Anthrax: Questions and Answers
What is anthrax?
Anthrax is an infection caused by the spore-forming bacteria called Bacillus anthracis. It is a zoonosis (disease transmissible from animals to humans) that typically affects ruminants (such as cows, sheep, and goats). The bacteria produce extremely potent toxins which are responsible for the symptoms, causing a high lethality rate. Humans can catch the disease from infected animals or through contaminated animal products.
Where is the disease found?
The disease is present in most parts of the world, but the frequency of outbreaks varies. Anthrax spores may remain dormant in the soil for long periods and resurface when the soil is disturbed, such as by flooding, torrential rains or landslides. The disease typically reappears when the spores are then ingested by grazing ruminants.
How is the disease transmitted?
Anthrax usually does not typically spread from animal to animal or human to human. When anthrax spores are ingested, inhaled or enter the body through skin abrasions or cuts, they can germinate, multiply and produce toxin. Insects can transmit the bacterium between animals. Animal feed can be contaminated by anthrax if it contains bone meal of infected animals. Humans can get infected if they handle or are involved in the slaughter of a sick animal, or are in contact with contaminated animal products (such as meat, blood, wool, hides, bones). Anthrax can also be contracted in laboratory accidents. Furthermore, anthrax can be contracted by heroin-injecting drug-users through injection of contaminated heroin. Moreover, Bacillus anthracis has always been high on the list of potential agents with respect to biological warfare and bioterrorism.
What are the clinical presentations of anthrax in humans?
There are three forms of anthrax in humans. Quick and appropriate medical evaluation and treatment are essential for all three forms.
Cutaneous, or skin, anthrax is the most common form. It is usually contracted when a person with a break in their skin, such as a cut or abrasion, comes into direct contact with anthrax spores. The resulting itchy bump rapidly develops into a black sore. Some people then develop headaches, muscle aches, fever and vomiting.
Gastrointestinal anthrax is caught from eating meat from an infected animal. It causes initial symptoms similar to food poisoning, but these can worsen to produce severe abdominal pain, vomiting of blood and severe diarrhoea.
The most severe, and rarest, form of human anthrax is called inhalation or pulmonary anthrax. This form of the disease is caused when a person is directly exposed to a large number of anthrax spores suspended in the air, and breathes them in. The first symptoms are similar to those of a common cold, but this can rapidly progress to severe breathing difficulties and shock.
Can I catch anthrax from another person?
In the case of cutaneous anthrax, there is a small risk of direct infection from the lesions on another person's body. Inhalation anthrax cannot be transmitted from person to person: it can only be contracted by directly inhaling anthrax spores.
How is anthrax in humans treated?
Hospitalization is required for all human cases of anthrax. Individuals potentially exposed to anthrax spores may be provided with prophylactic treatment. Anthrax responds well to antibiotics, which need to be prescribed by a medical professional. Always follow medical advice on how to take the antibiotics. Precisely follow the instructions and do not shorten the course of treatment. Should any side effects of the treatment be noted, please consult a physician at once. Nobody should attempt to use antibiotics or any other drugs to treat or protect themselves without first getting medical advice.
Is there a vaccine for anthrax?
Anthrax vaccines for livestock and humans exist. Veterinary vaccines are used for control of anthrax in livestock. Human vaccines are in limited supply and used primarily for protection of selected individuals with possible occupational exposure to anthrax.
How can anthrax be prevented?
Preventing the disease in animals will protect human health. Breaking the cycle of infection is the basis for control of anthrax in livestock. If a potential infectious source is known to exist, this should be eliminated without delay.
In the event of a case or outbreak occurring in livestock, control measures consist of correct disposal of the carcass(es), decontamination of the site(s) and of items used to test and dispose of the carcass(es), and initiation of treatment and/or vaccination of other animals as appropriate. The best disposal method is incineration. The carcass should not be opened, since exposure to oxygen will allow the bacteria to form spores.
Early detection of outbreaks, quarantine of affected premises, destruction of diseased animals and fomites, and implementation of appropriate sanitary procedures at abattoirs and dairy factories will ensure the safety of products of animal origin intended for human consumption.
If a domestic animal is sick or has just died, can its meat and hides be used?
Any animal that is sick, behaves strangely or has died suddenly should not be used for food or for making any product, as it may have succumbed to an infectious disease. Make sure to follow national rules on veterinary inspection prior to slaughter as these measures ensure food safety as well as safety of persons involved in the slaughter.
All parts of an animal that has died of anthrax should be safely disposed of.