DISEASE
Herpes Simplex Viruses 1 and 2

AUTHOR
Katrina Armstrong, Biol 230, Spring 2009

CAUSATIVE AGENTS
Herpes simplex viruses 1 and 2 (HSV-1/HSV-2) are classified as enveloped viruses (def), which contain double stranded DNA and are surrounded by polyhedral capsids (def). Herpes simplex is a member of the Herpesviridae family of viruses and varies in size from 150-200 nm (def). Once infected with HSV, the virus moves to sensory nerves in the infected area, where they live as perpetual (def), latent(def) viruses.

EPIDEMIOLOGY
The Herpes simplex virus is the causative agent of what is known to many as a cold sore or fever blister.  This form of the virus is often referred to as HSV-1, and is typically marked by fluid filled, often painful lesions of the skin or mucus membranes of the orofacial (def) area, and blisters last between 2-21 days. Surprisingly, we are all at risk of contracting HSV-1. It is estimated through studies reported by The University of Maryland Medical Center, that by the time children reach adolescence, approximately 62% of them have been infected with the virus…and by the time they reach their 40’s, 90 % are infected.

HSV-2 is referred to as genital herpes. While some may develop lesions in the genital (def) area, it is said that the majority of the population infected with the virus are undiagnosed or asymptomatic (def). Risk factors include any sexually active individual. For whatever reason, women are said to be more at risk than their unprotected sex partner.

Although these viruses are most often referred to according to their location, it is important to understand any region of the body can be affected by either virus. For example, it is estimated that in the US, the number of genital infections caused by HSV-1 is about 50% of first episodes of genital infections.

While prevalence (def) of HSV varies throughout the world, the CDC (def) states an estimated 45 million people are already infected, and with the addition of up to a half a million reported annually, it is not surprising the HSV is the most common sexually transmitted disease among females in our country. In the US, healthy adults are infected with HSV-2 more often than those in Europe. While African Americans appear more susceptible (def) , it is more common to find active genital symptoms in Caucasians. Most recently, the highest incidence in acquiring HSV-2 have been in white adolescents.

Some risk factors of acquiring HSV-1 in childhood include: poor hygiene, overcrowding, low socioeconomic status, and birth in an underdeveloped country.

Some risk factors for HSV-2 include: those with early onset of sexual activity, people with multiple lifetime sexual partners, infected sexual partner.

TRANSMISSION
HSV is contracted through close or intimate contact with the infected person while he/she is shedding (def) the virus through secretions in saliva (def), genitalia (def) or active lesions. It is important to note that shedding is possible without active/visible lesions.

HSV-1 can be contracted through saliva by means of kissing, sharing utensils, personal hygiene items such as toothbrushes and razors, and/or receiving oral sex from an infected individual.
HSV-2 is contracted during sexual contact with an infected individual.

HSV can also be transmitted during childbirth by a process known as vertical transmission (def). In an immature immune system, HSV can be fatal (def) for infants as it has the ability to cause encephalitis (def). While the risk of infection is somewhat reduced without active lesions during delivery, infection occurs in the birth canal.

Note-HSV can also cause herpes whitlow (def),herpes gladiatorum (def), herpes keratitis (def), and more serious disorders such as : Herpesviral encephalitis (def),  Mollaret’s meningitis (def), neonatal herpes (def), bipolar disorders, (def) and Alzheimer’s (def)…although the last 2 mentioned are said to be dependent on genetic makeup of infected individual. As with most viruses and infections, the immune compromised patient can be susceptible to severe complications as a result of HSV infection.

SIGNS AND SYMPTOMS
Signs and symptoms of HSV-1 typically include: burning or tingling around the mouth or nose, small, painful fluid filled lesions (def), fever, sore throat and swollen lymph glands(def) in the neck.

Signs and symptoms of HSV-2 typically include: Vaginal discharge, dysuria (def), fever, malaise (def), myalgia (def), swollen glands in the groin (def) area, red, open, blister like lesions on genitalia, inner thighs, and in women inside the vagina-lesions can be, but are not always painful.

Possible triggers of HSV-1 and HSV-2 outbreaks include: Sun exposure, fever, menstruation, emotional stress, illness, or a weakened immune system.

PREVENTION AND TREATMENT
Prevention of HSV-1 includes exclusion from sharing utensils and dishes, personal hygiene items such as toothbrushes and razors, kissing or oral sex from someone with visible lesions. If you have HSV-1, use frequent hand washing, using sunscreens and reduce stress.

Prevention of HSV-2 includes exclusion from sexual activity if your partner has an outbreak and avoids touching any visible lesions If sexually active, insist on latex condoms, and limit the number of sex partners. Recommendations are the same if you are the infected individual.

Treatments prescribed for HSV include topical, oral, and injectable agents. Docosanol, AKA Abreva, is a topical cream available for the direct application to an area of skin with active lesions. It works by preventing HSV’s fusion to cell membranes, therefore prohibiting the entry of the virus to the skin. Another topical agent, Tromantadine, is a gel that changes the compostion of skin cells, inhibiting the release of the virus. ZIlactin is a topical pain medication that forms a barrier on the applied lesion, keeping it from increasing in size.

Oral antiviral medications given for controlling/decreasing the duration of outbreaks include acyclovir, valaciclovir, famiciclovir, and penciclovir. Aciclovir is the recommended medication given to expectant mothers in their final trimester of pregnancy, in an effort   to prevent the transmission of HSV to her newborn.

Herpevac (def) is a vaccine which is being studied by NIH (def). In the study, the vaccine given to women has shown to be approximately 48% effective in preventing HSV-2 seropositivity (def) and about 78% in preventing symptomatic HSV-2. Herpavac showed no evidence of preventing HSV-2 in males, and only showed to reduce the symptoms of women who newly acquired the virus during the time they received the vaccine. Since 20% of the people in our country already have HSV, it was concluded that the population of females who would benefit from such a vaccine was greatly reduced. Additional studies are ongoing.

Finally, stress management and support groups may be beneficial, as outbreaks are often thought to be stress related.

BIBLIOGRAPHY

“Herpes Simplex Virus." 12/23/2007. The Unviversity of Maryland Medical Center. 17 Apr 2009 <http://www.umm.edu/altmed/articles/herpes-simplex-000079.htm>.

"Herpes simplex." Wikipedia. 2009. 17 Apr 2009. <http://en.wikipedia.org/wiki/Herpes_simplex>.
            "Herpes simplex virus." Wikipedia. 2009. 13 Apr 2009. <http://en.wikipedia.org/wiki/Herpes_simplex_virus>.

Kaiser, Ph. D., Gary. "Lecture Notes."Spring Semester . 2009.

Kreibs, CNM, MSN, Jan. "Understanding Herpes SImplex Virus: Transmission, Diagnosis, and Considerations in Pregnancy Management." June 17, 2008. Medscape. April 17,2008 <http://www.medscape.com/viewarticle/573984>.

On Line Dictionary. Web.18 Apr 2009. <http://dictionary.reference.com/?qsrc=2890>.
Webster,Merriam. "Dictionary." CD-ROM. CD-ROM.2005 ed. CD-ROM.