A study of Chikungunya outbreak in Delhi

Chikungunya virus, an alphavirus belonging to the Togaviridae family, caused large scale outbreaks in several parts of southern, western and eastern India in 2006. We report Chikungunya outbreak in Delhi in 2010. This study was conducted in the virology laboratory of Maulana Azad Medical College and associated Lok Nayak Hospital, Delhi from August 2010 to February 2011. Serum samples of 324 patients presenting with fever, arthralgia, myalgia, rash etc. were tested for anti-Chikungunya IgM antibody using MAC ELISA. 148/324 (45.6%) samples were positive for anti Chikungunya IgM antibody. More females were affected compared to males (1: 1.34). The most common age group affected was 31-40 year. Characteristically, paediatric age group was least affected with cases in children accounting for only 3.3%. The number of cases increased with increasing age group. The commonest clinical presentation was arthralgia (100%) followed by fever (88%). Complications such as bleeding manifestations and encephalitis were seen in 2.7% patients. This report confirms emergence and establishment of CHIKV in the northern region of India, which is also endemic for dengue viruses. There is an urgent need for early and aggressive vector control and containment measures for risk reduction.