Bangladesh does not have any updated information about the changes occurring in the genes of dengue virus, making it increasingly difficult to curb the deadly impact of the vector-borne germ infecting numerous people and causing deaths with a high mortality rate.
Virologists and physicians emphasise that for any viral diseases knowing the virus variants closely is essential for adopting pragmatic preventive actions, treatment and vector management plans.
Microbiology professor Tahmina Shirin, also director of the Institute of Epidemiology, Disease Control and Research, said that they were serotyping the dengue virus to identify the dominating variant of the four dengue serotypes.
Last week she said that the institute, the main government agency for such job, was planning for聽 genome sequencing of the dengue virus.
According to the Directorate General of Health Services, till 8:00am Saturday at least 271 people died and 55,663 others were hospitalised since January this year.
One individual died and 477 were hospitalised in the past 24 hours till 8:00am Friday, according to the health directorate.
The disease killed 1,705 people and sent 3,21,179聽 people to hospital in 2023 alone, while 853 deaths and 2,44,246 hospitalisations were recorded between 2000 and 2022, the DGHS data shows.
Dengue hospitalisations had been reported at 28,429 and 62,382, respectively, in 2021 and 2022, when the outbreak in the country caused 105 and 281 deaths respectively.
In 2019, over 1,01,354 dengue patients were hospitalised and over 276 deaths were reported. In 2020 during the Covid-19 pandemic, 1,405 people were hospitalised and seven died of dengue.
Observing the changing nature and symptoms of the disease, experts suspect that mutations by now have occurred to the dengue virus.
They said that being a RNA virus, dengue germ has its genome based on ribonucleic acid (RNA) which gives it the ability to mutate fast to adapt to the adverse environment.
The Covid-19 virus, which is also a RNA virus, had over 50 mutations in different countries, experts said, adding that such mutations might be occurring to the dengue virus also.
Virology professor Nazrul Islam, also former vice-chancellor of Bangabandhu Sheikh Mujib Medical University, have said that mutations are possible in the dengue virus as it is a common feature of the RNA viruses.
Physicians have observed many dengue patients getting hospital admission with symptoms different from those whom they treated in the past, while the death rate among the hospitalised dengue patients has gone up.聽
Entomologist professor Golam Sarwar of the National Institute of Preventive and Social Medicine, and also a member of the government expert committee to fight dengue, observes that apart from the dengue virus, the mosquito that acts as its vector is also highly likely to have mutated.
鈥楾he use of insecticides has certainly affected change in the cellular functions of the mosquito. I believe both the virus and mosquito have mutated but we don鈥檛 have the data making its management challenging,鈥� he said.
Physicians see changes in dengue symptoms as many patients are being diagnosed with the infection, while showing no typical symptoms of fever, pain or vomiting.
Tahmina Shirin said that they conducted virus surveillance in the first week of this October that showed the presence of three virus serotypes鈥擠ENV-2, DENV-3 and DENV-4 among total four serotypes.
She said that this year DENV-2 serotype dominated with infecting 70 per cent of the total patients. Serotype DENV-3 has been found in 20 per cent patients, while the DENV-4 is diagnosed among the rest 10 per cent patients.
Public health campaigners and virologists view that with the mutations occurring in the virus, its control mechanisms must also change.
For effective mosquito control, patient management and vaccination, authorities must have accurate data and evidence about the germ鈥檚 mutations, they said.
Mujibur Rahman, professor of medicine at Popular Medical College, said that mutations occurring in all the four serotypes of the dengue virus were highly likely.
He also mentioned about receiving patients with symptoms of Chikungunya infection, besides dengue patients.
In the past the two diseases did not usually occur at the same time in the country, Mujibur, also a former professor of Dhaka Medical College, pointed out, saying that finding Chikungunya patients in dengue season might indicate a changing pattern of the spread of the two infections caused by two different viruses.
Professor Mujib, however, could confirm Chikungunya through diagnostic tests in only two of his patients arriving with the disease symptoms, Others with the symptoms left without diagnostic tests, he said.
