DNA virus infections

Hepatitis B family and genus

Hepadnaviridae orthohepadnavirus

hepatitis b transmission

blood and body fluids

sexually transmitted, vertical transmission, iv drug abuse, sharps exposure, sharing other items with an infected individual

60-150 day incubation range

hepatitis b symptoms in children <5 and newly infected

asymptomatic

hepatitis b symptoms in people >5 and older

30-50% symptomatic

acute, chronic, reactivation infections

hepatitis b acute infection characteristics

mild to severe symptoms

can persist up to 6 mo

abdominal pain, fever, fatigue, nausea, loss of appetite, dark urine, joint pain, jaundice

increased severity >60 y.o.

overall low fatality rate <1%

hepatitis b chronic infection characteristics

leads to death from cirrhosis or liver cancer

continual viral replication

liver cancer may be curable but there can be severe liver damage

reactivation of hepatitis b virus infection characteristics

sudden reappearance of HBV DNA in previously resolved infection

usually follows immunosuppression or HCV coinfection

~__% of individuals infected with Hepatitis B after childhood become chronically infected.

5

HepB virion

Dane particle

a person that has a dane particle with subviral particles

noninfectious (dane particle has no nucleic acid)

immunized protection against hepatitis b (no virus exposure)

HBsAg -

AbHBsAg (IgG) -

susceptible to hepatitis B (at risk of infection)

HBsAg -

AbHBsAg -

AbHBcAg -

resolved infection (natural infection with full viral particle)

HBsAg -

AbHBsAg (IgG) +

AbHBcAg (IgG) +

Hepatitis B vaccine contains

Antibodies against the surface antigen of the dane particle

chronic infection of hepatitis b

HBsAg +

AbHBsAg -

AbHBcAg +

HBeAg +

Acute infection

HBsAg +

AbHBsAg - (IgM +)

AbHBcAg (IgM) +

HBcAg +

First serological marker for the hepatitis b surface antigen appears

1 month after infection

serological indication of hepatitis b surface antigen

indicates active infection (acute/chronic)

positive test must be repeated and confirmed by neutralization assay

negative result of hepatitis b surface antigen serological test

appearing after symptoms means the person is recovered

typically 15 weeks after symptoms appear

HBeAg and Anti-HBe antibody

indicates high viral replication

acute infection

highly infectious

antibody indicates lower levels of virus (pt is recovering)

IgM to HBc serological detection

basis of diagnosis

first antibodies to appear

persist for several weeks-months

indicate recent, acute infection

decrease over time (IgM goes down, IgG goes up)

Total anti-HBc antibody detection

includes IgM and IgG anti-HBc

indicates past infection

persists indefinitely

diagnosis of chronic infection

anti-HBs antibody detection

appears after HBsAg disappears

indicates recovery and immunity from infection

produced in response to vaccination

“core window”

“core window” of Hepatitis b infection

neither HBsAg nor anti-HBs is detectable

rely on IgM and IgG of anti-HBc

Chronic HBV infection

HBsAg is positive

total anti-HBc (IgG) +

IgM (anti-HBc) -

HBeAg +

HBeAg positive of Hepatitis B infection

active viral replication (lots of HBeAg)

prevention of hepatitis b

avoid unsafe practices to avoid exposure

vaccination (birth, children <19 y.o., individuals at risk of exposure, travel to endemic areas, HepC infection, HIV infection, Institutionalized areas)

Drug treatments for hepatitis b

oral anti-virals

DNA termination interfering drugs

HBV DNA polymerase inhibiting drugs

immune response modulators (interferon alpha)

Hepatitis B can live for ____ in dried blood on a counter top.

months

Herpesviridae Simplexvirus

human herpes virus 1

human herpes virus 2

Herpesviridae varicellovirus

human herpes virus 3 (varicella-zoster virus)

herpesviridae lymphocryptovirus

human herpes virus 4 (Epstein-Barr virus)

Herpesviridae Cytomegalovirus

human herpes virus 5 (cytomegalovirus)

herpesviridae roseolovirus

human herpes virus 6A and 6B

human herpes virus 7 (rash viral disease)

herpesviridae rhadinovirus

human herpes virus 8 (kaposi’s sarcoma-associated virus)

All herpesviridae cause

latent infections

herpesviridae mode of transmission

contact with infected oral or genital secretions, inhalation of aerosolized virus, contact with contaminated blood or fluids

Herpesviridae viral particle composition

linear dsDNA

Icosahedral capsid

tegument

lipid envelope

glycoproteins

tegument in herpesviridae

outside nucleocapsid and inside the envelope

herpesviridae simplex virus (HSV 1/2) transmission

infection of mucosal epithelium (oral/genital)

contact with infected secretions, blood or transplacentally

infect oral/thoracic ganglia and genitcal/sacral ganglia

HSV 1 symptoms

cold, sore, pharyngitis, keratitis

immunocompromised- pneumonia, disseminated infection, hepatitis

less severe if cause of genital infection- may not recur

HSV 2 symptoms

genital lesions, meningitis

neonatal encephalitis

neonatal encephalitis due to HSV2

approaches 50% mortality if primary infection for the mother occurs during pregnancy

always symptomatic with ~60% fatality even with treatment

caused by fetus passing through birth canal of mother that is infected

treatment is a c-section to avoid the birth canal

reactivation of infection of hsv 1/2 can be caused by

stress, sunburn, not eating/sleeping, etc.

HSV 1/2 treatment and prevention

antivirals

supportive care

no treatment for cold sores

prevention of HSV 1/2

counseling if already infected

limit exposure to infected bodily secretions

if antiviral treatment occurs during primary outbreak of hsv 1/2

there is less likely to be a secondary outbreak

suppressive therapy for hsv 1/2 decreases outbreaks by_____ but are not a permanent option.

70-80%

ELISA to detect HSV 1/2

uses blood specimen

specific and rapid detection of antibodies

will typically be positive for hsv 1 even if a person has never been infected

Viral culture to detect HSV 1/2

uses cells from the base of a weeping lesion

only useful in active infection

PCR to detect HSV 1/2

uses tissue, CSF, cells

sensitive but not FDA approved

Herpesviridae varicellovirus

chickenpox

chickenpox transmission

inhalation of virus particle, touching contaminated surfaces

symptoms of chickenpox

incubation up to 21 days

rash- fluid filled vesicles itchy, takes up to 7 days for vesicles to dry

severe complications for immunocompromised patients

1-2 days pre-rash (chickenpox)

fever, tiredness, loss of appetite, headache

complications from chickenpox for immunocompromised patients

secondary bacterial infections, pneumonia, encephalitis, sepsis, dehydration, death

prevention and treatment for chickenpox

vaccination against chickenpox (infant/children)

vaccination against shingles (adults)

antivirals for severe disease

supportive care consisting of non-aspirin analgesics and lotion

shingles

Herpesviridae VZV

mechanism of shingles reactivation

VZV reactivation from ganglionic neurons

peripheral spread herpes zoster

central spread to brain causing meningoencephalitis

central spread to arteries causing vasculopathy temporal arteritis

central spread to spinal cord arteries and spinal cord infarction

symptoms of reactivation of vzv (shingles)

1-2 days prior to symptoms: tingling and itchy feelin on localized part of skin

blisters and pain can last for weeks

vaccine concentration for shingles is over ___x more than for chickenpox

10

Herpesviridae lymphocryptovirus

mononucleosis (EBV)

mononucleosis

latent b cell infection

90% of population is exposed by 20 years old

malignancies- Burkitt’s lymphoma

mononucleosis transmission

saliva and other body fluids, shared objects

symptoms of mononucleosis

incubation and viral shedding for 30-50 days before symptoms

asymptomatic, fatigue, fever, sore throat, lymphadenopathy, splenomegaly, heptomegaly, rash

typical illness lasts 2-4 weeks to months

prevention and treatment of mononucleosis

supportive care only

testing to detect viral capsid antigen, early antigen, EBV antigen, monospot

monospot detection in mononucleosis

test to detect the antibody produced against cellular proteins (dead/dying cells)

nonspecific to mononucleosis

herpesviridae cytomegalovirus

Cytomegalovirus

transmission of cytomegalovirus

infects WBC

transmitted by blood/body fluids including saliva, tears, semen, breast milk, sexual contact, transplantation, transfusion

transplacental

Cytomegalovirus symptoms

asymptomatic, fever, sore throat, fatigue, lymphadenopathy

immunocompromised patients can get pneumonia, hepatitis, dissemination infection

congenital cmv

transplacental

most are asymptomatic

can cause: premature birth, decrease in size/weight, seizures, microcephaly, hearing loss, vision loss, coordination/balance problems

if it is maternal primary infection of CMV while pregnant,

20-40% chance of congenital infection due to mother lacking protective antibody

prevention/treatment for cmv

supportive care and antivirals for immunocompromised patients

congenital infection- antivirals only if displaying signs and symptoms

herpesviridae roseolovirus

human B lymphotropic virus (HHV6)

Human herpes virus 7 (HHV7)

human b lymphotropic virus

roseola infantum, lymphoproliferative, mononucleosis

human herpes virus 7

causes roseola infantum

5 childhood exanthems of roseolovirus

1. measles (Morbillivirus)

2. scarlet fever (group a strep)

3. rubella (rubivirus)

4. duke’s disease (no longer used)

5. B19 (erythroparvovirus)

6. roseola infantum (HHV6/7)

herpesviridae rhadinovirus

Kaposi’s sarcoma-associated virus

Kaposi’s sarcoma-associated virus

1st detected in HIV patients

associated with Kaposi’s sarcoma in AIDS and non-AIDS associated disease

primary effusion lymphoma

poxviridae orthopoxvirus

variola virus (smallpox), Cowpox virus, Monkeypox virus

smallpox

only human pathogen

bioterrorism agent

vaccination ended in 1972

cowpox virus

role in discovery of vaccination

smallpox is stated to be eradicated in ____.

1980

vaccinia

agent ins smallpox vaccine

monkeypox virus

rare in human infection

central and western africa

poxviridae structure

largest virus

unusual brick-shaped nucleocapsid and biconcave core

transmission of poxviridae

inhalation of virus particle and respiratory epithelium exposure

variola virus (smallpox) symptoms and stages

7-19 day incubation- not contagious

high fever, headache body ache ~2days- possibly contagious

rash/sores start in mouth then travel to the body and fill with fluid (~day 4)- most contagious

sores turn to pustules, crust and scab (~day 10)- contagious

crusted/scabbed lesions fall off ~day 6- contagious

all scabs hae fallen off- not contagious

smallpox virus fatality rate

10-50%

smallpox vaccination

vaccination (given within 3 days of exposure) and will give possible full protection or aid in mild disease

vaccination given within 4-7 days of exposure may still provide protection and possible mild disease

once rash appears, the vaccination will not protect

treatment of smallpox

antimicrobials that are stockpiled

Edward Jenner

vaccinated James Phipps with cowpox and deliberately infected him with smallpox.

james remained free

poxvirdae orthopoxvirus monkeypox

smallpox-like disease in monkeys

causes smallpox in humans but less severe

transmission for monkeypox

exposure to infected animals and humans with open sored

physical contact with human-to-human transmission has been documented

monkeypox symptoms

incubation 3-17 days

asymptomatic

painful lesions (firm/rubbery/well-circumsised, deep-seated adn often develop umbilication

fever chills, headache, lymphadenpathy, purlulent or bloody steaks, rectal pain, or bleeding, sore throat, nasal congestion.

treatment of smallpox

vaccination for prevention

antivirals that target the inhibition of p37 for immunocompromised

adenoviridae is

dsdna, nonenveloped

adenoviridae mastadenovirus

human mastadenovirus (adenovirus)

adenovirus has ____ different strains

>50