Viral hemorrhagic fever is a title given to a spectrum of diseases caused by viruses that affect the vascular bed. Fever, myalgia, and prostration occur early; and petechial hemorrhages, hypotension, and conjunctivitis are common findings. Bleeding from mucous membranes, shock, and death may follow.
Yellow fever killed ten percent of the population of Philadelphia during an epidemic in 1793, and the illness devastated 23,000 to 30,000 French soldiers in Haiti in 1800, helping that country to secure independence from Napoleon. Mosquitoes transmit the disease. Prevention may be accomplished by control of the vector.
Marburg and Ebola viruses, which originated in Africa, are morphologically identical, and they produce similar symptoms. Marburg carries a mortality of about 25% whereas Ebola has a rate up to 90%.
Lassa and the South American Hemorrhagic Fever viruses can produce severe disease. Rodents serve as their host and humans contract the disease by contact with rats or mice or their urine of feces.
The Crimean-Congo virus causes severe disseminated intravascular coagulopathy.
An early attempt at biological warfare occurred during the Civil War. Dr. Luke Blackburn of the Confederate Secret Service shipped clothes contaminated with blood, vomit, and excrement from people with yellow fever to the United States, expecting to infect union troops. He did not realize at the time that the mosquitos were the vector for spread of the disease, and no epidemic ensued. Following WWII, the United States and the Soviet Union developed weapons for the dissemination of viral hemorrhagic viruses.