Study On The Anthrax Disease Biology Essay

In 2001, letters containing the virulent Ames strain of anthrax spores were mailed to several news media offices killing five people and infecting 17 others. I found this story and the use of anthrax as a bioterrorism weapon fascinating

Anthrax is a life-threatening infectious disease that normally affects animals, especially goats, cattle, sheep, and horses. Anthrax can be transmitted to humans by contact with infected animals or their products. However, anthrax does not spread from person to person.

Anthrax is an acute disease caused by the bacterium B. anthracis. Most forms of the disease are lethal, and it affects both humans and other animals. As a member of the genus Bacillus, B. anthracis can form dormant endospores that are able to survive in harsh conditions for decades. For example, spores have been known to have re-infected animals over 70 years after the burial sites of anthrax-infected animals were disturbed. When spores are inhaled, ingested, or come into contact with a skin lesion on a host, they may become reactivated and multiply rapidly. If the spores of anthrax are inhaled, they migrate to lymph glands in the chest where they proliferate, spread, and produce toxins that often cause death.

The symptoms vary depending on whether the anthrax spores were inhaled, ingested or through the skin.

Inhalation Anthrax

The first symptoms are subtle, gradual and flu-like. However as the illness worsens there may be severe respiratory distress, shock and coma. Spores are transported in the lymph nodes where they multiply producing deadly toxins, resulting in severe haemorrhage and necrosis. Usually causing death as although prescribed antibiotics are effective in eradicating the bacteria they do not destroy the toxins already released by the anthrax bacteria.

Gastrointestinal Anthrax

This form of anthrax is the rarest form. Gastrointestinal infection in humans is most often caused by eating anthrax-infected meat and is characterized by serious gastrointestinal difficulty, vomiting of blood, severe diarrhoea, acute inflammation of the intestinal tract, and loss of appetite. Some lesions have been found in the intestines and in the mouth and throat. After the bacterium invades the bowel system, it spreads through the bloodstream throughout the body, making even more toxins on the way. Gastrointestinal infections can be treated but usually result in fatality rates of 25% to 60%, depending upon how soon treatment commences.

Cutaneous Anthrax

Cutaneous anthrax is typically caused when B. anthracis spores enter through cuts on the skin. This form of Anthrax is found most commonly when humans handle infected animals and/or animal products. Cutaneous anthrax is rarely fatal if treated, because the infection area is limited to the skin. The cutaneous form of anthrax starts as a red-brown raised spot that enlarges with redness around it, blistering, and hardening. There lymph nodes get swollen in this area. Symptoms include muscle aches and pain, headache, fever, nausea, and vomiting. The illness usually resolves in about six weeks, but deaths may occur if patients do not receive appropriate antibiotics.

The bacteria may be found in cultures or smears in cutaneous anthrax and in throat swabs and sputum in pulmonary anthrax. Chest X-rays may also show characteristic changes in and between the lungs. Other than Gram stain of specimens, there are no specific direct identification techniques for identification of Bacillus species in clinical material. A specific feature of Bacillus species that makes it unique from other aerobic microorganisms is its ability to produce spores. Although spores are not always evident on a Gram stain of this organism, the presence of spores confirms that the organism is of the genus Bacillus.

French scientist Louis Pasteur developed the first effective vaccine for anthrax in 1881.

In most cases, early treatment can cure anthrax. The cutaneous form of anthrax can be treated with common antibiotics such as penicillin,tetracycline, erythromycin, and ciprofloxacin. The pulmonary form of anthrax is a medical emergency. There are several vaccines in current use. The Russian vaccine, called STI is a live-attenuated vaccine based on spores from the Stern strain of B. anthracis. The STI vaccine’s serious side-effects restrict use to healthy adults.

If a person is suspected as having died from anthrax, every precaution should be taken to avoid skin contact with the potentially contaminated body and fluids exuded through natural body openings. The body should be put in strict quarantine. Full isolation of the body is important to prevent possible contamination of others. Protective, impermeable clothing and equipment such as rubber gloves, rubber apron, and rubber boots with no perforations should be used when handling the body. No skin, especially if it has any wounds or scratches, should be exposed.

Anthrax cannot be spread directly from person to person, but a person’s clothing and body may be contaminated with anthrax spores. Effective decontamination of people can be accomplished by a thorough wash-down with antimicrobial effective soap and water. Burning clothing is very effective in destroying spores. After decontamination, there is no need to immunise, treat, or isolate contacts of persons ill with anthrax.

Early antibiotic treatment of anthrax is essential, delay significantly lessens chances for survival.

Treatment for anthrax infection and other bacterial infections includes large doses of intravenous and oral antibiotics, such as fluoroquinolones. In possible cases of inhalation anthrax, early antibiotic prophylaxis treatment is crucial to prevent possible death.

Anthrax spores can survive for very long periods of time in the environment after release. Methods for cleaning anthrax-contaminated sites commonly use oxidizing agents  and liquid bleach products containing sodium hypochlorite. These agents slowly destroy bacterial spores.  The pH of the solution should be tested with a paper test strip; and treated surfaces must remain in contact with the bleach solution for 60 minutes.

Anthrax spores can and have been used as a biological warfare weapon. There is a long history of practical bioweapons research in this area. For example, in 1942, British bioweapons trials severely contaminated Gruinard Island in Scotland with anthrax spores of the Vollum-14578 strain, making it a no-go area until it was decontaminated in 1990.

There are a number of economic impacts of a wide release of anthrax. These include loss of life and direct compensations to families. In addition healthcare, loss of property, decontamination, evacuation and return. After the 2001 attacks the cleanup of postal facilities and offices cost $130 million and took 26 months.