What You Need to Know About Anthrax Infections

— -- Anthrax is again making headlines after Pentagon officials announced on Wednesday that the U.S. military had inadvertently sent live spores to laboratories in nine states and South Korea.

At least 22 people at Osan Air Base in South Korea are being monitored and were given precautionary medical measures because they "may have been exposed" to the spores during a training event, according to a statement from the air base.

Here's a guide to anthrax to explain how someone can get infected and how it can be stopped or treated.

What Causes Anthrax?

Anthrax is caused by a bacteria called Bacillus anthracis that forms naturally in the soil, where it can remain dormant for decades, according to the U.S. Centers for Disease Control and Prevention.

Animals such as cows or sheep are normally affected, though in rare cases people can be infected as well if they come into contact with the spores in the dirt or through food. In rare cases, the bacteria has infected a person after being injected. Once the spores enter the body through the respiratory tract, digestive tract or through the skin, the spores can become active and start to multiply.

It's most commonly found in areas of Central and South America, sub-Saharan Africa, Asia, southern and eastern Europe, and the Caribbean, according to the CDC.

What Are the Symptoms?

Those people who were possibly exposed to spores at laboratories would be at highest risk for inhaling spores, which could result in respiratory distress as the bacteria multiply. This type of anthrax infection is considered the most dangerous form of the disease with just 10 to 15 percent of untreated people surviving, according to the CDC.

Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, explained the bacteria can cause an "intoxication" by releasing toxins into the body.

"It can cause a severe illness associated with fluid accumulated in the lungs," said Schaffner. "The anthrax bacteria multiplies and lets lose these toxins."

Once in the lungs, the bacteria can start to release toxins in the lungs that can lead to fluid build-up and even death. An incubation period can last from one day to two months, as the bacteria continue to grow.

Should the bacteria reach a certain point they can infect tissue or enter the blood stream and cause sepsis. Symptoms include fever chills, shortness of breath and dizziness.

Those exposed to anthrax can develop different symptoms depending on if the spores are inhaled, digested, injected with a needle or affect the skin.

What Can You Do If You're Exposed to Anthrax

Those exposed to spores can be put on post-exposure prophylaxis, which can consist of 60 days of antibiotics with three doses of an anthrax vaccine.

In addition to those at risk for exposure, the vaccine is available to those exposed to spores. The vaccine can stimulate antibody production that provides protection after the person stops taking antibiotics and protect a patient from dormant spores that may remain in the body.

Those who may have been exposed at Osan Air Base were given precautionary measures, including examinations, antibiotics and in some instances, vaccinations, according to a statement from the base.

ABC News' Dr. Richard Besser, chief health and medical editor, and Luis Martinez contributed to this report.