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Pathology => Human Diseases => Syphilis
Syphilis
INTRODUCTION
Syphilis, infectious disease caused by the spirochete Treponema pallidum (see Bacteria) and usually transmitted by sexual contact or kissing. Infection from contaminated objects is infrequent, because drying quickly kills the organisms. A fetus carried by a woman with syphilis may contract the disease, a condition called congenital syphilis.
HISTORICAL BACKGROUND
Authorities believe that syphilis was introduced into Europe in 1493 by crew members returning from Christopher Columbus's first expedition to America; by the 16th century, syphilis had become the major public disease. The spirochete responsible for syphilis was discovered only in 1905, however, by the German zoologist Fritz Schaudinn. In 1906 the German bacteriologist August von Wassermann developed the first blood reaction test for the disease's diagnosis, and in 1909 the German bacteriologist Paul Ehrlich discovered the first effective treatment: the arsenic-containing compound Salvarsan. In 1943 the antibiotic penicillin was shown to be highly effective against syphilis, and it is still the preferred treatment for the disease.
Effective therapy and intensive public-health measures reduced the number of cases reported in the U.S. from 106,000 in 1947 to 25,500 in 1975, but the number rose again to more than 39,000 cases in 1988. During the 1970s most cases of syphilis in men occurred in homosexuals, but the increase in the 1980s appeared to be largely among heterosexuals. This trend increased the incidence of congenital syphilis, which causes a high rate of morbidity and mortality in infants. People who also have AIDS are more likely to develop serious forms of syphilis and to suffer relapses after treatment that usually would be curative.
STAGES AND SYMPTOMS
The primary stage of syphilis is characterized by a small lesion, called a chancre, which appears at the site of infection three to six weeks after exposure. Fluid from the chancre is extremely infectious. In the secondary stage, occurring about six weeks later, a generalized rash appears. Painless ulcers develop in the mouth, and broad, wartlike lesions, which also are highly infectious, may appear in the genital area. Headache, fever, and enlarged lymph glands are sometimes observed. These symptoms usually disappear in 3 to 12 weeks.
The disease then enters a latent stage in which no outward signs or symptoms occur, but inflammatory changes may take place in the internal organs. The latent stage can last 20 to 30 years. In 75 percent of the cases, no further symptoms appear. When the final stage, tertiary syphilis, does occur, however, it may produce hard nodules, called gummas, in the tissues under the skin, the mucous membranes, and the internal organs. The bones are frequently affected, as well as the liver, kidney, and other visceral organs. Infection of the heart and major blood vessels accounts for most deaths.
A prominent part of neurosyphilis, which occurs in nearly 15 percent of the tertiary cases, is tabes dorsalis, or locomotor ataxia (see Paralysis). Also present are a lack of muscular coordination, loss of urinary control, and degeneration of the reflexes; psychosis may ensue. Infection in the uterus may lead to miscarriage, to stillbirth, or to the birth of a child with congenital syphilis. Infected children often bear typical signs, such as high forehead, saddlenose, and peg-shaped teeth. By the second decade of life, central nervous system deterioration may appear.
DIAGNOSIS AND TREATMENT
Syphilis is detected by symptoms and verified by one of several tests performed on the blood or spinal fluid, the most common of which is the VDRL (venereal disease research laboratory) test. The preferred drug for treatment is benzathine penicillin, which is given in two injections one week apart for all stages but neurosyphilis. For this advanced stage, the antibiotic is given three times at weekly intervals. Syphilis control includes tracking down all sexual contacts of infected persons and treating those who had contact during the infectious period. Use of condoms offers some protection against contracting syphilis.
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