Entomo-epidemiological investigations of chikungunya outbreak in Delhi, India

Abstract

Context: An outbreak of fever with severe joint pain started in the Palam area of Delhi in August 2010. An entomological and epidemiological investigation of this outbreak was conducted to ascertain the nature and cause of the outbreak. Aim: Aim of the study was to investigate the nature and cause of the outbreak and to contain its further spread. Settings and Design: It was a cross-sectional study conducted in the Palam area of south-west Delhi, situated at a distance of about 20 km from Medical College. It is one of the field practice areas for training of undergraduate and postgraduate students of Department of Community Medicine of Medical College of Delhi. Materials and Methods: All patients attending OPD of Primary Health Center (PHC) Palam, complaining of ever with incapacitating joint pain, were screened for chikungunya fever. Of the 750 suspected chikungunya patients, 130 blood samples were randomly drawn amongst these patients. Out of the 130 tested, 97 (70.8%) were positive for the IgM antibodies against chikungunya virus. House-to-house survey was conducted in the affected area for more cases and to find out the vector-breeding sites. Statistical Analysis: Frequency distributions were calculated for age and sex. Results: The main breeding sites of the mosquitoes were the desert coolers of houses, water stored in metal and plastic containers, and water collections at construction sites. Aedes mosquito was present in almost all the houses surveyed in the area. Conclusions: It was concluded that the routine campaigns need to be organized regularly within the community highlighting the potential breeding grounds of mosquitoes and the possible control methods. Source reduction strategies like cleaning of desert coolers on weekly basis, emptying of water containers, and close monitoring of construction sites for potential breeding of the vector needs to be done on a regular basis to avoid future outbreaks.