A microscopic look at anthrax bacteria.
A microscopic look at anthrax bacteria. Visuals Unlimited/Corbis
The federal government has spent $40 billion since the 2001 anthrax letter attacks to improve its civilan efforts to detect and respond to bioterrorist threats. The focus is on detecting an attack, with sensors to monitor the air for deadly pathogens placed in major cities around the country.
The government has also increased its stockpile of vaccines and antibiotics and is expected to soon open a new biosurveillance center at the Department of Homeland Security.
But little has changed in terms of treatment and prevention of anthrax since the deadly mailings that began seven days after the Sept. 11, 2001, terrorist attacks.
Here, an up-close look at anthrax.
What is anthrax?
Anthrax is an acute infectious disease caused by the bacterium Bacillus anthracis. Anthrax bacteria live in and on infected animals, and anthrax spores can live in the soil for decades. The disease most commonly occurs in wild and domestic animals such as sheep, cattle, goats, camels and antelopes. But it can also occur in humans when they are exposed to infected animals or tissue or when anthrax spores are used as a bioterrorist weapon.
How do you get it?
B. anthracis spores can live in the soil for many years, and humans can become infected with anthrax by handling products from infected animals or by inhaling anthrax spores from contaminated animal products. It's rare to find infected animals in the United States. Anthrax spores can be used as a bioterrorist weapon, as was the case in 2001, when B. anthracis spores had been intentionally distributed through the postal system, causing 22 cases of anthrax, including five deaths.
Is it easy to become infected?
Anthrax is not easy to catch: Years ago, researchers tested workers in a goat-hair mill in Pennsylvania and found that although they regularly inhaled low concentrations of anthrax spores, they didn't get sick. And it's important to note: People do not transmit anthrax from one to another. It is not contagious.
What are the types of anthrax infection?
There are three forms of anthrax infection: inhalation (in which the bacteria lodge deep in the lungs), cutaneous (skin), and intestinal. By far the most common form is cutaneous.
The five people killed in the 2001 letter attacks all died from inhalation anthrax, which develops after breathing in spores. The spores work their way deep into the lungs and are picked up by immune cells that carry them to lymph nodes, where they multiply and release poisons that cause hemorrhaging and other problems. Not all spores can set up an infection; they have to be small enough to work their way deep into the lungs.
— Cutaneous anthrax occurs when anthrax bacteria are transmitted to humans from contaminated meat, wool or hides. They enter the skin, usually through cuts and abrasions; 95 percent of anthrax cases are cutaneous.
— Gastrointestinal anthrax comes from ingestion of contaminated, undercooked meat.
How deadly is it?
— Cutaneous: 20 percent fatality rate (without antibiotic treatment).
— Gastrointestinal: 25 to 60 percent fatality rate (the effect of early antibiotic treatment on that fatality rate is not known).
— Inhalation: 75 percent fatality rate, even with medical treatment.
What are the symptoms?
These symptoms can occur within seven days of infection:
— Fever (temperature greater than 100 degrees F). The fever may be accompanied by chills or night sweats.
— Cough, usually a nonproductive cough, chest discomfort, shortness of breath, fatigue, muscle aches.
— Sore throat, followed by difficulty swallowing, enlarged lymph nodes, headache, nausea, loss of appetite, abdominal distress, vomiting, or diarrhea.
— A sore, especially on your face, arms or hands, that starts as a raised bump and develops into a painless ulcer with a black area in the center.
What's the treatment?
The FDA has approved the antibiotics ciprofloxacin, doxycycline and penicillin for the treatment of anthrax in adults and children.
Is there a new vaccine?
BioThrax, first licensed in 1970, remains the only FDA-approved vaccine for anthrax, and it isn't recommended for the general public. Anyone who may be exposed to anthrax, including certain members of the U.S. armed forces, veterinarians and laboratory workers, are advised to get the vaccine. Also, in the event of an attack using anthrax as a weapon, people exposed should get the vaccine.
The Department of Health and Human Services, which secures vaccines for the nation's biodefense stockpile, is investigating next-generation vaccines that result in fewer side effects and require fewer injections for immunity.
Emergent BioSolutions, the maker of BioThrax, has a vaccine in clinical trials that it considers more potent than BioThrax, which requires six doses over 18 months for immunity.
Why do animals get anthrax more often?
Cattle and other grazing animals are constantly disturbing the soil as they eat, dispersing anthrax in the immediate area of their noses. Likewise, spores adhere to animal hides through contact with spores in soil and the environment. Animal handlers, including veterinarians and ranch hands, are usually vaccinated against anthrax because of the risk of cutaneous anthrax (and, to a lesser extent, inhalation anthrax).