Background and potential as a bioweapon
Viral hemorrhagic fever refers to a group of diseases produced by a number of ribonucleic acid (RNA) viruses. The group includes Lassa, Marburg, Ebola, and Congo-Crimean hemorrhagic fever viruses. These viruses could potentially be used as bioweapons because they are highly infectious by aerosol, are associated with high morbidity, and in some cases, high mortality, and are not responsive to antibiotic therapy.
Viral hemorrhagic fever
is an acute febrile illness characterized by malaise, prostration, vascular
permeability and circulation abnormalities. Viral hemorrhagic fever viruses
are transmitted to humans by contact with infected animal reservoirs or arthropod
vectors. The viruses that cause hemorrhagic fever naturally reside in an animal
reservoir host or arthropod vector. They are totally dependent on their hosts
for replication and survival. Rats, deer mice, house mice, and other field rodents
are example of reservoir hosts. Ticks and mosquitoes may serve as vectors transmitting
the disease from the host animal to humans. The viruses carried in rodent hosts
are transmitted when humans have contact with urine, fecal matter, saliva, or
other body excretions from infected rodents. The viruses associated with arthropod
vectors are spread most often when the vector mosquito or tick bites a human,
or when a human crushes a tick. The Ebola, Marburg, Lassa, and Crimean-Congo
hemorrhagic fever viruses are spread from one person to another.
Initial symptoms of viral hemorrhagic fever include a high fever, fatigue, dizziness, muscle aches, loss of strength, and exhaustion. Patients with severe cases of viral hemorrhagic fever often show signs of bleeding under the skin, in internal organs, or from body orifices like the mouth, eyes, or ears. Shock, coma, delirium, and seizures may also occur in severely ill patients.
There is no treatment other than supportive care for patients with viral hemorrhagic fever. Patients generally die or begin to recover by the second week of illness. The only established vaccine available for any of the hemorrhagic fever viruses is Yellow Fever vaccine, which is mandatory for travelers to endemic areas of Africa and Southern America.
Click for Healthcare worker guidance from the CDC for assessing VHF.