The Calcutta Municipal Corporation (CMC) has spent nearly Rs 100 crore in the past 10 years to curb the mosquito menace in the city. Since 40 years before that, the civic body’s health department has had a wing dedicated to preventing mosquito-borne diseases.

After outbreaks of kalazar (spread by sand fly), cholera and enteric diseases (caused by flies) in the late-1970s, the section, known as mosquito-control wing, was renamed vector-control wing. Despite its presence, residents of the city have suffered from malaria, dengue and Japanese encephalitis every year.

This year, too, over 25 people have died of mosquito-borne diseases.

“What ought to have been done for curbing mosquito-borne diseases has never been done by the CMC. The infrastructure of the vector wing is not adequate to tackle the seasonal outbreak of diseases spread by mosquitoes,” said a civic official.

Metro spoke to serving and retired officials of the vector-control wing to find out about the steps taken to keep the vector menace at bay and how much more could have been done.

What the CMC has done in the past 10 years to control mosquito-borne diseases

• Appointed a full-time entomologist
• Sprayed larvicide on puddles after the monsoon
• Carried out anti-larvae operations in public institutions
• Increased the number of malaria clinics from 35 to 82
• Organised awareness campaigns after outbreaks of malaria
• Procured pesticide “over and above the central grant”
• Carried out fogging sporadically
• Kept malaria clinics open on Sundays and holidays
• Slapped caution notices on owners of premises where mosquitoes have been found to breed

What the civic body could have done to control mosquito-borne diseases

• Cleared clogged surface drains so that water could flow freely. Malaria and dengue-causing mosquitoes breed in clogged drains but do not lay eggs on flowing water.
  
  Most of the surface drains in Calcutta have not been cleaned for over 20 years. In many places, stalls have mushroomed by covering drains.
  
  “To clear the clogged surface drains, the civic body would have to remove the hawkers first. The CMC lacks the political will to carry out such an operation,” said an official.
  
  
  
• Ensured round-the-clock supply of filtered water so that households did not have to store water. Since filtered water is currently available only thrice a day, people tend to keep it in containers and tanks, which turn into breeding grounds of mosquitoes.
  
  For 24-hour supply the city needs 160 million gallons of treated water. The Palta waterworks alone produces 260 million gallons a day.
  
  “The civic body is capable of supplying water 24x7. But some administrative issues will have to be settled before that,” said an official.
  
  
  
• Opened a malaria clinic in every ward. There are now 82 malaria clinics in 141 wards. CMC officials claimed that they were in the process of setting up more clinics.
  
  
  
• Set up infrastructure for detection of dengue and Japanese encephalitis in the CMC clinics.
  
  Malaria is caused by parasites and can be detected through blood slide test. Dengue and Japanese encephalitis are caused by viruses, which can be detected only through a serum test. The CMC currently does not have the infrastructure for serum test.
  
  
  
• Employed an assistant entomologist in each of the 15 boroughs, as suggested by an Indian Council of Medical Research team in 2005.
  
  “There aren’t enough entomologists with the civic body. For vector control, we need qualified entomologists in every ward,” said a CMC official.
  
  
  
• Sprayed larvicide once every six days throughout the year. “At present it is done only after the monsoon. Larvae control should be done throughout the year,” said a CMC official.
  
  
  
• Carried out round-the-year awareness campaign on mosquito-borne diseases.
  
  
  
• Held regular anti-mosquito operations in collaboration with the railways, public works department, state health department and Calcutta Port Trust.