Haemorrhagic fevers, Viral
Viral haemorrhagic fevers are a group of illnesses caused by four distinct families of viruses: arenaviruses, filoviruses, bunyaviruses, and flaviviruses. In general, the term “viral haemorrhagic fever” is used to describe a severe multisystem syndrome in which the overall vascular system is damaged, impairing the body’s ability to regulate itself. These symptoms are often accompanied by haemorrhage (bleeding), although the bleeding itself is rarely life threatening. While some types of haemorrhagic fever viruses can cause relatively mild illnesses, many of them cause severe, life-threatening disease. Viruses associated with most viral haemorrhagic fevers are zoonotic, which means they naturally reside in an animal reservoir or arthropod vector. Vaccines have been developed for yellow fever and Argentine haemorrhagic fever, but there are no vaccines that protect against the other haemorrhagic fevers. For those haemorrhagic fevers, the most effective prevention is to avoid contact with host species.