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 (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.

Francisella tularensi

Tularemia is an infectious disease caused by a hardy bacterium, Francisella tularensis, found in animals (especially rodents, rabbits, and hares).

People can get tularemia many different ways, such as through the bite of an infected insect or other arthropod (usually a tick or deerfly), handling infected animal carcasses, eating or drinking contaminated food or water, or breathing in F. tularensis.

What is smallpox?

Smallpox is a serious disease caused by a virus - the Variola virus. Before the discovery of a vaccine in 1796, smallpox was common throughout the world. The last case of smallpox in the world was in 1978. The United States stopped routine smallpox vaccinations in 1972, since the side effects from the vaccinations were greater than the risk of getting the disease.

How is smallpox spread?

Smallpox can be spread when an infected person talks, coughs, or sneezes near another person.

General Information

Sarin is a human-made chemical warfare agent that is classified as a nerve agent. Sarin is a clear, colorless, and tasteless liquid that has no odor in its pure form. Sarin, also known as GB, can evaporate into a vapor (gas) and spread into the environment. Sarin is not found naturally in the environment, but was developed in 1938 in Germany as a pesticide.

General Information

Ricin is a poison made from the waste left over from the processing of seeds of the castor bean plant, Ricinus communis. Castor beans are processed throughout the world to make castor oil and ricin is part of the waste "mash" produced when castor oil is made. Ricin can be in the form of a powder, a mist, or a pellet, or it can be dissolved in water or weak acid. Exposure to ricin would require a deliberate act to make the substance and introduce it into the systems of victims. Unintentional exposure to ricin is very unlikely.

Yersinia pestis

Plague is an infectious disease that affects animals and humans. It is caused by the bacterium Yersinia pestis. This bacterium is found in rodents and their fleas and occurs in many areas of the world, including the United States.

Y. pestis is easily destroyed by sunlight and drying. Even so, when released into air, the bacterium will survive for up to one hour, although this could vary depending on conditions.

Botulism ( Clostridium botulinum toxin )

Botulism is a muscle-paralyzing disease caused by a toxin made by a bacterium called Clostridium botulinum . 

There are three main kinds of botulism: