An anthrax infection in Minnesota is being investigated by the FBI and the Minnesota Department of Health. The bureaus are saying that the case was caused by a very rare instance of inhaled anthrax, is currently not being considered a criminal or terrorist act.

Anthrax spores occur naturally in the environment, and the disease is regularly found in hooved animals such as cows. The deadly infection -- which has been associated with terrorism since 2001, when envelopes of white powder were sent to various offices in United States -- can be picked up by handling infected animal meat or hides.

The infected person was hospitalized with fever and pneumonia in Minnesota after traveling through North Dakota, Montana, Wyoming and South Dakota.

"All evidence points to this case of anthrax being caused by exposure to naturally occurring anthrax in the environment," Minnesota state epidemiologist Ruth Lynfield told AFP.

"Anthrax is not spread from person to person, and it is extremely rare for humans to become sickened with anthrax, especially through inhalation."

In 2001, 22 people contracted Anthrax. Five of those people died.

Symptoms of the illness include fever and muscle aches which last several days and then disappear. The disease then returns, causing lung problems, breathing difficulty and shock. According to the health department, Anthrax is fatal in 90 percent of cases when not treated.

The Minnesota Department of Health has not yet provided more information on the infected individual.