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Traveler Summary

Key Points

  • Anthrax is a bacterial infection acquired by touching infected animals or their contaminated wool and hides, eating contaminated meat, or inhaling bacterial spores.
  • Risk is very low for travelers.
  • Symptoms of skin anthrax include itching and ulcerated lesions covered by blackened dead tissue. Gastrointestinal anthrax presents with nausea, vomiting, fever, and abdominal pain. Symptoms of inhalation anthrax initially resemble a viral illness but usually progress to involve severe consequences.
  • Consequences of inhalation infection include respiratory failure, shock, and inflammation of the brain, resulting in death. Gastrointestinal anthrax may result in generalized infection of blood and internal organs.
  • Prevention includes avoiding contact with infected animals and their wool and hides and avoiding consumption of contaminated meat.
  • Vaccination is not recommended for travelers unless indicated for occupational or other special reasons. A preexposure vaccination series is 5 or 6 doses over 18 months. A postexposure vaccination series is 3 doses combined with antibiotic use.
  • The most common side effects of the vaccine are local reactions.
  • Duration of vaccine protection is 1 year after completing the series. Annual boosters are required to maintain immunity.

Introduction

Anthrax is an infection caused by anthrax bacteria. The disease can develop long after exposure to the bacteria, which (in humans) can cause infection of the skin or, more rarely, the digestive tract or lungs.

Risk Areas

Anthrax occurs globally, most commonly in agricultural regions with inadequate control programs for anthrax in livestock such as Central and South America, sub-Saharan Africa, central and southwestern Asia, and southern and eastern Europe. It occurs most often in herbivore mammals such as cattle, sheep, goats, camels, and antelope. Occurrence in industrialized countries is uncommon.

Transmission

Anthrax has three major routes of transmission: skin, digestive tract, and lungs.

Skin infection can result from direct contact with infected animals or their contaminated wool and hides, usually in agricultural settings (e.g., ranches, slaughterhouses, veterinary clinics, butcher shops) or industrial settings (e.g., wool or hide processing factories).

Digestive tract infection (rare) may result from consumption of contaminated meat.

Lung infection (rare) may result from inhalation of anthrax bacteria spores and is typically a result of an intentional act in which infectious spores have been hidden in white powdery substances.

Risk Factors

Anthrax usually occurs as an occupational disease (including laboratory workers) or as an industrial disease. Travelers are at very low risk.

Symptoms

In general, symptoms of anthrax start within 7 days of exposure.

Skin anthrax presents with itching, followed by a painless, skin lesion (usually appearing on the face, neck, or arms) that changes from a bump to a blister then to an ulcer covered with blackened dead tissue. Fever, malaise, headache, and swollen glands may also occur.

Inhalation anthrax begins like a viral respiratory illness, followed by shortness of breath, mild fever, and muscle aches. Breathing becomes more difficult, and low blood pressure (progressing to shock) ensues.

Gastrointestinal anthrax presents with nausea, vomiting, fever, and abdominal pain and tenderness.

Consequences of Infection

Inhalation anthrax may spread to the brain and cause severe inflammation, swelling, and death. Rarely, gastrointestinal anthrax may spread and cause generalized infection of blood and internal organs.

Need for Medical Assistance

Persons with skin lesions or ulcers after animal exposure and persons with respiratory symptoms after exposure to an unknown white powdery substance should seek medical attention.

Both vaccine and antibiotics are essential for preventing infection. Antibody preparations and anthrax immune globulin are also available.

Prevention

Nonvaccine: Travelers going to countries where anthrax is common and vaccine coverage of livestock is low should avoid contact with livestock and animal products. Consumption of meat from animals of uncertain origin should also be avoided.

Vaccine: Preexposure vaccination is not indicated for travelers without other reasons for vaccination (e.g., military personnel, occupational exposure). Postexposure vaccination is indicated for unvaccinated persons with potential exposure to aerosolized anthrax.

Persons with underlying medical conditions or who have concerns about the vaccine should speak to their health care provider before vaccine administration.

Side effects: The most common side effects of the vaccine include pain, redness, and swelling at the injection site. Headache, fever, chills, and muscle aches are less common. Severe local reactions are rare and can include extensive swelling of the forearm.

Timing: The preexposure series consists of 5 doses (given at 0, 1, 6, 12, and 18 months). An alternative 6 dose regimen is licensed. A booster dose is given 1 year after the 18-month dose and annually thereafter if risk of exposure continues or immunity is to be maintained.

The postexposure series consists of 3 doses (given on day 0, week 2, and week 4) plus at least 60 days of antibiotic use.

Antibiotic therapy (postexposure)

Antibiotic therapy is started as soon as possible after exposure (preferably within 48 hours) and continues for at least 60 days.