The term biotoxin refers to naturally occurring, poisonous agents that can cause illness or injury to humans, animals, and marine life. These agents may come from bacteria, fungi, algae, viruses, or plants.

Some of the more well-known bacterial biotoxins include Bacillus anthracis (anthrax), Ricin, Nicotine, Brucella melitensis and Brucella suis (brucellosis), Vibro cholerae (cholera), and Yersinia pestis (plague).


Diseases spread by viral biotoxins include encephalomyelitis, viral hemorrhagic fever (i.e. yellow fever, ebola-marburg, dengue fever), and variola major (smallpox).

Biotoxins may be distributed through windborne spores or through contaminated food or water. Some biological agents have also been aerosolized or deliberately introduced into food and water supplies for use as biological weapons.


Biotoxins are found in a variety of places including plants, foodborne sources (unpasteurized dairy products, undercooked meat from animals infected with a toxin, etc.), and for some toxins human-to-human infection is possible. Contact with fungi and mold, contaminated water, and in extreme instances bioterrorist activity.

Causes and symptoms

Most biotoxin infections will result high fever and have other secondary symptoms including dizziness, exhaustion, muscle aches, loss of strength, and exhaustion. Marine biotoxins are often responsible for large-scale fish kills and can cause severe illness in humans who consume tainted fish or shellfish. Symptoms of shellfish poisoning include diarrhea, stomach cramps, headache, nausea, vomiting, and in extreme cases neurotoxic effects including paralysis, seizures, and death. Common marine biotoxins include ciguatera fish poisoning (CFP) toxin and domoic acid. Harmful algae blooms (HAB) are sometimes called red tides or brown tides. Some HABs, such as Pfiesteria piscicida, can be sources of marine biotoxins that potentially harm marine life and humans.


The primary way to avoid biotin contact is to refrain from contact with known toxins, people, animals, surfaces, and waste infected with biotoxins. Seem immediate medical attention if symptoms appear after known contact with a toxin, virus, or other contagion. Contact a physician if symptoms occur.

In the United States, legislation such as the Pollution Prevention Act have been put in place to protect the public from contamination. Food and water sources are monitored regularly by the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA).

See also Anthrax ; Brucellosis ; Cholera ; Dengue fever ; Mold ; Plague ; Smallpox ; Viruses ; Yellow fever .



Maczulak, Anne E. Pollution: Treating Environmental Toxins. New York: Facts on File, 2010.


Center for Disease Control. “Biotoxins: Emergency preparedness and Response.” (accessed October 3, 2012)

Environmental Protection Agency. “Selected Biotoxin Methods.” (accessed June 2, 2018).


National Office for Marine Biotoxins and Harmful Algal Blooms, Woods Hole Oceanographic Institution, Biology Dept., MS No. 32, Woods Hole, MA, 02543, (508) 289-2252, Fax: (508) 457-2180,, .

Paula Anne Ford-Martin
Alyson C. Heimer, MA

  This information is not a tool for self-diagnosis or a substitute for professional care.