Diagnosis of Chikungunya dominated co-infection with dengue during an outbreak in south India (2010 and 2012).

Following a report of dengue outbreak from January 2010 to 2012 in the Tirunelveli, Theni, Dharmapuri and Thiruvallur districts of Tamil Nadu state, India, an investigation was carried out. The study was to demonstrate the probable presence of Chikungunya viral antibodies in patients clinically suspected of dengue fever. Out of 331 samples analysed, dengue viral antibodies were observed in 14.8% (n = 49) of patients, while 16.6% (n = 55) were positive for Chikungunya viral specific IgM antibodies. In the four districts surveyed, patients found positive for Chikungunya were found to be higher than dengue. The clinician should consider Chikungunya in the differential diagnosis of dengue-like infection appearing in the community.