Several new varieties of viral hepatitis emerged in the 1960s, then in the 1980s. Hepatitis A, B, and C are now well identified. Hepatitis D is a defective virus (it cannot reproduce unless B is present). Hepatitis E is not very common in the United States. These diseases illustrate how, through scientific inquiry, a generic ailment, "viral hepatitis," came to be known first as having an "infectious" and then a "serum" variety (passed by blood transfusion). These two varieties came to be associated with viral forms A and B. Other cases that remained, the so-called Non-A, Non-B instances, were eventually examined closely enough to isolate Hepatitis C as the principal agent of disease.
Hepatitis is a disease of the liver. The liver controls sugar, produces bile and coagulating agents, makes certain hormones, filters, detoxifies blood, makes vitamins, etc. Diseases of the liver have wide ramifications. Hepatitis A is the least dangerous; B and C can be transmitted through blood — as well as sexual contact, and needle sharing. The diseases often occur in conjunction with AIDS. Both are dangerous and can be lethal. Hepatitis C is the most serious of the three and is associated with the majority of liver transplants.
Legionnaire's disease came to be recognized when, in 1976, a deadly outbreak of pneumonia occurred at a convention of the American Legion in Philadelphia. The disease may equally well have become known as the "air-conditioning" disease. The bacterium, Legionella pneumophila, lives in water systems but reaches high numbers in the stagnant, warm waters found in plumbing systems, hot water tanks, and cooling towers of large buildings. The disease illustrates how changes in the physical structures of our lives can cause the concentrations of bacteria that have been around for a very long time. Those who smoke and have other underlying diseases (kidney, cancer, diabetes, or respiratory diseases) are most at risk. About 15% of those who contract pneumonia die. The disease has not been associated with home or auto air-conditioning systems.
Toxic shock syndrome appeared in the early 1980s in association with a kind of "super- absorbent" tampon no longer on the market. The agent is the bacterium called Staphylococcus aureus. The disease is abbreviated as TSS. The bacteria produce a toxin that results in shock and multiple organ dysfunction or failure (kidney, liver). Low blood pressure, confusion, seizures, nausea, vomiting, and diarrhea are associated with TSS. Treatment is by intravenous fluids, blood pressure support, and dialysis (if kidney dysfunction is present). To prevent the disease, women are advised to use tampons only intermittently in the menstrual cycle and to avoid highly absorbent tampons. The actual cause for the concentration of the bacterium is still being debated. Tampons are said to cause small ulcerations that aid the entry of the bacterium into the body. Other theories hold that stagnating blood in or behind the tampon facilitates bacterial growth. A few men and children have also shown up with the disease. Staphylococcus aureus — like Legionella pneumophila — are making use of human inventions in order to proliferate.
AIDS may have reached us by way of the monkeys. Simian immunodeficiency virus (SIV) may have migrated, adapted itself to humans in Africa where contact with monkeys, including consumption of monkey meats, sometimes happens. The Chimpanzee variety of SIV is very similar in structure to AIDS, but the origin is not well established. Ebola virus also was also to have come from monkeys — but the disease, absent in the United States, fortunately, is now being traced to lower forms of life, possibly bats. Our fervent hope is that this disease will never make it into the U.S. statistics on notifiable diseases. Ebola made its appearance in 1972. Two serious outbreaks have occurred (1976, 1995) in Africa, with hundreds dead. Lesser outbreaks occurred as recently as 2001. Death rates are in the 70-80% range.
Lyme disease was first discovered in Old Lyme, Connecticut, in 1975. This is another disease that reaches humans through an animal linkage — this time the deer tick. The disease has flu-like symptoms and is treated with antibiotics. Secondary and tertiary stages appear if the disease is left untreated and causes arthritis-like symptoms in the joints and nervous symptoms like speech impairment, hallucinations, decreased consciousness, and confusion. Another animal-based disease, Hanta virus, appeared in 1993, spread by mice. No data are shown for the disease because it is not contagious and is, therefore, not routinely reported on by the Centers for Disease Control.
Source: Centers for Disease Control and Prevention. Summary of notifiable diseases, United States, 1999. MMWR 1999 and earlier years.
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