Sexually Transmitted Diseases
Sexually transmitted diseases (STDs) are caused by organisms ranging from viruses to arthropods; however, we will discuss only certain STDs caused by viruses and bacteria. Unfortunately, for unknown reasons, humans cannot develop good immunity to any STDs. Therefore, prompt medical treatment is needed after exposure to an STD. Condoms help prevent the spread of STDs; the use of a spermicide containing nonoxynol 9 in conjunction with a condom gives added protection.
Curing the STDs caused by viruses (for example, AIDS, genital herpes, and genital warts) is difficult, but the symptoms can be treated. Those STDs caused by bacteria (for example, gonorrhea, chlamydia, and syphilis) are treatable with antibiotics.
AIDS
The virus that causes acquired immunodeficiency syndrome (AIDS) is called human immunodeficiency virus (HIV). HIV attacks the type of lymphocyte known as helper T cells. Helper T cells, stimulate the activities ofB lymphocytes, which produce antibodies. After an HIV infection sets in, helper T cells begin to decline in number, and the person becomes more susceptible to other types of infections.
AIDS has three stages of infection called category A, B, and C. During a category A stage, which may last a year, the individual is an asymptomatic carrier. There may be no symptoms, but the individual can pass on the infection. Immediately after infection, and before the blood test becomes positive, there is a large number of infectious viruses in the blood that could be passed on to another person. Even after the blood test becomes positive, the person remains well as long as the body produces sufficient helper T cells to keep the count higher than 5003 During the category B stage, which may last six to eight years, the lymph nodes swell, and there may also be weight loss, night sweats, fatigue, fever, and diarrhea. Infections like thrush (white sores on the tongue and in the mouth) and herpes reoccur. Finally, the person may progress to category C which is AIDS, characterized by nervous disorders and by the development of an opportunistic disease, such as an unusual type of pneumonia or skin cancer. Opportunistic diseases occur only in individuals who have little or no capability of fighting an infection. Without intensive medical treatment, the AIDS patient dies about seven to nine years after infection. Now, with a combination therapy of several drugs, AIDS patients are beginning to live longer in the United States.
An HIV infection is transmitted by sexual contact including vaginal or rectal intercourse and oral/genital contact. Also, needle-sharing among intravenous drug users is high-risk behavior. HIV first spread through the homosexual community, and male-to-male sexual contact still accounts for the largest percentage of new AIDS cases in the United States. But the largest increases of new AIDS cases are occurring through heterosexual contact or by intravenous drug use. Now women account for 20% of all newly diagnosed cases of AIDS. The rise of the incidence among women of reproductive age is paralleled by a rise in the incidence of AIDS in children younger than 13. Babies can become infected before or during birth, or through breast feeding after birth.
Genital Herpes
Genital herpes is caused by herpes simplex virus. Type 1 usually causes cold sores and fever blisters, while type 2 more often causes genital herpes. Many times, a person infected with type 2 has no symptoms, but if symptoms are present, there are painful ulcers on the genitals that heal and then recur. The ulcers may be accompanied by fever, pain upon urination, and swollen lymph nodes. At this time, the individual has an increased risk of acquiring an AIDS infection. Exposure in the birth canal can cause an infection in the newborn, which leads to neurological disorders and even death. Birth by cesarean section prevents this possibility.
Genital Warts
Genital warts are caused by the human papillomaviruses (HPVs). Many times, carriers do not have any
sign of warts, or merely flat lesions may be present. If visible warts are removed, they may recur. HPVs are now associated with cancer of the cervix, as well as tumors of the vulva, the vagina, the anus, and the penis. Some researchers believe that the viruses are involved in 90-95% of all cases of cancer of the cervix.
Gonorrhea
Gonorrhea (gah-nah-re'ah) is caused by the bacterium Neisseria gonorrhoeae. Diagnosis in the male is not difficult, since typical symptoms are pain upon urination and a thick, greenish yellow urethral discharge. In males and females, a latent infection leads to pelvic inflammatory disease (PID), in which the vasa deferentia or the uterine tubes are affected. As the inflamed tubes heal, they may become partially or completely blocked by scar tissue, resulting in sterility or infertility. If a baby is exposed during birth, an eye infection leading to blindness can result. All newborns are given eyedrops to prevent this possibility.
Chlamydia
Chlamydia (klah-mI'de-ah) is named for the tiny bacterium (Chlamydia trachomatis) that causes it. Chlamydia is the most common cause of nongonococcal urethritis (NGU), which is often difficult to distinguish from gonococcal urethritis. Since an infection can also cause PID, physicians routinely prescribe medicines for both gonorrhea and chlamydia at the same time. Chlamydia also causes cervical ulcerations, which increase the risk of acquiring AIDS. If a baby comes in contact with chlamydia during birth, inflammation of the eyes or pneumonia can result.
Syphilis
Syphilis (sI'ful-lis), which is caused by the bacterium Treponema pallidum, has three stages, which are typically separated by latent periods. In the primary stage, a hard chancre (ulcerated sore with hard edges) appears. In the secondary stage, a rash appears all over the body-even on the palms of the hands and the soles of the feet. During the tertiary stage, syphilis may affect the cardiovascular and/or nervous system. An infected person may become mentally retarded or blind, walk with a shuffle, or show signs of insanity. Gummas, which are destructive ulcers, may develop on the skin or within the internal organs. Syphilitic bacteria can cross the placenta, causing birth defects or a stillbirth. A blood test is available to diagnose syphilis.
