INFECTIONS WITH SPECIFIC ORGANISMS

Infections with specific organisms Literally thousands of organisms can produce clinical illness. Some of these organisms have been discussed above in relation to the organs that they infect. In this section, others are discussed further because of their significance as a cause of generalized infection in individual persons or their importance to public health. Ralph D. Feigin Renu Garg Bacteria Anthrax The disease anthrax, named from the Greek word for coal, is so called because, when it attacks a person's skin, a sore with a coal-black centre develops. In more than 90 percent of the cases of anthrax in human beings, the bacilli remain within the skin sore. In cutaneous (skin) anthrax, there is always considerable swelling around the lesion and bouts of shivering and chills, but there is little other disability. The organism that is responsible for causing anthrax, Bacillus anthracis, may escape from the sore, however, and spread up a lymph channel to the nearest lymph node, where it is usually halted. Only seldom does it invade the bloodstream, causing rapidly fatal septicemia (blood poisoning), internal bleeding, and, sometimes, anthrax meningitis. When the anthrax bacilluswhich comes from infected animal products, usually hides, wool, and hair or bonesis breathed in and attacks the lungs, a suffocating bronchitis results from which few persons survive. This illness is sometimes called woolsorters' disease. Intestinal anthrax is a very rare and fatal form of the disease that comes from eating the flesh of animals that have died of anthrax. The disorder causes inflammation of the stomach and intestines with ulcers much like the sores that appear in cutaneous anthrax. Bacillus anthracis is a spore-bearing germ capable of remaining alive in pastures for years. In damp, warm pastures the bacilli multiply rapidly, but when the pastures dry out, the bacilli form spores. The disease is often fatal to cattle, sheep, goats, and other herbivores, and they sometimes die in the thousands. Their hides, wool, and bones are sometimes heavily contaminated with B. anthracis. The bacillus is not highly infectious in human beings and does not depend upon multiplication within them for survival. Cutaneous anthrax is treated with penicillin and the outlook is good if it is treated early. It can be prevented by the vaccination of exposed workers and by the sterilization of contaminated materials, such as imported wool.