Chikungunya virus infection in Reunion Island in 2005-2006: severe emerging adult forms in the intensive care unit

In April 2005, an outbreak of Chikungunya fever, an arthralgic disease caused by a mosquito-borne alphavirus, spread over a number of islands in the Indian Ocean including Reunion Island and Mayotte, imported from cases in Comoros. In Reunion Island, 270,000 cases occurred resulting in an incidence of 34%, including severe clinical patterns unknown at that time. Here, we describe the characteristics of forty-three severe cases of Chikungunya virus (CHIKv) infection admitted between May 2005 and May 2006, in our 16-bed intensive care unit (ICU) in Saint-Denis as well as the organizational impact of the outbreak on the day-to-day operations in the ICU. Clinical presentations included severe neurological involvement (meningo-encephalitis, N = 5; Guillain-Barre syndrome, N = 2), liver failure (N = 5), organ failure related to co-morbidities (chronic cardiac failure, N = 7; cardiac arrest, N = 4; other failures, N = 18). Twenty-one patients (49%) died. ICU reorganization was difficult given the small number of beds available in Reunion Island (44 beds/million) and CHIKv infection affecting 20% of the health workers. Half of the ICU beds were devoted to CHIKv-infected patients, resulting in a dramatic shortage of means for patient admission. The study highlights the emergence of severe clinical forms of CHIKv infections, not yet described and related to patients' comorbidities. CHIKv infection should no longer be considered as a rare exotic tropical disease. Its spread in Italy in 2007 and in the South of France in 2010 showed that CHIKv may impact European clinical practice in the future. Due to the severity of CHIKv-related diseases as assessed in our series, medical systems in Europe should be aware of the potential consequences of such an outbreak in an ICU.