Dengue threat lurks over Karachi

In her tiny flat close to the congested Saddar Bazaar of Pakistan’s port city of Karachi, housewife Saeeda Amjad, 30, carefully closes the windows. "The Karachi breeze in the evenings is really pleasant, and normally we would leave the windows ajar, but now the dangerous mosquitoes are back," says Saeeda.

Saeeda has also hung insect repellent coils in her living room to protect her three children from the black-and-white-striped female 'aedes' mosquito, which carries the dengue fever virus.

Symptoms of dengue fever vary according to a patient’s age, but it is characterised by a severe, flu-like illness that affects infants, young children and adults. The disease seldom causes death.

Dengue haemorrhagic fever (DHF) is a potentially deadly complication with high fever, red or purple spots on the body - often with enlargement of the liver - and in severe cases, circulatory failure.

According to the World Health Organization, dengue has recently become a major public health concern globally. It is generally found in tropical and sub-tropical regions, and more specifically in urban and semi-urban areas.

In 2006, 4,600 patients were admitted to hospitals in Karachi, a city of at least 14 million people. Of these patients, 1,600 were confirmed to be suffering from dengue fever. There were at least 52 dengue-related deaths last year in Sindh province, almost all of them in Karachi. It is thought other deaths may have gone unreported, with patients not being admitted to hospitals, especially if they lived in remote villages or towns.

With recent hotter weather in Karachi and rain creating small pools of still water all over the city, there has been a new outbreak of dengue fever in the city, home to at least 14 million inhabitants.

Dengue at a glance

WHO estimates there may be 50 million cases of dengue infection worldwide every year The disease is endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, Southeast Asia and the Western Pacific In 2001, there were more than 609,000 reported cases of dengue in the Americas, of which 15,000 were dengue haemorrhagic fever (DHF) Not only is the number of cases increasing as the disease spreads to new areas, but explosive outbreaks are occuring, the world health body warns An estimated 500,000 cases of DHF require hospitalisation each year, of whom a very large proportion are children At least 2.5 percent of cases die Without proper treatment, DHF case fatality rates can exceed 20 percent With modern intensive supportive therapy, such rates can be reduced to less than 1 percent

Three patients confirmed to be suffering from the illness were admitted to the Agha Khan University Hospital in Karachi between 12 and 24 February, Dr Abdul Majid, Sindh’s special health secretary, confirmed.

Hospitals continue to receive new patients on almost a daily basis suspected to be suffering from dengue.

Health specialists have been warning for weeks that the disease could resurface in Karachi, as winter ends and warmer temperatures produce conditions conducive to the hatching of the aedes mosquito eggs.

Disease could spread

At a seminar held at the Dow University of Health Sciences at the end of February, Professor Khalid Mehmood warned that the disease could spread across Karachi at any time. He and other experts have called for large-scale anti-mosquito spraying as part of measures to tackle the threat.

Abdul Majid stressed the government was taking measures to prevent a wider occurrence of the disease. A dengue unit has been set up by the Sindh government to supervise improved hygiene and mosquito extermination.

It is not only Karachi that is being affected. Even before winter has fully passed in the eastern Punjab province, at least 10 cases have been reported there.

Of these, two victims - a young labourer in the central Punjab town of Daska who had recently returned from Karachi, and a young woman visiting from Australia who was admitted to the Sheikh Zayed Hospital in Lahore - have died.

It is not known where they contracted the dengue virus.

Until 2006, Pakistan had no significant dengue problem, but health experts now say more needs to be done as the situation has changed.

"The dengue virus can spread rapidly, especially as the number of infected people among the population expands. People still know very little about this disease and they need to be educated on how to prevent it," Dr Shahid Qaiser, a Karachi-based physician, said.

Official campaigns last year focused on the need to drain reservoirs of standing water, even in flower pots or old tires, and to prevent mosquito bites by using netting and repellents. The government is now planning to renew this drive, getting the message across through television.

But whether this will be enough will only be known in the months ahead as warm weather brings swarms of mosquitoes to Pakistan’s cities.

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