20 Causes of STDs
The following is a list of the most common STDs, their causes.
- 6 STDs caused by bacteria
- 5 STDs caused by viruses
- 1 STD caused by protozoan
- 2 STDs caused by fungi
- 2 STDs caused by parasites
Chancroid is a bacterial infection with the bacteria Hemophilus ducreyi. The infection initially manifests in a sexually exposed area of the skin. The infection typically appears on the penis but also occasionally occurs in the anal or mouth area. Chancroid starts out as a tender bump that emerges 3 to 10 days (the incubation period) after the sexual exposure. The bump then erupts into an ulcer (an open sore), which is usually painful. Often, there is an associated tenderness of the glands (lymph nodes), for example, in the groin of patients with penile bumps or ulcers. Chancroid is a relatively rare cause of genital lesions in the U.S., but is much more common in many developing countries.
The diagnosis of chancroid is usually made by a culture of the ulcer to identify the causative bacteria. A clinical diagnosis (which is derived from the medical history and physical examination) can be made if the patient has one or more painful ulcers and there is no evidence for an alternative diagnosis such as syphilis or herpes. The clinical diagnosis justifies the treatment of chancroid even if cultures are not available. Incidentally, the word chancroid means resembling a "chancre," which is the medical term for the painless genital ulcer that is seen in syphilis. Chancroid is also sometimes called "soft chancre" to distinguish it from the chancre of syphilis, which feels hard to the touch.
Chancroid is almost always cured with a single oral dose of azithromycin (Zithromax) or a single injection of ceftriaxone (Rocephin). Alternative medications are ofloxacin (Cipro) or erythromycin. Whichever treatment is used, the ulcers should improve within 7 days. If no improvement is seen after treatment, the patient should be reevaluated for other causes of the ulcers. HIV-infected individuals are at an increased risk of failing treatment for chancroid. They should therefore be followed especially closely to assure that the treatment has worked. In addition, someone diagnosed with chancroid should be tested for other sexually transmitted diseases (such as chlamydia and gonorrhea), because more than one infection can be present at the same time.
A health-care professional should evaluate anyone who has had sexual contact with a person with chancroid. Whether or not the exposed individual has an ulcer, they should be treated if they were exposed to their partner's ulcer. Likewise, if they had contact within 10 days of the onset of their partner's ulcer, they should be treated even if their partner's ulcer was not present at the time of the exposure.
Genital herpes is a viral infection that causes clear blisters that overlie ulcers on the skin or mucosa (lining of the body's openings) of sexually exposed areas. Two types of herpes viruses are associated with genital lesions; herpes simplex virus-1 (HSV-1) and herpes simplex virus-2 (HSV-2). HSV-1 more often causes blisters of the mouth area while HSV-2 more often causes genital sores or lesions in the area around the anus (perianal region).
Most people infected with HSV-2 have not been diagnosed as being infected. If symptoms occur, they appear approximately 3 to 7 days after an initial exposure to herpes. Many men experience mild symptoms, which resolve spontaneously. Others can develop severe bouts of painful blisters on the penis that can be accompanied by fever and headache. Once a herpes infection occurs, it is life-long and can be characterized by recurrent sporadic outbreaks. The outbreaks occur because the dormant HSV is activated. Outbreaks occur at different rates in different individuals. The recurrences can be associated with stress or other infections. They also occur with increased frequency in those who have weakened immune systems, such as with HIV infection. These outbreaks usually are characterized by mildly to moderately painful clusters of blisters over the infected area. The recurrences usually resolve spontaneously, with the blisters disappearing in about 5 days. HSV in HIV-infected individuals, however, can cause more severe disease, which often causes ulcers rather than blisters and persists for a longer time.
Estimates are that as many as 50 million persons in the United States are infected with genital HSV. Genital herpes is spread only by direct person-to-person contact. Again, most infected people have not been diagnosed. Most genital herpes is passed on by people who do not have active signs of disease at the time of transmission.
The suspicion for genital herpes is usually based upon the appearance of multiple, painful clusters of small blisters over the penis or anal area. The definitive diagnosis is based on a culture of the virus. The culture is done by opening a blister, swabbing the base of the ulcer, and sending the swabbed material to the laboratory for culture.
Blood tests that detect antibodies to the HSV reveal whether someone is infected with herpes. These antibodies are proteins that are produced by the body in an immunological (defensive) response specifically targeted against this virus. The antibodies, however, do not indicate whether the person's current lesions are actually due to the herpes or another disease. The antibody test, therefore, is of minimal value in diagnosing genital herpes.
Patients who are newly diagnosed with genital herpes should be aware that:
Affected individuals should notify their sex partners that they are infected with HSV. They should avoid sexual activity not only when the blisters are present, but also when a pre-outbreak tingling, which sometimes is felt over the involved skin, occurs. Since HSV can be spread even during periods when there are no symptoms, condoms or other latex barriers should be used routinely during sexual contact with an infected person. This should be done even if the condoms are not needed at that time to prevent other STDs or to avoid pregnancy. Also, women with genital herpes should be aware of the possibility that HSV can be spread to a newborn if the mother has an outbreak at the time of delivery. Finally, people with HSV infection should understand the clear, but limited role, of antiviral medications for the initial outbreak and for subsequent outbreaks and for suppressive therapy to prevent recurrences in patients with frequent outbreaks.
Several antiviral drugs have been used to treat HSV infection, including acyclovir (Zorivax), famciclovir Favmvir), and valacyclovir (Valtrex). Although topical (applied directly on the lesions) agents exist, they are generally less effective than other medications and are not routinely used. Medication that is taken by mouth, or in severe cases intravenously, is more effective. Affected individuals need to understand, however, that there is no cure for genital herpes and that these treatments only reduce the severity and duration of outbreaks.
Since the initial infection with HSV tends to be the most severe episode, an antiviral medication usually is warranted. These medications can significantly reduce pain and decrease the length of time until the sores heal, but treatment of the first infection does not appear to reduce the frequency of recurrent episodes.
In contrast to a new outbreak of genital herpes, recurrent herpes episodes tend to be mild, and the benefit of antiviral medications is only derived if therapy is started immediately prior to the outbreak or within the first 24 hours of the outbreak. Thus, the antiviral drug must be provided for the patient in advance. The patient is instructed to begin treatment as soon as the familiar pre-outbreak "tingling" sensation occurs or at the very onset of blister formation.
Finally, suppressive therapy to prevent frequent recurrences may be indicated for those with more than six outbreaks in a given year. Acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) may all be given as suppressive therapies.
People who have been exposed to someone with genital herpes should obtain counseling about herpes symptoms, the nature of the outbreaks, and how to prevent acquiring or transmitting herpes in the future. If the exposed person experiences an outbreak of herpes, he or she should be further evaluated to consider treatment.
Lymphogranuloma venereum is an uncommon genital or anorectal (affecting the anus and/or rectum) disease that is caused by a specific type of bacteria, Chlamydia trachomatis. With this infection, men typically consult a doctor because of tender glands (lymph nodes) in the groin. These patients sometimes report having recently had a genital ulcer that subsequently resolved. Other patients, particularly women and homosexual men, can have rectal or anal inflammation, scarring, and narrowing (stricture), which cause frequent, scant bowel movements (diarrhea) and a sense of incomplete evacuation of the bowels. Other symptoms of lymphogranuloma venereum include perianal pain (around the anal area) and occasionally drainage from the perianal area or the glands in the groin. If an ulcer appears, it is often gone by the time infected people seek care. Note that another strain (type) of Chlamydia trachomatis, which can be distinguished in specialized laboratories, causes inflammation of the urethra.
First, or primary, infection is characterized by an ulcer or irritation in the genital area and occurs 3 to 12 days following infection; these early lesions heal on their own within a few days. Two to six weeks later, the secondary stage of infection is characterized by spread of the infection to lymph nodes, causing the tender and swollen lymph nodes in the groin. The scarring that sometimes occurs following lymphogranuloma venereum arises if the infection is not treated adequately in its early stages.
The diagnosis of lymphogranuloma venereum is suspected in a person with typical symptoms and in whom other diagnoses, such as chancroid, herpes, and syphilis have been excluded. The diagnosis in such a patient is usually made by a blood test that detects specific antibodies to Chlamydia, which are produced as part of the body's immunologic (defensive) response to that organism.
Once lymphogranuloma venereum is diagnosed, it is usually treated with doxycycline. If this is not an option, for example, because of intolerance to the drug, erythromycin can be given as an alternative.
A person who has been sexually exposed to a person with lymphogranuloma venereum should be examined for signs or symptoms of lymphogranuloma venereum, as well as for chlamydial infection of the urethra, since the two strains of Chlamydia trachomatis can coexist in an infected person. If the exposure occurred within 30 days of the onset of their partner's symptoms of lymphogranuloma venereum, the exposed person should be treated.
Syphilis is an infection that is caused by a microscopic organism called Treponema pallidum. The disease can go through three active stages and a latent (inactive) stage.
In the initial or primary stage of syphilis, a painless ulcer (the chancre) appears in a sexually-exposed area, such as the penis, mouth, or anal region. Sometimes, multiple ulcers may be present. The chancre develops any time from 10 to 90 days after infection, with an average time of 21 days following infection until the first symptoms develop. Painless, swollen glands (lymph nodes) are often present in the region of the chancre, such as in the groin of patients with penile lesions. The ulcer can go away on its own after 3 to 6 weeks, only for the disease to recur months later as secondary syphilis if the primary stage is not treated.
Secondary syphilis is a systemic stage of the disease, meaning that it can involve various organ systems of the body. In this stage, therefore, patients can initially experience many different symptoms, but most commonly they develop a skin rash, frequently on the palms of the hands, that does not itch. Sometimes the skin rash of secondary syphilis is very faint and hard to recognize, and it may not even be noticed in all cases. In addition, secondary syphilis can involve virtually any part of the body, causing, for example, swollen glands (lymph nodes) in the groin, neck, and arm pits, arthritis, kidney problems, and liver abnormalities. Without treatment, this stage of the disease may persist or resolve (go away).
Subsequent to secondary syphilis, some people will continue to carry the infection in their body without symptoms. This is the so-called latent stage of the infection. Then, with or without a latent stage, which can last as long as twenty or more years, the third (tertiary) stage of the disease can develop. Tertiary syphilis is also a systemic stage of the disease and can cause a variety of problems throughout the body including:
A diagnosis of the chancre (primary stage of disease) can be made by examining the ulcer secretions under a microscope. A special microscope (dark field), however, must be used to see the distinctive corkscrew-shaped Treponema organisms. Since these microscopic organisms are rarely detected, the diagnosis is most often made and treatment is prescribed based upon the appearance of the chancre. Diagnosis of syphilis is complicated by the fact that the causative organism cannot be grown in the laboratory, so cultures of affected areas cannot be used for diagnosis. Syphilis is diagnosed with a blood test even in stage 1.
For secondary and tertiary syphilis, the diagnosis is based upon antibody blood tests that detect the body's immune response to the Treponema organism.
The standard screening blood tests for syphilis are called the Venereal Disease Research Laboratory (VDRL) and Rapid Plasminogen Reagent (RPR) tests. These tests detect the body's response to the infection, but not to the actual Treponema organism that causes the infection. These tests are thus referred to as nontreponemal tests. Although the nontreponemal tests are very effective in detecting evidence of infection, they can also produce so-called false positive results for syphilis. Consequently, any positive nontreponemal test must be confirmed by a treponemal test specific for the organism causing syphilis, such as the microhemagglutination assay for T. pallidum (MHA-TP) and the fluorescent treponemal antibody absorbed test (FTA-ABS). These treponemal tests directly detect the body's response to Treponema pallidum.
Patients with secondary, latent, or tertiary syphilis will almost always have a positive VDRL or RPR, as well as a positive MHA-TP or FTA-ABS. Several months after treatment, the nontreponemal tests will generally decrease to undetectable or low levels. The treponemal tests, however, will usually remain positive for the remainder of the patient's life whether or not they have been treated for syphilis.
Depending on the stage of disease, the treatment options for syphilis vary as summarized in the table below. Depending on the stage of disease and the clinical manifestations, the treatment options for syphilis vary. Long-acting penicillin injections have been very effective in treating both early and late stage syphilis. The treatment of neurosyphilis requires the intravenous administration of penicillin. Alternative treatments include oral doxycycline or tetracycline. Nothing is as effective as penicillin. Patients with penicillin allergies will often undergo immonotherapy in order to tolerate penicillin to be treated for syphilis.
Anyone who has been sexually exposed to an individual with the ulcer or skin rash of syphilis can potentially become infected. Persons who were exposed within 90 days preceding their partner being diagnosed with primary, secondary, or latent syphilis should be treated with one of the regimens for primary or secondary disease, even if antibody tests are negative. If the exposure occurred more than 90 days before the partner was diagnosed, the exposed individual should undergo a nontreponemal test (RPR or VDRL tests). If the test is not readily available and/or follow-up is not guaranteed, the person should be treated as for primary or secondary syphilis. Finally, long-term sex partners of people with later (greater than 1 year duration) latent infection or tertiary syphilis should be evaluated by a physician and undergo blood tests for syphilis. The decision regarding treatment should be based upon whether the person has any symptoms of primary, secondary, or tertiary syphilis and the results of their blood tests for syphilis. Final decisions on the extent of the treatment for syphilis should be made after consultation with an infectious disease specialist.
More than 40 types of human papillomavirus (HPV), which are the cause of genital warts (known as condylomata acuminata or venereal warts), can infect the genital tract of men and women. These warts are primarily transmitted by sexual intimacy. Note that these are generally different from the HPV types that cause common warts elsewhere on the body. Genital warts are smoother and softer lesions than the typically rougher and firmer common warts. Genital warts usually appear as small, fleshy, raised bumps, but they can sometimes be extensive and have a cauliflower-like appearance. In men, the lesions are often present on the penis or in the anal region. In most cases genital warts do not cause any symptoms, but they are sometimes associated with itching, burning, or tenderness.
HPV infection has long been known to cause cervical cancer and other cancer of the genitals and anus (anogenital) in women, it has also been linked with both anal and penile cancer in men. In patients who are simultaneously infected with HIV, the HPV infection is more severe and the associated cancers are even more frequent.
HPV infection is common and does not usually lead to the development of warts, cancers, or specific symptoms. In fact, the majority of people infected with HPV have no symptoms or lesions. Determination of whether or not a person is infected with HPV involves tests that identify the genetic material (DNA) of the virus. Furthermore, it has not been definitively established whether the immune system is able to permanently clear the body of an HPV infection. For this reason, it is impossible to predict exactly how common HPV infection is in the general population, but it is believed at least 75% of the reproductive-age population has been infected with sexually-transmitted HPV at some point in their life. Asymptomatic (those without HPV-induced warts or lesions) people who have HPV infections are still able to spread the infections to others through sexual contact.
Treatment of external anogenital warts
There is no cure or treatment that can eradicate HPV infection, so the only currently possible treatment is to remove the lesions caused by the virus. Unfortunately, even removal of the warts does not necessarily prevent the spread of the virus, and genital warts frequently recur. None of the available treatment options is ideal or clearly superior to others.
A treatment that can be administered by the patient is a 0.5% solution or gel of podofilox (Condylox). The medication is applied to the warts twice per day for 3 days followed by 4 days without treatment. Treatment should be continued up to 4 weeks or until the lesions are gone. Alternatively, a 5% cream of imiquimod (Aldara, Zyclara) is likewise applied by the patient three times a week at bedtime, and then washed off with mild soap and water 6 to 10 hours later. The applications are repeated for up to 16 weeks or until the lesions are gone. Sinecatechin 15% ointment, a green tea extract with an active product (catechins), is another topical treatment that can be applied by the patient. This drug should be applied three times daily until complete clearance of warts, for up to 16 weeks.
Only an experienced clinician can perform some of the treatments for genital warts. These include, for example, placing a small amount of a 10% to 25% solution of podophyllin resin on the lesions, and then, after 1 to 4 hours, washing off the podophyllin. The treatments are repeated weekly until the genital warts are gone. An 80% to 90% solution of trichloroacetic acid (TCA) or bichloracetic acid (BCA) can also be applied weekly by a physician to the lesions. Injection of 5-flurouracil epinephrine gel into the lesions has also been shown to be effective in treating genital warts.
Alternative methods include cryotherapy (freezing the genital warts with liquid nitrogen) every 1 to 2 weeks, surgical removal of the lesions, or laser surgery. Laser surgery and surgical excision both require a local or general anesthetic, depending upon the extent of the lesions.
Both people with HPV infection and their partners need to be counseled about the risk of spreading HPV and the appearance of the lesions. They should understand that the absence of lesions does not exclude the possibility of transmission, and that condoms are not completely effective in preventing the spread of the infection. It is important to note that it is not known whether treatment decreases infectivity. Finally, female partners of men with genital warts should be reminded of the importance of regular PAP smears to screen for cancer of the cervix and precancerous changes in the cervix (since precancerous changes can be treated, reducing a woman's risk of developing cervical cancer). Similarly, men should be informed of the potential risk of anal cancers, although it is not yet been determined how to optimally screen for or manage early anal cancer.
A vaccine is available to prevent infection by four common HPV types associated with the development of genital warts and cervical and anogenital cancer. This vaccine quadrivalent (Gardasil) has received FDA approval for use in males and females between 9 and 26 years of age and confers immunity against HPV types 6, 11, 16 and 18. Another vaccine directed at HPV types 16 and 18, known as bivalent (Cervarix), has been approved for use in females aged 10 to 15. Both vaccines are approved to prevent genital warts in men.
The urethra is a canal in the penis through which urine from the bladder and semen are emptied. Urethritis (inflammation of the urethra) in men begins with a burning sensation during urination and a thick or watery discharge that drips from the opening at the end of the penis. Infection without any symptoms is common. The most common causes of urethritis are the bacteria Neisseria gonorrhoeae and Chlamydia trachomatis. Both of these infections are usually acquired through sexual exposure to an infected partner. The urethritis can extend to the testicles or epididymis via the vas deferens, causing orchitis or epididymitis. These complicated and potentially severe infections can cause tenderness and pain in the testicles. For example, they occasionally develop into an abscess (pocket of pus) requiring surgery and can even result in sterility.
A person with symptoms of urethritis as described above should seek medical care. An evaluation for urethritis generally requires a laboratory examination of a sample of urethral discharge or of a first-in-the-morning urine sample (urinalysis). The specimens are examined for evidence of inflammation (white blood cells). Urethritis has traditionally been classified into two types: gonococcal (caused by the bacterium responsible for gonorrhea) and nongonococcal.
Chlamydia is the major cause of nongonococcal urethritis. If evidence of urethritis is present, every effort should be made to determine if it is caused by Neisseria gonorrhoeae, Chlamydia trachomatis, or both. Several diagnostic tests are currently available for identifying these organisms, including cultures of the urethral discharge (obtained by swabbing the opening of the penis with a cotton swab) or of the urine. Other tests rapidly detect the genetic material of the organisms. Ideally, treatment should be directed towards the cause of infection.
If appropriate and timely follow-up is impossible on the patient's part, however, patients should be treated for both N. gonorrhoeae and C. trachomatis as soon as urethritis is confirmed, because these organisms commonly occur in the same people, produce similar symptoms, and can cause serious complications if left untreated.
Chlamydia is an infection caused by the bacterium Chlamydia trachomatis that most often occurs in sexually active adolescents and young adults. However, chlamydia has a special age group associated with it. It can cause urethritis and the resultant complicating infections of epididymitis and orchitis. Recent studies have proven, however, that both infected men and infected women commonly lack symptoms of chlamydia infection. Thus, these individuals can unknowingly spread the infection to others. Consequently, sexually active individuals should be routinely evaluated for chlamydial urethritis. Note that another strain (type) of Chlamydia trachomatis, which can be distinguished in specialized laboratories, causes LGV (see above). The American College of Obstetrics and Gynecology recommends that all women up to age 26 have annual screening for chlamydia.
A convenient single dose therapy for chlamydia is oral azithromycin (Zithromax). Alternative treatments are often used, however, because of the high cost of this medication. The most common alternative treatment is doxycycline. Patients should abstain from sex for 7 days after the start of treatment and to notify all of their sexual contacts. People with chlamydia are often infected with other STDs and therefore should undergo testing for other infections that may be present at the same time. Their sexual contacts should also then be evaluated for chlamydial infection.
The most common reason for the recurrence of chlamydia infection is the failure of the partners of infected persons to receive treatment. The originally infected person then becomes reinfected from the untreated partner. Other reasons are the failure to correctly follow one of the 7-day treatment regimens or the use of erythromycin for treatment, which has been shown to be somewhat less effective than azithromycin or doxycycline. Complicated chlamydial infections, epididymitis, and orchitis are generally treated with a standard single-dose therapy as used for Neisseria gonorrhoeae (described below) and 10 days of treatment for Chlamydia trachomatis with doxycycline. In this situation, a single dose therapy for chlamydia is not an option.
What should a person do if exposed to someone with Chlamydia?
Persons who know that they have been exposed to someone with chlamydia should be evaluated for the symptoms of urethritis and tested for evidence of inflammation and infection. If infected, they should be treated appropriately. Many doctors recommend treating all individuals exposed to an infected person if the exposure was within the 60 days preceding the partner's diagnosis. All diagnoses of chlamydia need to be reported to the public health department.
Gonorrhea is an STD that is caused by the bacteria Neisseria gonorrhea. In women, this infection often causes no symptoms and can therefore often go undiagnosed. In contrast, men usually have the symptoms of urethritis, burning on urination, and penile discharge. Gonorrhea can also infect the throat (pharyngitis) and the rectum (proctitis). Proctitis results in diarrhea (frequent bowel movements) and an anal discharge (drainage from the rectum). Gonorrhea can also cause epididymitis and orchitis (inflammation of the testicle). What is more, gonorrhea can cause systemic disease (throughout the body) and most commonly results in swollen and painful joints or skin rash. Many patients with gonorrhea also are infected with chlamydia.
Symptoms of gonorrhea usually develop in men within 4 to 8 days after genital infection, although in some cases they may occur after a longer time period.
Gonorrhea may be diagnosed by demonstration of the characteristic bacteria when urethral secretions are examined microscopically. Gonorrhea can also be diagnosed by a culture from the infected area, such as the urethra, anus, or throat. In patients with systemic gonorrhea with, for example, arthritis or skin involvement, the organism can occasionally be cultured from the blood. Newer, rapid diagnostic tests that depend upon the identification of the genetic material of N. gonorrhoeae are also available. Gonorrhea and Chlamydia can now be diagnosed with a urine sample.
The treatment of uncomplicated gonorrhea affecting the urethra or rectum is ceftriaxone by IM (intramuscular) injection in a single dose or a single oral dose of cefixime (Suprax). An intramuscular injection of spectinomycin (not available in the U.S.) is also an alternative treatment. Single doses of other cephalosporins such as ceftizoxime, cefoxitin, administered with probenecid (Benemid), or cefotaxime have also been used to treat gonorrhea.
Many persons with gonorrhea are simultaneously infected with chlamydia. Those treated for gonorrhea, therefore, should also be treated for chlamydia with azithromycin or doxycycline, both of which are taken by mouth. Throat infection (pharyngitis) caused by gonorrhea is somewhat more difficult to treat than genital infection. The recommended antibiotic for treatment of gonococcal pharyngitis is a single IM injection of ceftriaxone IM.
Systemic gonorrheal infections involving the skin and/or joints is generally treated with either daily injections of ceftriaxone in the muscle tissue (intramuscularly) or in the vein (intravenously) every 24 hours, or ceftizoxime intravenously every 8 hours. Another option for the treatment of disseminated (throughout the body) gonococcal infections is spectinomycin (not available in the U.S.) intramuscularly every 12 hours.
Because of increasing resistance to these drugs, the fluoroquinolone antibiotics (such as ofloxacin [Floxin] and ciprofloxacin [Cipro]) are no longer recommended for treatment of gonococcal infections in the U.S.
A person who is sexually exposed to an individual that is infected with gonorrhea should seek medical attention. If the last sexual contact was within 60 days of the partner's diagnosis, the person should be treated for both gonorrhea and Chlamydia. People whose last sexual contact was more than 60 days before the partner's diagnosis should be evaluated for symptoms and have diagnostic studies performed. Treatment for individuals whose exposure was relatively in the more distant past should be limited to those who have symptoms or positive diagnostic tests.
HIV is a viral infection that is primarily transmitted by sexual contact or sharing needles, or from an infected pregnant woman to her newborn. Negative antibody tests do not rule out recent infection. Most (95%) people who are infected will have a positive HIV antibody test within 12 weeks of an exposure. The HIV ultimately causes suppression of the body's immune (defense) system. Although there are no specific symptoms or signs that confirm HIV infection, many people will develop a nonspecific illness 2 to 4 weeks after they have been infected. This initial illness may be characterized by fever, vomiting, diarrhea, muscle and joint pains, headache, sore throat, and/or painful lymph nodes. On average, people are ill for up to 2 weeks with the initial illness. In rare cases, the initial illness has occurred up to 10 months after infection. It is also possible to become infected with the HIV virus without having recognized the initial illness.
The average time from infection to the development of symptoms related to immunosuppression (decreased functioning of the immune system) is 10 years. Serious complications include unusual infections or cancers, weight loss, intellectual deterioration (dementia), and death. When the symptoms of HIV are severe, the disease is referred to as the acquired immunodeficiency syndrome (AIDS). Numerous treatment options now available for HIV-infected individuals allow many patients to control their infection and delay the progression of their disease to AIDS. The Centers for Disease Control recommends screening for HIV in all individuals at annual physicals, as many people are completely asymptomatic.
Hepatitis B is liver inflammation (hepatitis) that is caused by the hepatitis B virus (HBV). HBV is one of several viruses that cause viral hepatitis. Most individuals that are infected with HBV recover from the acute phase of the hepatitis B infection, which refers to the initial rapid onset and short course of the disease. These persons develop immunity to the HBV, which protects them from future infection with this virus. Still, some individuals infected with HBV will develop chronic or long-lasting liver disease. These persons are potentially infectious to others. Moreover, patients with chronic hepatitis B are at risk for developing, over many years, severe and complicated liver disease, liver failure, and liver cancer. These complications at times lead to the necessity of a liver transplant.
Hepatitis B is transmitted in ways that are similar to the spread of HIV. These modes of transmission are primarily through sexual contact, exposure to contaminated blood, such as from sharing needles, or from infected pregnant women to their newborns. Only half of acute hepatitis B infections produce recognizable symptoms.
A highly effective vaccine that prevents hepatitis B is currently available. It is recommended that all babies be vaccinated against HBV beginning at birth, and all children under the age of 18 who have not been vaccinated should also receive the vaccination. Among adults, anyone who wishes to do so may receive the vaccine, and it is recommended especially for anyone whose behavior or lifestyle may pose a risk of HBV infection. Examples of at-risk groups include:
The vaccine is given as a series of three injections in the muscle tissue of the shoulder. The second dose is administered one month after the first dose and the third dose is given 5 months after the second dose. In the event that a non-immunized individual (who would not have protective antibodies against HBV) is exposed to the genital secretions or blood of an infected person, the exposed person should receive purified hepatitis B immunoglobulin antibodies (HBIG) and initiate the vaccine series.
The diagnosis of hepatitis B is made by blood tests for the hepatitis B surface antigen (HBsAg, the outer coat of the virus), hepatitis B surface antibody (HBsAb), and hepatitis B core antibody (HBcAb). If the HBsAb antibodies are in the blood, their presence indicates that the person has been exposed to the virus and is immune to future infection. Furthermore, this person cannot transmit the virus to others or develop liver disease from the infection. The HBcAb antibodies identify both past and current infection with the HBV. If the HBsAg antigen is in the blood, the person is infectious to others. There are also two possible interpretations to the presence of this antigen. In one, the person has been recently infected with HBV, may have acute viral hepatitis, and will develop immunity in the coming months. In the other interpretation, the person is chronically infected with HBV, may have chronic hepatitis, and is at risk for developing the complications of chronic liver disease.
Hepatitis C is liver inflammation (hepatitis) that is caused by the hepatitis C virus (HCV). The HCV causes acute and chronic viral C hepatitis. While it is primarily spread by exposure to infected blood, such as from sharing needles for drug use, piercing, tattooing, and occasionally sharing nasal straws for cocaine use, people who have sex with prostitutes are at a increased risk for Hepatitis C. Most infected people have no symptoms, so a delayed or missed diagnosis is common. In contrast to hepatitis B, where chronic infection is uncommon, the majority of people infected with hepatitis C develop chronic (long-term) infection. As is the case with hepatitis B, chronically infected individuals are infectious to others and are at an increased risk of developing severe liver disease and its complications, even if they have no symptoms.
Hepatitis C infection is diagnosed by using a standard antibody test. The antibody indicates an exposure to the virus at some time. Thus, the hepatitis C antibody is found in the blood during acute hepatitis C, after recovery from the acute hepatitis, and during chronic hepatitis C. Individuals with a positive antibody test can then be tested for evidence of virus in the blood by a test called the polymerase chain reaction (PCR), which detects the genetic material of the virus. The PCR test rarely is needed to diagnose acute hepatitis C, but sometimes can be helpful to confirm the diagnosis of chronic hepatitis C. Patients who test positive for Hepatitis C should be referred to a hepatologist for evaluation and possible treatment.
Human herpes virus 8 is a virus first identified in the 1990s that has been associated with Kaposi's sarcoma and possibly with a type of cancer called body cavity lymphoma (a tumor that arises from the lymph tissue). Kaposi's sarcoma is an unusual skin tumor that is seen primarily in HIV infected men. Human herpes virus 8 has also been isolated in the semen of HIV infected individuals. Because of these factors, the possibility has been raised that human herpes virus 8 is a sexually transmitted infection. Several important issues related to the role of human herpes virus 8 as a disease-causing agent have not yet been fully determined, such as whether human herpes virus 8 actually causes disease, how it is transmitted, what diseases it might cause, and how to treat these disease(s). Recent reports have shown that in children and men who have sex with men, a new (acute) infection with human herpes virus 8 can lead to an illness characterized by fever and rash, and/or to enlarged lymph nodes, fatigue, and diarrhea.
Ectoparasitic infections are diseases that are caused by tiny parasitic bugs, such as lice or scabies. They are transmitted by close physical contact, including sexual contact. The parasites affect the skin or hair and cause itching.
Pubic lice, also called nits, are small bugs that actually are visible to the naked eye. That is, they can be seen without the aid of a magnifying glass or microscope. The scientific term for the responsible organism, the crab louse, is Phthirus pubis. These parasites live within pubic or other hair and are associated with itching.
A lice-killing shampoo (also called a pediculicide) made of 1% permethrin or pyrethrin is recommended to treat pubic lice. These shampoos are available without a prescription.
None of these treatments should be used for involvement near the eyes because they can be very irritating. The patient's bedding and clothing should be machine-washed with hot water. All sexual partners within the preceding month should be treated for pubic lice and evaluated for other STDs.
Scabies is an ectoparasitic infection caused by a small bug that is not visible with the naked eye, but can be seen with a magnifying glass or microscope. The bug is a mite known as Sarcoptes scabiei. The parasites live on the skin and cause itching over the hands, arms, trunk, legs, and buttocks. The itching usually starts several weeks after exposure and is often associated with small bumps over the area of itching. The itching of scabies is usually worse at night.
The standard treatment for scabies is with a 5% cream of permethrin, which is applied to the entire body from the neck down and then washed off after 8 to 14 hours. An alternative treatment is one ounce of a 1% lotion or 30 grams of lindane cream of strokes, applied from the neck down and washed off after approximately 8 hours. Since lindane can cause seizures, it should not be used after a bath or in patients with extensive skin disease or rash. This is because the lindane might be absorbed into the blood stream through the wet or diseased skin. As an additional precaution, this medication should not be used in pregnant or nursing women or children younger than 2 years old.
Ivermectin (Stromectol) is a drug taken by mouth that has also been successfully used to treat scabies. The CDC recommends taking this drug at a dosage of 200 micrograms per kilogram body weight as a single dose, followed by a repeat dose two weeks later. Although taking a drug by mouth is more convenient than applying the cream, ivermectin has a greater risk of toxic side effects than permethrin and has not been shown to be superior to permethrin in eradicating scabies.
Bedding and clothing should be machine washed in hot water (as with the treatment of pubic lice). Finally, all sexual and close personal and household contacts within the month before the infection should be examined and treated.
Sexually transmitted diseases (STDs) are infections that are transmitted during any type of sexual exposure, including intercourse (vaginal or anal), oral sex, and the sharing of sexual devices, such as vibrators. Medically, STDs are often referred to as STIs (sexually transmitted infections). This terminology is used because many infections are frequently temporary. Some STDs are infections that are transmitted by persistent and close skin-to-skin contact, including during sexual intimacy. Although treatment exists for most STDs, some of these infections are incurable, such as HIV, HPV, hepatitis B and C, and HHV-8. Furthermore, many infections can be present in, and be spread by, patients who do not have symptoms.
The most effective way to prevent the spread of STDs is abstinence. Alternatively, the diligent use of latex barriers, such as condoms, during vaginal or anal intercourse and oral-genital contact helps decrease the spread of many of these infections. Still, there is no guarantee that transmission will not occur. In fact, preventing the spread of STDs also depends upon appropriate counseling of at-risk individuals and the early diagnosis and treatment of those infected.
The following is a list of the most common STDs, their causes.