Herpes 101


Most of us suffered through these itchy red bumps as kids. But did you know that they're caused by a herpes virus?
Most of us suffered through these itchy red bumps as kids. But did you know that they're caused by a herpes virus?
©iStockphoto.com/jarenwicklund

What do you think of when you see the word "herpes"? Painful blisters on the genital area, right? You probably know that there's no cure and that you can get it through sexual contact. Often, though, that's the extent of the average person's knowledge when it comes to herpes.

Have you ever gotten a painful, tingling fever blister on your lip? If you get cold sores, then you have herpes. If you haven't gotten cold sores, you're still not home free -- if you've had chicken pox, you're carrying a different type of herpes.

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Herpes is actually a family of eight different viruses known as Herpesviridae. It's a DNA virus, which means that its genetic material is made of DNA and it replicates through RNA in the nucleus of a cell. The blisters are just the physical symptoms of the virus. If you "have" herpes, that means that you've been infected by one of these viruses at some point and it's living in your cells. Exactly where it lives depends on the type of herpes virus. Most of them are transmitted through exchange of fluids, such as semen, mucus or saliva. Some of the viruses can be passed from mother to child during pregnancy.

Most herpes viruses are cyclic. When the virus is active, an infected person experiences symptoms and associated illnesses. There's also an increased risk of passing the virus on to someone else. During the shedding stage of the cycle, the virus replicates itself, which can occur even when the virus is inactive. Even without symptoms, there is still a risk of infecting others. Many people have no idea that they have a herpes virus because they've never had any symptoms. Some types of herpes are especially prevalent; it's estimated that as many as 60 percent of adults in the United States carry the oral herpes virus and 20 percent carry the genital herpes virus [source: CDC].

Now that you know a little about herpes in general, let's start with learning about these two most well-known types.

Herpes Simplex Viruses

Cold sores, also known as fever blisters, are caused by herpes simplex virus 1.
Cold sores, also known as fever blisters, are caused by herpes simplex virus 1.
©iStockphoto.com/artefy

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­Although oral herpes is typically known as cold sores or fever blisters, while genital herpes gets the distinction of the name "herpes," they're actually quite similar. Fifty percent of their DNA is the same [source: HHV-6 Foundation]. Oral herpes is herpes simplex 1 (HSV-1), while genital herpes is herpes simplex 2 (HSV-2).

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Both HSV-1 and HSV-2 cause fluid-filled blisters or lesions, which carry virions, or infectious particles. These blisters last from a week to a month, becoming open sores that crust over with scabs. The outbreak following the initial infection (usually a few days to a few weeks afterward) is usually the worst -- the ones after that are less painful. Some people actually confuse their mild outbreaks with other skin conditions. Early after infection, some people experience prodrome, a tingling, itching feeling that occurs in an area where blisters will shortly develop.

The main difference between HSV-1 and HSV-2 is their preferred sites of transmission and infection. HSV-1 generally results from oral contact, and the blister outbreaks are contained to the lips, mouth and face. The infection lies in a cluster of nerve cells near the ear called the trigeminal ganglion. HSV-2 generally results from genital contact with blisters in the genitals, anus and inner thighs, and it lives in nerve cells in the sacral ganglion, near the base of the spine.

Many people believe that HSV-2 is more dangerous than HSV-1, but that's not true. In fact, some researchers argue that HSV-1 is more dangerous because it's more prevalent. Both types of herpes can cause fevers and swollen lymph nodes. Urinating can be extremely painful when having an outbreak of HSV-2 as the urine hits the open sores. HSV-1 infections can also spread to the eyes (herpes keratitis), face and chest (herpes gladiatorum), and fingers and thumbs (herpetic Whitlow). In rare cases, it can spread to the brain and cause herpes encephalitis or Molliet's meningitis, types of brain inflammation that can result in death. There has been some research associating herpes simplex viruses with Alzheimer's and Bell's palsy, although definitive links haven't yet been proved.

Next, we'll look at how the herpes simplex viruses are spread and how their symptoms can be treated.

Transmission of Herpes Simplex Viruses

Newborn with neonatal herpes infection
Newborn with neonatal herpes infection
CDC/Judith Faulk

­As mentioned previously, oral herpes is usually transmitted through oral contact, such as kissing or sharing food or beverages with an infected person. Genital herpes infections usually result from sexual activity. However, you can get oral herpes (HSV-1) on the genitals and genital herpes (HSV-2) on the mouth through oral-to-genital contact. (The former is more likely than the latter.)

It's also possible to get HSV-2 on the genitals if you already have HSV-1 there, but it's not as common to get HSV-2 on the mouth if you already have HSV-1. The HSV-1 infection usually prevents HSV-2 from infecting the same area. In addition, genital HSV-1 isn't usually spread through genital-to-genital contact.

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The site of infection also tends to influence how often the viruses reactivate. Away from their "home sites," HSV-1 and HSV-2 infections tend to be mild. Overall, there's no hard and fast rule about how often a person with HSV-1 or HSV-2 will experience an outbreak. Children and people with weaker immune systems may experience more outbreaks. Otherwise-healthy people may experience them rarely or only when exposed to certain triggers such as stress, prolonged exposure to sunlight or foods containing caffeine.

Neonatal herpes can result from either HSV-1 or HSV-2 infections, although HSV-2 is the most common. It occurs most often when the mother has an active outbreak and the baby is delivered vaginally. In newborns, herpes can affect the skin, eyes or mouth (SEM herpes); the central nervous system (CNS herpes); or other internal organs (disseminated or DIS herpes). Babies can have more than one type. CNS and DIS herpes have the highest incidence of death. The former can cause seizures and swelling in the brain, while the latter can lead to organ failure.

Pregnant women can avoid passing HSV-2 on to their newborns by delivering via C-section if they have an outbreak. They can also take medications to suppress their outbreaks. We'll look at treating and preventing the spread of herpes simplex viruses next.

Treating Herpes Simplex Viruses

­While there's no cure for any type of herpes, there are treatments to help manage the symptoms, such as over-the-counter pain relievers like acetaminophen or ibuprofen. Anti-inflammatory drugs can also soothe the pain and itching. There are ointments available over the counter for HSV-1 that can help with the pain, but Abreva is the only one that has been shown to make the sores go away faster.

Many people with herpes simplex viruses take antiviral medications. Oral drugs such as Valtrex, Zovirax and Famvir are most effective when taken as soon as possible after the person becomes infected -- they can slow the buildup of the virus in the nerve cells. Zovirax and another antiviral medication called Denavir are also available in a cream that can be applied to the sores, but most health care providers prescribe them for HSV-1 only, believing that genital blisters should be left dry and uncovered to speed healing.

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Although they can't completely stop the virus from replicating itself, these types of drugs interfere with the replication process. When outbreaks do occur, they're usually less severe and go away sooner. There has also been research to show that some people taking antiviral medications daily (as opposed to only when they have an outbreak) shed far fewer virions -- 94 percent fewer,­ according to one study [source: Herpes Resource Center­]­.

Not having sex during a genital outbreak and using condoms or dental dams during inactive periods can help reduce the risk of infection. It's recommended to avoid kissing or sharing food with others during an oral herpes outbreak and to use condoms or dental dams if performing oral sex. (Since most people acquire HSV-1 during childhood, health providers don't tell people with it to avoid kissing when there isn't an outbreak.)

Herpes is most easily diagnosed during an outbreak so the health provider can swab the sores and perform a viral culture. There are also several different blood tests available that test for the presence of HSV antibodies. Some often give false positives, while others can't distinguish between HSV-1 and HSV-2 or whether the infection is oral or genital.

The two herpes simplex viruses are just two of the eight herpes viruses. Next, we'll look at the virus that causes chicken pox: varicella zoster.

Varicella Zoster Virus: Chicken Pox

Chicken pox is a familiar sight to many of us. Luckily, it's not usually dangerous.
Chicken pox is a familiar sight to many of us. Luckily, it's not usually dangerous.
©iStockphoto.com/AlesVeluscek

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­The varicella-zoster virus (VZV) is also known as human herpes virus 3 (HHV-3). It can cause two different types of infection: chicken pox and shingles. Like all herpes viruses, VZV is highly contagious. Children normally catch it by being in direct contact with someone who has chicken pox (even if they don't have the rash yet, they're contagious beforehand). They can also get it by coming in contact with the coughs and sneezes of an infected person.

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After being infected, it can take up to three weeks to develop the lesions, which usually finish completely forming within a week. They've often been described as a "dew drop on a rose petal" because there are red areas with small blisters on top. Most chicken pox lesions are on the face and torso, although they can show up anywhere.

After a week or two, the lesions are usually completely scabbed over and no longer considered contagious. Antihistamines and lotions, creams and ointments can help the itching; so can lukewarm baths with oatmeal powder or baking soda. Some children run fevers and should be treated with acetaminophen instead of aspirin to avoid the possibility of Reye's syndrome. Chicken pox isn't really dangerous in healthy children. After one bout of chicken pox, the immune system generally suppresses it -- you can't contract chicken pox twice.

Adults who get chicken pox usually experience more severe symptoms and often prescribed the antiviral Zovirax to lessen the duration. They may also have more extreme complications, such as skin infections or pneumonia. If a pregnant woman contracts chicken pox, she can pass the virus on to her fetus. Fetal varicella syndrome can result in brain and organ damage. Like any other person with a weaker immune system, if a baby contracts chicken pox, he or she is at higher risk for complications like pneumonia.

A varicella zoster vaccine, Varivex, has been available since 1995. Many schools today require kids to get it along with the other typical childhood vaccines. Adults who have never had chicken pox may also get the vaccine. It prevents chicken pox infections in up to 90 percent of people, but doesn't provide lifelong immunity, so boosters are necessary [source: American Academy of Family Physicians].

If they do have chicken pox, however, a small number of people can also contract shingles later in life. We'll look at that next.

Varicella Zoster Virus: Shingles

After the outbreak of chicken pox, the varicella-zoster virus lies dormant in the nerve cells of the brain or spine. About a quarter of the people who have had chicken pox will contract shingles decades after having that initial infection. Shingles is most common in people over the age of 50 and people with weakened immune systems due to medication or other diseases, including cancer and AIDS.

Shingles usually results in a small patch of lesions, often in a striped formation. It's generally on the torso or face but can spread to the eyes (herpes zoster ophthalmicus) and potentially cause glaucoma. The lesions are itchy and painful just like those with chicken pox, but they often resemble hives rather than the characteristic chicken pox blisters.

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Prior to developing the rash, people with shingles may experience other symptoms: fevers, headaches, burning, tingling, numbness and extremely sensitive skin. The rash and the accompanying symptoms usually last for a few weeks to a month. Some people have scarring and discoloration at the rash site for the rest of their lives. Others have zoster sine herpete -- all of the other symptoms without the rash.

People with shingles can also experience nerve damage following the outbreak. Post-herpetic neuralgia, caused by VZV at the site of the rash, can result in chronic extreme pain, sensitivity and numbness. In rare cases, shingles can also cause inflammation disorders such as encephalitis or myelitis as well as paralysis (usually temporary) and hearing loss.

Shingles patients can take pain relievers and anti-itching medications to help with the rash. They're also treated with one of the antiviral medications and steroids to reduce inflammation. You can't give shingles to someone else, although people who haven't had chicken pox or the vaccine can acquire VZV if they come in direct contact with the blisters.

A vaccine specifically to prevent shingles was approved by the FDA in 2006. Zostavax is essentially a stronger version of Varivex, the vaccine to prevent chicken pox. In clinical trials it was shown to reduce the incidence of shingles by more than 50 percent and reduce the incidence of post-herpetic neuralgia by nearly 67 percent [source: New England Journal of Medicine]. It's recommended for all adults age 60 or over, including those who have already had a shingles outbreak.

Not all types of herpes cause blisters or lesions. In the next section, we'll check out the Epstein-Barr virus.

Epstein-Barr Virus

This type of herpes is very different from both herpes simplex and varicella zoster. The Epstein-Barr virus (EBV) is also known as human herpes virus 4 (HHV-4). Rather than remaining dormant in the nerve cells after infection, EBV resides in B lymphocytes, a type immune system cell. Up to 95 percent of adults between the ages of 35 and 40, as well as half of all 5-year-olds, have been infected by EBV [source: CDC].

If a child is infected with EBV, he or she may just have mild flulike symptoms -- or no symptoms at all. Between 35 and 50 percent of mononucleosis cases in adolescents and young adults, however, are caused by EBV [source: CDC]. It's transmitted through saliva and is highly infectious. People with mono can expect high fevers, extreme fatigue, sore throat, loss of appetite, broken blood vessels in the eyes, and swollen lymph nodes and spleen. Treating mono equals lots of bed rest, fluids and pain relievers. Most of the symptoms usually clear up in two to four weeks, and the immune system suppresses any further occurrences of mono.

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Most healthy people recover with no lasting effects, although there are some potential complications. The enlarged spleen can rupture and the liver can become inflamed and cause jaundice (yellowing of the skin). People with mono can become anemic or have some of the nervous system disorders caused by other types of herpes, such as encephalitis or myelitis. The risk of developing these complications is higher in people with weak immune systems.

In some people, mono doesn't go away after a month or even six months, at which point it's called chronic EBV infection. Some researchers have theorized that EBV may cause chronic fatigue syndrome, but this hasn't been proven. EBV has also been linked to two rare types of cancer: nasopharyngeal carcinoma and Burkitt's lymphoma. Nasopharyngeal carcinoma, which affects the respiratory tract, has been found primarily in China and North Africa. Burkitt's lymphoma occurs primarily in Africa and affects the jawbone. It often exists along with malaria because of the person's reduced immune system response. EBV has also been linked to lymphomas (cancer beginning in the immune system) in AIDS patients and other immune system disorders in organ transplant patients. A vaccine for EBV is currently in clinical trials.

Next, we'll look at another type of herpes virus that can cause mononucleosis: cytomegalovirus.

Cytomegalovirus

Babies born with cytomegalovirus may have jaundice, or yellowed skin, due to liver problems. Jaundice is usually treated with a light that helps to break down the bilirubin, a byproduct of the body's red blood cell production.
Babies born with cytomegalovirus may have jaundice, or yellowed skin, due to liver problems. Jaundice is usually treated with a light that helps to break down the bilirubin, a byproduct of the body's red blood cell production.
©iStockphoto.com/AlesVeluscek

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Unlike Epstein-Barr virus, the chicken pox or shingles, you likely haven't heard of cytomegalovirus (CMV). However, as many as 80 percent of American adults have been infected with it by the age of 40 [source: CDC]. CMV is also known as human herpes virus 5 (HHV-5). Like Epstein-Barr, CMV resides in the h. It's also transmitted through bodily fluids such as saliva, although it's not considered highly contagious.

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Most of the time, CMV doesn't cause any symptoms. Some people get mononucleosis, a fever or mild flulike symptoms that are often passed off as something else. It rarely returns after the initial infection, so most people who have it don't know about it. Sometimes CMV can cause other illnesses in people with weakened immune systems, such as liver failure, pneumonia, gastrointestinal disease or blindness.

CMV has the dubious distinction of being the most common congenital (present at birth) virus, which means that infected pregnant women pass CMV on to their unborn fetuses. Women who get CMV during pregnancy have about a 40 percent chance of passing it on to their baby [source: American Pregnancy Association]. Pregnant women in the United States can have their blood tested for the presence of CMV antibodies.

Most babies born with CMV don't have any symptoms. About 10 percent show temporary symptoms like liver or spleen problems that eventually resolve. A very small percentage of babies born do suffer severe complications: seizures, loss of hearing and vision, mental and physical disabilities, delayed development and even death. Some infected children don't demonstrate any of these symptoms for months or years after birth, or experience worse symptoms later in life after showing initially mild symptoms.

The spread of CMV can be prevented by engaging in good hand washing practices. Pregnant women need to avoid saliva and other lovely secretions from children. Some patients with weakened immune systems take antiviral drugs to suppress CMV and avoid some of its more dangerous complications, but these aren't usually used on pregnant women or babies with CMV.

Roseolovirus, another type of herpes, can also affect babies. We'll learn about it in the next section.

Roseolovirus

Roseolovirus is the name for two different types of herpes viruses -- human herpes viruses 6 and 7. As with other types of herpes, they're transmitted primarily through saliva and other bodily fluids. Although HHV-6 and 7 differ slightly in the way that they replicate in the body, they're very similar genetically.

Most people who are infected with HHV-6 don't have any symptoms. Those who do will experience them before the age of 2, and by this age, almost 100 percent of children in the United States have it [source: HHV-6 Foundation]. It usually presents as roseola, a rash also known as rose fever or baby measles (although there's no relation to measles). Before getting the rash, children often run a high fever and have swollen lymph nodes. The rash consists of flat pinkish red spots that usually start on the trunk and spread to the rest of the body. The high fever can cause seizures in some children with roseola, so it needs to be treated with acetaminophen or ibuprofen. In rare cases, it can cause problems with the nervous system or gastrointestinal tract. Otherwise, the rash and other symptoms usually subside within a few weeks without any lasting problems. Most children who get roseola never have it again.

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Adults rarely get HHV-6. When they do, it's usually in the presence of other diseases such as AIDS or cancer, which cause a suppression of the immune system response. In many cases, these adults have already had HHV-6 but their weakened immune systems can't suppress reactivation of the virus. HHV-6 in adults can cause more serious symptoms such as hepatitis and encephalitis. It's also been linked to some types of cancer, including acute lymphoblastic leukemia, multiple myeloma and Hodgkin's disease.

HHV-7 isn't as well understood as HHV6. It's found in most of the population in the United States, but people are usually infected with it as adults rather than as children. It's also believed to cause roseola, but some researchers believe that it's a roseolalike illness called pityriasis rosea rather than roseola. HHV-7 has been linked to hepatitis in adults.

Although AIDS patients are often more susceptible to the severe complications of all types of herpes, the eighth type of herpes is most often directly associated with an AIDS-related disease. Next, let's look at Kaposi's sarcoma.

Kaposi's Sarcoma Herpes Virus

AIDS researcher Dr. Giuliano Rizzardini takes a blood sample from an AIDS patient with Karposi's sarcoma at a village outside Gulu, Uganda.
AIDS researcher Dr. Giuliano Rizzardini takes a blood sample from an AIDS patient with Karposi's sarcoma at a village outside Gulu, Uganda.
Malcolm Linton/Liaison/Getty Images

­Kaposi's sarcoma herpes virus (KSHV), or human herpes virus 8 (HHV-8), is spread through fluid transmission and can also be passed from mother to baby during pregnancy. It's mainly associated with a specific type of cancer called Kaposi's sarcoma. Although Kaposi's sarcoma is usually found in AIDS patients, there are several different types. The tumors found in each type usually look the same, but the rate at which the cancer spreads and who it affects can differ.

Epidemic Kaposi's sarcoma is considered an AIDS-defining illness. Because of this, it's also called AIDS-associated Kaposi's sarcoma. The HIV infection allows HHV-8, which lies dormant in the immune system and would normally be fought off, to manifest in the form of dark purple or black raised tumors on the head, neck and trunk. They may also be found in the mucus membranes and spread to internal organs. There's also a rare non-epidemic form of KS usually found in gay or bisexual men who don't show any signs of HIV infection.

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Some patients who are immunocompromised due to organ transplants may contract transplant-related Kaposi's sarcoma. Organ transplant recipients are often on medications that suppress the immune system to keep the body from rejecting the new organ. This allows HHV-8 to become active. About one in 200 transplant patients in the United States will develop this type of Kaposi's sarcoma [source: American Cancer Society].

Classic or Mediterranean Kaposi's sarcoma is a rare, slow-spreading disease most often found in older men with Mediterranean or Eastern European backgrounds. It's often found in conjunction with another type of cancer, usually a lymphoma. The other two types of KS are associated with people living in Africa. African lymphadenopathic Kaposi's sarcoma is a very aggressive form of the disease found in young children. Sometimes there are no external lesions; the lymph nodes and organs are affected. Most children affected with it don't live more than a year after diagnosis. Young to middle-aged African men may have a slower-spreading type called African cutaneous Kaposi's sarcoma.

There is no cure for any type of Kaposi's sarcoma, but it can be managed successfully with drugs and other therapies. Patients with epidemic KS may slow down the progression of their disease with HAART (highly active antiretroviral therapy), a form of drug therapy that slows the progression of AIDS and its related diseases.

Most people who are infected with KSHV don't develop Kaposi's sarcoma. The majority of Kaposi's sarcoma patients in the United States have AIDS-associated KS, so preventing it means practicing safer sex to avoid HIV infection.

To learn more about herpes, condoms and your immune system, take a look at the next page.

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