STDs: A Common Cause for Concern
STDs: A Common Cause for Concern
Sexually transmitted diseases (STDs) are a group of infectious diseases that are passed from person to person primarily by sexual contact. More than twenty diseases are classified as STDs. Their symptoms vary, their severity and effects vary, and they are caused by varied kinds of organisms, so no one description fits all STDs.
It is important to understand that though most STDs involve the genitals, the symptoms and effects of STDs can occur anywhere in the body. Similarly, the appearance of symptoms in the genital area does not automatically indicate infection by an STD. There are many other diseases that affect the genitals, from bacterial infections to cancer, that are not classified as STDs because they are not transmitted through sexual contact.
Besides their common method of transmission, STDs have another important feature in common: They are occurring at epidemic levels in human populations around the world, and the rate of infection is rising sharply, especially among young people. This is particularly bad news because STDs are not merely nuisance diseases. They cause serious and lasting health problems and have huge medical and economic costs.
How STDs Are Spread
The infectious organisms that cause STDs survive and thrive in specific areas on or within the body. A type of tissue known as the mucous membrane is the preferred habitat for most of the microscopic germs that cause STDs. This soft, warm, moist tissue is found within the penis, vagina, anus, mouth, and eyes. Therefore, STDs are usually spread by direct physical contact between an infected person and the genitals, mouth, or anus of another person. Vaginal, anal, and oral sexual activity provides opportunities for the spread of these germs from one person to another. Less direct forms of sexual activity, such as kissing or close body contact, can also transmit STDs through the exchange of saliva or other body fluids, although this route of transmission is much less common.
Nonsexual Transmission of STDs
Nonsexual transmission of STDs is not a contradiction: Because many of the germs that cause STDs thrive in semen, blood, and saliva, nonsexual exposure to one of these fluids can be sufficient to transmit an STD. A person does not need to be sexually mature or sexually active to acquire one of these diseases; even babies can contract an STD, as disease organisms in an infected mother's blood or breast milk can be transferred to her child during pregnancy, childbirth, or nursing.
Transmission of STDs is even possible without direct contact with an infected person. Indeed, it is possible for an infected person to transmit an STD to someone else without ever meeting them. For example, the use of unsterilized dental or medical instruments has been known to mediate the transfer of infected blood and saliva from one patient to another. This method of infection is rare in developed countries such as the United States, but occurs more frequently in poor countries where shortages of medical supplies are common and sterilization procedures are not strictly followed. More well known is transmission of STDs through infected blood in the course of a blood transfusion.
The most common method of nonsexual transmission of STDs in developed countries is by intravenous (IV) injection of drugs, such as heroin, as small amounts of blood are transferred between infected individuals and others who might subsequently share the same needle. The danger of sharing needles is illustrated by the fact that in 1999 half of the Americans who were infected with HIV (the virus that causes the deadly sexually transmitted disease AIDS) were exposed to the virus through IV drug use.
The manner in which an STD is acquired makes no difference in the way it can then be spread. Thus STDs that are contracted nonsexually can be spread both nonsexually and through sexual contact, just as someone who becomes infected with an STD through sexual activity can pass on the disease to someone else sexually and nonsexually.
Significantly, because each STD is caused by a different organism, it is quite possible to contract more than one STD at a time. In fact, research has shown that the presence of some STDs increases a person's susceptibility to other STD infections. The U.S. Centers for Disease Control and Prevention (CDC) estimates, for example, that a person already infected with one STD is three to five times more likely to acquire HIV if exposed to the virus than a non-infected person who is exposed to HIV.
STDs Are Not Spread by Casual Contact
Though STDs can be spread nonsexually, the nonsexual transmission of these diseases is almost always limited to direct and immediate contact with infected body fluids. This is because the infectious organisms that cause STDs cannot survive for extended periods outside a living person. Once these organisms are removed from their normal habitat within the body and exposed to the air, they quickly perish. This means that it is nearly impossible to contract an STD through day-to-day casual interactions such as handshakes, hugs, or the use of public toilet seats, since any disease organisms that are deposited at these external contact points soon die. Even in the rare instance where live organisms are transferred by casual contact, they cannot cause disease unless they penetrate the surface of the skin or come in contact with mucous membranes.
For the most part, skin offers sufficient protection against casual transmission of STDs. Exceptions to this rule are found in the case of two STDs, pubic lice and scabies. The tiny insects that cause these diseases are hardy enough to survive for days on bedding, clothing, or furniture. Thus direct contact between a person's skin and one of these contaminated surfaces can be sufficient to acquire these STDs. However, transmission by this route is very rare. Most people acquire pubic lice and scabies through sexual activity.
STDs Are Common and on the Rise
The fact that sexual activity is a fundamental, or innate, human behavior ensures that STDs occur everywhere among the human population. STDs are among the most common infectious diseases worldwide, with over 350 million new cases occurring across the globe each year. Fifteen million of these new cases occur in the United States alone, a rate of new infection higher than that of any other country in the industrialized world. Indeed, the CDC, the federal agency that monitors the incidence of disease and charts outbreaks, notes that in 1995 five of the ten most frequently reported diseases in the United States—chlamydia, gonorrhea, AIDS, primary and secondary syphilis, and hepatitis B—were STDs, accounting for 87 percent of the total reported cases of these ten diseases. The World Health Organization (WHO) estimates that over 70 million Americans are infected with at least one STD.
Clearly, some STDs are more common than others. In the United States each year, 5.5 million people become infected with a viral STD known as the human papillomavirus (HPV), cited by many as the most common STD. According to an NBC news report, "Some experts estimate that as many as 75% of reproductive age Americans may have been infected with the virus [HPV], which sometimes disappears within months and sometimes hangs on for years."1 The parasitic STD trichomoniasis is also extremely common, with over 5 million Americans contracting this disease each year. The STD spreading at the fastest rate, the bacterial infection called chlamydia, currently infects approximately 3 million people annually, and a million Americans acquire genital herpes each year. The relatively few (forty thousand) new cases of HIV infection in the United States does not indicate that the incidence of HIV is diminishing; a January 2003 report by the Association of American Colleges estimates that worldwide more than 5 million people were infected with HIV in 2002 alone.
Recent surveys conducted by a number of health organizations, including CDC and WHO, show that both common and uncommon STDs are on the rise. New cases of chlamydia, HPV, and genital herpes are rising at exponential rates. New cases of genital herpes, for example, have increased by 30 percent in the past twenty years; 45 million Americans, close to one in five over the age of twelve, are infected with this viral STD. Even some STDs whose incidence declined sharply with the introduction of antibiotics have recently seen an upswing. New cases of syphilis, for instance, which were reported at a relatively low and stable level of about one thousand per year in the United States, shot up to more than six thousand in 2001. Gonorrhea is another STD that seemed to be well controlled by antibiotics, with cases steadily decreasing over the last few decades. However, from 2000 to 2002 the incidence of gonorrhea infection in the United States jumped by 9 percent.
HIV infection rates, which steadied and even fell as much as 47 percent in the mid-1990s with increased public awareness of AIDS, have skyrocketed since 1999. That year forty thousand new HIV cases were diagnosed in the United States; though U.S. incidence has remained about the same since then, the HIV epidemic is rising particularly sharply in Eastern Europe and Central Asia, with new cases rising 25 to 30 percent per year in China.
Factors in the Spread of STDs
The acceleration in the incidence of STDs can be attributed to several recent developments in modern societies. The booming world population has been one contributing factor. As population grows and cities become more crowded, contact between people increases and the incidence of STDs increases too. Modern populations are also more mobile than people in the past. Thanks to the widespread construction of roads and train lines, people are now able to routinely move from place to place, transmitting STDs and other diseases wherever they go. Air travel has increased the spread of STDs immeasurably by transporting infected people from one side of the globe to the other in a matter of hours.
The fact that certain STDs can be spread by contaminated blood is another factor in their rising incidence, since medical blood transfusion is a much more common procedure in today's society than it ever was in the past. In the 1980s, before HIV was identified as the cause of AIDS and screening tests were developed to detect HIV in the blood supply, many people were unknowingly infected with HIV-contaminated blood received during blood transfusions.
Sexual attitudes and behaviors have also changed since the invention of the birth control pill in the late 1950s made pregnancy a much less likely result of sexual relations and helped to launch the so-called sexual revolution of the 1960s. For the first time sexual relations were promoted as healthy, pleasurable activities free of the life-long commitment of monogamy or child rearing. As a result, more people tended to have a greater number of sexual partners, which increased the likehood that an infected person would transmit an STD.
According to public health officials, people are not only engaging in sexual relations with a greater number of partners but also are less likely to take precautions to prevent the spread of STDs. Helen Gayle, the director of the CDC's National Center for HIV, STD, and TB Prevention attributes this indifference to the medical successes of the past few decades, when some STDs declined to all-time lows. Gayle says that the recent increase in the incidence of many STDs "should serve as a wake-up call to all people at risk that high-risk sexual behaviors continue to have very real consequences."2
The effect of recent developments has been further amplified by the fact that it can take up to several years after STD infection for symptoms of disease to develop. With such a long delay, many, if not most, people transmit an STD before they realize that they have a disease.
Actual Incidence Far Exceeds Reported Cases
Experts estimate that the total number of people infected with STDs is actually much greater than the number of reported cases. For example, the most highly reported STD infection in the United States is chlamydia. In 1999 660,000 cases of chlamydia were recorded in the United States. The CDC estimates the actual number of cases, however, is approximately 3 million.
One reason for this discrepancy is that in the absence of symptoms many infected people do not know they have a disease and do not seek treatment. Also, a diagnosis of a sexually transmitted disease has traditionally carried a social stigma, and many health care providers choose not to record or report an STD diagnosis to protect their patients' privacy. Connie, a social worker in a San Francisco STD clinic, says that her patients are very concerned that their positive diagnosis is kept confidential. As Connie explains, "There are still a lot of negative connotations associated with having an STD. Nice people aren't supposed to get them, so patients that I see often worry that they will be viewed as sexually promiscuous if anyone were to find out."3
Indeed, some people are so embarrassed by the prospect of having an STD that they avoid treatment even when symptoms are obvious. This reluctance is often intensified if the infected person is young and still living in the family home. As Connie explains:
It isn't as if they have a broken arm or a flu. They'd go to their parents or the school nurse in a second to seek help for those types of problems.… Most teens are rather horrified at the idea of discussing any sexual health problem with their parents. For one thing, it would mean admitting that they are sexually active.… It often isn't until they feel a significant amount of pain or are seeing mucus in their urine, that they come in here for help.4
Although worsening symptoms may force many infected individuals to eventually seek treatment, other people with only mild or no symptoms may remain untreated and risk infecting others.
Who Is Affected by STDs?
Any sexually active person anywhere is at risk of contracting an STD. STDs affect people of all racial, ethnic, cultural, social, economic, and religious groups. To a lesser degree, people of any age, sexually active or not, can contract an STD nonsexually via contaminated body fluids.
However, some groups and activities carry higher risk than others. The majority of new cases occur in people ages fifteen to twenty-five years. Teenagers are one of the highest-risk groups for contracting STDs, with over one quarter of new cases occurring in people under the age of twenty. According to the CDC, this is because teens are more likely than other age group to have multiple partners and to engage in unprotected sex, two high-risk behaviors. Indeed, 45 percent of fifteen- to seventeen-year-olds participating in a Henry J. Kaiser Family Foundation, MTV, and Teen People magazine survey reported having three or more sexual partners, and only 57 percent said they used a condom every time they had sex.
This high-risk behavior is resulting in an enormous number of preventable infections. The rates of infection by chlamydia, genital herpes, HPV, gonorrhea, and HIV are higher among teens than among any other age group. Forty percent of all new cases of chlamydia are diagnosed in people under twenty years of age: Among sexually active teens, more than one in ten females and one in twenty males are infected with this disease. Genital herpes is also rampant among the teen population with the highest rates of infection occurring among Caucasian teenagers; at current rates of infection, 15 to 20 percent of teens will be infected with genital herpes by the time they reach adulthood.
People under twenty-five years old also have the highest risk of contracting HIV. Roughly 50 percent of all new cases of HIV are diagnosed in people younger than twenty-five with the fastest-growing incidence among heterosexual females thirteen to nineteen years of age. Thus HIV infection is clearly not limited to the high-risk behaviors with which it is closely associated, primarily IV drug use and unprotected anal sex.
Young Females at Greatest Risk
Although young people of both sexes are at high risk for acquiring STDs, females have an even greater likelihood of infection than males. In addition to the increased rates of chlamydia and HIV in female teens compared to their male peers, the rates of HPV are also highest in young women. Screens for HPV infection have consistently identified this STD in 28 to 46 percent of women twenty-five years of age or younger. Gonorrhea also hits the young female population hardest, with the fifteen- to nineteen-year-old group acquiring the greatest number of infections.
"STDs are inherently sexist," says H. Hunter Handsfield, director of Seattle and King County's STD control program. "They are transmitted more efficiently from male to female than vice versa."5 This is because the delicate mucosal tissue in the vagina is extremely susceptible to small tears and abrasions which permit infection by STDs. For example, the chance that a female will contract gonorrhea from one act of intercourse with an infected male may be as high as 90 percent, whereas the risk of transmission to a male from an infected female falls to 20 to 30 percent. Similarly, the transfer of HIV infection has been estimated to be eight times higher from male to female than the reverse. Research has also shown that the cervical tissue (connecting the vagina and uterus) of females under twenty years of age is even more susceptible to infection by chlamydia and gonorrhea than that of older females.
Dating habits and social patterns also influence the susceptibility of females to STDs. For example, hetrosexual females often become sexually involved with males who are older than themselves. Older partners are more likely to have been sexually active longer with more partners and are therefore more likely to be infected with an STD than younger males.
The Effects of STDs
STDs have a wide range of medical, economic, and social effects, depending on specific disease and treatment options, but collectively it is clear that STDs exact a huge toll on humanity. The most immediate effect is the acute symptoms of disease an infected individual suffers, including pain and discomfort that disrupts a person's personal habits, sexual activity, and ability to work for days or weeks despite effective treatment.
Although some STDs can be cured, many lead to chronic health problems such as repeated outbreaks and chronic inflammation that is potentially disabling and disfiguring. Of increasing concern to health care providers and public health agencies are the long-term effects of STDs, which can cause a wide range of other diseases from chronic hepatitis to cancer.
The long-term complications of STDs are well recognized in females, in whom the symptoms of STDs such as gonorrhea, syphilis, and chlamydia are masked and take longer to develop. Females thus remain infected for longer periods of time before seeking treatment. This delay in treatment can give the infection time to spread to the internal reproductive organs resulting in the development of pelvic inflammatory disease (PID). PID is a leading cause of chronic pelvic pain, internal abscess formation, and infertility in women. Over one million women in the United States experience an acute episode of PID each year with one hundred thousand becoming infertile as a result. In addition, PID causes a large proportion of ectopic pregnancies, a potentially life-threatening condition in which a fertilized egg fails to descend into the uterus. Continued development of the egg in the fallopian tube can result in rupture of the tube and death of the pregnant woman.
HPV infection causes serious complications in females; HPV is linked to more than half the cases of cervical cancer in American women. Approximately 12,800 cases of cervical cancer were diagnosed in the United States in 2000, and close to 4,600 women died of the disease in 2001.
STD infection in pregnant women can also have devastating consequences for the baby, both during and after pregnancy. A high number of spontaneous abortions, stillbirths, and premature deliveries are caused by STD infections. Syphilis is particularly dangerous in pregnant women, killing up to 40 percent of unborn fetuses. STDs can also cause brain damage, blindness, disfigurement, and chronic respiratory distress in children born to infected mothers. In addition, the STD itself may be transmitted, with the child exhibiting the same symptoms as the infected mother. Among the most serious infections that can be spread from mother to child is HIV, since the child will then develop AIDS. The risk of HIV transfer from mother to child may be as high as 25 percent and usually occurs during birth. However, HIV can be transmitted during pregnancy and even afterward, with 10 to 15 percent of mother-child transmission occurring through breast milk.
The most serious long-term effects of STDs are associated with AIDS, the most intensely researched and most dangerous STD because it is incurable and fatal. The scope and scale of the AIDS epidemic is unprecedented: More than 65 million people worldwide have been infected with HIV since the epidemic began in the 1970s, 25 million of whom have died as of January 2003. AIDS is the fourth-leading cause of death worldwide and the leading cause of death in Africa, reducing average life expectancy on the African continent from sixty-two to forty-seven years and severely destabilizing African society.
From an economic perspective, the consequences of STDs are enormous. The yearly cost of treating STDs in the United States alone exceeds $10 billion, a figure that does not include the indirect but substantial costs associated with loss in work productivity and attempts to overcome infertility caused by STDs. Direct treatment of HPV costs $1.6 billion annually. It is difficult to estimate the worldwide financial cost of HIV/AIDS, but a 2003 Association of American Colleges and Universities briefing suggests that an annual international investment of between $8.7 billion and $12 billion in HIV/AIDS care, services, and prevention is required.
Clearly STDs have calamitous effects on humankind. Given the significant medical, financial, and social costs of STDs, controlling their spread is essential. The first step in combating STDs is accurate diagnosis and prompt treatment.