What are characteristics of anthrax?

Causative agent: _Bacillus anthracis_

- Gram-positive, rod-shaped, spore-forming bacteria.

Geographic distribution: Worldwide.

Pathogenesis: Spores are highly resistant to environmental conditions and can survive for decades in soil. When spores are inhaled, they are phagocytized by alveolar macrophages and germinate into vegetative forms. The bacteria multiply and produce toxins which cause tissue destruction and edema. Toxins include:

- Lethal toxin: Inhibits protein synthesis

- Edema toxin: Increases capillary permeability

Clinical features:

- Cutaneous anthrax: Most common form, usually occurs on exposed areas of skin (face, neck, forearms, hands). A small painless papule develops and progresses to a black necrotic eschar. Regional lymphadenopathy and mild constitutional symptoms may be present. Mortality is low if treated early and appropriately.

- Pulmonary anthrax: Inhaled spores may cause pulmonary anthrax. Symptoms may resemble community acquired pneumonia, with fever, chills, myalgias, cough and dyspnea. Mediastinal widening may be seen on chest x-ray. Rapid deterioration and septic shock may occur. Mortality is high.

- Gastrointestinal anthrax: Ingestion of contaminated meat may result in gastrointestinal symptoms including nausea, vomiting, abdominal pain, and diarrhea. Toxemia may develop, leading to shock, and mortality is high. Gastrointestinal anthrax is rare.

- Meningitis: A rare form of anthrax that occurs when spores enter the central nervous system. Symptoms include headache, stiff neck, nausea, vomiting, confusion and seizures. Mortality is high if untreated.

Diagnosis: Diagnosis of anthrax is based on clinical findings, laboratory tests, and epidemiologic information. Laboratory tests may include:

- Gram stain and culture of lesions or body fluids

- Polymerase chain reaction (PCR) to detect _Bacillus anthracis_ DNA

- Serology to detect antibodies against _Bacillus anthracis_

Treatment: Treatment of anthrax is based on early diagnosis and administration of appropriate antibiotics. Antibiotics that are effective against _Bacillus anthracis_ include:

- Penicillin

- Doxycycline

- Ciprofloxacin

- Vancomycin

Prevention: Prevention of anthrax infection includes:

- Vaccination: Anthrax vaccine is available for individuals at high risk of exposure, including military personnel, laboratory workers, and veterinarian.

- Personal protective equipment: Wear appropriate protective clothing and equipment when handling potentially contaminated materials.

- Environmental control: Proper disposal of animal carcasses and decontamination of contaminated areas.

Epidemiology: Anthrax is primarily a disease of animals, but can also infect humans. Humans can become infected through contact with infected animals or animal products, such as wool, hides, or meat. Anthrax can also be spread through inhalation of spores or ingestion of contaminated food or water.