Rapid, unplanned urbanisation is the main reason behind the current outbreak of dengue in West Bengal, medical professionals have said. They are of the opinion that large-scale construction work in Kolkata as well as semi-urban areas provide ample breeding grounds to the female Aedes aegypti mosquito, the vector of the disease which breeds in clean, stagnant water. As per the latest government estimates, 40 people have died due to dengue while at least 20,500 have been diagnosed with the disease.

Elaborating on the urban nature of dengue, virologist Amitava Nandi said the Aedes aegypti mosquito mostly breeds in stagnated water in containers. “Social change due to urbanisation has triggered a sharp increase in the use of artificial containers in cities. Products which were earlier sold in paper bags are sold in plastic packets and containers, providing more breeding space to the mosquito,” Dr. Nandi told The Hindu .

With container use becoming popular in semi-urban and rural areas, dengue is no longer confined to large cities, he added.

The medical professionals also pointed out that unplanned building construction without a proper drainage system in the semi-urban and rural areas contributed to the spread of dengue.

“Even in the rural areas of North 24 Paraganas district [which, according to the State government, is the worst affected by dengue], unplanned building construction has increased over the last decade,” said Shanta Dutta, director of the National Institute of Cholera and Enteric Diseases (NICED).

Till September this year, about 15% of the blood samples at NICED tested positive for dengue, she said. “Since late September, it has gone up to 40 to 45%,” she added.

The severity of the situation can be seen from the fact that 108 dengue patients are admitted in the State run Beliaghata Infectious Diseases (ID) hospital. “Apart from these 108 patients, 214 have been admitted with fever. If they are diagnosed with dengue, the number of such patients will increase,” said U.K. Bhadra, principal of the hospital.

They also point out that no curative medicine is available for dengue — only supportive treatment can be provided.

“Dengue deaths can be avoided with early detection and proper treatment. Increasing public awareness on the disease is the key,” said Dr. Dutta.