Short Note 4 Essentiality of Source Reduction in both Key and Amplification Breeding Containers of Aedes aegypti for Control of DF/DHF in Delhi, India B.N. Nagpal, Aruna Srivastava#, M.A. Ansari and A.P. Dash Malaria Research Centre, 20 Madhuban, Delhi - 110 092 Delhi, the Capital of India, reported the city Municipal Corporation of Delhi (MCD). first-ever outbreak of dengue fever in The MCD organized a campaign aimed at 1967[1]. Since then the city has experienced source reduction, which was backed by cyclic epidemics every 2-3 years. During vehicle-mounted thermal fogging for the 1996, a large epidemic swept the city when control of the outbreak. However, the 10,252 cases were hospitalized and 423 reduction in the DF incidence was not deaths were recorded[2]. The disease has found to be commensurate with the inputs now become endemic and the yearly made into the campaign. At the request of incidence has varied between 160 and 300 the MCD, a team of experts from the cases of DF/DHF, with a couple of deaths[3]. Malaria Research Centre undertook a Aedes aegypti has been invariably found to comprehensive survey in five affected be associated with these outbreaks in Delhi. localities, viz. Dayanand Colony (Lajpat Overhead tanks (OHTs) and ground level Nagar Phase IV), Lajpat Nagar (Phases I and tanks (GLTs) as key containers, and II), Kotla Mubarakpur, Dayalpur Extension evaporation coolers have repeatedly been and Harsh Vihar – Tulsi Niketan, to identify reported as seasonal amplification sites[4,5]. both the key containers (OHTs and GLTs) The key containers maintain mosquito and the amplification containers breeding throughout the year, whereas (evaporation coolers, earthen pots, flower coolers amplify the Aedes population from vases, household ornamental fountains, etc.) May to November, and thereafter they go during November 2003 as per WHO dry[6]. techniques. The results of the study are included in this communication. During 2003, DF/DHF resurged in some localities in Delhi and a total of 2,604 The results of the larval survey of Aedes DF/DHF cases and 33 deaths were aegypti in five dengue-affected localities in registered up to 9 November 2003 by the Delhi as mentioned above are given in the # E-mail: [email protected], [email protected] 216 Dengue Bulletin – Vol 28, 2004 Source Reduction for DF/DHF Control in India Table. The results revealed that among the also interact with householders and key containers, out of 243 OHTs and 20 impress upon them to remove small GLTs, 64 OHTs (26.34%) and 8 GLTs (40%) water collections indoors/outdoors, were found positive for breeding of Aedes specially water evaporation coolers. aegypti. On the other hand, out of the 533 During the survey it was found that evaporation coolers, which are identified as fogging generally lacked a ‘pre-fogging the major amplification-breeding site, public information campaign’ requiring the checked, none was found positive for public to keep the house doors/windows breeding of Aedes aegypti. Ornamental open to permit the entry of fog. Health fountains inside the drawing rooms and workers, while interacting with mud-pots containing water for birds were householders, invariably talked about the supporting the heavy breeding (>1,000 removal of breeding from coolers and tanks larvae in each site) of Aedes aegypti. The but did not point out other sites of breeding. maximum positivity of OHTs was found in The crosschecking teams of the MCD also Kotla Mubarakpur (39.39%), followed by laid emphasis on inspection of evaporation Phases I and II of Lajpat Nagar (30%) and coolers as focal points and did not verify Dayanand Colony (20.69%). Two OHTs OHTs/GLTs and trash materials, as they located on the roofs of the market area were found it a time-consuming affair. In urban found supporting the breeding of Aedes areas, for security reasons or houses being albopictus. In a children’s home for boys locked, access by health workers into the belonging to the Social Welfare Department houses was also a constraint. of the Delhi Government, five out of 12 OHTs were found positive for Aedes aegypti In view of the aforesaid, it can be while two were found dry. It would thus concluded that: (i) source reduction should appear that during the MCD campaign, cover both the key containers as well as the source reduction efforts had concentrated amplification breeding sites, viz. evaporation on evaporation coolers, and key containers coolers and other trash articles breeding the and other trash materials breeding the vector species; (ii) the fogging operation species remained intact in domestic habitats. should be preceded by a pre-fogging information campaign in order to seek full cooperation of communities to derive IEC Activities of MCD optimal benefits from fogging; (iii) the IEC The IEC activities of the MCD generally campaign based on KAP studies should be covered the following aspects: prepared with particular emphasis on community participation; (iv) special efforts (1) Creating awareness through media and should be focused on behavioural change in spreading vocal messages through the accordance with the guidelines laid down use of loudspeakers in DF-affected by WHO[7]; and (v) health staff of the MCD localities, distribution of pamphlets, should be trained in entomological etc.; surveys/techniques related to Aedes (2) MCD workers who visit houses for breeding, prevention and its control. physical verification of breeding sites Dengue Bulletin – Vol 28, 2004 217 218 Source ReductionforDF/DHFCont Table. Breeding of Aedes aegypti in key and amplifier containers in dengue-affected localities of Delhi during November 2003 Key containers Amplification containers Ground level tanks Overhead tanks (OHTs) Evaporation coolers Other domestic containers Locality (GLTs) Examined +ve % Examined +ve % Examined +ve % Examined +ve % Dayanand 58 12 20.69 13 5 38.46 147 0 0 1 1 100 rol inIndia Colony (Lajpat Nagar Phase IV) Lajpat Nagar 80 24 30.00 – – – 138 0 0 2 2 100 (Phases I and II) Kotla 66 26 39.39 7 3 42.86 134 0 0 2 2 100 Mubarakpur Dengue Bulletin Dayalpur 5 0 0.0 – – – 69 0 0 – – – Extension Harsh Vihar – 34 2 5.88 – – – 45 0 0 – – – Tulsi Niketan – Vol28,2004 Total 243 64 26.34 20 8 40.00 533 0 0 5 5 100 * Ornamental fountain and trash –: NIL Source Reduction for DF/DHF Control in India Acknowledgement former Deputy Director, National Vector- Borne Diseases Control Programme, for his The authors are thankful to Dr K.N. Tiwari, valuable suggestions and guidance. We Municipal Health Officer-cum-Director, acknowledge the efforts of the field staff for Health Services, Municipal Corporation of assisting in carrying out the survey. Thanks Delhi, for providing assistance in the are also due to Mr Sanjeev Gupta for his conduct of the study, and to Mr N.L. Kalra, help in various ways. References [1] Balaya S, Paul SD, D'lima LV and Pavri KM. [5] Ansari MA and Razdan RK. Seasonal Investigations of an outbreak of dengue in prevalence of Aedes aegypti in five Delhi in 1967. Indian Journal of Medical localities of Delhi, India. Dengue Bulletin, Research, 1969, 57: 767-774. 1998, 22: 28-32. [2] Sharma S, Sharma SK, Mohan A, Wadhwa [6] Katyal R, Gill KS and Kumar K. Seasonal J and Dar L. Clinical profile of dengue variation in Aedes aegypti population in haemorrhagic fever in adults during the Delhi, India. Dengue Bulletin, 1996, 20: 1996 outbreak in Delhi, India. Dengue 78-81. Bulletin, 1998, 22: 20-27. [7] Parks W and Lloyd L: Planning social [3] Katyal R, Kumar K, Gill KS and Sharma RS. mobilization and communication for Impact of intervention measures on dengue fever prevention and control. A DF/DHF cases and Aedes aegypti indices step-by-step guide. WHO, Geneva, 2004. in Delhi, India: an update 2001. Dengue Bulletin, 2003, 27: 163-167. [4] Krishnamurthy BS, Kalra NL, Joshi GC and Singh NN. Reconaissance survey of Aedes mosquito in Delhi, Bull Ind Soc Mal Com Dis, 1965, 2: 56-67. Dengue Bulletin – Vol 28, 2004 219 .