HIV and Sexually Transmitted Diseases
Issues of reproductive health, including sexually transmitted diseases (STDs), are among the most common reasons that women come to learn of their HIV positive diagnosis. This article will focus on treatable STDs encountered among women in the US and their relationship to HIV disease.
Gonorrhea and chlamydia are two common STDs which do not cause ulcers of the genitals. There were approximately 325,000 gonorrhea cases reported in the United States for 1996, and approximately 490,000 cases of chlamydia. Rates of gonorrhea in the U.S. are highest among minorities living in poverty, while chlamydia tends to be widely distributed among all racial and ethnic groups. The disease rate for chlamydia alone exceeds that of any other infection in the U.S. for which notification of public health agencies is required, and the reported rate of disease for women is more than five times that of men. The difference in reported rates for men and women is attributable to national screening strategies that are designed to focus on women. Screening strategies reflect the fact that the complications of chlamydia infection in women are severe (for example, infertility) and many infected women have no symptoms at all. Gonorrhea and chlamydia are similar in that they predominate in adolescents, they both infect the cervix, and they both cause a serious infection of the upper reproductive tract (uterine lining and fallopian tubes) known as pelvic inflammatory disease.
Infection of the vagina due to Trichomonas is reported to be the most common treatable STD in women by the World Health Organization. In the U.S., doctors are not required to notify public health authorities when a case is diagnosed, so that estimates of the extent of disease among women compared to that of other STDs are difficult to make. Trichomoniasis does not cause severe complications of the female reproductive tract as seen with gonorrhea or chlamydia; thus, trichomoniasis has been regarded as a nuisance condition of little consequence. However, it can cause severe itching and irritation in women, and it has been reported to be the most common STD in HIV-infected women in many clinic settings.
Genital Ulcer Disease (GUD)
In the U.S., genital ulcers are almost always caused by either herpes or by syphilis. Chancroid, another cause of GUD, causes occasional urban epidemics of genital ulcers in the southeastern U.S., but there were less than 400 cases reported to the CDC in 1996, making it much less significant than syphilis and genital herpes. Chancroid is more common in the developing world.
Genital herpes is classically caused by herpes simplex virus 2 (HSV-2), but also can be caused by the same virus that causes cold sores (HSV-1). Cases of genital herpes are not reported routinely to public health authorities. Because infection is lifelong and recurrent outbreaks are part of the disease, the rate of new infections in the U.S. is difficult to estimate. However, it is clear from population surveys that genital herpes has become much more frequent in the U.S. since the 1970s, with rates of infection rising dramatically among adolescents and young adults.
Unlike herpes, syphilis is a readily curable infection that public health authorities have targeted for extinction in the U.S. After a rise in U.S. syphilis rates in the late 1980's associated with the use of crack cocaine, the disease is now on the decline. As with gonorrhea, syphilis is often concentrated among minority men and women living in poverty, with rates among African-Americans 40 to 50-fold greater then among whites.
STDs and HIV Progression
Researchers have been concerned about the possibility that STDs might accelerate the progression of HIV disease. This concern is based on observations that activation of the body's immune system, either through infections or administering vaccines, may temporarily increase HIV viral load. While the clinical importance of such viral load increases is not definitively known, studies of HIV positive persons with tuberculosis (TB) -- an infection that may cause increases in HIV viral load -- have demonstrated more rapid HIV disease progression. Could similar effects be caused by STDs? An increase in the amount of HIV in genital secretions has been noted with several different STDs, but it is not clear whether this increase in HIV replication is confined to the genital compartment or more wide spread in the body. Because some STDs, such as syphilis, cause widespread immune stimulation, an increase in plasma viral load (in the blood) would be predicted.
Impact of STDs on HIV Transmission
The possibility that STDs act as "cofactors" to facilitate HIV spread has been an important public health question in the past decade. HIV has spread through heterosexual contact in some parts of the developing world such as sub-Saharan Africa, where other STDs are very prevalent, at a startling rate. Studies have now conclusively shown that untreated STDs in a community enhance the spread of HIV. Improved STD services at the community level in rural Tanzanian villages resulted in a 38% lower rate of new HIV cases compared to villages where "usual care" for STDs was delivered. At the individual level, treatment of gonorrhea, chlamydia, and genital ulcers at a women's clinic in Abidjan (the Ivory Coast) resulted in lowering the amount of HIV in vaginal secretions. Thus, it is clear that untreated STDs make those who are HIV-infected more likely to pass HIV along to their sex partners. It is also clear that untreated STDs make those who are HIV negative more susceptible to acquiring HIV infection from an HIV positive partner. This "epidemiologic synergy" between HIV and other STDs makes early STD diagnosis and treatment a high priority wherever HIV poses a threat to the public health. In the U.S., meeting this priority will require better access to quality reproductive healthcare for both HIV positive and HIV negative women.
Standard treatment regimens for most STDs are effective in those who also have HIV infection. Initial reports focusing on the interaction of HIV and syphilis indicated that those with HIV and syphilis might suffer complications of syphilis (neurosyphilis, syphilis of the brain, has been a particular concern) more frequently than those without HIV who acquire syphilis. However, a recent CDC study evaluating the response to treatment for early-stage syphilis among those who were HIV positive and HIV negative found that there were was no major difference between groups. Most experts currently recommend a spinal tap to rule out evidence of central nervous system infection in HIV positive individuals who have a blood test positive for syphilis but who do not have clinical signs proving that their infection was recently acquired (either a genital ulcer or a characteristic syphilis rash).
Because routes of transmission are similar for HIV and other STDs, similar prevention methods work to keep those who have HIV from acquiring another STD or from transmitting HIV to their partners, and prevent those who are HIV negative from acquiring HIV/STDs. Decreasing the frequency of partner change, seeking STD treatment early (as soon as any symptom appears), and using condoms consistently are behaviors under an individual's control that can minimize STD/HIV transmission risk. However, because some women may have little control over whether a male partner uses a condom, there is clearly an urgent need for better female-controlled prevention methods. Vaginal microbicides that are safe and acceptable are undergoing testing, mostly in developing countries, as a way to limit the heterosexual spread of HIV.
At the community level, STD/HIV prevention methods include adding HIV/STD education to the information taught in schools, improving the quality of STD/HIV counseling and treatment among primary care providers, and increasing access to reproductive health care among those who are uninsured. Expanded access to substance abuse treatment may have an indirect effect on STD prevention at the community level if expanded services decrease an important driving force for high risk sexual behavior.
Emily Erbelding, MD, MPH, is Assistant Professor of Medicine at Johns Hopkins University and an attending physician in the Moore Clinic at Johns Hopkins Hospital. She serves as Medical Director of the Baltimore City Health Department's HIV Early Intervention Program.