What is anthrax?
Anthrax is a serious infectious disease caused by gram-positive, rod-shaped bacteria known as Bacillus anthracis. Anthrax can be found naturally in soil and commonly affects domestic and wild animals around the world. Although it is rare in the United States, people can get sick with anthrax if they come in contact with infected animals or contaminated animal products. Contact with anthrax can cause severe illness in both humans and animals.
Anthrax is not contagious, which means you can’t catch it like the cold or flu.
How do animals get infected with anthrax?
Domestic and wild animals such as cattle, sheep, goats, antelope, and deer can become infected when they breathe in or ingest spores in contaminated soil, plants, or water. In areas where domestic animals have had anthrax in the past, routine vaccination can help prevent outbreaks.
How do people get infected with anthrax?
People get infected with anthrax when spores get into the body. When anthrax spores get inside the body, they can be “activated.” When they become active, the bacteria can multiply, spread out in the body, produce toxins (poisons), and cause severe illness.
This can happen when people breathe in spores, eat food or drink water that is contaminated with spores, or get spores in a cut or scrape in the skin. It is very uncommon for people in the United States to get infected with anthrax.
Certain activities can also increase a person’s chances of getting infected. For more information, see How People Are Infected.
Where is anthrax found?
Anthrax is most common in agricultural regions of Central and South America, sub-Saharan Africa, central and southwestern Asia, southern and eastern Europe, and the Caribbean.
Anthrax is rare in the United States, but sporadic outbreaks do occur in wild and domestic grazing animals such as cattle or deer. Anthrax is more common in developing countries and countries that do not have veterinary public health programs that routinely vaccinate animals against anthrax. In the United States, yearly vaccination of livestock is recommended in areas where animals have had anthrax in the past. For more information, see Travelers.
4 types of anthrax
When anthrax spores get into the skin, usually through a cut or scrape, a person can develop cutaneous anthrax. This can happen when a person handles infected animals or contaminated animal products like wool, hides, or hair. Cutaneous anthrax is most common on the head, neck, forearms, and hands. It affects the skin and tissue around the site of infection.
Cutaneous anthrax is the most common form of anthrax infection, and it is also considered to be the least dangerous. Infection usually develops from 1 to 7 days after exposure. Without treatment, up to 20% of people with cutaneous anthrax may die. However, with proper treatment, almost all patients with cutaneous anthrax survive.
When a person breathes in anthrax spores, they can develop inhalation anthrax. People who work in places such as wool mills, slaughterhouses, and tanneries may breathe in the spores when working with infected animals or contaminated animal products from infected animals. Inhalation anthrax starts primarily in the lymph nodes in the chest before spreading throughout the rest of the body, ultimately causing severe breathing problems and shock.
Inhalation anthrax is considered to be the most deadly form of anthrax. Infection usually develops within a week after exposure, but it can take up to 2 months. Without treatment, only about 10 – 15% of patients with inhalation anthrax survive. However, with aggressive treatment, about 55% of patients survive.
When a person eats raw or undercooked meat from an animal infected with anthrax, they can develop gastrointestinal anthrax. Once ingested, anthrax spores can affect the upper gastrointestinal tract (throat and esophagus), stomach, and intestines.
Gastrointestinal anthrax has rarely been reported in the United States. Infection usually develops from 1 to 7 days after exposure. Without treatment, more than half of patients with gastrointestinal anthrax die. However, with proper treatment, 60% of patients survive.
Recently, another type of anthrax infection has been identified in heroin-injecting drug users in northern Europe. This type of infection has never been reported in the United States.
Symptoms may be similar to those of cutaneous anthrax, but there may be infection deep under the skin or in the muscle where the drug was injected. Injection anthrax can spread throughout the body faster and be harder to recognize and treat. Lots of other more common bacteria can cause skin and injection site infections, so a skin or injection site infection in a drug user does not necessarily mean the person has anthrax.
The symptoms of anthrax depend on the type of infection and can take anywhere from 1 day to more than 2 months to appear. All types of anthrax have the potential, if untreated, to spread throughout the body and cause severe illness and even death.
Cutaneous anthrax symptoms can include:
- A group of small blisters or bumps that may itch
- Swelling can occur around the sore
- A painless skin sore (ulcer) with a black center that appears after the small blisters or bumps
- Most often the sore will be on the face, neck, arms, or hands
Inhalation anthrax symptoms can include:
- Fever and chills
- Chest Discomfort
- Shortness of breath
- Confusion or dizziness
- Nausea, vomiting, or stomach pains
- Sweats (often drenching)
- Extreme tiredness
- Body aches
Gastrointestinal anthrax symptoms can include:
- Fever and chills
- Swelling of neck or neck glands
- Sore throat
- Painful swallowing
- Nausea and vomiting, especially bloody vomiting
- Diarrhea or bloody diarrhea
- Flushing (red face) and red eyes
- Stomach pain
- Swelling of abdomen (stomach)
Injection anthrax symptoms can include:
- Fever and chills
- A group of small blisters or bumps that may itch, appearing where the drug was injected
- A painless skin sore with a black center that appears after the blisters or bumps
- Swelling around the sore
- Abscesses deep under the skin or in the muscle where the drug was injected
To Keep in Mind
Injection anthrax symptoms are similar to those of cutaneous anthrax, but injection anthrax can spread throughout the body faster and be harder to recognize and treat than cutaneous anthrax. Skin and injection site infections associated with injection drug use are common and do not necessarily mean the person has anthrax.
CDC guidance and case definitions are available to help doctors diagnose anthrax.
Who is at risk?
Anyone who has come in contact with anthrax spores could be at risk of getting sick. Most people will never be exposed to anthrax. However there are activities that can put some people at greater risk of exposure than others.
- People Who Handle Animal Products
- Livestock producers
- Laboratory Professionals
- Mail handlers, military personnel, and response workers who may be exposed during a bioterror event involving anthrax spores
Recommendations for protecting workers are available from CDC’s National Institute for Occupational Safety and Health. This guidance covers the use of respirators, protective clothing, and the anthrax vaccine.
The anthrax vaccine is currently provided only to people who are at an increased risk of coming in contact with anthrax spores, such as members of the U.S. military, certain laboratory workers, and some people who handle animals or animal products (for example, farmers, veterinarians, and livestock handlers). The vaccine is not licensed for use in children under age 18, adults over age 65, or pregnant and nursing women.
To learn more about risks related to specific occupations, visit Information for Specific Groups.