Crimean -Congo Hemorrhagic Fever

Crimean-Congo Hemorrhagic Fever (CCHF) is an acute viral hemorrhagic disease which is transmitted to humans by the bite of the Hyalomma tick or by direct contact with blood of an infected animal or human. CCHF was first recognized in the Crimean peninsula in the mid-1940s, and the same virus was isolated from a patient in Democratic Republic of Congo, in 1956. Person-to-person transmission of CCHF virus occurs through direct exposure to blood or other secretions; in addition, nosocomial transmission is well-documented with case fatality rates ranging from 30 70%. Tick bite is one of the most important risk factors for CCHF acquisition and Hyalomma tick is its main reservoir in the nature, but many domestic animals including cattle, sheep, goats, hare, buffalo, and even ostrich can be infected by this virus. Disease in animals is subclinical and they are infected only for one week. During the viremia phase, direct exposure to blood or other secretions can infect human. Hyalomma ticks favor dry climates and arid-type vegetation, and are abundant in European countries bordering the Mediterranean Sea; numerous animals may act as CCHF virus hosts. In recent years, a number of cases have been reported from Africa, Eastern Europe and Asia. Healthcare workers are also at risk of infection through unprotected contact with infected blood and other body fluids. Incubation phase is about 3 to 4 days after tick bite and 3-14 days when the patient is exposed to infected blood and other body fluids. Typical CCHF progresses rapidly with high fever, malaise, severe headache, myalgia, and gastrointestinal symptoms like abdominal pain and nausea. CCHF is confirmed either by detection of specific immunoglobulin M antibodies or a four-fold increase of immunoglobulin G titers using enzyme-linked immunoassays, indirect immunofluorescent assays, or through RT-PCR. Supportive therapy is an essential part of the case management. Intensive monitoring of fluid volume and blood component replacement is recommended. Oral ribavirin is the therapy of choice in the clinical practice. If the patient meets the criteria for probable CCHF, treatment with ribavirin protocol needs to be started immediately. Interferon and Immunoglobulin have significant antiviral activity in vitro against CCHF. Recently, we face many cases of CCHF in several provinces of Iran. The aim of this article is to review clinical manifestations, treatment and prevention of this disease.