Viral Hemorrhagic Fever

INTRODUCTION Viral hemorrhagic fevers (VHFs) refer to a group of illnesses caused by several families of viruses, including: Filoviridae (Ebola and Marburg viruses) Arenaviridae (Lassa fever and New World hemorrhagic fever) Bunyaviridae (Rift Valley fever, Crimean-Congo fever, and agents of “hemorrhagic fever with renal syndrome” [HFRS]) Flaviviridae (yellow fever, Omsk hemorrhagic fever, Kyasanur Forest disease, and dengue) Many VHF viruses are virulent, and some are highly infectious (e.g., filoviruses and arenaviruses) with person-to-person transmission from direct contact with infected blood and bodily secretions. Effective therapies and prophylaxis are extremely limited for VHF; therefore, early detection and strict adherence to infection control measures are essential. The Working Group for Civilian Biodefense considers some hemorrhagic fever (HF) viruses to pose a serious threat as potential biological weapons based on their risk of morbidity and mortality, feasibility of production, and their ability to cause infection through aerosol dissemination. These include Ebola, Marburg, Lassa fever, New World arenaviruses, Rift Valley fever, yellow fever, Omsk hemorrhagic fever, and Kyasanur Forest disease. This chapter will focus only on these VHF viruses and will not include a discussion of dengue fever (see Chapter 54, Fever in the Returning Traveler), hemorrhagic fever with renal syndrome (see Chapter 70, Hantavirus), and Crimean-Congo hemorrhagic fevers.