Diagnosing Genital Herpes -
Guidelines for Health Care Providers

Genital HSV-2 infections are reaching epidemic proportions in the United States. Recent Centers for Disease Control (CDC) data indicate that as many as 21.9% of the population between 12 and 74 years of age are infected with HSV-2. The overwhelming majority of these are genital infections. The prevalence is higher among persons who attend sexually transmitted diseases (STD) clinics and in many obstetrical practices. These data represent a 30% increase in HSV-2 seroprevalence in the early 1990's as compared with the late 1990's. The United States is not the only country that has seen a marked increase in genital herpes in the last twenty years. Genital herpes epidemics are now well documented in Europe, Africa, and South America.

There are multiple reasons for this rise in HSV-2 infections worldwide. However, a major contributor is the fact that most HSV-2 seropositive persons are unaware of their infections. Yet, new diagnostic tests are now available that could definitively identify those with HSV-2. Accurate diagnosis is key to treatment and prevention of genital herpes. Genital herpes:

• Can be diagnosed
• Can be treated
• May be prevented

Recognizing genital herpes

Most people who have HSV-2 infection are unaware that they have it. Only about 20% of those infected with HSV-2 have symptoms that are recognized as genital herpes. Most do not recognize the symptoms. Much of this lack of recognition is due to the unfamiliarity with the signs and symptoms of herpes which are often mild and are easily confused with other conditions. However, once taught about the symptoms of disease, the majority of people infected with HSV-2 will return to the clinic within one year with a clinically symptomatic recurrence of genital herpes. In other words, with a little instruction, persons who have HSV-2 can be taught to recognize a recurrence of genital herpes. Recognizing a recurrence is key to controlling the disease and reducing the possibility of transmitting the infection to others.

Treating genital herpes

Three different antiviral drugs are currently available for the management of genital herpes. These medications can be taken episodically to treat a recurrence or daily to suppress recurrences from occurring. One of these medications has also been shown to reduce transmission to sexual partners if taken daily. The therapy and regimen depend on patient preference and disease characteristics as well as physician preference.

Patients can be shedding virus when they are asymptomatic. Studies have shown that almost all persons who have HSV-2 shed virus when there are no signs or symptoms of disease. Some of this is because the virus causes small microscopic ulcers that are too small for anyone to see. Others times it is because the ulcers are on internal genital areas such as the cervix or perirectal area. It is believed that transmission occurs most often when a patient is unaware that they are infected or who are either having no symptoms or very mild symptoms of disease. This is because in studies in which one measures viral reactivation on a daily basis, from 60 to 90% of the days in which HSV is found in the genital region occurs asymptomatically. Increased shedding can occur immediately before or after a recurrence. If a person knows they are infected, they can be taught to recognize the signs and symptoms of disease. Recognition of recurrences and avoidance of intercourse during this time can help decrease the likelihood of recurrences.

Latex condoms are effective in preventing transmission. They are, however, not always effective because they do not necessarily cover the area of the body that is shedding the virus. While the virus cannot penetrate the condom, it does not always cover the infected area, thus, skin-to-skin contact and transmission can occur. This should not discourage the use of condoms. They are effective in preventing other STDs and they can be helpful in preventing transmission of genital herpes if it covers the infected area. A recent study has also shown that daily therapy with the antiviral drug valaciclovir can also reduce the transmission of HSV-2 between sexual partners (see therapy section).

Diagnosis and management are key to controlling this epidemic.

Why is it important to diagnose genital herpes?

Genital herpes while considered to be a rather benign infection does have severe complications. It is a chronic infection that will affect the person emotionally, physically, and sexually for the rest of their life. Often these patients are misdiagnosed with another infection, thus, treated inappropriately. This is costly and poor clinical practice. If a pregnant woman becomes infected, especially during the third trimester, she is at increased risk of transmitting it to her newborn. Neonatal herpes is a life-threatening infection that is associated with severe morbidity. Genital herpes infections have also been associated with the increased risk of acquisition of HIV. Open lesions present a portal of entry for the HIV virus. Lastly, HSV infection can allow HIV replication in cells previously immune to HIV. These complications emphasize the importance of letting a person know whether or not they are infected.

How do I determine if a patient is infected?

Herpes can be diagnosed clinically, by culture, and by serology. As mentioned earlier, often patients are asymptomatic or mildly symptomatic. Clinical diagnosis is difficult in these cases. Also, patients do not always present with lesions. At this time the clinician must rely on a history and ask the patient to return when there are lesions. Cultures are very helpful if the patients presents early in the recurrence. However, viral shedding only lasts a few days and often the lesion has crusted or disappeared by the time the patients sees the clinician. Thus, a negative culture will not definitely rule out herpes. A new test which measures HSV DNA in a swab called a PCR assay may be more sensitive for detecting HSV in a lesion than a viral culture. The PCR assay is, however, more expensive than a viral curlture. PCR assays need to be sent to regional reference laboratories.

The most reliable diagnosis for most patients is an antibody test that is specific and sensitive for HSV-2 antibodies in serum. These tests are new and are major improvements over older assays which did not distinguish between past HSV-1 and past HSV-2. Persons with past HSV-2 infections make antibodies to the HSV-2 virus. These new assays can distinguish between antibodies to HSV-2 from HSV-1. These assays are new and all laboratories do not do them. You need to specifically ask for these assays. Additionally, a test is now available for use in the clinic or the doctor's office. This test is a type-specific HSV-2 serologic test that can give results within 15 minutes of pricking the patient's finger.

We recommend you review the details about these here.

Who should be tested for presence of HSV-2?

The persons who are at greatest risk of an infection and its complications are the first groups that should be targeted for testing. Most people want to know whether they have acquired HSV-2 in the past and are at risk of passing the virus to others. They expect to be informed when they go to see their physician. Studies have shown that 92% of people want to know if they are infected, 90% want to know if their partner is infected, and 65% think that HSV testing is part of routine screening for STDs. Unfortunately, many clinics claim they are doing STD checks or workups but do not test for herpes. PAP smears are not a test for genital herpes.

Listed below are guidelines for three greatest risk groups. However, if any person regardless of risk group exhibits the signs or symptoms of disease, they should be tested for presence of virus and counseled appropriately.

1. Persons attending Sexually Transmitted Diseases (STD) clinic or those who have been diagnosed with another STD

We feel all persons who attend an STD clinic should get a serology for HSV-2. Why? Because lots of studies show that from 25 - 70% of STD clinic attendees have already acquired HSV-2 infections and 90% do not know this. Moreover, if you know you have herpes, you will either treat it or use condoms to prevent transmitting it to others. Most STD clinics tell their clients they are doing an STD check, but almost none do an HSV serology. Some may offer it if pressed. We feel you should do an HSV serology especially if the client has ever had any of the following:

• a history of lesions, ulcers, pimples, itching and discharge
• been diagnosed with another STD should be tested for HSV-2 virus.

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2. Third trimester pregnant women and their partners

A recent article by a number of authorities on neonatal herpes have recommended herpes serologies be drawn on all pregnant women. Usually just before the third trimester - week 28. The purpose of this is to identify women at risk of acquiring herpes near term and passing it onto their infant. Women who are HSV-2 seronegative, that is do not have herpes, should be told not to have unprotected sexual intercourse in the third trimester. This will prevent acquiring genital herpes in late pregnancy. Click here to read more about this.

• Women who contract an HSV infection in the third trimester are at greatest risk of transmitting disease to their newborn.
• Test all women regardless of their history or their partner's history.
• Women who do not have HSV-2 should be told to not have unprotected sex.
• Oral/genital sex in the third trimester unless they know their partners status.

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3. People who have a history of symptoms suggestive of genital herpes

These persons are at greatest risk of having unrecognized disease, thus, they are at greatest risk of transmitting it unknowingly to their partner.

• Detailed sexual histories should be obtained on all person's attending the clinic.
• Any person with a positive history suggestive of a genital infection should be tested.
• Any person presenting with symptoms suggestive on a genital infection should be tested.

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