Institute, the University of Queensland, icddr,b, and the US Centers for Disease Control and Prevention (CDC).

Their study, titled "Fitness compatibility and dengue virus inhibition in a Bangladeshi strain of Aedes aegypti infected with the Wolbachia strain wAlbB", was recently published in Scientific Reports, part of the Nature [a scientific journal] portfolio.

In laboratory tests, the newly developed mosquito strain, named wAlbB2-Dhaka, demonstrated a 92.7% reduction in dengue virus transmission compared to uninfected mosquitoes.

Researchers also found that the Dhaka-adapted strain performed just as well as native mosquitoes in terms of reproduction and survival – key factors for large-scale release.

How it works

Wolbachia is a natural bacterium found in many insects, but not in Aedes aegypti, the main dengue vector. Scientists infect these mosquitoes with Wolbachia in the lab. The bacterium blocks viruses like dengue, Zika, and chikungunya from multiplying inside the mosquito, preventing transmission to humans.

Wolbachia is passed from mother to offspring, allowing it to spread naturally through mosquito populations. Over time, virus-spreading mosquitoes are replaced by Wolbachia-infected ones, reducing disease transmission and the need for chemical insecticides.

 Field trials

"There are understandable concerns about releasing mosquitoes, but these are not genetically modified. They carry a natural bacterium that makes them harmless and even helpful," said Dr Mohammad Shafiul Alam, a scientist at icddr,b.

"Wolbachia has been safely used in other countries and could serve as a powerful defence against dengue here."

Lead author of the research Hasan Mohammad Al-Amin noted that the findings set the stage for field trials in Bangladesh, although real-world application would require thorough planning and government collaboration.

In 2023, Bangladesh saw its deadliest dengue outbreak on record, with more than 1,700 deaths and over 321,000 reported cases. Urbanisation, climate change, and increasing insecticide resistance have made traditional mosquito control less effective – prompting the need for innovative approaches like Wolbachia.

To facilitate future trials, icddr,b has signed a Material Transfer Agreement (MTA) with QIMRB, securing access to the Wolbachia-infected mosquitoes for non-commercial use in Bangladesh.

"We are ready to support the Bangladesh government in conducting field trials of this promising method," said Dr Tahmeed Ahmed, executive director at icddr,b.

"In parallel, we are also advancing dengue vaccine research and would welcome collaboration to fast-track vaccine access through local trials."

If proven effective in the field, the Wolbachia strategy could become a vital component of Bangladesh's long-term strategy to combat mosquito-borne diseases.