Kolkata rains: Intermittent dry spells ring alarm bells in dengue season

KOLKATA: The alternating wet-and-dry spells have raised the fear of a

dengue

outbreak in the city. The disease, which has so far been restricted largely to the northern fringes of Kolkata, could spread in the prevailing weather conditions that are ideal for an epidemic, warned experts.

With last week’s heavy showers leaving extensive areas replete with stagnant water — an ideal breeding ground for the virus-carrying aedes aegypti — the relatively dry and humid days this week will help larvae multiply. So far, three persons have succumbed to dengue since June.

Over the last three years, end-July and early-August had seen a massive spurt in dengue cases, pointed out

Irfaan Akhtar

, consultant microbiologist and infection control officer,

Fortis Hospital

. “This is the period when the disease spreads. It invariably originates in the Dum Dum-Salt Lake belt and travels along EM Bypass where construction activities are rampant. Last week’s heavy rain and the brief dry, humid period that followed are causes for concern,” said Akhtar. Aedis aegypti larvae breed in fresh, clean water.

Even though the number of patients has been low so far this year, the city’s just entering the worst phase, according to Debashish Saha, consultant, AMRI Hospital. “The temperature has ranged between 28°C and 32°C, which is ideal for aedis aegypti to breed,” said Saha.

But a few heavy spells of shower like the one on Thursday afternoon could help curb the spread, Saha added. “The more intense the rain, the better are the chances of the larvae getting wiped out,” he explained.

The next two weeks could be crucial and the rain pattern will determine if dengue will spread, according to Animesh Gupta, senior consultant (general medicine and critical care), RN Tagore International Institute of Cardiac Sciences. “In August, the intensity of rain varies. So, a wet spell is often followed by a lull, allowing water to collect. A five-day dry spell could be enough to breed larvae,” said Gupta.

But efforts by the civic bodies have helped keep an epidemic at bay. “Five years ago, when Kolkata had a major epidemic, people would hardly get blood tests done in time. But now, blood tests are quickly done and more people seek treatment early,” said Akhtar.