Fogging can be harmful to health if carried out too often: Health officials

With increasing number of dengue cases being reported across the state, officials said that they are under pressure to take more steps, including fogging, to prevent spread of the disease.

Speaking about their priorities, an official said that treatment of dengue patients was the government’s first priority. “We are trying to focus on the treatment of the patients. Controlling breeding of mosquitoes is secondary,” said the official. Meanwhile, city health officer Dr Senthil Nathan said, “We are using anti-larval sprays that kill the larvae in water bodies and storm water drains to prevent breeding of mosquitoes.”

He added that while spraying kills larvae, fogging kills adult mosquitoes but neither can guarantee a mosquito free environment. “Fogging outdoors, though done often, does not really kill all the mosquitoes,” said Nathan.

“When fogging is carried out outdoors, mosquitoes fly inside houses and when it is carried out indoors, they fly out of it. But the process does kill a large number of mosquitoes,” he added. The health officer also said that two fogging vehicles are sent to each zone every day to carry out fogging activities.

According to the World Health Organisation (WHO), fogging must not be carried out too often as it can pollute the environment. ‘Residents must remain outdoors while fogging is carried out inside their houses as it can cause allergic reactions if people inhale the gas,’ said a note from the WHO.

Meanwhile, director of Department of Public health Kolandaisamy said, “Fogging operations are not enough to protect everyone or prevent all dengue cases.”

He added, “To reduce and control outbreak of dengue, authorities and residents have to ensure that there are no breeding grounds such as water collected in waste tyres, drums and buckets in their areas. People should also take special precaution to not be bitten by mosquitoes early in the morning and evening.”