RESUMEN
BACKGROUND: In addition to classical manifestations of Chikungunya infection, severe infections requiring hospitalization were reported during outbreaks in India in 2006. OBJECTIVES: To describe the systemic syndromes and risk groups of severe Chikungunya infections. STUDY DESIGN: We prospectively investigated suspected Chikungunya cases hospitalized in Ahmedabad, Gujarat during September-October 2006, and retrospectively investigated laboratory-confirmed Chikungunya cases hospitalized with neurologic syndromes in Pune, Maharashtra. Hospital records were reviewed for demographic, comorbidity, clinical and laboratory information. Sera and/or cerebrospinal fluid were screened by one or more methods, including virus-specific IgM antibodies, viral RNA and virus isolation. RESULTS: Among 90 laboratory-confirmed Chikungunya cases hospitalized in Ahmedabad, classical Chikungunya was noted in 25 cases and severe Chikungunya was noted in 65 cases, including non-neurologic (25) and neurologic (40) manifestations. Non-neurologic systemic syndromes in the 65 severe Chikungunya cases included renal (45), hepatic (23), respiratory (21), cardiac (10), and hematologic manifestations (8). Males (50) and those aged >or=60 years (50) were commonly affected with severe Chikungunya, and age >or=60 years represented a significant risk. Comorbidities were seen in 21 cases with multiple comorbidities in 7 cases. Among 18 deaths, 14 were males, 15 were aged >or=60 years and 5 had comorbidities. In Pune, 59 laboratory-confirmed Chikungunya cases with neurologic syndromes were investigated. Neurologic syndromes in 99 cases from Ahmedabad and Pune included encephalitis (57), encephalopathy (42), and myelopathy (14) or myeloneuropathy (12). CONCLUSIONS: Chikungunya infection can cause systemic complications and probably deaths, especially in elderly adults.