Psychotherapy

Psychotherapy, treatment of individuals with emotional problems, behavioral problems, or mental illness primarily through verbal communication. In most types of psychotherapy, a person discusses his or her problems one-on-one with a therapist. The therapist tries to understand the person’s problems and to help the individual change distressing thoughts, feelings, or behaviors.

Retrovirus

Retrovirus, any virus belonging to the family Retroviridae, whose members share a unique method of replicating themselves when they infect living cells. Retroviruses store their genetic information in molecules of ribonucleic acid (RNA). However, unlike other RNA viruses, retroviruses use RNA as a template (master pattern) for forming deoxyribonucleic acid (DNA), the genetic material that puts viral replication instructions into effect. This process, called reverse transcription, is the exact opposite of the normal flow of genetic information in living things in which DNA serves as the template for RNA formation.

Retroviruses affect a wide range of animals, although the best-known types are those that target vertebrates. Some retroviruses are harmless, but many can cause malignant transformation—a genetic change that makes healthy cells cancerous. Disease-forming retroviruses can cause diseases such as leukemia in mammals and malignant tumors and other disorders in birds. From a human perspective, by far the most significant retroviruses are a small group called lentiviruses, which include human immunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS).

Lyme Disease

Lyme Disease, bacterial disease transmitted to people by ticks. Lyme disease is caused by a spiral-shaped bacterium known as Borrelia burgdorferi. This bacterium is frequently carried by ticks of the genus Ixodes, primarily the deer tick (also known as the black-legged tick) and the related Western black-legged tick. Immature ticks become infected by feeding on small rodents, such as the white-footed mouse, and other mammals that are infected with the bacteria.

Early symptoms of Lyme disease include a red, circular, smooth rash that expands in size and may resemble a bull's-eye. The rash is painless, does not itch, and may disappear on its own. Several days to several weeks after infection, an infected person may develop flulike symptoms such as fever, headache, a stiff neck, joint and muscle pain, and severe fatigue.

Doctors often treat patients early in the disease solely on the basis of their symptoms and if they have had a known or likely exposure to infected ticks. In the later stage of disease, blood tests are available that measure the body's antibody response against the Borrelia burgdorferi bacteria. These tests are unreliable if used within four weeks of infection because antibody levels may be too low to be detected. Tests designed to detect the presence of the bacterium itself are under development.

Physicians treat Lyme disease with antibiotics. Most patients in the early stages of Lyme disease respond well after two to four weeks of medication. Patients may have persistent fatigue and achiness after treatment, but these symptoms generally resolve within six months. Patients in a later stage of the disease with more severe symptoms may require treatment with one or more intravenous antibiotics for up to six weeks. People in the later stage of the disease typically respond slowly to antibiotic treatment and some people may continue to suffer from symptoms for years.

Relapsing Fever

Relapsing Fever, acute infectious disease caused by spirochetes of the genus Borrelia and transmitted by the bite of ticks of the genus Ornithodoros and of body lice. The course of the disease is characterized by an incubation period of 3 to 18 days; onset of the acute stage begins with a chill followed by fever accompanied by headache, pains in the muscles and in the abdomen, and vomiting. The attack ends suddenly three to six days later, and the patient, although weak, is apparently recovering. After several more days, however, the acute stage recurs and lasts for three or four days. The patient then usually recovers, but in some cases one or more further recurrences may ensue; further relapses are most common in tick-borne relapsing fever.

Relapsing fever generally occurs in areas where poor nutrition and unhygienic conditions are prevalent; in times of famine the incidence of the disease may reach epidemic proportions. Treatment includes complete bed rest, a fluid diet, and tetracycline or chloramphenicol, usually taken orally.

Fever

Fever, also known as pyrexia, rise in the body’s temperature, as measured in the mouth, above 37° C (98.6° F). Fever is a symptom of many disorders, such as infection by a virus or a bacterium, and it is not itself a disease. The term fever is also used to name certain diseases, such as relapsing fever, rheumatic fever, scarlet fever, undulant fever, and yellow fever, in which high fever is a major symptom. The first signs of fever may be chilly sensations, with associated periods of flushed or warm feelings. The temperature may rise slowly or rapidly and may fluctuate. A rise in temperature may be accompanied by shaking chills. A falling temperature may bring on heavy sweating.

Although fever is basically a protective mechanism, it often produces weakness and fatigue. During a fever the body loses large amounts of salts and water through sweating, and the patient’s desire for food or water is greatly reduced. Prolonged fever may result in the destruction of body protein and fat, which can lead to serious weight loss.

Fever is generally treated by lowering the body’s temperature with aspirin, and by applying cool compresses or alcohol sponges. To replace the fluids lost from the body by sweating, patients are usually given large quantities of liquids to drink. In the case of very high fever, cold baths and ice packs on the body can be effective.