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59 Cards in this Set
- Front
- Back
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ARBOVIRUS
Three key properties of "Arbovirus" |
1.) Transmitted btw vertebrate hosts by the BITE of infected hematophagous arthropod
2. Multiply AND Produce Viremia in vertebrate host 3. Multiply in the tissues of arthropod vectors. |
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ARBOVIRUS
T/F : Arbovirus is a TAXONOMIC classification! |
- False
- It is an EPIDEMIOLOGICAL classification |
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Describe the virion envelope for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
ENV - 45 nm
ENV - 60 nm ENV - 80 to 120 nm |
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Describe the matrix for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
YES
YES NO |
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Describe the Nucleocapsid for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
ICOS
ICOS Variable |
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Describe the packaged enzymes for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
NONE
NONE RNA-Dependent RNA PY |
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Describe the genome for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
ssRNA
ssRNA ssRNA |
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Describe the genome sense for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
Positive
Positive Negative/Ambisense |
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Describe the number of segments for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
Nonsegmented
(1 molecule) Nonsegmented (1 molecule) Segmented (3 segments) |
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Describe the replication strategy for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
Positive
Positive Negative/Ambisense |
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Describe the first step in replication for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
Genome translated to polyprotein
5' 2/3rd genome translated to polyprotein Positive sense copy of genome tranSCRIBED |
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Describe the subgenomic RNAs for the following virus families:
- Flaviviridae - Togaviridae - Bunyaviridae |
NONE
YES YES |
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What are the factors influencing Epizootic/Epidemic outbreaks? x5
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COMPETENCE for enzootic & epizootic vectors
ABUNDANCE of enzootic & epizootic vectors HUMAN behavior ABUNDANCE of vertebrate reservoir hosts Genotype of virus (e.g. - virulence mutations) |
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Commonalities between arbovirus infection of humans:
- what kind of inoculations - inoculation by? - typical "dead end" host - exceptions to "dead end" host? x2 |
SubQ
Arthropod vector Dead-End ==> Human Host (mostly) Denque & Yellow fever virus (exception) |
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Commonalities between arbovirus infection of humans:
- MOST symptoms are? - Common symptoms involve? - Prognosis of common Sx? - Earliest symptoms - Severity of disease dependent on what? |
Asymptomatic***
BIPHASIC FEBRILE ILLNESS Resolve without complication Flu-like (fever, HA, malaise, myalgia) Age dependent (Worse in very young or very old) |
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ARBOVIRUS ATTACK RATES
- Discuss the RATIO of arboviral infections that is VERY HIGH |
Ration of inapparent (ASYMPTOMATIC) to apparent (SYMPTOMATIC)
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ARBOVIRUS ATTACK RATES
- Discuss the ATTACK rate |
LOW
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The usual inability of an arbovirus to establish a symptomatic infection in the host is due to what 2 factors?
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- Virus Dosage (NOT genetics)
- Human genetics/IMMUNE response |
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St. Louis Encephalitis Virus:
- Family - Genus - Reservoir Host - Vector |
Flaviviridae
Flavivirus Avian Mosquito |
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St. Louis Encephalitis Virus
- Largest US epidemic # of cases - Most recent outbreak where? - Affects what US states? x7 |
2000
Monroe, LA (69 cases) OH-MS valley, East TX, FL, KS, CO, CA |
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St. Louis Encephalitis Virus:
- SE US seroprevalence - Symptomatic case fatality - Symptomatic to infected ratio - Symptomatic to infected ratio in elderly - Epidemic attack rate |
~6%
7% (age-dependent) 1:800 1:85 Less than 1:100 |
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West Nile Virus (Old World):
- Family - Genus - Reservoir Host - Vector |
Flaviviridae
Flavivirus Avian Mosquito |
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West Nile Virus (Old World):
- "Hyperendemic" where? - High seroprevalence precludes what? - Eventual decline of endemic transmission would do what? |
Africa and Middle East
Epidemic outbreaks Increase risk of epidemic |
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Why do most West Nile virus symptoms go unrecognized?
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Clinically undifferentiated from febrile disease in children
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West Nile Virus in low immunity areas.
- epidemic attack rate - severity of symptoms - mortality rate - CNS infection? |
60%
Mild Very LOW RARE |
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Eastern & Western Equine Encephalitis Virus:
- Family - Genus - Reservoir host - Vector |
Togaviridae
Alphavirus Avian Mosquitoes |
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Eastern & Western Equine Encephalitis Virus has the highest rate of impact on children it infect of what symptoms? x3
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Encephalitis
Seizures Sequelae |
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Eastern & Western Equine Encephalitis Virus comparison:
- average human cases per year - fatality rate |
WEE - 34/year 10% fatality
EEE - 7/year 30-70% fatality |
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Eastern & Western Equine Encephalitis Virus comparison:
- Case to Infection ratio for children |
WEE: 1:50 in children < 5 yr
EEE: 1:8 in children < 10yr |
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Eastern & Western Equine Encephalitis Virus comparison:
- Case to Infection ratio for adults |
WEE: 1:1000
EEE: 1:23 |
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Eastern & Western Equine Encephalitis Virus comparison:
- Sequelae |
WEE: 5% of survivors
EEE: 35-80% have permanent neurologic impairment. |
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ARBOVIRUS INFECTIONS
- what are the "commonalities" x7 |
D ASS ERA
- Dead end host is humans (except in DEN & YFV) - Asymptomatic usually - Symptomatic is Biphasic Febrile Dz - SubQ inoculation by arthro-vector - Early Sx is "flu-like" - Resolves usually without complications - Age dependent severity |
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ARBOVIRUS INFECTIONS
- what does it mean that humans are "dead end hosts?" - why? |
- No further transmission from humans
(after getting it from arthropod vector subQ) - b/c LOW dosages in blood (not related to viral genetics) (although, human genetics may play a role) |
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ARBOVIRUS INFECTIONS
- Worse Dz & Higher mortality in whom? x2 |
Age Dependent Severity, so
- Very young - Elderly |
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ARBOVIRUS INFECTIONS
- Attack rate (Sx:ASx) in those infected - why such numbers? |
- Low attack rate
- inability of arbovirus to establish symptomatic infection in host (Due to Virus DOSE) (Human genetics or Immune response also can play a role) |
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ARBOVIRAL HEMORRHAGIC FEVER
T/F : AHF is a potentially LETHAL Dz syndrome |
True
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ARBOVIRAL HEMORRHAGIC FEVER
- Potentially LETHAL Dz syndrome characterized by what progressive Sx? x8 |
- Fever, Malaise, Myalgia
(progress to) - Mucosal bleed - GI bleed - Vomiting (progress to:) - Hypotension - Edema |
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ARBOVIRAL HEMORRHAGIC FEVER
- Clinical manifestations begin with what 3 symptoms? - Progressing to? x4 - Bad news if progressed to? x2 |
(F CP)
- Flushing - Conjunctival injection - Petecial hemorrhage (Frank @ HSC) - Frank Mucosal Hemorrhage - Hypotension - Shock - Circulatory collapse - DIC - Multi-organ failure |
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YELLOW FEVER HISTORY
- Last US epidemic in? - Famous Firsts? x2 - Old world or New world? |
- New Orleans, LA in 1905
(>3,000 cases, 452 deaths) - 1st Filterable Human Pathogen (Walter Reed) - 1st Live Attenuated Vaccine - 17D (Max Theiler - Nobel in 1952) - Both (1st reported cases in both in 1600s) |
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YELLOW FEVER
- Range of YFV expanding to? x2 |
Re-EMERGENCE in Africa
Re-ESTABLISHMENT in SE USA |
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YELLOW FEVER
- Describe the Hepatic induced Coagulopathy & Hemorrhagic manifestations. x7 |
Yellow man BB of GE is full of PEP
- Black Vomit (hematemesis) - Bloody Diarrhea (melana) - Gum bleed - Epistaxis (nasal hemorrhage) - Petechial hemorrhage - Ecchymotic hemorrhage - Purpuric hemorrhage |
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YELLOW FEVER
- Systemic manifestations x2 - Poor prognosis if? - what reflects degree of hepatic injury? |
- Jaundice
- Albuminuria - Early Jaundice @ day 3 - Transaminase elevation |
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YELLOW FEVER
- Late stage symptoms? x6 - Late CNS Sx? x3 - Death is usually when? |
MA MASH
- Myocardial Dysf(x) - Arrhythmia - Metabolic Acidosis - Acute Tubular Necrosis - Shock - Hypotension SCC - Seizures - Confusion - Coma - 7 to 10 days post onset |
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RIFT VALLEY FEVER VIRUS
- Outbreaks where? |
(North & South valley)
- North Africa - Sub-Saharan Africa |
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RIFT VALLEY FEVER VIRUS
- In 2000, first reports of RVF virus noted where? x2 - concern b/c |
SAY
- Saudi Arabia - Yemen - threatens Asia & Europe |
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RIFT VALLEY FEVER VIRUS
- Primarily affects what reservoir hosts? - Epizootic outbreaks when? - Epizootic outbreaks signaled by? |
- Livestock
(sheep, cattle, camel, goats) - Heavy rainfall & Flood - Abortion Storm in livestock |
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RIFT VALLEY FEVER VIRUS
- During outbreaks, humans infected in 3 ways? |
MBA
- Mosquito vector - Blood or Body fluid contact - Aerosolized inhalation |
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CRIMEAN CONGO HEMORRHAGIC FEVER
- reservoir host - vector Endemic where? x3 |
- Rodents
- Ticks - Asia - Eastern Europe - Africa |
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CRIMEAN CONGO HEMORRHAGIC FEVER
- recent outbreaks seen where? x5 |
PIKAS
- Pakistan - India - Kosovo - Albania - South Africa |
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CRIMEAN CONGO HEMORRHAGIC FEVER
- During CCHF epizootic, humans infected in what 2 ways? |
- Tick bite
- Blood / Body fluid contact |
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CRIMEAN CONGO HEMORRHAGIC FEVER
- Severity in humans? - Mortality rate? |
- SEVERE Dz in humans
- HIGH mortality rate |
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CRIMEAN CONGO HEMORRHAGIC FEVER
- Majority of cases in what types of people? x4 |
SAVE
- Slaughterhouse workers - Agricultural workers - Vets - Etc..... |
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ARBOVIRAL HEMORRHAGIC FEVER
- For Differential Dx, of paramount importance are what factors? x3 - What is NOT a diagnostic for AHF? |
Pre-Coss Pie
- Place of Residence / Exposure - Community Occurrence & Serodiagnosis of Similar cases - Prior Infection / Exposure - Specific Sx is NOT Diagnostic |
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ARBOVIRAL HEMORRHAGIC FEVER
- Differentials include what? x7 |
Ladies were Leeping for MORRIS
- Leptospirosis - Malaria - Other arbovirus infections causing fever & rash - Rubella - Rubeola - Influenza - Scrub typhus |
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YELLOW FEVER VIRUS VACCINE
- called what? - what type of vaccine what is? - what YFV strain isolated in 1928 - how did they attenuate it? |
- 17D vaccine
- Live-Attenuated vaccine - Aisibi strain -Passaged 200 times in Mouse Brain & Chick Embryo |
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YELLOW FEVER VIRUS VACCINE
- how did they grow it? - how did they safety test it? |
- Embyonated egg
- Safety test in Monkeys |
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YELLOW FEVER VIRUS VACCINE
- how many produced annually? - is this enough? |
- 13 million
(11 million used in Brazil) - Not enough if YFV Re-Emerges (currently Re-Emerging in Africa) (currently re-estabishment in SE US) |
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YELLOW FEVER VIRUS VACCINE
- recommended for? - contraindicated for? x3 |
- those traveling to endemic areas
- Pregnant - Immunosuppressed - Infants less than 6 months old |
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YELLOW FEVER VIRUS VACCINE
- is it safe? - is it efficacious? - seroconversion rate? - what type of immunity imposed by vaccine? |
- among safest
- among most efficacious - 96% seroconversion - Long lasting immunity |
