ABSTRACT
There are three major tickborne viral hemorrhagic fevers: Congo-Crimean hemorrhagic fever (CCHF), which is distributed throughout Europe, Asia, the Middle East, and Africa; Kyasanur Forest disease, which occurs in western India and was recently detected in Saudi Arabia; and Omsk hemorrhagic fever, which occurs in western Siberia [1,2]. These diseases are caused by RNA viruses that have zoonotic lifecycles in specific rural areas. Man is typically infected as an incidental host. Each disease has a short incubation period (less than 2 weeks), and can present with a similar clinical illness. These viruses produce vascular lesions with increased vascular permeability and, in severe cases, frank hemorrhagic symptoms. Patients typically present with acute onset of fever, headache, myalgias, nausea, and vomiting. The face is often flushed with conjunctival injection. Laboratory values will show a leukopenia and thrombocytopenia. After 3 to 5 days, the patient develops hemorrhagic symptoms with petechiae, ecchymoses, and bleeding from the gums, nose, gastrointestinal tract, uterus, or lungs.