New Delhi: To contain the spread of vector-borne diseases such as malaria, dengue, and chikungunya, the New Delhi Municipal Council (NDMC)and SDMC have deployed a 3-step plan. First, is to spread awareness among residents and check for stagnant water (which is a breeding ground for mosquito larvae). The second is to get rid of existing mosquito larvae and the third is to kill adult mosquitoes.
Dr Vijay Patel, Senior Medical Officer, Malaria Action Plan, NDMC, said "there are currently eight active cases of dengue and 2 of chikungunya" in their jurisdiction.
"We employ two types of measures, anti larvae and anti-mosquito. To kill mosquito larvae in stagnant water in puddles, drains, etc., we wrote letters to all government building caretakers and CPWD engineers, asking them to get their overhead tanks covered if they're uncovered. We also wrote to the resident commissioners of all Bhawan (such as Bihar Niwas, Orissa Niwas, etc) in the NDMC area, asking them to cover their overhead tanks and not let rainwater collect on their premises", he said.
Another breeding ground is garbage that has been lying outside, and construction material near buildings, where standing water collects. This is the preliminary step. After that, the NDMC deploys Domestic Breeding Checkers (DBCs) to conduct house to house survey/checks. The DBCs go from house to house and check coolers, pots, etc for larvae and spray insecticides.
"If we find larvae for the first time, we issue a notice and spray insecticide. We advise them about hygiene and steps to stop mosquito larvae from hatching in their house. If we find larvae in the same residence again, then we issue them a challan", Dr Patel adds.
Speaking about the disruption caused by the coronavirus outbreak, he said, "However one problem we are facing due to the COVID-19 pandemic is that people are not allowing DBCs to enter their homes to check for larvae. But,
we still manage to check overhead tanks (in govt buildings) and coolers (in residences) since they are outside and don't require close proximity. Before the pandemic, we used to conduct awareness activities in schools but since classes have moved online due to the pandemic, we haven't been able to do so".
Dr LR Verma, Additional Medical Health Officer (Vector-Borne Diseases), SDMC said that among other insecticides, they also use a non-chemical pesticide, BTI (Bacillus thuringiensis var. israelensis), a microbial bio-pesticide. BTI is a genetically engineered pathogenic bacterium that produces a poison which only destroys mosquito larvae. Since the beginning of this year, there have been 26 reported cases of malaria, 42 of dengue, and five of chikungunya (as of September 12), in the SDMC area, Dr Verma said.
To kill adult mosquitoes, the NDMC, as well as the SDMC, employ fogging. Dr Patel said "fogging is mostly an eyewash measure. Fogging is only done in areas where an active case is found. Otherwise, we don't do general fogging. It
causes pollution and it temporarily removes mosquitoes from the area but doesn't kill them effectively. We want that mosquitoes shouldn't hatch larvae in the area in the first place." However, Dr Verma said, "while it might not be as effective as regularly spraying
insecticides, which we anyway do, it does reassure the general public, since it is a more visible measure, and that is also important".