The stop-start rain over the last couple of days is ideal to create mosquito breeding sites that must be destroyed with urgency in the next few days to prevent a spurt in the mosquito population, doctors and entomologists said on Monday.
The Alipore Met office ruled out rain for the next few days. The second half of Monday had a clear sky with a visible sun.
Heavy rain washes away eggs laid by mosquitoes but drizzles or light rain provide the water required for eggs to turn into adult mosquitoes.
An entomologist said dry and humid weather for a few days following rain are the ideal conditions for mosquitoes to breed. “The rain over Saturday and Sunday has created many waterlogged pockets,” said Amlan Das, an associate professor of zoology at Calcutta University.
“If the water is not cleared in the next week, the water will then become ideal breeding grounds for mosquitoes,” said Das, who specialises in entomology.
About 300 dengue cases have been reported in Kolkata since January and about 2,300 malaria cases have been reported in the same period, said an official of Kolkata Municipal Corporation (KMC).
KMC field workers are supposed to visit any place in a ward at least every 10 to 14 days. Many Kolkatans had told The Telegraph recently that field workers were visiting their neighbourhoods with longer gaps or had not visited at all in recent months.
A KMC official said each ward had about 25 field workers who are divided into groups to visit the wards. Their task is to look for mosquito breedings, and clear and spray larvaecides.
Mayor Firhad Hakim said on Saturday that the KMC was conducting a more intense awareness campaign against vector-borne diseases now than it was doing before.
The website of the World Health Organization (WHO) says that dengue can be prevented by “preventing mosquitoes from accessing egg-laying habitats”, “disposing of solid waste properly and removing artificial man-made habitats that can hold water” among others.