Herpes simplex

Definition

Herpes is an infection caused by a herpes simplex virus 1 or 2, and it primarily affects the mouth or genital area.

Description

There are two strains of herpes simplex viruses. Herpes simplex virus type 1 (HSV-1) is usually associated with infections of the lips, mouth, and face. It is the most common herpes simplex virus among the general population and is usually acquired in childhood. Herpes simplex virus 2 (HSV-2) is sexually transmitted and is usually associated with genital ulcers or sores. Individuals may harbor HSV-1 and or HSV-2 and not have developed any symptoms.

Transmission

HSV-1 causes lesions inside the mouth that are often referred to as cold sores or fever blisters, and it is transmitted by contact with infected saliva. By adulthood, up to 90 percent of the population has antibodies to HSV-1. HSV-2 is sexually transmitted and not everyone develops symptoms when they have it. Up to 30 percent of adults in the United States have antibodies against HSV-2. Cross infection of type 1 and 2 viruses may occur from oral-genital contact. Herpes viruses can be transmitted to a newborn during vaginal delivery in mothers infected with herpes viruses, especially if the infection is primary (first occurrence) and is active at the time of delivery. The virus can lead to complications such as meningoencephalitis, which is an infection of the lining of the brain and the brain itself. It can also cause eye infections, in particular, of the conjunctiva and cornea.

Demographics

The prevalence of herpes simplex in the United States is as follows:

• Seventy to ninety percent of adults test seropositive (present in blood serum) for HSV-1.
• Up to 30 percent of adults test seropositive for HSV-2.
• The highest incidence of HSV-1 is in children six months to three years of age.
• The highest incidence of HSV-2 is in young adults between the age of 18 and 25 years.
• HSV-2 antibodies are present in approximately 20 percent of Caucasians and about 65 percent of African-American adults.

Causes and symptoms

A primary infection of HSV-1 typically occurs between six months and five years of age and is systemic (affecting the whole body). Transmission is generally via respiratory droplets (HSV-1) or direct contact (HSV-1 and HSV-2). The virus enters the body through mucosal surfaces, replicates in the cell nucleus, and then kills the host cell. The initial infection is self-limiting, but the immune system does not destroy the virus. The virus migrates along nerves to an area of regional ganglia (nerve centers) and then typically enters into a latent (sleeping) phase. Reactivation of the virus occurs in 50 percent of patients within five years, and it can be triggered by various factors:

• fatigue
• stress
• trauma
• immunocompromise (lack of normal immune response)
• illness, such as a cold
• fever
• sunburn
• menstruation
• sexual intercourse

The symptoms of a herpes infection can vary tremendously. Many infected individuals have few, if any, noticeable symptoms. Those who do have symptoms usually notice them from two to 20 days after being exposed to someone with HSV infection. Symptoms can last for several weeks, but the first episode of herpes is usually worse than subsequent outbreaks. The predominant symptom of herpes is the outbreak of painful, itching blisters filled with fluid on and around the external sexual organs or, for oral herpes, on or very near the lip. Females may have a vaginal discharge and experience flu-like symptoms with HSV2 outbreaks, including fever, headache , muscle aches, and fatigue. There may be painful urination, and swollen and tender lymph glands in the groin. More often than not the blisters disappear without treatment in two to 10 days, but the virus remains in the body, lying dormant among clusters of nerve cells until another outbreak is triggered.

Many people are able to anticipate an outbreak when they notice a warning sign (a tingling sensation, called a prodrome) of the approaching illness. It is when they feel signs that an outbreak is about to start that they are particularly contagious, even though the skin still appears normal. Most people with genital herpes have five to eight outbreaks per year, but not everyone has recurrent symptoms. In time, the number of outbreaks usually decreases. Oral herpes can recur as often as monthly or only one or two times each year. Sores typically come back near the site of the first infection, but there are fewer sores with recurrences that heal faster and are less painful.

When to call the doctor

Anyone who has a history of herpes infection and current lesions should notify the physician if the lesions do not resolve after seven to ten days or if a condition exists that weakens the immune system. Children with a herpes infection most commonly have sores in the mouth usually caused by HSV-1. This infection causes fever, irritability, pain , decreased appetite, and ulcers in the mouth. The most common complication is dehydration secondary to a refusal to drink fluids because of mouth pain and difficulty swallowing. Treatment is usually not required, and symptoms generally improve in three to five days. If, however, the child does not improve, develops a fever, and becomes lethargic, the pediatrician should be called immediately.

Herpes infections that spread throughout the body in a newborn are usually more serious, but fortunately less common than the other types of neonatal infections. They typically occur in the first week of life, with symptoms including fever, difficulty breathing, seizures, lethargy, and irritability. Since many infants in the first month of life can have a herpes infection and not have skin lesions, it takes a great deal of time and effort to diagnose and treat these infections early. Herpes should be considered in any acutely ill newborn, especially if bacterial cultures are negative and the baby is not improving after two to three days. Parents should be informed to watch the baby closely if either one of them has a history of herpes infections.

Diagnosis

Testing for neonatal herpes infections may include special smears and/or viral cultures, blood antibody levels, and polymerase chain reaction (PCR) testing of spinal fluid. Cultures are usually obtained from skin vesicles, eyes, mouth, rectum, urine, stool, and blood. For older children and adults, if there is a question as to the cause of a sore, a tissue sample or culture can be taken to determine what type of virus or other microorganism is responsible. For herpes, it is preferable to have this test done within the first 48 hours after symptoms first show up for a more accurate result.

Treatment

There are three drugs proven to treat genital herpes symptoms: acyclovir, sold under the brand name Zovirax, Famvir, and Valtrex. These are all taken in pill form. Formulas applied to the surface of the skin provide little benefit, and they are not recommended. Drug therapy is not a cure, but it can make living with the condition easier. For an initial outbreak with symptoms such as sores, a doctor should begin a brief course of antiviral therapy to relieve the symptoms or prevent them from getting worse. Seven to ten days of treatment is recommended but if the lesions do not heal, a longer period of time may be required. Following the initial outbreak there are two options to consider for further outbreaks. One is intermittent treatment, which involves the physician prescribing an antiviral drug to keep on hand in case an individual has a flare-up. The pills can be taken for three to five days as soon as sores are noticed or when an outbreak tingling sensation occurs. Sores heal and disappear on their own, but taking the drugs helps to alleviate the symptoms. For individuals who have frequent outbreaks, a suppressive treatment may work better. This treatment involves taking an antiviral drug every day. For example, someone who typically has more than six outbreaks a year, suppressive therapy reduces the number of outbreaks by 70 to 80 percent. Moreover, many who take the antiviral drugs daily have no outbreaks at all.

A false-color transmission electron microscopy (TEM) image of a herpes simplex virus.

(Custom Medical Stock Photo, Inc.)

In the early 2000s herpes vaccines are being investigated, and an effective vaccine may be available in before 2010. Vaccines will only function to prevent the infection in new patients. Those who already have the simplex virus disease will probably not benefit.

Nutritional concerns

Diet is a very important factor in keeping herpes in remission. It has been found that foods high in arginine may cause herpes outbreaks. Supplementation with free-form lysine has shown to be beneficial in controlling herpes along with a diet high in lysine and low in arginine. The amount of lysine required to control herpes varies from case to case, but a typical adult dose to maintain remission is 500 mg daily, and active herpes requires 1–6 g between meals to induce healing.

Prognosis

There is no cure for herpes simplex. Once it is contracted, it is always in a person's system. However, with treatment therapies, the problems previously encountered are lessened considerably.

Prevention

Whereas it is almost impossible to keep a baby or child from being exposed to herpes simplex due to its universal presence, there are conditions that can be used to prevent its transmission. Hand washing is one of the biggest factors in the transmission of all diseases, and it is especially true of herpes simplex since it is spread by respiratory droplets through mucosal membranes. In terms of genital herpes, education regarding the use of condoms is the best tool. Young adults should also be reminded that herpes simplex can be transferred from oral-genital contact. Since many teenagers do not consider oral or anal sex as sexual intercourse per se, it is imperative to spell out exactly what, when, and how these viruses can be spread.

Parental concerns

It is important that the pediatrician discusses the possibility of herpes infections with new parents, particularly if they have a history of genital herpes. Signs and symptoms need to be gone over, i.e., lethargy, fever, as well as the fact that there may or may not be lesions present. A newborn's own immune system begins to function around the third month, and if a mother is breast-feeding, she is passing antibodies to her baby. The primary concern is that a herpes infection does not become systemic. Thus, if the child seems to be getting sicker instead of better, parents should call the doctor immediately.

Resources

BOOKS

Ebel, Charles, and A. Wald. Managing Herpes: How to Live and Love with a Chronic STD. Durham, NC: American Social Health Association, 2002.

The Official Patient's Sourcebook on Genital Herpes. San Diego, CA: Icon Group International, 2002.

Spencer, Judith V., et al. Herpes. Langhorne, PA: Chelsea House Publishers, 2005.

Westheimer, Ruth K. Dr. Ruth's Guide to Talking about Herpes. New York: Grove/Atlantic Inc., 2004.

ORGANIZATIONS

American Social Health Association. PO Box 13827, Research Triangle Park, NC 27709. Web site: http://www.ashastd.org/hrc/.

Linda K. Bennington, MSN, CNS