Will the dengue outbreak get worse in coming months?
Apart from climatic issues, the duration of a dengue outbreak actually depends on anthropogenic (environmental changes caused by or influenced by human activities) reasons as recent data suggest that dengue is no longer confined to monsoon
After going through the deadliest month ever in terms of dengue outbreaks with 342 tolls and 71,976 infection cases, the ongoing September has so far seen fewer possibilities of containing the virus soon as more than 2,500 new dengue patients are being hospitalised every day.
Till 20 September, the dengue-related death toll reached 274 although 10 days were left in the month. Experts have apprehended that the monthly death toll would surpass the record of August with the unabated transmission of the deadly virus.
Last year, October was the peak of the dengue outbreak with 21,932 infection cases while November witnessed 113 – the monthly highest in 2022 – deaths due to dengue.
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So, what is waiting ahead, particularly in October and November, when the country has been experiencing a delayed monsoon?
This is noteworthy that entomologists often term monsoon season as suitable for increased propagation of dengue virus-carrying Aedes mosquitos. They have already warned that the dengue outbreak will continue till November this year with an inflated infection rate outside Dhaka where dengue tests and anti-mosquito campaigns are comparatively weakest.
Moreover, a shortage of intravenous (IV) fluids in the market will only make the situation worse.
Unfortunately, the vector-borne dengue virus has labelled 2023 as the deadliest year for Bangladesh given the 867 deaths till 20 September. The dengue outbreak in Bangladesh was first highlighted officially in 2000. Between 2000 and 2022, 853 people died of dengue virus.
Apart from the climatic issue, the duration of a dengue outbreak actually depends on anthropogenic reasons as recent year data suggest that dengue is no longer confined to monsoons.
Professor Dr Kabirul Bashar, from the zoology department of Jahangirnagar University, explains how human-made causes determine the duration of a dengue outbreak.
"Dengue virus spreads geometrically when we fail to contain the density of Aedes mosquitos. On the other hand, the cycle of virus infection breaks if the infected patients stay inside mosquito nets.
So human activities will actually determine whether the outbreak will continue to November or stop in October this year," Kabirul recently told The Business Standard.
An analysis of the dengue-related death tolls in the last couple of years suggests that the year 2019 witnessed the highest monthly infection (52,636) as well as death (83)cases in August.
In 2021, the country saw the highest monthly deaths(34) in August but the highest infection cases (7,841)in September. The peak season shifted to October-November in 2022 with the monthly highest infection (21,932) and deaths (113) cases respectively.
The Directorate General of Health Services (DGHS)does not have complete data on dengue cases in 2020—the year ravaged by the Coovid outbreak.
The fact to worry about is dengue virus has been dominating outside Dhaka now. A survey by DGHS finds that the prevalence of Aedes mosquitoes has seen a sharp rise in rural areas with a notable increase in dengue cases in villages over the past few months.
Among the total hospitalised dengue patients, 60% are recorded at health facilities outside Dhaka. Until 2019, not a single district outside Dhaka recorded dengue cases.
The dominant strain responsible for the transmission of dengue in rural areas is Aedes albopictus, the survey finds. The species of Aedes comprises two main types – Aedes aegypti and Aedes albopictus. Aedes aegypti is predominantly found in urban areas, whereas Aedes albopictus is more active in rural settings.
According to entomologists, managing Aedes albopictus presents greater challenges compared to Aedes aegypti.
"Spead of the virus cannot be contained if it is not controlled within the territory where it originated. Due to the rapid movement of people, the dengue virus has spread from the capital city to villages where the anti-mosquito campaign is very weak," Kabirul said while expressing his concern, adding that the vectorial capacity of the Aedes albopictus urgently needs to be examined. Vectorial capacity describes the ability of a mosquito to spread a pathogen among hosts.
The spread of dengue across rural areas has become a serious concern in terms of emergency response. It has been evident that dengue test and treatment facilities have not been developed as much as in the cities despite having a vibrant community healthcare system that provides mostly maternity services.
People in rural areas, even if suffering from illness, are comparatively less conscious about their health than the city people. But when the health condition of dengue patients from rural areas deteriorates, they rush to Dhaka for better treatment. Often, their travel for medical purposes seems too late.
Recently, the director general of DGHS Professor Dr ABM Khurshid Alam termed dengue shock syndrome as a leading cause of fatalities.
The ails of IV fluid shortage
Apart from the requirement of necessary test facilities, the dengue-affected localities also need an adequate supply of medicines, particularly intravenous (IV)fluids. However, it has been reported that patients are now affected by a huge shortage of IV fluids due to the widespread dengue.
According to Dengue National Guideline, a patient needs IV fluids if he or she cannot have adequate oral fluid intake, or is vomiting, or experiencing impending shock and rising hematocrit despite oral rehydration.
In the open market, patients are being hostages of the shortage and the operational six private pharmaceutical companies producing saline are struggling to meet the demands.
The local companies collectively produce 1-1.2 lakh bags of IV fluids a day. But the amount seems inadequate this year.
Given the shortage of IV fluids, the Drug Administration has initiated importing 7 lakh bags of injectable saline from India.
Professor Sayedur Rahman, chairman of the Department of Pharmacology, Bangabandhu Sheikh Mujib Medical University (BSMMU), finds no problem with the import in an emergency situation. However, he questions the policymakers about the end of IV fluid production at the state-run factory operated by the Institute of Public Health (IPH).
"In the last couple of months, we have been seeing an increasing trend. But the main problem is the state-run IPH which produced IV fluids for the last five decades, cannot produce the product. Why?" Sayedur questioned.
The local private-run pharmaceutical companies export medicines to at least 150 countries while meeting 97% of domestic demand. Sayedur said, "Despite this, Bangladesh, a diarrhoea-prone country, is not self-sufficient yet in producing IV fluids for an emergency situation.
Why? The policymakers should answer the questions. Otherwise, the crisis of IV fluids will repeat in every emergency period."
To ensure an adequate supply of IV fluids and to control the "artificial" scarcity of medicine in the open market, the professor demanded that the imported saline bags be distributed around only the public hospitals through a government agency.
"Patients, particularly of the rural areas, will mostly visit the public hospitals. So, adequate supply of the necessary IV fluids must be ensured in there," Sayedur said.
