Serious disease transmitted to a newborn 3 forms: - Skin, eye and mucous membrane disease (SEM) - CNS - Disseminated

DD- COMMON VIRAL PATHOGENS Flashcards by MO ROUTH

8 herpesviruses which infect humans

-Herpes simplex virus, type 1 and type 2 (HSV1, HSV2)

– Varicella-zoster virus (VZV)

– Cytomegalovirus (CMV)

– Epstein-Barr virus (EBV)

– Human herpesvirus 6 (HHV6)

– Human herpesvirus 7 (HHV7)

– Human herpesvirus 8 (HHV8)/KSHV

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Herpesviridae: Following primary infection, the virus establishes a______ in the host (location depends on subfamily) and may reactivate at a later time

latent infection

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Human herpesvirus 8 (HHV8)/KSHV

herpesviruses which infect humans

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Herpesvirus structure

Enveloped
- Derived from host membrane

-Virally-encoded glycoproteins are important for binding to host cells

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Human herpesvirus 6 (HHV6)

herpesviruses which infect humans

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Herpesvirus structure- Tegument

Contains proteins that are fully formed and active and control viral entry, gene expression, and immune evasion

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Epstein-Barr virus (EBV)

herpesviruses which infect humans

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HSV1 and HSV2

Both viruses cause painful vesicles on the ______ at the site of inoculation

skin

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Cytomegalovirus (CMV)

herpesviruses which infect humans

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HSV1 is usually associated with _____ lesions

orofacial

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Varicella-zoster virus (VZV)

herpesviruses which infect humans

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HSV2 is usually associated with

genital lesions (genital herpes)

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Herpes simplex virus, type 1 and type 2 (HSV1, HSV2)

herpesviruses which infect humans

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Transmission of HSV usually occurs through close contact with a person who is shedding virus at

a mucosal surface

in genital/oral secretions

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Clinical Patterns of HSV Disease

Most primary infections with HSV are silent

Primary HSV-1 infection usually occurs during childhood

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Primary HSV-1 infection usually occurs during______

childhood

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Gingivostomatitis

common infection of the mouth and gums

Most common symptomatic infection

Clinical Patterns of HSV Disease

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Herpetic whitlow

a lesion (whitlow) on a finger or thumb caused by the herpes simplex virus.

Occupational hazard for doctors, dentists, nurses

Clinical Patterns of HSV Disease

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Encephalitis

Inflammation of the brain, often due to infection

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_____most common cause of encephalitis in US

HSV

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Herpes keratitis

Inflammation/infection of the cornea, leading to pain absence of trauma

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HSV reaches the cornea via the ophthalmic branch of the ______

trigeminal nerve

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Genital Herpes

Lesions last 10-14 days; usually very painful

Distinct from ulcers caused by syphilis (single hard painless
ulcer) and chancroid (soft painful ulcers associated with swollen inguinal lymph nodes)

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Neonatal HSV

Serious disease transmitted to a newborn

3 forms:

Skin, eye and mucous membrane disease (SEM)
CNS
Disseminated

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Following primary infection, HSV enters sensory nerve endings and travels up the axon and establishes a latent infection in:

sensory ganglia (alphaherpesvirus)

Reactivated lesions are infectious and people often continue to shed virus for a period of time_____ the lesions are healed

after

Definitive diagnosis of herpes can be obtained by:

– Viral culture of lesions – Direct IFA of lesions – PCR of lesions

Oral antiviral therapy (______ or a related antiviral) can be used for oral or genital HSV outbreaks

acyclovir

_____ is recommended for pregnant women with active | genital lesions at time of delivery

C-section

Prophylactic antiviral suppressive therapy has been shown to decrease outbreaks and viral shedding so is used in some patients, particularly with ______

genital herpes

Varicella-Zoster Virus

Varicella or chickenpox | highly contagious

acyclovir

Oral antiviral therapy can be used for oral or genital HSV outbreaks

Varicella-Zoster Virus | Transmission: highly contagious

– Primarily respiratory via droplet or aerosolized secretions (coughing, sneezing) – Contact with lesions

Varicella

The classic rash consists of lesions in multiple stages of development on any one part of the body (i.e. vesicles, pustules, scabs/crusts)

Complications of varicella

Pregnant women and immunocompromised patients are at high risk for morbidity and mortality

_____ has been shown to accelerate the resolution of chickenpox if the patient presents within 48-72 hours of onset

Acyclovir

__________vaccine is currently recommended for prevention of chickenpox

Live attenuated varicella

VZV is the only herpes virus in which asymptomatic viral shedding ______-in normal hosts who experience reactivation

does not occur

Herpes zoster or shingles: | occurs in 30% of individuals from

Varicella

Post-herpetic neuralgia | PHN

complication of shingles, which is caused by the chickenpox (herpes zoster) virus

Post-herpetic neuralgia | PHN

Debilitating neuropathic pain that can last weeks to months

Immune response to VZV

-Cell mediated immunity to VZV decreases w/ age – Incidence of shingles much higher in the elderly and immunocompromised – Persons with low cell mediated immunity to VZV at higher risk for VZV reactivation (shingles)

Cell mediated immunity to VZV is an important determinant | in who is at risk for

shingles

Diagnosis, Chickenpox and shingles are diagnosed | clinically or

– Direct IFA – HSV and VZV PCR – Viral culture

For shingles, acyclovir given within ______ of onset may decrease lesions and pain

48-72 hours

Cytomegalovirus

– Almost all are asymptomatic Primary infection in immunocompromised persons is serious and CMV can infect most organs (CMV retinitis and colitis in HIV patients)

Cytomegalovirus Transmission

A person can become infected with CMV when they | come in contact with infected body fluids

CMV infects the ___________, resulting in a persistent infection and intermittent viral shedding

epithelial cells of the salivary gland or the genital tract

Congenital CMV Syndrome

* Low birth weight * Microcephaly * Hearing loss * Mental impairment * Hepatosplenomegaly * Skin rash (blueberry muffin spots) * Jaundice * Chorioretinitis

Neonate viral syndromes

neonatal HSV, or congenital VZV and | CMV syndromes.

Most common symptomatic primary infection that occurs with HSV-1 infection.

Gingivostomatitis

condition where HSV infects the cornea of the eye

Herpes keratitis can be the result of a primary infection or from reactivation

``` Low birth weight Microcephaly Hearing loss Mental impairment Hepatosplenomegaly Skin rash (blueberry muffin spots)-due to extramedullary hematopoiesis in the skin Jaundice Chorioretinitis ```

Congenital CMV Syndrome

This is an extremely serious manifestation of herpes disease.

Encephalitis -can be caused by primary disease or reactivation.

Herpes encephalitis can occur either through | blood-borne (hematogenous) spread or ___________ of the virus.

neuronal transmission

Herpes infection of the brain results in a fulminant and hemorrhagic, ________. There is a strong predilection for the temporal lobes of the brain.

necrotizing encephalitis

Mortality is about 30% with treatment. HSV-1 causes most cases of childhood and adult. HSV-2 is the more common cause of neonatal herpes, Associated with maternal genital herpes infections.

Encephalitis

Gingivostomatitis is common in

HSV-1

Herpes Keratitis is occasional in

HSV-1

"Other" virus tests (when clinical doesn't work)

Viral culture of lesions Direct fluorescent antibody stain of lesions PCR of lesions (most expensive)

Chicken pox (varicella) is a highly contagious and common childhood disease, which is now preventable by vaccination. Chickenpox is primarily transmitted by the _____________ via droplet or aerosolized secretions (coughing, sneezing).

respiratory route

Incubation period: It takes from ________ after exposure for someone to develop chickenpox.

10-21 days

The initial lesions of_______ might be flat and rose | colored, but they quickly mature into the classic “dew drop on a rose petal” which is a vesicle on an erythematosus base

Chicken pox (varicella)

Pathogenesis of Chickenpox- The virus gains entry via the respiratory tract and spreads to the regional_______.

lymphoid system