GIS based community survey and systematic grid sampling for dengue epidemic surveillance, control, and management: a case study of Pondicherry Municipality

Authors:M. Palaniyandi, PH Anand and R. Maniyosai

Background of the study: The dengue epidemics have become major challenging problems in India, including Pondicherry Union Territories and have the national public health important for the recent years. The dengue epidemics were reported from 24 states/union territories of India with the total cumulative record of 206,142 cases and 872 deaths during the period of January 2008 to August 2014, especially it has been recorded high rate to 50,222 cases and 227 deaths, 75,454 cases and 167 deaths during 2012 and 2013 respectively. The both dengue and chikungunya have been transmitted by the Aedes genus mosquitoes (Ae aegypti or Ae. Albopictus). Hundreds of cases with multiple numbers of deaths occurred in Pondicherry, since 2007, and the huge number of dengue epidemics was reported in Pondicherry with 1102 cases and 5 deaths, 2215 cases during 2012, and 2013 respectively. Consequently, it has become very serious threat to the public in Pondicherry. The manmade breeding source of environmental determinants of dengue epidemic risk factors have been creating conducing environment and are fueling for sporadic disease epidemics in the city for the recent years.
Methods and Materials: The MapInfo 4.5 professional and the Arc View 3.2 GIS platform was used for applying the systematic 0.5 km X 0.5 km grid sampling procedure is applied for sampling, and the virtual GPS 12 XL is used to conduct rapid reconnaissance housing and the community survey for mapping the dengue vector mosquitoes breeding habitats positives with geo-coordinates of house locations and to assess the people’s perception against the dengue vector breeding habitats and the knowledge of protection measures against to the mosquitoes biting.
Result and Discussion: The present study is made for preventing the spread of dengue epidemic transmission, and to monitor its vector (Aedes aegypti) mosquito breeding environments, and a combination of environmental and socioeconomic variables to mapping areas at risk of epidemic transmission. These variables include mosquito counts, population density in inhabited areas, total populations in the blocks /wards, access to drinking water supply, Out of 12 wards, 4 wards (30%), found were identified as of high risk, namely, Villianur (Town), and followed by Villianur Pudu Nagar, Odiyampet, and Anna Nagar; 4 wards (30%), were identified as of medium risk, namely, Jaya Nagar and followed by Olugrate, Moolakulam, and Kamban Nagar, remaining 3 wards (30%) were identified as of low risk and 1 ward (10%), Anna Nagar extention, were identified as of no risk. The GIS based systematic grid sampling methods used can be implemented as routine procedures for control and prevention. A concerted intervention in the medium- and high-risk level blocks identified in this study could be highly effective in dengue vector habitats source reduction towards the control and management of epidemic transmission in the urban areas.
Conclusion: GIS has been used to visualize and identify spatial heterogeneity of dengue vector density in the urban area as a whole. Dengue vector mosquito (Ae. aegypti) data is used to assess current risk areas (Fig. 2), spatial agreements of correlating immature mosquito counts with environmental and socioeconomic parameters. The result provided that socioeconomic and environmental condition in the study region, estimates for identifying the socioeconomic and environmental key variables associated with dengue and chikungunya epidemics, visualising the risk of epidemic and vulnerable areas, estimates the population at risk of exposure to the epidemic, prioritization of areas/wards / blocks for vector control and management, GIS based spatial solution for vector control and management and a protective measures against dengue vector biting, and to be calling attention to the importance of dengue transmission at work, schools and other public spaces. The spatial component of transmission could be isolated, after controlling for variables of interest, thus contributing to future studies that consider new hypotheses and variables in the analysis. Consequently, GIS may perhaps, assisting to dengue epidemic surveillance and controlling the epidemic situation in the urban areas as whole.

.

 

Download Full Article: Click HereClick Heresee