Organism

This is a bacterial infection caused by Bacillus anthracis. This organism is associated with soil and farm animals, and particular risk groups for infection include farmers, vets, leather and abattoir workers, and workers in textile mills. It has also become notorious recently as a possible agent for biological terrorism, following several cases in the United States.

The organism is a particular risk because of its ability to form spores which can withstand extremes of temperature and humidity, and persist for years. The organism causes skin infection (cutaneous anthrax) or blood stream infection with severe and usually fatal pneumonia. Rarely it causes outbreaks of food poisoning, again with severe and rapidly progressing infection and death.

Transmission

Skin infections are usually transmitted by direct contact with the organism in soil, on living or dead animals, or other sources such as wool, hides, rugs and bone meal. Pneumonia is acquired by inhaling spore form of the organism. This usually occurs during industrial processes such as processing animal hides, wool or bone. Intestinal anthrax results from eating contaminating undercooked meat. Transmission of infection directly from one person to another has not been described, although the organism may be transmitted via contaminated clothing or wound dressings.

Regions Affected

Bacillus anthracis is found world-wide, but is particularly associated with farming areas. It is more common in south and Central America, Asia, Africa, and southern/eastern Europe. Animal cases may occur as a result of feeds containing contaminated bone meal. The soil in many parts of the world is contaminated by anthrax spores, posing a continuing risk to human and animal health.

Prevention

A number of precautions should be taken during commercial preparation of meat and other animal products, for example the wearing of protective clothing and masks while working with such materials, the thorough disinfection of hair, wool, animal hide and bone meal prior to processing, and education of workers about personal cleanliness and care of skin abrasions. Workers should also be trained to recognise the early symptoms of disease. Individuals at high risk of infection should be vaccinated as described below.

Any human cases of anthrax should be reported to the local health authority, isolated during their illness and care taken with contaminated clothing and other articles. All cases should be investigated thoroughly to identify the source of infection. Patients should be treated with antibiotics; individuals who have clearly been exposed may also be given antibiotics to prevent infection, and also vaccinated.

Immunisation

Individuals who are at high risk of infection, including workers in wool/textile factories, vets, farmers and abattoir workers, should be vaccinated with anthrax vaccine. Three doses are given at 3 weekly intervals, with the fourth dose at 6 months. Reactions to the vaccine are uncommon, and there are no specific contraindications. The vaccine may also be used to protect military personnel against potential exposure to anthrax used as an agent of bioterrorism. Individuals who are known to have been exposed to anthrax may be given vaccine (3 doses at 2 weekly intervals, starting as soon as possible after exposure), as well as an antibiotic such as Doxycycline or Ciprofloxacin to prevent infection.

Symptoms/Signs

Cutaneous anthrax usually starts as an itchy spot which enlarges, blisters and then becomes an ulcer, usually with a black base. It may be surrounded by red, tender skin, but the ulcer itself is generally not particularly painful.

Source: www.privatehealth.co.uk
Last Editorial Review: 25/1/2010