Background: The association of the present Chikungunya pandemic with a mutation in the Chik virus is already established in many parts of the world, including Kerala. Kerala was one of the worst-affected states of India in the Chikungunya epidemic of 2006-2007. It is important to discuss the clinical features of patients affected by Chikungunya fever in the context of this change in the epidemiology of the disease.

Aim: This study tries to analyze the clinical picture of the Chikungunya patients in Kerala during the epidemic of 2007.

Setting and design: A cross-sectional survey was carried out in five of the most affected districts in Kerala, India.

Materials and methods: A two-stage cluster sampling technique was used to collect the information. Ten clusters each were selected from all the five districts, and the size of the clusters were 18 houses each. A structured interview schedule was used for data collection. Diagnosis based on clinical signs and symptoms was the major case-finding strategy.

Results and conclusion: Of the 3623 residents in the surveyed households, 1913 (52.8%) had Chikungunya clinically. Most of the affected were in the adult age group (73.4%). Swelling of the joints was seen in 69.9% of the patients, followed by headache (64.1%) and itching (50.3%). The knee joint was the most common joint affected (52%). The number of patients with persistence of any of the symptoms even after 1 month of illness was 1388 (72.6%). Taking bed rest till the relief of joint pain was found to be a protective factor for the persistence of the symptoms. Recurrence of symptoms with a period of disease-free interval was complained by 669 (35.0%) people. Older age (>40 years), a presentation of high-grade fever with shivering, involvement of the small joints of the hand, presence of rashes or joint swelling during the first week of fever and fever lasting for more than 1 week were the significant risk factors for recurrence of symptoms predicted by a binary logistic regression model. In conclusion, we found that there is substantial acute and chronic morbidity associated with the Chikungunya epidemic of 2007.