Apart from a few moments of suppository-induced respite, his temperature would not drop below 103 degrees Fahrenheit, according to his mother Khadija Begum.
Concerned about his condition, his family got him tested for dengue and the result came back positive. Soon afterwards, Fahim had to be admitted to a hospital when his platelet count began to drop, his mother said.
The recent plunge in COVID-19 infections can only offer small comfort to Bangladesh's strained public healthcare system as the attention shifts to a perennial health crisis -- dengue.
Worryingly, the mosquito-borne viral infection appears to be more prevalent among children under the age of 10 this time.
Experts blamed the authorities for failing to destroy the breeding grounds of the dengue-carrying Aedes mosquitoes.
As a result, children as young as 6 months of age are currently languishing in the dengue ward of Dhaka Shishu (Children) Hospital. Aside from the medicines, some of them needed IV fluids to treat the condition.
Parents of the hospitalised children also called into question the initiatives taken by Dhaka's city corporations to quell the threat of dengue.
Fahim's family believe that he may have contracted the virus while playing outdoors with other children in the neighbourhood.
"We live in Moddho Pikepara. There is an under-construction building next to our house which has a deep pit and it is now filled with water. That is a breeding ground for dengue mosquitoes," Fahim's brother Habibur Rahman said.
"There's no routine effort to deal with mosquitoes there. Sometimes, they (exterminators) come once a month."
According to the Directorate General of Health Services, 16,451 patients sought treatment for dengue this year, the second-highest tally of cases in the past 22 years.
As many as 6,349 people were hospitalised for dengue in the first 22 days of September. Among them, 13 have died.
Another 254 dengue patients were admitted to hospitals across the country in the 24 hours to 8 am Thursday, with 23.9 percent of them aged under 10 years. At least 3.2 percent of those patients were aged below one year and 20.6 percent belonged to the age range of 11 to 20 years.
Hospitals have been admitted dengue patients under the age of 10 for three days in a row, they said.
On Tuesday, 28.4 percent of the dengue patients were below 10 years, according to the health directorate.
The doctor then ran a dengue test and suggested that she be admitted to a hospital, according to her mother Shila Akhter.
Shila is at a loss as to how or when her child got bitten by a mosquito. "She only goes out for tuition and to play with other kids. I don't know [when a mosquito bit her]. We tested her for dengue only when she started vomiting and had diarrhoea,” she said.
Like other parents, Shila also lamented the city authorities' initiatives to annihilate Aedes mosquitoes.
"No matter how much we clean our home, it will be futile unless our surroundings, roads and alleys are also clean. It is the city corporation's responsibility to spray pesticide (to kill mosquitoes)".
“Today my daughter contracted the disease. Tomorrow it'll be someone else's child. They must conduct the cleaning drive."
Two-year-old Zakia, who lives in Kalyanpur, is taking IV fluids to recover to regain some of her strength.
Last year, everyone in Zakia's family except for her contracted dengue, said her mother 'Shilpi'. But this time, Zakia is the only one to catch the virus.
“Her body temperature shot up to 104 degrees Fahrenheit and would hardly come down. Then, she tested positive for dengue. Now she's a bit better."
Shilpi urged everyone to keep their homes clean in a bid to combat the dengue menace. "This Aedes mosquito must be breeding somewhere. Or else, why would dengue spread like this?"
A slew of children with high fever has been visiting the emergency department of Shishu Hospital in recent days.
Dengue patients have been on the rise at the hospital since August, most of whom were below 10, said Medical Officer Sultana Rima.
“Most of them suffer from fever, while some of them have diarrhoea, headache and nausea. We're admitting those who are in severe distress and asking the others to stay home and take treatment. They should get tested again and show us the result."
Children aged below 10 years wear clothes that leave most of their bodies exposed, and therefore, they are more susceptible to mosquito bites, said public health expert Dr Lelin Chowdhury.
“You'll see that in a family, it is mostly children who are contracting dengue. This is because the older members wear clothes that cover their bodies better while going out. When the mother works at home, she is moving inside the house doing her chores."
“But children have most of their body parts exposed as they wear short clothes when at home, whether they are playing, watching cartoons or even sleeping. Sometimes in summer, they are left unclothed because of the heat. The mosquitoes, therefore, can easily bite children," he said.
The foremost means to curb the dengue menace is to kill the mosquitoes or at least control its breeding, the physician said.
"We need to ensure there is no stagnant water pool in and around the house. Pesticides should be sprayed to kill mosquitoes and larvae. The local administration and the city corporation must do it regularly."
A clean household without any stagnant water body can never be a breeding ground for mosquitoes. But even then, the threat of dengue will remain if the surroundings are not clean as the Aedes mosquito can fly up to 100-200 metres, Lelin said. "Mosquitoes can breed in a public place a few metres away from our home and then bite us inside the house. This is not solely the responsibility of an individual," he said.
The local government, as well as citizens, must play their part properly to prevent the spread of Aedes mosquitoes, the public health expert said.
He recommended dressing children in long pants and full-sleeved shirts as well as using mosquito nets to protect them from the disease.
WHAT DHAKA CITY AUTHORITIES SAY
Dhaka's bifurcated city authorities said they are conducting a two-pronged drive to contain the spread of dengue, but they believe greater public awareness is needed for the initiatives to succeed.
Dhaka South City Corporation CEO Farid Ahmed said, "We are conducting a combing operation. The health directorate is providing information about the dengue hotspots and based on that, pesticides are being sprayed around vulnerable houses.”
He hopes that the dengue outbreak will be brought under control within the next two weeks. “People lacked awareness [about the disease] before. But that is changing now. It is only possible to contain the spread of dengue if there is mass awareness.”
Brig Gen Md Zobaidur Rahman, chief health officer of Dhaka North City Corporation, said the authorities were carrying out mosquito eradication programmes in each area every week.
"We are taking a lot of measures to control dengue. We are trying to get people to know and understand the threat. When people become more aware, dengue will be less prevalent.”
He also stressed the need for public participation in the fight against dengue. "If someone stores water in a tub or somewhere in a rooftop garden, we can't throw it away. We do not have access to these places. Self-awareness is very important in these cases.”