Crimean-Congo hemorrhagic fever

Abstract

The objectives of this presentation is updating all the information related to Crimean-Congo Hemorrhagic Fever (CCHF). The titles of the presentation will be epidemiology, pathogenesis, treatment, prevention and vaccination. CCHF is a fatal viral infection with the reported mortality rate of 3-30%. Every year >1000 laboratory confirmed cases were reported from Africa, Asia and Europe. Recent autochthonous cases were reported from Spain in August of 2016. In pathogenesis of CCHF infection like in other viral hemorrhagic fevers, inflammatory processes are key elements of immune response, and the release of proinflammatory cytokines were suggested to be related with the disease course and clinical outcome. Since then, some other studies also reported the critical role of proinflammatory cytokines in disease course, however complete understanding of the pathogenesis of CCHF infection was needed. Many studies showed the beneficial effect of ribavirin previously, benefit was shown by a recent powerful study, which included 281 laboratory confirmed CCHF patients. Severity-scoring index was defined, and the patients were grouped as mild, moderate, and severe accordingly. The CFR among patients who received ribavirin was significantly lower than that among those who did not receive ribavirin (1.49% vs 17%; P =.001). Among severely ill patients, use of corticosteroid therapy was beneficial (P =.014). After stratifying patients on the basis of the SSI described here, ribavirin was found to be effective in reducing the CFR among moderately ill patients, whereas steroids were found to be beneficial among patients with more severe disease.

These findings support the theoretical hypothesis on the beneficial role of ribavirin therapy during the earlier, viremic phase of the disease course. In later phases of the disease, corticosteroids could be effective in severely ill patients, in whom enormous amounts of cytokines have been released. In summary, in CCHFV infection ribavirin was found to be effective in treatment, in post-exposure prophylaxis, and should be given as early as possible. In post-exposure prophylaxis ribavirin should be given. Other drugs like favipiravir were studied in vitro and also could be considered in vivo. Vaccine studies are being performed in several centers, but there is no product yet.