INFECTIOUS AGENT
Viral hemorrhagic fevers (VHFs) are caused by several families of enveloped RNA viruses: filoviruses (Ebola and Marburg viruses), arenaviruses (Lassa fever, Lujo, Guanarito, Machupo, Junin, Sabia, and Chapare viruses), bunyaviruses (Rift Valley fever [RVF], Crimean-Congo hemorrhagic fever [CCHF], and hantaviruses), and flaviviruses (dengue, yellow fever, Omsk hemorrhagic fever, Kyasanur Forest disease, and Alkhurma viruses); see the Dengue and Yellow Fever sections in this chapter.
TRANSMISSION
Some VHFs are spread person to person through direct contact with symptomatic patients, body fluids, or cadavers or through inadequate infection control in a hospital setting (filoviruses, arenaviruses, CCHF virus). Zoonotic spread may occur from contact with the following:
Livestock via slaughter or consumption of raw meat from infected animals and, potentially, unpasteurized milk (CCHF, RVF, Alkhurma viruses)
Bushmeat, likely via slaughter or consumption of infected animals (Ebola, Marburg viruses)
Rodents via inhalation of or contact with materials contaminated with rodent excreta (arenaviruses, hantaviruses)
Other reservoir species, such as bats (Ebola, Marburg viruses)
Vectorborne transmission also occurs via mosquito (RVF virus) or tick (CCHF, Omsk, Kyasanur Forest disease, Alkhurma viruses) bites or by crushing infected ticks.