Viruses II Flashcards
(46 cards)
Creutzfeldt-Jakob disease (CJD)
2 forms: variant and non-variant.
Non-variant: rare, fatal. onset at 60-70 years old
–> rapid progressive dementia, myoclonus, loss of motor function
no treatment.
“Slow” viruses
RNA viruses: Measles variant, Rubella (–> panencephalitis)
Retroviruses: HTLV-1, HIV-1 (–> AIDS)
DNA virus: JC (–> leukoencephalopathy)
Mumps virus
SS RNA, - polarity, paramyxovirus (~measles)
Aerosol transmission; vaccine = part of MMR (live attenuated).
Sx: swollen parotid glands, orchitis (testicular swelling).
dissem. to: brain, heart and kidneys ==> aseptic meningitis
Rubella virus
SS RNA + polarity, togavirus, 1 serotype.
Aerosol transmission, and can cross placenta.
Sx: mild maculopapular rash starting on face and spreads to body, low fever, No Koplik’s spots; self resolves.
Congenital Rubella syndrome
prenatal rubella infection via placenta,
= very serious, worst if in 1st trimester.
–> stillbirths/spontaneous abortions, or congenital heart or brain abnormalities.
Parvovirus B19
small SS DNA, - polarity; “slapped-cheek syndrome”
transmission: aerosol, transfusions, placental.
Sx: mild = bright red cheeks and low fever, resolves in ~7 days
severe: aplastic (anemic) crisis if from infected bone marrow,
or fetal heart failure if 1st trimester infection.
Hepatitis (general symptoms and diagnosis)
= inflammation and necrosis of liver;
Sx: jaundice, dark urine, pale feces, anorexia, fever, vomit/nausea
Dx: elevated serum transaminase (“ALT” or “AST”) and anti-HBc antibodies
Hepatitis A
picornavirus (~polio)
transmission: fecal-oral, w/ low viremic load
Sx: often asymptomatic, not chronic (not carrier, no carcinomas)
No treatment.
vaccine: Inactivated virus
Hepatitis B
enveloped DS DNA, w/ unique replication process;
transmission: via blood/semen *often w/ HIV-1
(ie: IV drugs/tatoos/blood transfusion, sex, mother->baby)
Sx: start asymptomatic, but carrier if Ags for >6 mo.; HCC if chronic (esp. w/ EtOH abuse)
treatment: NRTIs, or INF-alpha
Vaccine: 3 doses HB-Ag (–> immunity for surface antigen)
Hepatitis C
Flavivirus (~polio), enveloped SS RNA, + polarity
transmission: blood/semen. *often w/ HIV-1, acute liver disease
Sx: chronic, carriers have 25% risk cirrhosis (increased with EtOH abuse),
Treatment: INF, Ribavirin, NS3 protease Inhib., *high resistance!
No vaccine.
Hepatitis D
SS closed circ. RNA, - polarity, **w/ envelope encoded by HepB!
transmission: blood/semen needs HepB to infect
Sx: Chronic, increases severity in HepB carriers
Treatment: none
Vaccine: HepB vaccine works to prevent HepD too
Hepatitis E
SS RNA (same family as Norovirus), + polarity.
transmission: fecal-oral, can aerosol from/into water
increase risk if immunosuppressed
Sx: Not chronic, “enteric” hepatitis
No vaccine or treatment. Prevent w/ safe drinking H2O.
Viruses that can cause hepatitis as secondary infection:
- Cytomegalovirus
- Yellow Fever Virus (arbovirus)
- Varicella Zoster virus (“VZV)
- Ebola Virus
- Rubella virus
Enteroviruses
picornavirus (~polio), start in GI then spread to CNS, etc.
sero70: acute hemorrhagic conjunctivitis
(#1) sero71: aseptic meningitis
==> biphasic: a) mild fever + upper resp. infection
b) postional headache, neck rigidity, fever + photophobia
Severe: encephalitis, paralysis
NO treatment or vaccine.
Coxsackievirus(es)
“enteric virus,” starts in GI, then spreads…
- B: myocarditis + DM2 (bc molecular mimicry)
w/ long-lasting immunity post-infection.
- A16 = “hand foot and mouth disease” -> vesicular lesions.
+/- herpangia. Self-resolving.
Herpangia
vesicular lesions in back of mouth, on either side of uvula.
Caused by coxsackievirus A16,
= self-resolving.
Echovirus
“enteric virus,”
starts in GI, then spreads to meninges
Sx: asymptomatic OR rash on face.
HPV vaccine
tetravalent subunit vaccine (= 100% non-infectious)
against HPV 16, 18 (-> cervical carcinoma) and HPV 6, 11 (-> genital warts)
Hantavirus Pulmonary syndrome (HPS)
caused by Sin Nombre Virus,
Sx: fever, bilateral pulmonary infiltrates, dyspnia/hypoxia, chills/myalgia.
Transmission: aerosol of infected rodent feces (no human-human)
Treatment: supportive care (intubation), quickly becomes severe.
Sin Nombre Virus (SNV)
bunyavirus, 3 RNA segments, neg. polarity;
(w/ RNA-dep. RNA polymerase)
Causes Hantavirus Pulmonary Syndrome.
transmission: aerosol of infected rodent excreta
(= asymptomatic infection common in rodents)
Enteric viruses confined to GI system:
all cause diarrhea, cramps/pain, nausea and fever.
- Adenovirus; 2. Coronavirus
- Rotavirus (mild, in young children)
- Norovirus (abrupt, projectile vomit)
- Astrovirus (~asymptomatic)
Rabies virus
SS RNA, - polarity (~measles), 1 serotype.
transmission: animal bites
Sx: numb/tingling near bite, confusion, encephalitis, paralysis and respiratory failure
Treatment: Inactivated virus vaccine (HDCV) before symptoms
steps to for Rabies infection
- Virus enters wound, binds to host nACh R
- travels from periphery to CNS (via axonal retrograde transport)
- Multiplies in CNS
- travels to salivary glands, etc. –> shed in saliva
diagnosis challenge for rabies virus
anti-rabies Ab = slow to appear – may not find on 1st test;
BUT, if still suspect rabies: Repeat testing every 2 days.
