mb w7 (viral infect cont)

recap

Herpesviridae = family of DNA viruses cause disease in human/animal

• 8 human herpesviruses (HHV-1 to HHV-8)

HHV-1 (HSV-1): oral herpes (cold sores)

HHV-2 (HSV-2): genital herpes

HHV-3 (VZV): chickenpox & shingles

HHV-4 (EBV): infectious mononucleosis, Burkitt’s lymphoma, nasopharyngeal carcinoma

HHV-5 (CMV): mononucleosis-like illness, retinitis (immunocompromised) HHV-6: roseola (sixth disease)

HHV-7: roseola-like illness

HHV-8 (KSHV): Kaposi’s sarcoma

• rhadinovirus = KSHV = Kaposi's sarcoma herpesvirus (not be confused with Kaposi's varicelliform eruption

Human Herpesvirus 3 (HHV-3) = Varicella-Zoster Virus

• cause varicella (chickenpox) & herpes zoster (shingles)

• 2 diff disease due to identical organism

• chicken pox = primary infection

• herpes zoster = reactivation of illness

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Varicella (Chickenpox)

• cause = VZV

• transmit = enter via mucosa of upper resp tract (high infect) > viremia > spread to skin > replic in epith cells > vesicular rash

• incubation = 2 weeks

• clinical finding = malaise, fever, diffuse vesicular rash (oral mucosa too)

• treatment = self limiting, symptomatic management

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Varicella-Zoster Infects

• cause = reactivation of VZV

• pathogenesis = latent in dorsal root / cranial nerve ganglia

• triggers = immunosuppresion, trauma, drug, malignancy

• clinical = malaise, fever, severe localized pain, vesicular rash along a nerve (dermatomal distrib / dermatome

• - roses from hell vasicular rash

• treatment = analgesic (for pain), antiviral (acyclovir), vaccine (for prim infect + reactive)

HHV-4 = Epstein-Barr Virus

• etiology = Epbar virus (EBV) (HHV-4)

• target tissue = lymph nodes & spleen (incs lymphocytes aka B cells)

^establishes lifelong latency w potential reactivate

assoc diseases

• infectious mononucleosis (kissing disease)

• burkitt lymphoma & other B-cell lymphomas

• nasopharyngeal carcinoma

• oral hairy leukoplakia

• post-transplant lymphoproliferative disorders

transmission/patho = via saliva (kissing disease or shared drink)

incubation = 4-7 week

clinical = fever, sorethroat, enlarged tender nodes, fatigue, mild jaundice, gingival bleed

disease characs

• acute infect of lymphoid tissue

• most common adolescent (15-20)

• self limiting (fatique)

HHV-5 = Cytomegalovirus (CMV)

• etiology = CMV (herpesvirus fam, HHV-5)

• congenital infection (intrauterine/perinatal)

• usually asymptomatic in healthy ppl

high risk = neonates (newborn) can be deaf & intellectual disability later

• immunocomps = transplant receipient, leukemia ppl, HIV/AIDs ppl

CMV is a AIDs-defining infection

transmit = body fluids

incubation = 4-8 week

clinical

• infants = severe disease (CNS damage, jaundice, pneumonitis, dev delay)

• adults = mononucleosis-like illness

• RETINITIS

latency + reactivation = high prevalence

• no proven regimens for therapy and prevention of CMV infect

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treatment for EBV & CMV

EBV (infectious mononucleosis)

• support care (rest hydrate)

• no specif antiviral therapy

• steroids (only in severe)

SUPPORTIVE CARE

CMV - antivirals for high-risk patients

• Ganciclovir / Valganciclovir

• used in immunocomps or severe disease

• supportive care in mild cases

MAY REQ ANTIVIRALS IN HIGH RISK PATIENT

Which virus causes chickenpox?

A. Herpes simplex virus

B. Varicella-zoster virus

C. Epstein–Barr virus

D. Cytomegalovirus

Which route is the most common mode of transmission for chickenpox?

A. Fecal–oral transmission

B. Vector-borne transmission

C. Respiratory droplets and direct contact

D. Contaminated food

Which statement regarding varicella-zoster virus is CORRECT?

A. It is an RNA virus

B. It remains latent in salivary glands

C. It can reactivate later in life as shingles

D. It is transmitted primarily through blood transfusion

A university student presents with fever, fatigue, sore throat, and cervical lymphadenopathy. Which virus is the most likely cause?

A. Varicella-zoster virus

B. Cytomegalovirus

C. Epstein–Barr virus

D. Herpes simplex virus type 1

A patient with advanced HIV infection develops retinitis caused by a herpesvirus. Which virus is the most likely cause?

A. Epstein–Barr virus

B. Varicella-zoster virus

C. Cytomegalovirus

D. Herpes simplex virus type 1

Congenital CMV infection is clinically important because it may cause:

A. Dental caries only

B. Hearing loss and developmental abnormalities

C. Appendicitis

D. Hyperthyroidism

Papillomavirus - warts

• etiology = HPV

• patho = infect epithelial cells of skin & mucous mems

clinical

• cutaneous warts (common, plantar, flat)

• genital wart

• laryngeal wart

oral finding

• papular or nodular lesion

• surface = papillary *cauliflower like* projections

• transmit = direct contact

• treatment = excision (surg remove) or chemical remove (trichloracetic acid)

know theres many types w different conditions

range from benign proliferative lesions > oncogenic disease

depend on strain & loc

HPV vax = Gardasil

• only for 6, 11, 16, 18

• 16/18 = high risk type assoc w oropharyngeal cancer

• 6/11 = low risk type (90% genital warts)

HPV infect cause nearly all cervical cancers

Hepatitis

• inflam disease of liver caused by variety of virus (transmit dep on type)

• acquire thru blood, body fluid, food/water, too much alc (non-infectious cause)

• common symptom = malaise, jaundice, dark pee, pale fatty stool

• at least 6 strains of hep viruses (A-G)

• if see “non-hep” = less common form that dont fit classifs

Hep A

• eti = small non-envelope single-strand RNA virus (picornavirus)

• transmit = prim fecal-oral route (contam food/water)

• mostly children

• infectious before symptoms appear

• virus present in feces + saliva

• no chronic infect/carrier state

symptoms

• fever, nausea, abd discomfort, jaundice (common in adult)

• resemble influ-like illness

• self limiting (goes away on own)

diagnosis

• IgM anti-HAV (hep A virus) → early/acute infect

• IgG anti-HAV → later in disease/immunity

outcome + prevent

• lifelong immunity after infect

• no chronic disease or carrier state

• combined hep A+B vaccine (initial then booster)

• low risk for dentistry bc fecal-oral route

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Hep B

• eti = enveloped double-stranded DNA virus (hepadnavirus)

• target = infect lymphocyte → liver inflam

• many transmit = body fluid, needle share, sex, mother-child

dental relevance = blood contam saliva

clinical

• many infect initially asymptomatic

• fatigue nausea abd pain jaundice

carrier state

• most recover completely, little develop chronic carrier state

• chronic lead to → cirrhosis, hepatocellular carcinoma (liver cancer)

• remain infect for yrs for chronic

diagnosis = blood testing

• serological markers determ > active infect, immunity, infectivity, carrier state

important markers

• HBsAg – Indicates current infection/carrier state

• anti-HBs – Indicates recovery or immunity after vaccination

• HBeAg – Indicates high infectivity

• anti-HBc – Indicates previous or ongoing infection

prevent = hep B vax

• recombinant vax (use DNA techno in yeast cells, not live)

• engerixB, recombivax

treatment = antiviral therapy (for chronic)

occupational risk = dental bc blood bourne

Hep C

• eti = hep C virus (HCV) enveloped single stranded RNA virus (flavivirus)

• formerly non-A, non-B hepatitis

• primarily blood borne

• exist as 6 genotypes

• viral rna remain intact up to 7 days room temp

transmit

• injection/drug use, blood stuff, needle, org transplant, sex, mom-kid

clinical

• often asymptomatic

• symptoms. fatigue nausea abd discomf (SIMILAR TO B)

chronic infect

• 80% develop this, can persist for decades

• lead to cirrhosis, chronic liver disease, hepatocellular carcinoma

diagnose

• serological blood testing (ELISA)

• PCR testing for detect early infect

treat

• not always required

• direct acting antivirals (DAA)

• high cure rate

prev

• no vax available

dent/oral manifestation

• greatest risk is needle-stick injury

• oral lichen planus

• salivary gland disease

• inc risk oral malignancy

What is the primary route of transmission for Hepatitis A?

A. Blood transfusion

B. Sexual contact

C. Fecal–oral route

D. Needle-stick injuries

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Hepatitis B is primarily transmitted through:

A. Airborne droplets

B. Blood and body fluids

C. Insect bites

D. Contaminated food only

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A patient who carries Hepatitis B virus without symptoms is referred to as:

A. Immunocompromised

B. Opportunistic

C. A carrier

D. Seronegative

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Which statement about Hepatitis A is CORRECT?

A. It commonly causes chronic liver disease

B. It is usually self-limiting

C. It requires integration into host DNA

D. It is primarily blood-borne

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Which preventive measure is MOST effective against Hepatitis A?

A. Antibiotics

B. Antifungal therapy

C. Vaccination and good hygiene

D. Corticosteroids

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Which route is MOST associated with Hepatitis C transmission?

A. Fecal–oral route

B. Respiratory droplets

C. Blood exposure

D. Contaminated water

Hep D - Delta Hepatitis

• eti = HDV hepatitis d virus (defective single-strand RNA envelope from HBV)

• requires ACTIVE HBV INFECT to survive & replic

• ^borrows its outer viral envelope from its surface antigen

• HDV inc severity of HBV (CO-INFECTION/SUPERINFECTION)

transmit = blood, needle, sex, perinatal

epidemiology = common in inject drug user, africa, amazon, middle east

clinical

• often asymptomatic

• freq cause jaundice

• severe acute hepatitis

• fulminant liver disease

• chronic infect -→ cirrhosis (late stage liver infect)

diagnose = detect of delta antigen/antibody (ELISA)

treat = limited resp to interferon therapy

prev = hep B vax

Hep E

• eti = hep E virus (HEV) single stranded RNA virus

• similar to Hep A

• self limiting, no chronic

transmit = fecal-oral route thru water

• areas of poor sanitation

epidemiology

• large outbreak/epidemic may occur

• adolescent/young adult

• intrafamilial/parental spread rare

high risk = pregnant (esp 3rd trimester) → inc mortality

diagnosis = ELISA, PCR, Western blot

dental = minimal bc fecal oral not blood

Hep G - Human Pegivirus (HphV-1)

eti = RNA virus related to Hep C virus (family Flaviviridae)

• transmit = blood

• common in injection drug user / blood recepient

• little/no symptom, clinically unclear

overall dental implics

• real risk of viral infect in dental setting

• HCV transmit prim assoc w exposure to blood & needlestick

HIV = human immunodeficiency virus

eti = HIV virus enveloped single stranded RNA (retroviridae)

• involve destruct of immune sys, infect CD4 + T lympocytes (helper t-cells reg immune resps)

• make ppl suscept to life threatening infect/disease

contains

• reverse transcriptase enzyme

• viral RNA genome

2 major types

1. HIV-1 = (common worldwide)

2. HIV-2 = (less transmissible, mainly africa)

• without treatment HIV progress to AIDS in 2-12 yrs

transmit

• sex (most common)

• blood, needle, preg/birth/breastfeed

• not rlly saliva

STEPS OF INFECT

1. HIV selectively attach to T4 lymphocytes (helper)

2. viral RNA quickly converted → viral DNA (via reverse transcriptase)

3. viral DNA integ > host cell DNA

• permanent infect of lymphocyte & future cells

4. can be latent for years then start prod new virus particles

5. virus prod continue to destroy

3-4 week after infect…symptoms (PHOTO)

diagnosis

• antibodies (to recog) dev 6-12week after infect

• window period before detectable

screening in 2 assays

• HIV antigen/antibody test

• ELISA (must retest bc of false negs)

then confirmatory testing

• western blot/sipplemental immunoassays

PCR testing

• detect viral RNA &. measure viral load

treatment

• no cure/vaccine

• treatment symptomatic

• combination of antiretroviral therapy (ART supress viral replication & preserve immune fxn)

AIDS (acquired immunodeficiency syndrome)

• advanced HIV infect stage

• as HIV replic/destroy T4, immune sys weakens

• diagnose when CD4+ count less than 200 cells/µL OR AIDs-defining illness develops

• opportunistic infects & malignancies become common

ex: pneumocytis jirovecii pneumonia (PCP is lung infect in immunocomps)

• kaposi sarcoma (cancer lining lymph & vessles make masses)

• tuberculosis

• toxoplasmosis

oral manifestation

• candidiasis - thrush seen in 85% cases

• distinct mouth odor

• hairy leukoplakia (lat borders of tongue)

• herpes typ1

• angular chelitis

• NUG

• kaposi sarcoma (vascular lesion in oral)

HHV-7 & HHV-8 (Kaposi Sarcoma-Assoc Herpesvirus)

HHV-7

• T-lymphotrophic virus

• assoc w rash illness (roseola-like)

HHV-8 (Kaposi Sarcoma Virus)

• cause kaposi

• vascular tumor seen in HIV/AIDs & immunocomps

• these establish latwncy

• HHV6 & HHV7 very common (70-90%)

KEY TAKEAWAYS

• these viruses are common

• establish latency

• HHV 8 strong link to malignancy (cancer)

Risk of HIV transmit in HealthCare***

• risk of HIV transmit after single needlestick = 0.3%

• lower than HCV (3-10%)

• much lower than HBV (up to 30%) MOST*

VIEW REVIEW PHOTO ***

review

HIV primarily targets which cells of the immune system?

A. Red blood cells

B. Neutrophils

C. CD4+ T lymphocytes

D. Platelets

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Which enzyme allows HIV to convert its RNA into DNA?

A. Integrase

B. Reverse transcriptase

C. Protease

D. DNA ligase

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Which route is the MOST common mode of HIV transmission worldwide?

A. Saliva

B. Sexual contact

C. Airborne droplets

D. Food contamination

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A patient is diagnosed with AIDS when:

A. HIV antibodies are first detected

B. The viral load reaches zero

C. CD4+ count falls below 200 cells/µL or an AIDS-defining illness develops

D. Oral candidiasis is present

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A dental hygienist experiences a needle-stick injury involving blood from a patient with untreated HIV infection. What is the approximate risk of HIV transmission after a single occupational needle-stick exposure?

A. 0.03%

B. 0.3%

C. 3%

D. 30%

Post-Exposure Prophylaxis (PEP) testable

• should begin soon as possible (within 2 hr)

• uses combination antiretroviral therapy (ART)

goal

• reduce risk of HIV infect after occupational expose

• early treat signif lower risk of seroconversion(body start producing antibodies in resp to infect)

Needlestick/sharp exposure protocol

1. Stop and attend to the injury immediately

• Allow the wound to bleed gently; do not squeeze or scrub

• Wash with soap and water; flush mucous membranes or eyes with water or saline

• Do not apply caustic agents

2. Report

• Notify the supervising dentist / employer at once and record the incident

3. Assess the exposure and the source

• Type of injury, device, depth, volume of blood, source patient status

• Seek the source patient’s consent for HBV, HCV and HIV testing

4. Seek medical assessment the same day

• Baseline serology for the exposed worker (HBV, HCV, HIV)

• Check the worker’s hepatitis B immunization and anti-HBs status

5. Post-exposure prophylaxis (time-critical)

• HIV: combination ART, ideally within 2 hours see PEP slide

• HBV: HBIG and/or vaccine if not immune

• HCV: no prophylaxis — monitor and treat early if seroconversion occurs 6. Follow-up serology and counselling as directed (typically to 6 months)