Quiz 4 Viruses Flashcards
Mumps
Paramyxovirus (-) SS RNA Enveloped Helical Airborne Spread 18-21 days incubation 1' tropism resp epithelium viremia important to spread to parotid/testes 2' tropism parotid virus shed through saliva Prodromal Sx: nonspecific fever / malaise / anorexia Clinical Sx: parotiditis usual presenting sx. Also Orchitis causes hemagglutination Live attenuated vaccine in MMR; 2 doses No Rx.
Measles
Paramyxovirus
(-) SS RNA
Enveloped
Helical
Airborne Spread
14 days incubation
1’ tropism respiratory epithelium
viremia important to spread
Prodromal: Kopliks spots/fever/malaise/cold like Sx, conjunctivitis/photophobia,
Clinical Sx: Rash of erythematous macules, encephalitis,
Complications Subacute Sclerosing PanEncephalitis
Sx. Measles prodrome + intellectual deterioration
Hemagluttination
Multinucleate giant cells
Rx w. Vitamin A.
Prions
Misfolded proteins Scrapie in sheep Kuru in New Guinea b/c cannibalism Creutzfeldt-Jakob Disease - genetic varient CJD - eating infected beef in UK causes encephalopathy and death. No cure, no Tx.
Transducing Tumor Virus
Retrovirus
inserts an oncogene from previous host cell and expresses it under the viral promoter
often defective virus due to additional genetic material
Rapid and spectacular tumor formation
No human examples
Non-Transducing Tumor Virus
Retrovirus
inserts viral promoter upstream of proto-oncogene
No human examples
potentially useful for gene therapy.
Trial used to treat SCID… causes leukemia
Long Latency Tumor virus
non-transducing retroviruses
HTLV 1&2 only human example
Genes: gag, pol, env, tax
increases likelihood of malignancy
DNA Tumor
DNA integrates
EBV, KSHV(HHV-8)
EBV causes translocation of c-myc gene to antibody promoter
KSHV requires immune suppression; highly angiogenic
HHV1
Herpes Simplex; HSV1 Enveloped linear dsDNA icosahedral saliva transmission Cold sores, temporal lobe encephalitis, keratosis, stomatitis latent in trigeminal ganglia activated by stress/fever/UV light 80% seroprevelance 7-14 day incubation Herpes simplex encephalitis; PCR of CSF Rx: triflurodine for recurrent keratitis adenine arabanoside for encephalitis acyclovir for systemic & encephalitis
HHV2
Herpes Simplex; HSV2 Enveloped linear dsDNA icosahedral sexual transmission; perinatal Genital herpes, neonatal herpes (fatal; and indicator for C-section) 7-14 days incubation primary infection bilaterally recurrent infection unilateral Rx w/ acyclovir
HHV3
Varicella-Zoster; Chickenpox-Shingles Enveloped linear dsDNA icosahedral airborne and contact transmission 14-21 day incubation fever, rash, lesions congenital can result in limb scaring and atrophy Post herpatic neuralgia post Zoster live attenuated vaccine Rx. passive IgG, acyclovir for shingles. foscarnet
HHV4
Cytomegalovirus; CMV
Enveloped
linear dsDNA
icosahedral
close contact, nasal fluid, semen, urine, vag secretions
3-12 weeks incubation
Most common congenital infection; crosses placenta
mononucleosis (negative heterophile test)
Large multinucleated cells & owl eye inclusions
common in preschool/daycare
TORCH infection; microcephalic; retardation; deafness; jaundice; hepato/spleanomegaly, anemia
Recurrent in immunocompromised; esophagitis; retinitis
Rx: gancyclovir; pooled IgG
HHV5
Epstein-Barr Virus; EBV
Enveloped
linear dsDNA
icosahedral
saliva, oral contact, shared items
4-6 Week incubation
causes Mononucleosis, Burkitts lymphoma, Hogkins lymphoma, nasopharyngeal carcinoma, hepatitis,
Sx. Fever, sore throat, lymphadenopathy,, oral hairy leukoplakia
Dx. Positive heterophile test w/ sheep RBCs
HHV6
Enveloped linear dsDNA icosahedral Roseola infantum; high fever, systemic rash 90% seroprevalence
HHV7
No disease
Enveloped
linear dsDNA
icosahedral
HHV8
Kaposi Sarcoma Herpes Virus Enveloped linear dsDNA icosahedral multiple pigmented, highly vascular lesions high Vascular Epithelial GF expression only in severe immunocompromised pts. 15-20% AIDS Pts
Herpes virus virology
fusion; adsoprtion; capsid to nucleus; genome integration
progeny assemble in nucleus & bud through
glycoproteins in PM –>cell fusion giant-multinucleate-cells
tegument proteins
Arbo viruses
Flavivirus - St. Louis Encephalitis - West Nile Virus - Yellow Fever Virus - Dengue Virus Togavirus - Western Equine Encephalitis - Eastern Equine Encephalitis
St. Louis Encephalitis
Flavivirus Enveloped (+) SS-RNA Icosahedral Arthropod Vector; Birds 7 day incubation human; 14 days in arthropod Encephalitis >50 years old increased risk viremia, multiplication in vasuclar endothelium prodromal malaise and fever,
West Nile Virus
Flavivirus Enveloped (+) SS-RNA Icosahedral Arthropod Vector; Aedes aegypti; Birds 7 day incubation Encephalitis >50 years old increased risk viremia following multiplication in vascular endthelium prodromal malaise and fever
Yellow Fever Virus
Flavivirus Enveloped (+) SS-RNA Icosahedral Arthropod Vector; Aedes aegypti; human only reservoir 7 day incubation Yellow fever; fever, nausea, jaundice high mortality infects vascular endothelium, Live attenuated vaccine
Dengue Virus
Flavivirus Enveloped (+) SS-RNA Icosahedral arthropod vector, Aedes aegpti; humans only resevoir 7 day incubation "Bone Break fever" 2nd infection hemorrhagic Dengue pain, headache, fever, joint pain, rash Hemorrhagic dengue = vomit blood, shock severe, not life threatening 4 serotypes
Western Equine Encephalitis
Togavirus Enveloped (+) SS-RNA Icosahedral Mosquitos; bird host 7 day incubation Encephalitis rural areas w/ high mosquito populations 10% fatal; many cases subclinical Infants and >50yo increased risk Humans & horses dead end hosts
Eastern Equine Encephalitis
Togavirus Enveloped (+) SS-RNA Icosahedral Mosquitos; bird host 7 day incubation period Encephalitis 75% case fatality some subclinical infections <10yo increased risk horses and humans dead end host; transmission through birds
Parvo B-19
Parvovirus
Enveloped
Linear single stranded DNA
Icosahedral
Airborne
7 day incubation
arrhythmia infectiousum in children “slapped cheek”
congenital 1-2trimester hydrops fetalis; edema; fetal death
transient aplastic crisis
acute arthritis most common presentation
RBC deficit puts get transient aplastic crisis
infects RBC precursors
normal immune = subclinical or fever/malaise.rash
passive immunzation w/ pooled IgG
Rubella
Togavirus
Enveloped
(+) SS-RNA
Icosahedral
Airborne transmission
18 day incubation
rubella(german measles) or congenital rubella
multiplies in resp epithelium
viremia develops; less infectious than measles
Early maternal infection w/ increased chance of congenital defects
Rash for 3 days; fever, lymphadenopathy
Congenital rubella; cateracts, heart defects, deafness, retardation