Dengue came back with the arrival of monsoon, infecting at least 42 people, most of them admitted to Dhaka Medical Collage Hospital, Holy Family Red Crescent Hospital, Dhaka Shishu Hospital, Al Raji Hospital and Samorita with dengue haemorrhagic fever since early June.

"This year dengue has struck the city earlier than expected in a sign of alarm," said Dr Rabeya Baten, medical officer of Samorita Hospital, who has received four patients early this month.

According to the health directorate control room, at least 195 people died of dengue and 14,089 were infected up to 2002.

DCC Chief Health Officer Azizul Hoque wrote to different city hospitals and clinics on June 20, asking them to keep the DCC posted on dengue patients and the areas they came from.

"On information, we will mark the areas as risky and launch a mosquito control drive there," a DCC health officer said.

The anti-mosquito drive hit snags as over 400 of 1,352 hand foggers went out of order and more than 300 machines went missing. Only about 500 machines are now working in the city's 10 zones.

"The inoperative machines were dumped at the Mosquito Control Department (MCD) in Lalbagh, DCC's 10 zonal offices and Nagar Bhaban," said an official of the DCC health department.

But neither the DCC health department nor the zonal offices asked the authorities to repair the inoperative machines.

DCC's senior pest control officer, Dr Nasim Us Seraj, said: "The breeding of larvae is under control."

The DCC-run aedes surveillance and monitoring cell was closed mysteriously amid the spread of dengue in 2002.

This year round, the DCC will not be able to fight dengue because of long suspension of surveillance, experts fear.

"We need more information on dengue-risk areas to take special measures. Now we are in the dark about which areas should get priority," another DCC official said.

"We are not sure whether information on dengue will be available, as hospitals are not obligated to update us on incidence of the disease," he said.

Before the closedown of the surveillance cell in 2002, the DCC identified at least 26 possible aedes-breeding zones, including Gulshan, Banani, Dhanmondi, Baridhara, Kalabagan, Kanthal Bagan, Jigatala, Lalbagh, Hajaribagh and Shankhari Bazar.

The DCC then marked eight of its 10 zones as having alarming concentration of aedes mosquitoes. The presence of 20 larvae in a container is said to be normal, the limit which has been far outstripped over the years, raising the number to 215 in a container.

The number of adult aedes mosquitoes in the city rose up to 10 times the normal. Unchecked infestation of eggs and larvae has allowed zillions of adult mosquitoes to grow. "The situation has not been changed so far," the health official said.

Experts said eggs of aedes could survive even for two years in odd weathers making cyst. When they come in touch with water for two or three days, they become larvae and aedes spreads its wings to strike.

This year the risk of dengue haemorrhagic fever is high, specialists predicted. During the monsoon, aedes larvae breed high in stagnant water around households.

"If preventive measures are not taken now, dengue will spread wide in two weeks," Rabeya Baten said.

The government allocated Tk 15 crore in proposed mosquito control budget for the fiscal 2004-2005, up from Tk 12 crore for the fiscal 2003-2004.

The health directorate has got approval for purchase of 90 new fogging machines. "Five fogger machines will be working in each ward from now on as part of dengue control measures. We will get Tk 90,000 for announcement by microphone in a ward to build anti-dengue awareness," the DCC chief health officer said.

The ICDDR,B research centre says the latest DCC larval survey found the highest aedes egg concentration in rooftop uncovered water tanks, open cemented water tanks in under-construction buildings and tyres in the open.

Dengue and dengue haemorrhagic fever have emerged over the years as a major public health risk. The primary vector mosquito has spread throughout the tropics and into susceptible human populations in urban areas.

Runaway urbanisation created new breeding grounds for the vector and quickened the spread of the disease.