Sexually Transmitted Diseases Caused by Viruses

-sexually transmitted infections (STI)

-venereal diseases (VD)

What are 2 other names for sexually transmitted diseases (STDs)?

illnesses that have a significant probability of transmission between humans by means of sexual behavior, including vaginal intercourse, anal sex, and oral sex

What are STDs/STIs/VDs?

no!

Are STIs/STDs only transmitted via sexual contact?

-using IV drug needles

-through any incident involving the contact of a wound with contaminated blood

-through childbirth or breast feeding

How else can some STIs be contracted, besides sexual behavior (vaginal intercourse, anal sex, and oral sex)?

there are ~20 million new cases of STIs/year in the US (significant!)

What is the incidence of STIs like in the US?

-Herpes Simplex Virus (HSV)

-Human papillomavirus (HPV)

-Zika Virus

-Hepatitis (HBV, HCV)

-Human immunodeficiency virus (HIV)

What are 5 major examples of viral STDs?

-blisters (sores)

-cervical cancer

What are the 2 main manifestations of Herpes Simplex Virus (HSV)?

-genital warts (benign papillomas)

-cervical cancer

What are the 2 main manifestations of Human papillomavirus (HPV)?

-Guillain-Barré Syndrome, GBS

-microcephaly

What are the 2 main manifestations of Zika Virus?

-cirrhosis

-hepatocellular carcinoma (HCV more than HBV)

What are the 2 main manifestations of Hepatitis (HBV, HCV)?

-AIDS

-secondary infections and cancer

What are the 2 main manifestations of Human immunodeficiency virus (HIV)?

Herpes simplex virus 1 and 2 (HSV-1 and HSV-2 -> are the two members of the herpesvirus family, Herpesviridae, that infect humans

What are the 2 main types of Herpes Simplex Virus (HSV), and explain?

Both HSV-1 and HSV-2 are ubiquitous and contagious.

Both HSV-1 and HSV-2 are ______ and ______.

have a core of dsDNA surrounded by a protein coat that exhibits icosahedral symmetry -> the nucleocapsid is surrounded by an envelope

What is the genetic composition of Herpesviruses like, and explain?

HSV-1 and HSV-2

What are the 2 sexually transmitted types of HSV?

usually causes oral herpes (cold sores), but can also infect genitals

What manifestation is HSV-1 mostly associated with?

usually causes genital lesions, but can also infect the mouth

What manifestation is HSV-2 mostly associated with?

genital herpes

What is the most prevalent STD in the US?

HSV prevalence:

>100 million Americans have oral herpes;

>45 million Americans have genital herpes

What are the prevalences of oral and genital herpes?

annually, 1M people in the US get new herpes infections

What does the CDC estimate about the incidence of herpes in the US?

Genital herpes infection is common in the US.

Genital herpes infection is ______ in the US.

16% of persons aged 14 to 49 years have HSV-2 infection

What is the prevalence of HSV-2 nationwide?

the overall prevalence of genital herpes is likely higher than 16% -> because an increasing number of genital herpes infections are caused by HSV-1

How does the overall prevalence of genital herpes compare to the prevalence of HSV-2 (16%), and explain?

in patient populations worldwide

Where have increases in genital HSV-1 infections been found?

through contact with lesions, mucosal surfaces, genital secretions, or oral secretions

How are genital herpes infections transmitted?

HSV-1 and HSV-2 can also be shed from skin that looks normal -> in persons with asymptomatic HSV-2 infections, genital HSV shedding occurs on 10% of days, and on most of those days the person has no signs or symptoms

What is significant to note about shedding of HSV-1 and HSV-2 from a host, and explain?

during sexual contact with someone who has a genital HSV-2 infection

Generally, when is the only time a person can get an HSV-2 infection?

from an infected partner who does not have a visible sore and may not know that they are infected (due to asymptomatic shedding)

When does transmission of genital herpes most commonly occur?

herpes sores are highly contagious, due to being loaded with viral particles -> need to avoid contact between lesions and someone else's body

What is the contagiousness of herpes sores like, and explain?

as a blister or as multiple blisters on or around affected areas, usually the mouth, genitals, or rectum -> the blisters break, leaving tender sores

How do symptoms of herpes simplex virus typically appear, and explain?

in ~1-2 weeks

When do HSV blister usually resolve?

no -> there is latency of the virus and risk of recurrence

Is the herpes virus eradicated from the host when HSV blisters resolve, and explain?

after lesions heal, the virus retreats up nerve fibers and stays dormant in nerve cells in the spinal column

How is there latency of the HSV virus in the host?

-they are in a location hidden from the immune system

-neurons are long-lived

What are 2 benefits (for pathogenesis) of HSV particles staying dormant in nerve cells in the spinal column?

flare-ups occur when the virus moves back down along the fibers to genitals or lips

What is the basis of herpes recurrence?

wide variety of factors:

-stress, anxiety, depression

-acidic food, UV light, fever, poor nutrition, fatigue

-general illness (from mild illnesses to serious conditions)

-immunosuppression due to AIDS or medications (ex: chemotherapy/steroids)

What is herpes recurrence triggered by?

symptoms during recurrent attacks tend to be milder than primary episode and heal more quickly

How do symptoms during HSV recurrent attacks compare to the primary episode?

latex condoms -> Herpes virus cannot pass through

Generally, what is the best way to reduce the risk of genital herpes transmission, and explain?

best to avoid sexual contact with the lesion area -> condoms should not be relied on when lesions are present

During an outbreak (~1-2x/yr), what is the best way to reduce genital herpes transmission, and explain?

safest strategy is to use condoms -> because there can sometimes be asymptomatic viral shedding

Between outbreaks, what is the best way to reduce genital herpes transmission, and explain?

no, since they do not cover entire genital area -> but they reduce risk significantly

Are condoms 100% effective at preventing herpes transmission, and explain?

medications are available that reduce the amount of asymptomatic viral shedding that occurs between outbreaks, which can significantly reduce the risk of transmission

What is the pharmacologic approach to reducing genital herpes transmission?

increased incidence of cervical cancer

What is the main herpes complication in women?

should get Pap smears every 6-12 months

What precaution should women with herpes take, due to the increased incidence of cervical cancer?

newborn baby can be infected by passage through birth canal of infected mother

What is another herpes complication associated with women?

can cause severe damage or death

What is the risk associated with a newborn baby being infected with herpes?

C-section recommended for women with active symptomatic disease

What precaution should women with herpes take, due to the risk of infecting their newborn baby?

ocular herpes -> can occur if virus is transferred from a sore to the eye and must be treated quickly to avoid eye damage

What is the main herpes complication in both men and women, and explain?

-reduce frequency of outbreaks

-treat symptoms of outbreaks and speed healing

What are the 2 main goals of herpes treatment?

-suppressive therapy

-episodic treatment

What are the 2 types of therapies for treating herpes?

medication taken daily to prevent recurrent outbreaks and also reduces asymptomatic viral shedding between outbreaks

What is suppressive therapy for herpes?

medication taken to treat outbreaks when they occur

What is episodic treatment for herpes?

antiviral drugs

What is a major drug category used in the treatment of herpes?

reduce viral shedding and the duration and severity of outbreaks (suppress viral) replication -> do not actually eliminate the virus

What is the function of antiviral drugs in treating herpes, and explain?

-Acyclovir (trade name Zovirax)

-Valacyclovir (trade name Valtrex)

-Famiclovir (trade name Famvir)

What are 3 examples of antivirals used to treat herpes?

gene editing -> CRISPR-SaCas9 used to target the herpes virus and cut specific DNA molecules to enable the elimination of viral particles from the host

What is the only way to fully deactivate and remove herpes virus from neuronal cells, and explain?

CRISPR-SaCas9 for herpes treatment:

a DNA virus from the papillomavirus family

Considering the genome and phylogeny, what is Human Papillomavirus (HPV)?

like all papillomaviruses, HPVs establish productive infections only in keratinocytes of the skin or mucous membranes

How does the function of HPVs compare to other papillomaviruses?

most are subclinical and will cause no physical symptoms

How do most HPV infections present?

the subclinical infections can become clinical and may cause benign papillomas (such as warts, verrucae, or squamous cell papilloma), or cancers of the cervix, vulva, vagina, penis, oropharynx, and anus

What can the symptoms of HPV infections be like in some individuals?

*low-risk

*high-risk

What are the 2 main categories of HPV variants?

6, 11, 40, 42, 43, 44, 54, 61, 70, 72, 81

What are the low-risk HPV types?

-benign cervical changes

-genital warts

What can the low-risk HPV types, namely HPV 6 and HPV 11, lead to?

16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, 82

What are the high-risk HPV types?

cervical cancer

What can the high-risk HPV types, namely HPV 16 and HPV 18, lead to?

they ate developed mostly against the high-risk stains, such as HPV 16 and HPV 18

What are vaccines against HPV like?

it has no envelope, is just a capsid with a circular genome

What is the structure of the HPV genome and proteins like?

E6 and E7

What are 2 significant proteins within the structure of HPV?

they are transforming proteins that are highly associated with cell transformation

What is the significance of E6 and E7 proteins in HPV?

they interfere with p53 and pRb functions

How do E6 and E7 proteins function in cell transformation?

HPV genome and proteins:

chronic infection -> the virus can establish long-term, latent infection in the skin

What is the duration of HPV infection like, and explain?

latent, chronic, long-term HPV infection:

>15% of Americans

>6 million new cases in US each year

What is the prevalence of HPV genital warts like?

via all type of sexual contact

How can genital warts be transmitted?

condoms do provide some protection, but do not prevent transmission of viral infections on vulva, base of penis, scrotum, and other genital areas not covered by condoms

What is the role of condoms like in preventing transmission of HPV genital warts?

people who are asymptomatic

Who is HPV most commonly transmitted by?

most people do not develop symptoms and are unaware they are infected

What are the typical symptoms of genital warts?

incubation period is approximately 3-8 weeks after contact with infected person

If visible warts do appear, what is the presentation like?

-females -> usually appear on lower vaginal opening, perineum, labia, inner vaginal walls, and cervix

-males -> usually on glans, foreskin, or shaft of penis

What is the presentation of genital warts like in females vs males?

can occur on the anus

What is the presentation of genital warts like in BOTH females and males?

-moist -> appear pink or red and soft

-dry -> appear hard and yellow-gray

How does the presentation of genital warts compare in moist vs dry areas?

removed by either cryotherapy (freezing) or chemical treatment, with larger warts potentially requiring minor surgery to remove

What is the treatment like for visible genital warts?

no! -> bc the virus can be deeply infecting the dermis

Does removal of genital warts prevent recurrence, and explain?

yes

Can genital warts disappear on their own?

it is recognized as the underlying cause of

cervical cancer since 1996 (NIH Consensus Conference on Cervical Cancer, 1996 and World Health Organization/European Research Organization on Genital Infection and Neoplasia, 1996)

What is the clinical significance of HPV?

summary of HPV infections:

-screening for precancerous changes (and treatment if problems found)

-vaccination against HPV -> best strategy for viral infection prevention

What are the 2 methods of preventing cervical cancer, and explain?

-developed by Dr. George N. Papanicolaou in 1940's

-most common cancer screening test

-key part of annual gynecologic examination

-has greatly reduced cervical cancer mortality in US

What are the 4 main features of the conventional Pap Smear?

3 years after first intercourse or by age 21

When should the 1st cervical cancer screening occur?

annually with regular Paps or every 2 years with liquid-based tests

How should regular cervical cancer screening be done?

can go to every three years

What does cervical cancer screening look like after three normal tests?

at 65-70 years with history of negative tests -> still need annual check-ups

When can cervical cancer screenings stop, and explain?

three:

*9-valent HPV vaccine (Gardasil 9, 9vHPV)

*quadrivalent HPV vaccine (Gardasil, 4vHPV)

*bivalent HPV vaccine (Cervarix, 2vHPV)

have been licensed by the U.S. Food and Drug Administration (FDA)

How many HPV vaccines are there, and explain?

each vaccine protects against a different number of HPV strains, both high and low risk strains

How do the different valency HPV vaccines compare?

HPV types 16 and 18 -> cause most HPV cancers

What HPV types do all three HPV vaccines protect against, and explain?

-children ages 11–12 years should get two doses of HPV vaccine, given 6 to 12 months apart -> HPV vaccines can be given starting at age 9 years

-everyone through age 26 years should get HPV vaccine if they were not fully vaccinated already

-HPV vaccination is not recommended for everyone older than age 26 years

-some adults aged 27 through 45 years who were not already vaccinated might choose to get HPV vaccine after speaking with their doctor about their risk for new HPV infections and possible benefits of vaccination for them

What are the 4 main HPV vaccine administration recommendations?

provides less benefit -> because more people in this age range were exposed to HPV already

What is the benefit of HPV vaccination for adults, and explain?