Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
90 Cards in this Set
- Front
- Back
|
Togaviridae - structure
|
enveloped, icosahedral capsid
|
|
|
Flaviviridae - structure
|
enveloped w/out distinct capsid structure
|
|
|
Togaviridae - genome
|
(+)ssRNA, mRNA-like
|
|
|
Flaviviridae - genome
|
(+)ssRNA (lacks polyA)
|
|
|
Togaviridae - host range
|
wide
|
|
|
Flaviviridae can infect cells bearing an antibody ____ receptor.
|
Fc
|
|
|
Togavirus bud at ____ ____.
|
plasma membrane
|
|
|
Flavivirus bud at ____ ____.
|
internal membranes
|
|
|
Dengue - vector
|
Aedes
|
|
|
Dengue - host
|
humans, monkeys
|
|
|
Dengue - distribution
|
worldwide, esp tropics
|
|
|
Dengue - disease
|
mild systemic; break-bone fever, dengue hemorrhagic fever, dengue shock syndrome.
|
|
|
Chikungunya (alphavirus) - vector
|
Aedes
|
|
|
Chikungunya (alphavirus) - host
|
humans, monkeys
|
|
|
Chikungunya (alphavirus) - distribution
|
Africa, Asia
|
|
|
Chikungunya (alphavirus) - disease
|
fever, arthralgia, arthritis
|
|
|
Yellow Fever - vector
|
Aedes
|
|
|
Yellow Fever - host
|
humans, monkeys
|
|
|
Yellow Fever - distribution
|
Africa, South America
|
|
|
Yellow Fever - disease
|
HEPATITIS, hemorrhagic fever
|
|
|
West Nile encephalitis - vector
|
Culex
|
|
|
West Nile encephalitis - host
|
birds
|
|
|
West Nile encephalitis - distribution
|
Africa, Europe, Central Asia, North America
|
|
|
Describe the "lifecycle" of arbovirus.
|
1) Arthropod (female mosquito, tick, fly) feeds on VIREMIC vertebrate host.
2) Virus in bloodmeal infects insect midgut epithelium 3) Virus replicates and increases in numbers. 4) Virus spreads by circulation to salivary gland. 5) Virus establishes persistent infection in salivary gland. 6) Saliva injected into host when arthropod takes blood meal. |
|
|
Are arboviruses usually pathogenic in arthropod host?
|
No, but there may be ovarian transmission.
|
|
|
Arbovirus infects which tissues?
|
endothelial cells, monocytes, macrophages, liver
|
|
|
What influences the severity of arbovirus disease?
|
viral strain, dose of virus, tissue or cell trophism of virus, host response to infection
|
|
|
Flaviviruses preferentially infect ____ via attachment to Fc-receptors.
|
macrophages
|
|
|
Toga- and Flaviviridae disease - direct or indirect pathology?
|
both
cytolytic virsuses that also cause immunopathology |
|
|
Toga- and Flaviviridae infection generates a strong ____ interferon response.
|
alpha+beta
|
|
|
Alphaviruses - symptoms
|
many have only mild flu-like symptoms (fever, chills, rash, aches)
can progress to encephalitis in WEE, EEE and VEE |
|
|
Flaviviruses - symptoms
|
most infections mild, but...
West Nile can lead to encephalitis or viral meningitis. Dengue and Yellow Fever can lead to hemorrhagic disease. |
|
|
West Nile - Clinical Diagnosis
|
mild non-specific illness for 2-3dd
symptoms: fever, headache, lethargy, myalgias, etc. self-limiting |
|
|
Who is at risk for complications due to West Nile?
|
Adults over 55, immunosupressed people
|
|
|
Yellow Fever - Clinical Diagnosis
|
Initial symptoms - jaundice (liver degeneration)
May have black vomit (gastrointestinal hemorrhages) |
|
|
Dengue Hemorrhagic Fever - clinical diagnosis
|
High fever, headache, rash, back and bone pain lasting 6-7dd.
|
|
|
Dengue Shock Syndrome - how does it happen?
|
Patient REinfected with a DIFFERENT strain of Dengue
Pt's antibodies are non-neutralizing but antibodies carry virus to macrophages Activates memory T-cells, releasing cytokines causing: hypersensitivity rxns, weakened vasculature, shock, internal bleeding |
|
|
Toga- and Flaviviruses cause lytic or persistent infections in ____.
|
vertebrates
|
|
|
Toga- and Flaviviruses cause lytic and persistent infections in ____.
|
invertebrates
|
|
|
Humans are (often/rarely) the natural host for Flavi- and Togaviruses.
|
rarely -- dead end virus
**exception - urban dengue |
|
|
Toga- and Flaviviruses - Lab Diagnosis
|
Special labs -- State Health Lab, CDC, etc
RT-PCR, serology, hemagglutinin inhibition, ELISA -- problem = crossreactivity |
|
|
West Nile Virus - Laboratory Diagnosis
|
Commercial IgM-capture ELISA used with CSF and serum.
Works until 8th day of illness. Retest serum at 2-3 weeks look for 4x increase in titer **problems -- crossreactivity with other flaviviruses. |
|
|
Toga- and Flavivirus - Treatment (antivirals??)
|
No antiviral... supportive care only
|
|
|
Toga- and Flavivirus - Prevention
|
best prevention = vector control
|
|
|
Togaviruses - vaccine?
|
Killed virus vaccines available against WEE, EEE, VEE, Japanese and Russian spring-summer encephalitis
**limited to those who may come into contact -- lab workers? |
|
|
Yellow Fever - vaccine
|
attenuated Yellow Fever vaccine -- military
|
|
|
West Nile - vaccine
|
in clinical trials
licensed equine vaccine (which is great for the horses...) |
|
|
Rubella may also be called ____ ____
|
German Measles
|
|
|
Structurally, Rubella virus is a ____, except that it's a respiratory virus, not an arbovirus, and it's not cytolytic.
|
togaviridae
|
|
|
Rubella infects the host by ____ ____.
|
aerosolized droplets
|
|
|
Where does Rubella replicate?
|
URT
|
|
|
Rubella can spread to the lymph nodes and cause ____.
|
lymphadenopathy
|
|
|
How does Rubella virus travel around the body?
|
viremia
|
|
|
Rubella virus replication in ____ and ____ cause maculopapular or macular rash.
|
tissues, skin
|
|
|
Why is it really important for women (of childbearing age) to be vaccinated against Rubella?
|
Infection at any stage of pregnancy can cause **congenital disease**
cataracts, mental retardation, deafness, heart defects and other unsavory things -- most damaging in 1st trimester |
|
|
Rubella -- disease syndromes in normal children
|
mild infection
2-3 week incubation period swollen glands maculopapular or macular rash |
|
|
Rubella -- disease syndromes in normal adults
|
**can be severe
Arthralgia and arthritis CME and hypersensitivity |
|
|
Rubella - hosts?
|
only humans
|
|
|
Rubella - serotypes?
|
only one
|
|
|
Rubella Virus - Laboratory Diagnosis
|
Serology is a meas of testing (not common) -- IgM, increase in titer
Anti-rubella titer is commonly measured in early pregnancy |
|
|
Rubella - antivirals?
|
nope
|
|
|
Rubella - vaccine
|
live vaccine (MMR)
|
|
|
Bunyaviridae - structure
|
enveloped spherical particle
|
|
|
Bunyaviridae - genome
|
(-)ssRNA - three segments (L,M,S)
**some have circular genome (LaCrosse) |
|
|
Bunyaviridae - symptoms of encephalitic diseaes (LaCrosse)
|
7 day incubation, sudden onset of symptoms lasting one week: fever, headache, lethargy
**50% have seizures |
|
|
Bunyaviridae - clinical syndromes of Hemorrhagic Fevers (Rift valley Fever, Hantavirus)
|
Petechial hemorrhages, ecchymosis, epistaxis, hematemsi, melena, bleeding gums
**50% mortality rate |
|
|
Hantavirus primarily infects and persists in the ____.
|
lungs
|
|
|
Hantavirus - direct pathology
|
produces direct cytolytic damage causing leakage of RBC and plasma through vascular endothelium.
|
|
|
Hantavirus - clinical progression
|
prodrome (fever, myalgia), progresses to interstitial pulmonary edema, respiratory failure and death.
|
|
|
California encephalitis virus - vector
|
mosquito
|
|
|
California encephalitis - who's at risk?
|
forrest rangers, campers, woodsmen (his words, not mine)
|
|
|
Hantavirus - how do you get it?
|
contact with rodents (inhaling dry urine)
|
|
|
Bunyavirus - diagnosis
|
**most patients only flu-like
Patients diagnosed on more severe clinical symptoms. Serology and direct detection can be used. |
|
|
Bunyavirus - antiviral?
|
of course not!
|
|
|
Hantavirus - treatment
|
supportive therapy for pulmonary symptoms
|
|
|
Arenaviridae - structure
|
enveloped viruses with pleomorphic shape
|
|
|
Arenaviridae - genome
|
two circular ssRNAs
One strand called A (-)ssRNA, the other is ambisence ssRNA |
|
|
Why do arenaviruses look grainy under electron microscope?
|
incorporate ribosomes
|
|
|
Arenavirus - what is the only important member in North America?
|
Lymphocytic choriomeningitis
|
|
|
Arenaviruses like to infect ____ which leads to ____ infection.
|
macrophages, persistent
|
|
|
What happens if a neonate is infected with Arenavirus?
|
virus can induce tolerance, producing lifelong carrier
|
|
|
Arenaviruses -- disease symptoms are caused by what?
|
T-cell immunopathology
|
|
|
Lymphocytic choriomeningitis - clinical symptoms
|
fever and flu-like
25% have CNS involvement (meningitis) |
|
|
Lassa Fever - Clinical Symptoms
|
hemorrhagic fever: fever, coagulopathy, petchia, sore throat, diarrhea, vomiting, visceral hemorrhage, liver & spleen necrosis
|
|
|
Lassa Fever - mortality rate
|
as high as 50%
|
|
|
Arenaviridae - how is it acquired?
|
inhalation, food, fomites
|
|
|
Lymphocytic choriomeningitis virus - carried by ____ and ____
|
hamsters and house mice
(one more reason to get rid of rodents, dude.) |
|
|
Arenaviridae - Laboratory Diagnosis
|
recent travel to tropics
**Specimens should be sent to a diagnostic facility with at least BSL 3 level containment |
|
|
Lassa Fever - antiviral?
|
Ribavarin
|
|
|
Arenaviridae treatment
|
supportive therapy
|
