Causes

Viral hemorrhagic fevers are spread by contact with infected animals or insects. The viruses that cause viral hemorrhagic fevers live in a variety of animal and insect hosts. Most commonly the hosts include mosquitoes, ticks, rodents or bats.

Some viral hemorrhagic fevers can also be spread from person to person.

How is it transmitted?

Some viral hemorrhagic fevers are spread by mosquito or tick bites. Others are spread by contact with infected body fluids, such as blood, saliva or semen. A few varieties can be inhaled from infected rat feces or urine.

If you travel to an area where a particular hemorrhagic fever is common, you can be infected there but not develop symptoms until after you return home. Depending on the type of virus, it can take from two to 21 days for symptoms to develop.