Anthrax

Anthrax is a zoonosis caused by Bacillus anthracis. There are four types of anthrax: inhalational anthrax (also known as woolsorter's disease and ragsorter's disease), cutaneous anthrax, injection anthrax and intestinal anthrax.

Epidemiology

The disease burden of anthrax decreased so dramatically in the Western world over the last century that concern about the disease became primarily driven by bioterrorism events, however, the disease remains endemic in some parts of the developing world and outbreaks have occurred in other parts of the world. For example, there have been outbreaks of the injection form of the disease in intravenous drug users in Europe, particularly Northern Europe ¹. 

Clinical presentation

Most cases of anthrax are of the cutaneous form ². Cutaneous anthrax is known classically as a disease that forms an eschar.

Inhalational anthrax is described as a disease that causes cough, fever and dyspnea.

Intestinal forms are associated with abdominal pain, although may also cause a pharyngitis.

In rare cases, anthrax can disseminate to the central nervous system and cause meningitis and/or encephalitis. All forms of anthrax may be fatal.

Pathology

Bacillus anthracis is found in soil and has a reservoir in animals. Although animals are typically understood as the vector for the disease, anthrax can also be acquired through insect bites ³. The various forms of anthrax are distinguished by their suspected acquisition route. Intestinal anthrax is ingested with the meat of infected animals, cutaneous anthrax is acquired through contact with infected animals or animal products such as hides, and injected anthrax is due to injected contaminated intravenous drugs (IVDU).

Additionally, some isolates of Bacillus cereus can cause an anthrax-like disease which may be similarly severe ^8,9.

Radiographic features

Inhalational anthrax is associated with pleural effusions and mediastinal widening ^4-6. There are a few reports in the literature of the imaging findings of anthrax-related meningoencephalitis ⁷, and it is generally described as a disease with multiple hemorrhagic lesions.

Treatment and prognosis

Management consists of antibiotics, which may be monotherapy or combination therapy depending on the severity of disease, with or without antitoxin ¹⁰.