The pre-Diwali rain has added a deadly sting to vector-borne diseases and the showers have marred the shopping spirit.

“This rainfall is causing water accumulation and creating more breeding places for mosquitoes. So the chances of the diseases being transmitted have increased,” said Amitabha Nandi, the director of the Centre for Tropical Medicine and Parasitology.

Saraswati Biswas, 53, a resident of Chetla Road, died at MR Bangur Hospital early on Sunday, taking the death toll from vector-borne diseases to 11 since last month.

“A local doctor had said she was suffering from viral fever but when her condition deteriorated on Saturday we admitted her to the hospital,” said Pramatha Biswas, the grieving husband. Sharmila died at 4.30am on Sunday.

The death certificate issued by the hospital stated the cause of death to be “cerebral malaria”, which experts said meant malignant malaria.

If the vector-borne diseases have spread fear in the time of festivity, the weekend showers that threaten to intensify have drowned Diwali shopping.

New Market wore a sorry look on Sunday with shops open but shoppers few.

“I have sold only five pairs of shoes all day,” said Sanjay Tewary, sitting idle in his 100-sq ft ladies footwear shop on Lindsay Street.

At Bazi Bazaar, the makeshift market on the Maidan with 80 stalls selling fireworks on the Maidan, footfalls were few and far between.

“We hardly had any customer flow. We spent the day saving the fireworks from the rain,” said a trader, who was banking on the Bazi Bazaar sales to see him through till the end of the year.

If shopkeepers were scurrying for cover, the state health department officials were scrambling to control disease and damage. The director of health services Sanchita Bakshi said her department was working in coordination with the Calcutta Municipal Corporation (CMC) to combat the threat. “We have asked the CMC to take all steps for vector control,” Bakhsi said.

But at Lady Dufferin Hospital, 23 of the 53 trainee nursing staff were reported to be suffering from dengue. “We had conducted blood tests of all 53 students and some of them tested positive, the results of which were made available on Saturday. The entire report has been sent to the state health department,” said Tanima Mondal, the medical superintendent of the hospital.

The CMC authorities had earlier slapped a notice on the hospital for allowing accumulation of water inside the campus. The potential breeding ground for mosquitoes is now an even bigger menace given the incessant rain.

Deaths due to vector borne diseases:

• Dengue: 3
• Malaria: 5
• Japanese Encephalitis: 1
• Meningoencephalitis: 1

One woman died due to unknown fever yesterday but with symptoms of dengue