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Anthrax: from a disease of livestock to an agent of bioterrorism

It has been around since to dawn of civilization. Many believe that the 5th plague in the Book of Genesis was caused by anthrax. It’s been recorded in the literature of many other ancient civilizations.

Bacillus anthracis gram stain Image/CDC

Bacillus anthracis gram stain
Image/CDC

First reports of outbreaks in Europe occurred in the 1800s associated with occupational exposure with people handling animal skins and wools.

Today, it’s notorious for its role in the 2001 bioterror attack where it was deliberately spread through the US mail.

So where in the world is anthrax found? Anthrax is found worldwide, however there is more risk in countries with less effective public health programs.

Areas currently considered high risk are South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean and the Middle East.

It occurs infrequently in livestock in North America, but there have been outbreaks in deer in Texas and buffalo in Canada.

Anthrax is a pathogen in livestock and wild animals. Some of the more common herbivores are cattle, sheep, goats, horses, camels and deers.

It infects humans primarily through occupational or incidental exposure with infected animals of their skins. Recently someone got infected by handling imported animal skins to be used for a drum set. The animal skin was contaminated with anthrax spores.

In recent decades human anthrax has declined due to anthrax vaccines for people who work in high risk industries, decreased importation of potentially contaminated animal products and better animal husbandry practices.

Anthrax is caused by the bacterium, Bacillus anthracis. This spore forming bacteria can survive in the environment for years because of its ability to resist heat, cold, drying, etc. this is usually the infectious stage of anthrax.

When conditions become favorable, the spores germinate into colonies of bacteria. An example would be a grazing cow ingests spores that in the cow, germinate, grow spread and eventually kill the animal.
The bacteria will form spores in the carcass and then return to the soil to infect other animals. The vegetative form is rarely implicated in transmission.

The organism also produces some dangerous toxins and proteins.

There are no reports of person to person transmission of anthrax. People get anthrax by handling contaminated animal or animal products, consuming undercooked meat of infected animals and more recently, intentional release of spores.

There are 3 types of anthrax with differing degrees of seriousness:

Cutaneous anthrax: this occurs when the spore (or possibly the bacterium) enters a cut or abrasion on the skin. It starts out as a raised bump that looks like an insect bite. It then develops into a blackened lesion called an eschar that may form a scab. Lymph glands in the area may swell plus edema may be present. This form of anthrax responds well to antibiotics. If untreated, deaths can occur if the infection goes systemic. 95% of cases of anthrax are cutaneous. The CDC states there are 1-2 cases annually in the US.

Gastrointestinal anthrax: this follows the ingestion of contaminated meats. It is characterized by stomach pain, severe bloody diarrhea, bloody vomit and an inflammation of the intestinal tract. Up to half of those infected will perish from this form of disease. This is a very rare type of anthrax.

Inhalation anthrax: also known as “woolsorter’s disease”, happens due to inhaling the spores. After incubating for less than a week; fever, aches, vomiting are early symptoms. After the initial symptoms, a short period of improvement (less than a day) may occur. It then progresses to severe respiratory distress. Shock and death soon follow. Later stages of this infection have nearly a 100% chance of death even with antibiotics. In the US this form is also very rare.

Diagnosis of anthrax is made on culture of the bacteria (see below). There are also molecular and serological methods available. Chest X-ray can also help in the diagnosis of inhalation anthrax.

Anthrax can be treated with antibiotics with varying rates of success based on how quickly treatment starts and the type of anthrax. Ciprofloxacin, doxycycline and penicillin are FDA-approved for the treatment of anthrax in adults and children.

What about an anthrax vaccine? According to the Centers for Disease Control and Prevention the following groups should be vaccinated:

• Persons who work directly with the organism in the laboratory
• Persons who work with imported animal hides or furs in areas where standards are insufficient to prevent exposure to anthrax spores.
• Persons who handle potentially infected animal products in high-incidence areas. (Incidence is low in the United States, but veterinarians who travel to work in other countries where incidence is higher should consider being vaccinated.)
• Military personnel deployed to areas with high risk for exposure to the organism (as when it is used as a biological warfare weapon).

The immunization consists of three subcutaneous injections given 2 weeks apart followed by three additional subcutaneous injections given at 6, 12, and 18 months. Annual booster injections of the vaccine are recommended thereafter.

 

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About the Author

- Writer, Co-Founder and Executive Editor of The Global Dispatch. Robert has been covering news in the areas of health, world news and politics for a variety of online news sources. He is also the Editor-in-Chief of the website, Outbreak News Today and hosts the podcast, Outbreak News Interviews on iTunes, Stitcher and Spotify Robert is politically Independent and a born again Christian Follow @bactiman63

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