The state government has instructed officials overseeing construction sites across Calcutta to ensure “all open pits where water might accumulate and remain stagnant” are “closed immediately” ahead of the dengue season.
In a recent circular issued by the PWD, engineers have been told that they would have to see to it that proper “drainage is ensured so that water does not accumulate in any part” and water should not be allowed to collect in debris at construction sites.
Air-conditioners will have to be cleaned regularly and “unwanted vegetation” should be removed so that mosquitoes do not get a chance to breed.
The circular states “construction sites have to be especially monitored so that mosquito larvae do not breed in the site” and “rubbish/garbage/debris should be removed”.
Sources in PWD said the circular had been sent to engineers who are in charge of construction sites across Calcutta, including the Assembly, Writers’ Buildings and the Nabanna Annexe.
At a meeting held recently, chief minister Mamata Banerjee had asked all departments to take immediate preventive steps to stop breeding of mosquitoes and prevent an outbreak of dengue, officials said.
The dengue virus is primarily spread by the Aedes aegypti mosquito, which is known to breed in clean, stagnant water. It takes a week since an egg is laid for an adult mosquito to emerge.
So, public health experts urge people to flush out stagnant water at least once a week.
About 3,000 people had tested positive for dengue in the Calcutta Municipal Corporation area last year. Unlike in the past, when dengue would rear its head during the monsoon, people had tested positive for the disease in almost every season last year.
“The kits that are used (for testing blood samples for dengue) need to be changed. The viruses are undergoing mutation and showing multiple strains. So, at times when a patient is showing all symptoms of dengue, the test is turning out to be negative,” said Amitabha Nandy, the director of the Centre for Studies on Infection and Immunity.