by Nadeem Qadir and Nazrul Islam in Dhaka,
Good news maybe around as one of the major health hazards of Bangladesh — dengue — might be eliminated as experts say infecting mosquitoes with a naturally occurring bacteria which could eventually see an end to the disease carried by the winged insect.
A total of 391 people were diagnosed with dengue since the beginning of this year. Bangladesh had a major dengue outbreak last year with 101,354 people infected and of them 179 died by official figures.
In a recent breakthrough test in Indonesia, it showed the process dramatically reduced the ability of mosquitoes to transmit dengue.
It was found that releasing mosquitoes infected with the bacteria Wolbachia into parts of Yogyakarta city reduced the number of dengue infections by 77% compared with untreated areas.
“We are really hopeful this will lead to local elimination [of dengue] in Yogyakarta city, and the next stage is to scale up beyond Yogyakarta to other parts of Indonesia,” Dr Katie Anders, director of impact assessment at the World Mosquito Program, and one of the study’s lead researchers, was quoted as saying by Britain’s Guardian newspaper in Thursday.
Mosquito eggs infected with Wolbachia were gradually distributed to homes in the city over a period of around six months. In total, about 6 million mosquitoes were released across an area of 13 square kilometres, where they then infected other wild mosquitoes.
The report said the infected mosquitoes did not behave differently, nor did their population fall, but their capacity to transmit the virus that causes dengue was vastly reduced.
Bangladesh could move to test a similar process to lessen one major health hazard of the country.
Informed health officials in Dhaka said they were told to be alert from May for dengue attack, but due to late rains there has been no serious outbreak of the Aedes mosquito-borne disease characterised by high-fever as well as body ache. It can be fatal in some cases.
The first official outbreak of dengue fever in Bangladesh was in 2000, and since then the number of hospitalised patients has exceeded 3000 patients six times—6232 in 2002, 3934 in 2004, 3162 in 2015, 6060 in 2016, 10 148 in 2018, and 100 107 as of Nov 30, 2019, with estimated projections of more than 112 000 cases by the end of 2019.
In 2019 affects all districts of the country, exhibits a clear predominance in men (64·11% for men vs 35·89% for women), and primarily encompassed younger adults (whereby people aged 15–35 years accounted for 51·42% of 29 855 total cases).
The other factor could be the serious efforts this year by Dhaka’s two city corporations to clean places where the Aedes mosquitoes breed.
One study said as national surveillance is passive and only government hospitals are included, it is highly likely that substantial under-reporting is taking place. Furthermore, the operational surveillance is not based on appropriate methods, such as the WHO projection done in July, 2019, where an estimated 358 960 people were deemed to be infected compared with only 7179 cases in official reports.
Experts said the findings provide fresh hope in the battle against dengue, which has grown in prevalence over recent decades, spreading to previously unaffected countries, and causing larger outbreaks in areas where it is already endemic.
The World Health Organization recorded 4.2 million cases in 2019. There is no specific treatment for dengue.
Bangladesh has been mulling for a project in association with the International Atomic Energy Agency to draw up a plan to test nuclear technic to suppress the mosquitoes spreading diseases since the 2019 outbreak of dengue.
A pilot project was in discussion for introduction of the Sterile Insect Technique or SIT since Bangladesh’s Insect Biotechnology Division of the Institute of Food and Radiation Biology of the Atomic Energy Research Establishment has its basic infrastructure.
A scientific officer at the division said proposal seeking budget allocation was sent to the National Economic Council to launch SIT pilot project in early 2020.
The SIT is a type of insect birth control that uses radiation to sterilize male insects. These are released in large numbers to mate with wild females, which then do not produce any offspring, reducing the target insect population over time, according to the WHO.