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ANTHRAX By: Justin Tursellino
Anthrax is a…. Anthrax is an infection caused by a bacterium, Bacillus anthracis. The infection can take three forms depending on the affected part of the body: cutaneous (on the skin), inhalational, and gastrointestinal. Natural anthrax is a rare disease in the United States. For the 45 years from 1955 through 1999, there were 236 reported cases of anthrax, and 224 of them were cutaneous. The last case of inhalational anthrax (other than those in 2001) was in 1976. Anthrax is not transmitted from one human to another but is generally contracted from infected animals. Cutaneous anthrax can be contracted by handling the hides or wool of infected animals. The 1976 inhalational case was evidently caused by the exposure of a home craftsman in California to imported yarns. The cases in 2001 are believed to have been caused by someone deliberately exposing people by sending spores through the mail. Many countries have investigated and experimented with anthrax as a biological weapon. Anthrax makes a potentially effective weapon because it causes deadly infections and its spores are hardy enough to survive dissemination through various routes. These characteristics also make it a potential weapon for terrorists.
Symptoms The three kinds of infection vary in their symptoms and prognoses: • Cutaneous anthrax is the most common form and is usually caused by the bacterium getting into a cut or abrasion on the skin, as can happen from contact with contaminated meat, wool, hides, or leather. The incubation period is 1 to 12 days. The infection begins as a bump that looks like an insect bite and within days opens into a painless ulcer with a black area in the center. Nearby lymph glands may swell. About 20% of untreated cases result in death, but death is rare in patients who receive antimicrobial therapy. • Inhalational anthrax is the most lethal form and is caused by breathing in spores. The incubation period is believed to be 1 to 7 days generally but may range up to 60 days. The initial symptoms resemble those of a viral respiratory illness, including sore throat, mild fever, muscle aches, and malaise. This first stage can last from hours to a few days, and the second stage may develop suddenly, with symptoms including shortness of breath, fever, shock, meningitis, and respiratory failure. The fatality rate is high, about 75% after symptoms begin, even with medical care, including antibiotics. • Gastrointestinal anthrax, caused by the consumption of raw or undercooked contaminated meat, has an incubation period of 1 to 7 days. The symptoms include severe abdominal distress and fever. The symptoms can be concentrated around either the pharynx (with lesions at the base of the tongue, sore throat, fever, and enlarged lymph nodes) or the lower bowels (with nausea, loss of appetite, vomiting, and fever, followed by abdominal pain, vomiting blood, and bloody diarrhea). The fatality rate is 25% to 60%.
Tests For Anthrax Anthrax tests fall into two categories: those for exposure and presence of anthrax in the environment and those for infection. Nasal swab tests can reveal the presence of spores, and thus exposure, but a positive test does not indicate infection. Even a person exposed to spores will not become ill unless the spores germinate, a process that can take up to 60 days. Therefore, nasal swabs are not recommended to document anthrax exposure or illness. Anthrax infection is diagnosed by culturing the bacterium, using a specimen appropriate to the form of the disease suspected (such as from blood, skin lesions, or respiratory secretions) or by measuring antibodies in the blood. For inhalational anthrax, a chest X-ray can also be helpful, as can a test of cerebrospinal fluid if signs of meningitis are present. Culturing of a sample (from either an environmental source or a bodily fluid, such as blood) can take several hours to several days. The specimen is incubated in artificial media, where the bacteria can grow. Conventional biochemical tests are then performed to identify the bacteria, and susceptibility testing is done to select the best antibiotic for therapy. A new, rapid test that could potentially be used on both environmental and body fluid samples has been developed . This test bypasses the need for culturing and detects the anthrax DNA directly. It is currently available for environmental samples and is being reviewed by the Food and Drug Administration for use on human samples. Anthrax spores are tasteless, odorless, and invisible. • Early symptoms of inhaled anthrax resemble the common cold or flu. • Symptoms are sore throat, mild fever, muscle aches, and/or tiredness. In early cases, your medic or physician may not suspect anthrax andmistakenly treat you for a cold or flu. • You may not know you are infected with anthrax until it’s too late. • It only takes 1 to 6 days after exposure for anthrax symptoms to develop. Inhalational anthrax progresses very rapidly, and can kill within a day or two after initial symptoms appear. If not treated immediately and aggressively in a state-of-art hospital center, once severe symptoms develop, 45% to 80% of patients could die.
