Human Impact & Home

Anthrax: Disease from a Naturally Occurring Bacteria

October 30, 2001

The anthrax bacteria, bacillus anthracis, as seen under a microscope. (Image: University of California - Davis)

While far more people die each year from influenza and other diseases than anthrax, it has created worldwide concern, particularly in the United States, because the bacteria which causes the disease has been intentionally distributed to people through the mail. Many ecology.com users have been using our search engines and asking us questions to see where anthrax fits within our natural environment. Here is the information most of you have been looking for.

Anthrax is an infectious disease caused by a bacteria called bacillus anthracis. This bacteria forms spores (single cell reproductive bodies, just like pollen in plants) which can cause the anthrax disease by spreading the bacteria to humans and animals. Anthrax occurs in humans in three forms: skin or cutaneous anthrax, gastro-intestinal, and inhalation. It is not contagious! Humans cannot contract anthrax from an infected human. Humans can contract anthrax through exposure to large numbers of the anthrax spores.

The anthrax bacteria occurs naturally, and it can live in soil and water for up to 20 years. Anthrax commonly occurs in agricultural regions in warm-blooded animals, usually wild and domestic herbivores such as cattle, sheep, camels, goats, antelopes, oxen and other vertebrates (animals with spines). It is rare to find animals infected with anthrax in the United States. Most cases of anthrax infections in animals occur in South and Central America, Asia, the Middle East and southern and eastern Europe.

The microscopic spores formed by the anthrax bacteria can cause the anthrax disease in humans. Pictured here are anthrax spores surrounding the bacteria. (Image: Anthrax Vaccine Immunization Program)

When anthrax does infect humans, it usually affects people who work with the infected animals, such as cattle ranchers, or by people who come into contact with infected, dead animals. Humans can also get anthrax by eating undercooked meat of infected animals. The recent human anthrax cases in the US, however, were deliberately caused by people who manufactured, or reproduced, the anthrax spores and distributed them through the mail.

People can be vaccinated against anthrax, and there are effective treatments for the disease once it has been contracted. The earlier treatment can be administered for anthrax, particularly inhalation anthrax, the better the chances will be of recovery. Inhalation anthrax is the most fatal form of anthrax in humans.

-- Eric McLamb

Also check out these sites...

• Anthrax: Centers for Disease Control
• The Anthrax Vaccine