Viral hemorrhagic fevers
DEFINITION
Viral hemorrhagic (hem-uh-RAJ-ik) fevers are infectious diseases that interfere with the blood’s ability to clot. These diseases can also damage the walls of tiny blood vessels, making them leaky. The internal bleeding that results can range from relatively minor to life-threatening.
Some viral hemorrhagic fevers include:
- Dengue
- Ebola
- Lassa
- Marburg
- Yellow fever
These diseases most commonly occur in tropical areas of the world. When viral hemorrhagic fevers occur in the United States, they’re usually found in people who’ve recently traveled internationally.
Viral hemorrhagic fevers are spread by contact with infected animals, people or insects. No current treatment can cure viral hemorrhagic fevers, and immunizations exist for only a few types. Until additional vaccines are developed, the best approach is prevention.
CAUSES
The viruses that cause viral hemorrhagic fevers live naturally in a variety of animal and insect hosts — most commonly mosquitoes, ticks, rodents or bats.
Each of these hosts typically lives in a specific geographic area, so each particular disease usually occurs only where that virus’s host normally lives. Some viral hemorrhagic fevers also can be transmitted from person to person.
How is it transmitted?
The route of transmission varies by specific virus. Some viral hemorrhagic fevers are spread by mosquito or tick bites. Others are transmitted by contact with infected blood 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 may become infected there and then develop symptoms after you return home. It can take up to 21 days for symptoms to develop.
SYMPTOMS
Signs and symptoms of viral hemorrhagic fevers vary by disease. In general, initial symptoms may include:
- High fever
- Fatigue
- Dizziness
- Muscle, bone or joint aches
- Weakness
- Symptoms can become life-threatening
Severe cases of some types of viral hemorrhagic fevers may cause bleeding, but people rarely die of blood loss. Bleeding may occur:
- Under the skin
- In internal organs
- From the mouth, eyes or ears
Other signs and symptoms of severe infections can include:
- Shock
- Nervous system malfunctions
- Coma
- Delirium
- Kidney failure
- Liver failure
When to see a doctor
The best time to see a doctor is before you travel to a developing country to ensure you’ve received any available vaccinations and pre-travel advice for staying healthy.
If you develop signs and symptoms once you return home,consult a doctor, preferably one who focuses on international medicine or infectious diseases. A specialist may be able to recognize and treat your illness faster. Be sure to let your doctor know what areas you’ve visited.
