Why so many dengue cases in Chennai?

By Shobana RadhakrishnanPavitharan*, a 30-year-old resident of Velachery, had a fever recently. Assuming it was a seasonal flu, he took over-the-counter medication and rested at home. On day three, he recovered from the fever. However, his fatigue remained and so he consulted with a doctor. The doctor ordered further tests and determined what Pavitharan had was dengue. The doctor also told him that his platelet counts were going down. Had he delayed the doctor’s consultation, the infection could have worsened.Pavithran says he is unaware of the source as his house does not have dengue-breeding points. “Corporation workers come for regular checks in our area. We do not have any waste material dumped at our home. Since I work from home, I was puzzled about how I contracted the virus,” he says.The Greater Chennai Corporation (GCC) asserts that it employs multiple mosquito control tactics. However, the number of dengue cases in Chennai and the state as a whole is gradually rising.As of September 1, 2024, Tamil Nadu has reported 11,743 dengue cases with four deaths. Of this, 57.6% of the dengue cases were from 10 districts including Chennai, Coimbatore, Krishnagiri, Tiruppur, Tiruvallur, Theni, Madurai, Tirunelveli, Thanjavur and Tiruchy while Chennai alone recorded the highest with 1,549 cases (13.8 %) cases, says the report from The New Indian Express..Compared to the 2023 yearly data where 9,121 cases were recorded in Tamil Nadu, we could see a sharp rise in cases in 2024. Notably, the number of dengue cases has also gone up since the outbreak of Covid-19 in 2020.Reasons behind the surge in dengue cases in ChennaiDr K Kolandaswamy, Former Director of Public Health and Preventive Medicine, points out that special drives to remove bulk scrap materials in the city have significantly reduced since the COVID-19 outbreak in 2020.Mosquitoes breeding in places with bulk scrap materials are infected with the dengue virus (transovarial transmission of the dengue virus), whereas those breeding in domestic areas are not. “This is why such bulk scrap materials are more dangerous hotspots than domestic areas and should be given special focus,” he says.Steps to control dengueSpecial drives for removing bulk scrap materials from private lands like workshops in Pudupettai (car scrap items) and Border Thottam (where old tyres are sold) used to be part of the routine activity pre-Covid. However, this has been significantly reduced over the past four years.Check at seized unused vehicles and remove them to control breeding. A lot of scrap materials were removed from railway yards in Perambur and Chennai Central during the 2017 dengue outbreak. It should be revisited now.Cities like Chennai have a lot of ongoing construction work for infrastructural development. Water stored for construction purposes in these areas is not attended to for many months altogether. This is one of the important hotspots to look into.Hospitals act as amplifiers as people from different areas come in every day. So it should be considered a hotspot.– Dr K Kolandaswamy, Former Director of Public Health and Preventive MedicineCitizen Matters reached out to the city government officials for their response. A senior health official says, “We are looking into scrap material removal at longstanding points not only in domestic areas but also in peri-domestic areas/ vacant lands, seized vehicles etc.”Measures taken by GCC to control dengue“The dengue cases are sporadic across all 15 zones in Chennai. This is a usual trend every year. The cases start increasing in August and go on up to November. We do not have an alarming situation now,” says the health official, adding that the GCC has intensified the domestic and peri-domestic breed checking.Kayalvizhi, Councillor of Ward 179 in Chennai, says that the Domestic Breeding Checkers (DBCs) and the National Urban Livelihoods Mission (NULM) workers are deployed at each ward to go door-to-door checking for scrap materials like coconut shells, unused tyres, open overhead tanks or any old items dumped in a place with the potential to breed mosquitoes. The workers use Abate, a larvicide, to prevent disease vectors from breeding in open-water tanks and create awareness among the public. Fogging activities are also carried out to control the adult mosquitoes.Antony, a resident of Madipakkam, says he found DBC workers visiting the houses and fogging done regularly in his locality but the corporation was not making efforts to clean the canals that are potential breeding points..When the DBC/NULM workers find someone with a fever, they immediately flag the respective Sanitary Inspector of the ward and ask the patient to get the fever panel test done to identify dengue cases at the early stage.“We get reports from both private and government hospitals every day. We look for increases in fever incidences in specific areas. We count suspected dengue cases as well and mark them as hotspots. We then intensify the measures accordingly. Since the cases are sporadic now, we do not have large hotspots in Chennai,” adds the health official.“Once a dengue case is confirmed, we gather the patient’s profile. For instance, if the patient is a child, we carry out prevention activities at their school and surrounding areas,” says a ward-level health worker.Dr Kolandaswamy says such measures will help handle epidemic situations but cannot be used as a regular strategy. “We are unable to control the large campuses and remove scrap materials on a large scale and so we are using these measures as a routine strategy,” he notes.The health worker says they also face challenges in getting citizens to cooperate, “In some places, residents do not let us inside their houses to check for breeding points. For instance, trays used to keep the plants on and the refrigerator trays are also some of the breeding points. We cannot identify such issues unless the public cooperates.”Will drone fumigation help to control dengue cases in Chennai?The GCC uses tech support like drone fumigation in the canals and inaccessible vacant lands. Despite the GCC investing in drones, no bidder has come forward to operate those drones even after multiple tenders were floated this year. This has led to six drones of GCC lying unused..Meanwhile, the health official says that drone fumigation has limited use since water bodies in the city are flowing and not static. The CC has also been desilting the waterbodies to ensure the free flow of water during monsoon. Pic: GCCDr Kolandaswamy feels drones will not be helpful, “The lifecycle of the mosquito from egg to adult is around three weeks (21 days). These mosquitoes will have egg-laying capacity three times in their lifetime and thousands of eggs will be laid each time. It cannot be controlled with drone fumigation.”Post-fever period in dengue is crucial, says doctorsThe complication in dengue sets in only after the fever subsides on the fourth or fifth day. So, the patients should be monitored and consulted with the doctor daily after the fever subsides.Hydration through oral fluids is an important aspect of recovery. Tender coconuts, rice/rasam porridge and ORS should be made available at the bedside for dengue patients. “Exclusive ‘hydration nurses’ should be designated at the dengue wards. This will reduce the need for IV fluids,” suggests Dr Kolandaswamy.Since the symptoms of dengue, common flu and viral fever are similar (such as fever and body pain), people tend to take it lightly. “Patients come in for treatment when the complications have already set in. It is challenging to handle the case at that stage,” note healthcare workers. As viral fever is also rapidly increasing in the state, Tamil Nadu’s Health Minister, Ma Subramanian, has urged people not to self-medicate for fever and other illnesses.Dengue is not fatal. However, self-medicating with over-the-counter medicines and consulting with quack doctors could lead to severe complications, and sometimes, even death. Getting tested on time when one has a fever/body pain is the first step in the process of recovery and for the larger public good..The article was originally published in Citizen Matters and has been republished with permission. Read the original article here.