Dengue infection is spreading afresh in Dhaka and its surrounding districts. Experts have warned that the infection would linger in the country. "A large section of people are already exposed to infection with at least two out of four types of the deadly virus. Unfortunately, it is beyond the control of authorities," said one expert.

Official estimates said at least 90 people have died of Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) since July when the viral infection, unknown to many, broke out. However, unofficial death toll is much higher.

Some doctors treating dengue patients described the fresh attack as 'grave'. "We thought dengue infection would come to an end shortly but the recent rise in admission of such patients worry us a lot," said a doctor at Dhaka Medical College Hospital where most of the dengue patients in the city are admitted.

At a city clinic, another doctor who treated more than 200 dengue fever

cases said, "Patients who are conscious about the risk of dengue attack are getting admitted to clinics."

Government officials who had earlier said that the viral infection would not linger after November now says it might continue till the end of January. "Aedes mosquito population is still abnormally high. Until we can control it, dengue infection would persist," said Dr Kanak Ranjan Talukdar, Director of Disease Control.

Reports from various city clinics said admission of dengue patients is on rise. More than 800 patients were admitted to clinics last month. According to a WHO estimate, there are 50 million cases of dengue infection worldwide every year. Two fifths of the world's population 2500 million are at risk of such infection.

The latest WHO report on 'Dengue and Dengue Haemorrhagic Fever' said not only the number of cases are increasing as the disease is spreading to new areas but explosive outbreaks are also occurring. An estimated 500,000 patients are hospitalised in the world each year with dengue infection and roughly five per cent of them die, it said.