Dengue sees higher infection rate in November

Abu Hasan (pseudonym) lives in Deen Mohammad Colony in the capital’s Bhasantek. He had to spend October dealing with dengue patients after his sister, sister-in-law and maidservant were diagnosed with the mosquito-borne disease, and one of the patients required an intensive care unit (ICU) facility.

“I spent the entire month with patients and hospitals. Time, money and fear; altogether it was a miserable time. We were worried about our children,” Abu Hasan shared his experience with Prothom Alo.

Dengue showed no sign of restraint in November with the first seven days of the month seeing the highest number of cases and deaths in a single week this year so far.

Usually, the prevalence of the Aedes mosquito-borne disease drops in November, but this year saw an exception raising concerns among public health experts.

According to a research article published in the US-based Journal of Medical Entomology, dengue deaths and infections were very unusual considering the epidemiological trend of the virus in the country.

Public health experts, physicians and entomologists maintained there is a lack of effective measures for the prevention of dengue infection and the medical system was not overhauled either.

Thirty-seven deaths from dengue and 7,257 cases were reported between 1 and 7 November while 22 deaths and 5,726 cases were reported in the corresponding period of the previous month and 28 deaths and 7,115 cases were recorded in the last week (25-31 October) of the last month.

Usually, dengue cases start dropping in September, but the highest number of infections was recorded in October 2022 and the highest number of deaths in November that year. However, dengue infections fell in November 2022, and that did not happen this year.

Public health expert Mushtaq Ahmed expressed to Prothom Alo that November never saw such a rise in dengue infections and it reached a peak.

This situation may continue for at least 15 days, and if necessary measures are not taken more deaths are likely to occur, he stated.

As of 9 November, 342 deaths were reported in the country, which is the second highest in a single year so far. A record of 1,705 people died from dengue in 2023.

A monthly growth factor (the ratio at which dengue cases change in a month compared to the previous month) is considered to determine the spread of an infectious disease.

Najmul Haider, a researcher from Keele University, the UK, determined a growth factor of dengue virus infection based on the prevalence of the disease over the past 23 years. A Reach article was published in the Medical Entomology in this regard.

According to this research, Bangladesh sees the highest rate of 2.42 per cent in dengue prevalence in June, and that means dengue infection may rise by 2.5 times more in July. Dengue cases halves to 0.45 per cent in October from 0.82 per cent in September.

Data from the past 23 years show 0.45 to 0.53 per cent of dengue patients died in Bangladesh. So, more than 100 people might die this November as per this research.

The growth factor of the research is faulty since it did not consider the unusual rainfalls caused by climate change and mosquito increase rate, said Mohammad Shafiul Alam, a scientist at International Centre for Diarrheal Disease Research (icddr,b).

However, researcher Nazmul Haider told Prothom Alo that the disease growth rate will not match every year. Surprisingly, the growth rate also exceeded the record high. As many as 6,521 dengue cases were reported in August. So, the number of cases should have been around 8,000 but it was over 18,000, which is more than double than the estimation.

Dengue is an infectious disease, and it spreads uncontrollably for various reasons including temperature, rainfalls, environment and people’s immunity power.