Hemorrhagic Fevers Definition

Life-threatening illness resulting from infection with various viruses, spread by the bites of mosquitoes and ticks, the hallmark of which is the collapse of multiple organ systems because damage to the blood vessels impairs their ability to contain and transport blood.

The dozen or so viruses that cause hemorrhagic fevers belong to four viral families: arenaviruses, bunyaviruses, filoviruses, and flaviviruses.

These viral families also contain viruses that cause infection other than hemorrhagic fever. For example hantavirus belongs to the bunyavirus family and the yellow fever virus belongs to the flavivirus family. Viral hemorrhagic fever infections occur in tropical regions, notably Africa and South America.

Hemorrhagic Fever Viruses

Guanarito VIRUSJunin virus
Lassa virusMachupo virus
Sabia virus
Crimean-Congo virusRift Valley virus
Ebola virusMarburg virus
Dengue virusOmsk virus

Causes, Treatment and Symptoms of Hemorrhagic Fevers

Rodents, primarily certain species of rats and mice, harbor the viruses. Mosquitoes and ticks that feed on the rodents continue to spread the virus among rodent populations. Rodent droppings and other excretions, such as saliva and urine, contain the viruses.

The viruses can then infect people who come into contact with the excretions. Contact with body fluids from an infected person further spread the virus. Symptoms of illness arise suddenly and are severe, typically including high fever, fatigue, evidence of internal bleeding, and weakness.

Subsequent symptoms develop as organs fail. The only treatment for viral hemorrhagic fevers is supportive; the illnesses are usually fatal. Outbreaks of viral hemorrhagic fevers occur periodically. Global efforts are under way to find medical treatments that can halt the course of disease as well as to contain rodent, mosquito, and tick populations.


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