Viral haemorrhagic fever is a general term for a severe illness, sometimes associated with bleeding, that may be caused by a number of viruses. The term is usually applied to disease caused by Arenaviridae (Lassa fever, Junin and Machupo), Bunyaviridae (Crimean-Congo haemorrhagic fever, Rift Valley Fever, Hantaan haemorrhagic fevers), Filoviridae (Ebola and Marburg) and Flaviviridae (yellow fever, dengue, Omsk haemorrhagic fever, Kyasanur forest disease).
Risk for Travelers
- The risk of acquiring VHF is generally very low for international travelers.
- Viruses with rodent reservoirs are transmitted when humans have contact with excreta from infected rodents. Several cases of Lassa fever have been confirmed in international travelers living in traditional dwellings in the countryside. Travelers staying in rodent-infested dwellings are at risk for HPS and HFRS.
- Viruses associated with arthropod vectors are transmitted through mosquito or tick bites or by crushing infected ticks. Some vectors also infect animals, including livestock, and humans can be infected through care, slaughter, or consumption of infected animals.
- Travelers at increased risk for exposure include those engaging in animal research, health-care workers, and others providing care for patients in the community, particularly where outbreaks of VHF are occurring.