The number of confirmed anthrax cases in the Siberia outbreak has grown to 20, up from nine yesterday. In addition, the Siberian Times reports that at least six of the cases are the severe gastrointestinal form, including the 12-year-old boy that died over the weekend. The remainder of the confirmed cases are the less severe cutaneous form.

Cutaneous anthrax lesion /CDC
Cutaneous anthrax lesion /CDC

While the number of herders in the region were numbered at 64, the number of patients hospitalized is now 90, suggesting the area of risk is larger than previously thought, prompting fears of additional spread in Russia.

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 three 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 percent of cases of anthrax are cutaneous.

• 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 percent chance of death even with antibiotics.

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