The skin, our largest organ, has specialized defenses. • ___ body organ • Designed to keep out ___ agents • 3 layers: ___, ___, ___ (subcutaneous)

Skin Microbiome • The skin is a complex ecosystem where ___ type varies from site to site • Normal microbiota reside on or in the ___, ___, ___, and ___ • Species found in warmer, moist areas (___) are very different from species found in dryer, cooler areas (___ or ___)

Examples of abundant skin residents include: • Mostly ___ cocci - ___ ___ - ___ ___ • Some ___ rods • ___

Change or abnormality in skin that is usually in a defined area; may be harmless or serious

Widespread eruption of lesions; may be symptomatic or asymptomatic

Flattened red lesions

Raised red lesions

Vesicle or pustular rashes characterize a variety of viral infections (not every skin rash or lesion indicates infection) • Other causes: - ___ ___ ___ - other diseases or ___ ___ - ___ ___ - ___ ___

Viruses • ___-___ (HHV-3) • ___-___ (HSV-1, HSV-2) • ___ (HPV) • ___ (Rubeola) • ___ ___ (Rubella)

Chickenpox and Shingles etiological agent: - HHV-3; ___-___ (Heroesviridae family) - Highly contagious via ___ ___ and ___ ___ with pox lesions • Chicken pox signs and symptoms: - ___ with itchy vesicular ___ - Complications: ___ ___ ___, ___, ____ • After primary infection, the virus is able to enter ___ nerves • Can become latent in ___ ___ ___ and is not affected by ___ ___ ___

• Adults who contract ___ for the first time tend to have more severe cases than children • Probably because the adult immune system mounts a ___ response • Zostavax vaccine: - ___ vaccine - Recommended for people over age of ___

Human Herpes Viruses 1 and 2 (Herpes Simplex Viruses) • ___ of the >80 types of heroes viruses infect humans • Human herpes simplex viruses (HSV) 1 and 2 - Produce vesicular skin ___ - ___ of people have antibodies to at least 1

• HSV-1 disease: - ___ herpes - characterized by ___ ___ (or ___ ___) - Can lie dormant in the ___ nerves • Transmission - ___ (kissing, sharing eating utensils) - contaminated ___ (towels, sheets) • Disease progression - Painful, itchy, vesicular lesions may develop on the lips about a ___ after infection - Initial infection may include ___ ___ or ___ symptoms - HSV-1 migrates to the ___ nerves; HSV-2 to the ___ nerves - Becomes ___ and may later cause flare-ups in about two-thirds of patients • Reactivation - Caused by ___ ___, ___, ___ ___, or ___ - Tend to be shorter and less ___ than initial infection • Diagnosis - Based on signs and symptoms - Infected tissue reveals host cells that have fused and become larger (___) - Detection by ___ analysis • Treatment - No ___/___ - ___ or ___ antiviral medications (acyclovir) reduce frequency and severity

Shingles is a ___ of the virus - Rash on the ___ and other ___-___ areas (face) - Appears as a band of ___ on one side of the body - Painful with ___ sensation - ___ medications (acyclovir) May limit outbreak - Can lead to a chronic pain condition called ___ ___ (PHN) - ___ can occur (rarely)

Genital herpes affects the reproductive system and can cause serious neonatal complications • Etiological agent - ___ ___ ___ ___ • Characteristics - ___ in 6 people aged 14-49 in the U.S. have HSV-2

Genital herpes • Transmission - Unprotectived oral sex may transmit ___ to the genital area - Oral sex may transmit ___ from the genitals to the mouth (not as common)

Genital herpes • Signs and Symptoms - Enters ___ cells - Causes an initial, severe outbreak of ___ as quickly as ___ days after transmission - “Dewdrop on a rose petal” lesion - ___ pustule above a ___ base

Genital herpes * Complications • Causes persistent ___ infections - Virus lies ___ in ___ nerves near the area where lesions had developed - Lesions return in times of ___ • Greater risk for ___ • ___ risk • ___ herpes

Genital herpes • Treatment - ___ cure - ___ can shorten outbreaks and suppress flare-ups • Prevention - ___ do not provide full protection

Certain viruses cause warts • Viruses that cause warts are very ___ • Most warts are harmless, but may ___, ___, or seem ___ • Spread by ___ ___, ___-___ ___, and by ___

Papillomaviruses • ___ different types of Papillomaviruses cause warts • Papillomavirus transmission: - Enter ___ by direct or indirect contact or through contaminated ___ • Papillomavirus signs and symptoms: - Painless benign growths on the ___ or ___ membranes

Papillomaviruses • Papillomavirus infections: - ___ warts - on feet - ___ warts - hands and toes - ___ warts - genital region - ___ warts - rest of body

Papillomaviruses • Papillomavirus treatment: - Most warts ___-___ - ___ treatment - frozen off - ___ - burned off - ___ removed - ___ treatment

Human papilloma viruses cause the most common STI in the world • Human Papillomavirus viruses (HPVs) - ___ known subtypes of HPV ( some cause warts, and some cause tumours) - ___ subtypes are sexually transmitted • Characteristics - Most common ___ in the world - HPVs are so common that almost every sexually active person will be infected with some type of HPV in their lifetime