HEALTH-INDIA: Firecrackers, Cold Weather Help Ward off Dengue

By Ranjit Devraj Reprint | | Print |

Ranjit Devraj

NEW DELHI, Oct 29 2003 (IPS) - The noise from firecrackers during the Indian festival of light or Diwali and the onset of cold weather it marks were more than welcome news for experts this year, who attribute to them the sudden drop in the number of dengue cases here in the capital.

”We expect the situation to be fully under control within a week,” Dr K N Tiwari, director of health services at Municipal Corp of Delhi (MCD) said in the days after Diwali, which this year fell on Oct. 25.

The MCD has been receiving considerable flak for doing precious little as the mosquito-borne virus lay siege to the city in October, leaving 24 people dead and nearly 2,000 others hospitalised.

Tiwari attributed the sharp fall in new cases of confirmed dengue to 10 over the last five days to the dropping of night temperatures to 17 degrees Celsius, and to their not rising above 20 degrees Celsius since Oct. 22.

The spell of cool weather is producing conditions inimical to the Aedes Aegyptii or the striped tiger mosquito that harbours the dengue virus.

”The low temperatures affect the lifecycle of the mosquito, as they stop multiplying in temperatures below 20 degrees,” explained Dr N P Singh, officer for dengue at the government’s 1,550-bed LNJP hospital.

Authorities also believe that the incessant barrage of loud, smoky fireworks and firecrackers customarily set off around Diwali may have seriously decimated the mosquito population.

Indeed, such are the decibels and smoke levels generated at Diwali that the Indian Supreme Court had ordered the government to enforce from this year a ban on the bursting of firecrackers at night.

But last week, the government slowed down its anti-cracker campaign and allowed people to let off every manner of fireworks, braving criticism from volunteer groups campaigning for quieter and more environment-friendly Diwalis.

”It is really silly to associate cracker fumes with dengue-causing mosquitoes,” said Dilip Biswas, former chairman of the Central Pollution Control Board (CPCB) and a leader of the ‘Say No to Crackers’ campaign.

But municipal commissioner Rakesh Mehta thinks there is no great science involved: ”Everybody knows that mosquitoes cannot survive the smoke and the small explosions.”

Local authorities claim that they have not exactly been sitting back and letting the fireworks and cold weather take care of dengue.

The local body has been busy serving notices to several well-known institutions in the capital for allowing mosquitoes to breed on their premises – and these include St. Columba’s Church and the Press Club of India.

”We have more than 2,000 health workers on the job checking residences and other premises for larvae-breeding,” city mayor Ashok Kumar Jain claimed at a press conference last week.

Starting this week, the MCD will be deploying 134 portable fogging machines newly imported from Germany – costing 1,000 U.S. dollars each – to bring dengue under control, though the whole exercise has been criticised as being too tardy.

Another measure introduced this week is the exemption of schoolchildren from wearing uniforms so that they can use garments that cover their arms and legs and protect themselves from Aedes Aegyptii – a known daytime biter.

The last time the national capital was hit by a dengue epidemic in 1996, the onset of cold weather and a noisy Diwali also brought about a dramatic drop in incidence of the disease, characterised by bleeding gums, rashes and pain around the eyes.

Dengue can also lead to haemorrhagic fever, in which the blood platelet count drops drastically. This can lead to death unless blood transfusion and intensive care are provided, but this happens in less than one percent of cases.

”There is no cause for alarm as this is a known disease and not something new like the Severe Acute Respiratory Syndrome (SARS), where the virus had to be identified first,” said Dr Shiv Lal, director of the National Institute for Communicable Diseases and an expert on mosquito-borne diseases.

This year’s sudden resurgence of dengue has been attributed to an unusually good monsoon season that had above-normal rainfall and uniform distribution across the country. Thousands of cases of dengue were reported from the southern Kerala and Karnataka, western Maharashtra states.

But in spite of warnings and the 1996 experience with a dengue epidemic, the national capital, a city of 14 million people, seemed to have been caught completely unprepared.

It was only after a senior doctor at the prestigious All-India Institute of Medical Sciences, Vivek Mohanty, succumbed to dengue on Oct. 9 that alarm bells began to ring and forced the Delhi High Court’s intervention.

The court ordered civic bodies like the MCD and the New Delhi Municipal Corp to report directly to its officers on how many people are actually suffering from dengue and what is being done to contain the disease.