Clinical features of chikungunya infection in Sri Lanka

Objective: To investigate the clinical features of chikungunya fever (CHIKF) outbreak in Sri Lanka in 2006 and to estimate the relative risk for CHIKF for various demographic factors. Methods: A total of 885 individuals belonging to 200 families were studied individually for surveillance of this disease, symptoms, contraction order within the family and means of treatments. Relative risks for CHIKF for demographic characters such as gender, age and educational levels were estimated. The associations of symptoms with age and gender were also studied. Results: The estimated surveillance of CHIKF in the studied population was 89.2%. The duration of suffering due to this disease was 50.9 d (95% CI, 47.3, 53.9 d) with fever for 3.9 d (95% CI, 3.7, 4.1 d). 93% of the CHIKF patients felt at least one type of joint pain and 8% felt joint swellings. Rash was observed in 15.1% of the patients. Buccal bleeding and mouth ulcer were observed in 1.5% and 9.3% respectively. About 22.7% of the CHIKF patients had vomiting. Female had 1.48 folder higher relative risk for CHIKF infection. The duration suffered due to CHIKF, duration of fever and contraction order within family were highly associated with age (P<0.000). Female patients had more than one folder higher relative risks for the symptoms such as rash, vomiting, buccal bleeding and mouth ulcer (P<0.000). Conclusions: The surveillance of CHIKF in Sri Lanka was a severe outbreak which infected much on female and caused more suffering on aged population. The symptoms such as rash, bleeding from mucosa, mouth ulcer and vomiting were highly associated with gender. The reasons for these observations need to be further explored.