Descriptive and Prognostic Study of Arbovirus Infections in France, Based on a Hospital Cohort of Children and Adults With Suspected Arbovirose.

There are hundred of arbovirus which have been shown to cause disease in humans. Their most common clinical symptoms are algo-eruptive (dengue, chikungunya, zika), hemorrhagic fever (dengue, yellow fever, Crimean-Congo hemorrhagic fever), neurological (West Nile, Zika, dengue, Japanese encephalitis) or arthritic afflictions (Chikungunya, O'nyong nyong). Dengue is a mosquito-born viral disease caused by 4 different serotypes of virus. Dengue fever (DF) is defined by the sudden onset of fever with non-specific constitutional symptoms, recovery occurring spontaneously in 3 to 7 days. The infection can sometimes progress to dengue hemorrhagic fever (DHF) characterized by a transient increase in vascular permeability provoking a plasma leakage syndrome. DHF can be complicated by shock and internal hemorrhage. Other rarer complications include encephalitis, hepatitis, rhabdomyolysis and myocarditis. There is currently no way of predicting the outcome of DF or DHF and the WHO classification lacks sufficient sensitivity and specificity to recognize and guide the management of severe forms of dengue. The pathophysiology of these forms is also poorly known. Since 2000s, the French West Indies and Guiana have become hyperendemic for dengue with simultaneous circulation of the 4 serotypes, regular large outbreaks and severe dengue including fatalities. Chikungunya is a re-emerging virus causing massive epidemics in Africa, in the Indian Ocean and Southeast Asia. The first autochthonous cases were described in French Antilles in Nov 2013. The disease typically consists of an acute illness like dengue fever with abrupt onset of a high-grade fever followed by constitutionals symptoms, poly-arthritis and skin involvement. Usually, the illness resolves in 4 to 6 weeks. However, severe clinical forms in early stage may appear and chronic clinical forms as incapacitating arthralgia which affect 40 to 60% of patients. In France, others arboviruses may cause severe emerging and re-emerging infectious diseases like Zika or West Nile. In non-immunized population these emerging diseases may cause outbreaks with specific severe clinical complications. The French interministerial mission on emerging infectious diseases coordinated by Professor Antoine Flahault, recommended such studies: large prospective multicenter cohort studies to characterize severe forms of arbovirus infections to seek predictive factors and to investigate the pathophysiology of the diseases.