MedicineNet.com
About Us | Privacy Policy | Site Map
November 25, 2009
MedicineNet home Picture Slideshows Diseases and conditions Symptoms and signs Procedures and tests Medications Health and Living Picture Image Collection MedTerms medical dictionary
Font Size
A
A
A


Viral Hemorrhagic Fever(s)

What are viral hemorrhagic fevers?

Viral hemorrhagic fevers (VHFs) refer to a group of illnesses that are caused by several distinct families of viruses. In general, the term "viral hemorrhagic fever" is used to describe a severe multisystem syndrome (multisystem in that multiple organ systems in the body are affected). Characteristically, the overall vascular system is damaged, and the body's ability to regulate itself is impaired. These symptoms are often accompanied by hemorrhage (bleeding); however, the bleeding is itself rarely life-threatening. While some types of hemorrhagic fever viruses can cause relatively mild illnesses, many of these viruses cause severe, life-threatening disease.

The Special Pathogens Branch (SPB) primarily works with hemorrhagic fever viruses that are classified as biosafety level four (BSL-4) pathogens. A list of these viruses appears in the SPB disease information index. The Division of Vector-Borne Infectious Diseases, also in the National Center for Infectious Diseases, works with the non-BSL-4 viruses that cause two other hemorrhagic fevers, dengue hemorrhagic fever and yellow fever.

How are hemorrhagic fever viruses grouped?

VHFs are caused by viruses of four distinct families: arenaviruses, filoviruses, bunyaviruses, and flaviviruses. Each of these families share a number of features:

  • They are all RNA viruses, and all are covered, or enveloped, in a fatty (lipid) coating.
  • Their survival is dependent on an animal or insect host, called the natural reservoir.
  • The viruses are geographically restricted to the areas where their host species live. Humans are not the natural reservoir for any of these viruses.
  • Humans are infected when they come into contact with infected hosts. However, with some viruses, after the accidental transmission from the host, humans can transmit the virus to one another.
  • Human cases or outbreaks of hemorrhagic fevers caused by these viruses occur sporadically and irregularly. The occurrence of outbreaks cannot be easily predicted.
  • With a few noteworthy exceptions, there is no cure or established drug treatment for VHFs.

In rare cases, other viral and bacterial infections can cause a hemorrhagic fever; scrub typhus is a good example.



Next: What carries viruses that cause viral hemorrhagic fevers? »

Printer-Friendly Format  |  Email to a Friend


Suggested Reading by Our Doctors
MedicineNet Doctors
  • Kidney Failure - Learn about kidney failure, in which the body has fluid retention, risen blood pressure, toxin build up and lack of red blood cells. Symptoms include fatigue, nausea, and apetite loss.
  • Fever - Get the facts on fever treatment (in children and adults). Learn ways to bring down a high fever and know the signs of other serious types of major illness.
  • Dengue Fever - Get the facts on dengue fever causes (virus transmitted by infected mosquito), symptoms, signs, treatment, statistics and information on dengue hemorrhagic fever (DHF).

Latest Medical News


Women's Health

Find out what women really need.


Are you Depressed? Take the Quiz

Your Guide to Symptoms & Signs: Pinpoint Your Pain



Viral Hemorrhagic Fever

What is shock?

Shock is a life-threatening medical condition whereby the body suffers from insufficient blood flow throughout the body. Shock often accompanies severe injury or illness. Medical shock is a medical emergency and can lead to other conditions such as lack of oxygen in the body's tissues (hypoxia), heart attack (cardiac arrest) or organ damage. It requires immediate treatment as symptoms can worsen rapidly.

Medical shock is different than emotional, or psychological, shock that can occur following a traumatic or frightening emotional event.

What are the types of shock?

Septic shock results from bacteria multiplying in the blood and releasing toxins. Common causes of this are pneumonia, intra-abdominal infections (such as a ruptured appendix) and meningitis.

Anaphylactic shock is a type of severe hypersensitivity or allergic reaction. Causes include allergy to insect stings, m...

Read the Shock (Medical) article »










Health categories:

Slideshows | Diseases & Conditions | Symptoms & Signs | Procedures & Tests | Medications | Health & Living | News & Views | Medical Dictionary

Popular health centers:

Allergies | Arthritis | Cancer | Diabetes | Digestion | Healthy Kids | Heart | Men's Health | Mental Health | Women's Health | More...

Publications:

ePublications (PDFs) | XML News via RSS | Audio Podcasts | Email Newsletters

MedicineNet.com:

About Us | Privacy Policy | Site Map | WebMD® | Medscape® | eMedicine® | eMedicineHealth® | RxList®

This website is certified by Health On the Net Foundation. Click to verify. This site complies to the HONcode standard for trustworthy health information:
verify here.

©1996-2009 MedicineNet, Inc. All rights reserved. Notices and Legal Disclaimer.
MedicineNet does not provide medical advice, diagnosis or treatment. See additional information.