Infectious Diseases

Sexually Transmitted Diseases

Sexually transmitted diseases (STDs) are a class of infectious diseases spread by intimate sexual contact between individuals. These diseases include the major venereal diseases such as nongonococcal urethritis, trichomoniasis, gonorrhea, genital herpes, genital warts, syphilis, and acquired immune deficiency syndrome.

Nongonococcal urethritis refers to any inflammation of the urethra that is not caused by gonorrhea. Factors such as trauma or passage of a nonsterile catheter through the urethra can cause this condition, but many cases are acquired through sexual contact. In most cases a bacterium such as Chlamydia trachomatis is responsible, but other bacteria may be involved. Chlamydia trachomatis infection is one of the most common sexually transmitted disease. It often is unrecognized in people who have it, and it is responsible for many cases of pelvic inflammatory disease. It can also result in sterility. Antibiotics are usually effective in treating the condition.

Trichomonas is a protozoan commonly found in the vagina of females and the urethra of males. If the normal acidity of the vagina is disturbed, Trichomonas can grow rapidly. Trichomonas infection is more common in females than in males. The rapid growth of these organisms results in inflammation and a greenish-yellow discharge characterized by a foul odor.

Gonorrhea is caused by Neisseria gonorrhoeae. The organisms attach to the epithelial cells of the vagina or to the male urethra. The invasion of bacteria establishes an inflammatory response in which pus is formed. Males become aware of a gonorrheal infection by painful urination and the discharge of pus-continuing material from the urethra. Symptoms appear within a few days to a week. Recovery may eventually occur without complication, but, when complications do occur, they can be serious. The urethra can become partially blocked, or sterility can result from blockage of reproductive ducts with scar tissue. In some cases, other organ systems such as the heart, meninges of the brain, or joints may become infected. In females the early stages of infection may not be noticeable, but the infection can lead to pelvic inflammatory disease. Gonorrheal eye infections may occur in newborn children of females with gonorrheal infections. Antibiotics are usually effective in treating gonorrheal infections, and the immune system often successfully combats gonorrheal infections in untreated individuals.

Genital herpes is a viral infection by herpes simplex type 2. Lesions appear after an incubation period of about 1 week and cause a burning sensation. After this, blisterlike areas of inflammation appear. In males and females, urination can be painful, and walking or sitting can be unpleasant, depending on the location of the lesions. The blisterlike areas heal in about 2 weeks. The lesions may reoccur. The viruses exist in a latent condition in the infected tissues and may produce inflamed lesions on the genital in response to factors such as menstruations, emotional stress, or illness. If active lesions are present in the mother's vagina or external genitalia, a caesaren delivery is performed to prevent newborns from becoming infected with the herpes virus. Because genital herpes is caused by a virus, there is no effective cure for the condition.

Genital warts result from a viral infection and are quite contagious. Genital warts are common, and their frequency is increasing. Genital warts can also be transmitted from infected mothers to their infants. Genital warts vary from separate, small, warty growths to large cauliflower-like clusters. The lesions are usually not painful, but they can cause painful intercourse, and the bleed easily. For women who have genital warts there is an increased risk of developing cervical cancer. Treatments for genital warts include topical agents, cryosurgery, or other surgical methods.

Syphilis is caused by the bacterium Treponema pallidum, which can be spread by sexual contact of all kinds. Syphilis exhibits an incubation period from 2 weeks to several months. The disease progresses through several recognized stages. In the primary stage the initial symptom is a small, hard-based chancre (shang'ker), or sore, which usually appears at the site of infection. Several weeks after the primary stage, the disease enters the secondary stage, characterized mainly by skin rashes and mild fever. The symptoms of secondary syphilis usually subside after a few weeks, and the disease enters a latent period, in which no symptoms are present. In less than half the cases, a tertiary state develops after many years. In the tertiary stage, many lesions develop that can cause extensive tissue damage that can lead to paralysis, insanity, and even death. Syphilis can be passed on to newborns if the mother is infected. Damage to mental development and other neurological symptoms are among the more serious consequences. Females who have syphilis in the latent phase are most likely to have babies who are infected. Antibiotics are used to treat syphilis, although some strains are very resistant to certain antibiotics.

Acquired immune deficiency syndrome (AIDS) is caused by infection with the human immunodeficiency virus (HIV), which appears to ultimately result in destruction of the immune system. The most common mechanisms of transmission of the virus are through sexual contact with a person infected with HIV and through sharing needles with an infected person during the administration of illicit drugs. Screening techniques now implemented make the transmission of HIV through blood transfusions very rare. Some rare cases of transmission of HIV through accidental needlesticks in hospitals and other health care facilities have been documented. There is no evidence that casual contact with a person who has AIDS or who is infected with HIV will result in transmission of the disease. Transmission appears to require exposure to body fluids of an infected person in a way that allows HIV into the interior of another person. Normal casual contact, including touching and HIV-infected person, does not increase the risk of infection.

Other Infectious Diseases

Pelvic Inflammatory disease (PID) is a bacterial infection of the female pelvic organs. It usually involves the uterus, uterine tubes, or ovaries. A vaginal or uterine infection may spread throughout the pelvis. PID is commonly caused by gonorrhea or chlamydia, but other bacteria can be involved. Early symptoms of PID include increased vaginal discharge and pelvic pain. Early treatment with antibiotics can stop the spread of PID, but lack of treatment results in a life-threatening infection. PID can also lead to sterility.