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20 Cards in this Set
- Front
- Back
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Zoonotic viruses
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- Have known animal reservoirs - All RNA viruses!
- Influenza, SARS, etc. - Some life-threatening, some not... - Establishing travel is key for patient history! |
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Rabies overview
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- Uniquely bullet-shaped, enveloped RNA rhabdovirus
- Diagnosis - negri bodies in neurons (usually autopsy) - Tends to avoid immune system until "too late" - Relatively high mortality |
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Rabies symptoms onset time factors
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- Depth of bite (superficial vs. deep)
- Distance of bite to brain - Age/overall health - Victims have affected salivary glands - difficulty swallowing water - hydrophobia - Agitation, coma, death |
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Rabies infection timeline
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- Inoculation via bite
- Viral replication in muscle - Virions enter PNS - Passive ascent via sensory fibers - Replication in DRG - Rapid ascent to brain - Infection of CNS (brain) - Infection descends via nervous system to eyes, salivary glands, skin, etc. - Foaming at the mouth = too late! - already in the brain... |
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Rabies mechanism of path. effects
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May bind to acetylcholine receptors in brain/nervous system
- Agitation, other symptoms |
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Animal carriers
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Mammals - skunk, raccoons, bats
- Airborne transmission in bat caves - Dogs vaccinated in US = otherwise major carrier! |
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Rabies treatment
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- Wash bite thoroughly with soap and water
- Use iodine scrub - kills viruses - Anti-rabies Ig's (recombinant, expensive) - at infection site and intramuscularly - Start vaccine |
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Togavirus classes
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Protoype viral class for other bunyavirus, flavivirus, arena, arbovirus also - constant nomenclature changes...
- 200 bunyaviruses alone... - Don't worry about individual classification of these b/c constantly changing - BOTTOM LINE = RNA viruses with envelope |
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Togavirus overview
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Enveloped RNA virus - wet transmission = mostly mosquito (some tick) bites (some rodent/bat urine, etc.)
- Have E1, E2 glycoproteins - binds CD81, other receptors - Spread mostly by mosquitoes, headache/encephalitic symptoms |
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Togavirus et al spread
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- Mostly via mosquitoes
- Back and forth between humans, animal reservoirs - Biggest prevention - spraying for mosquitoes - A few others carried by rodents... |
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Toga et all mild forms
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WEE, EEE, VEE, CEE, SLE
- Spread by mosquitoes - Flu-like symptoms - Treatment is only supportive |
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Toga et all more severe forms
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Dengue fever, Yellow fever, West Nile encephalitis
- all have flu-like symptoms - spread by mosquitoes - Dengue = can progress to hemorrhagic form - very life threatening - Dengue shock syndrome = from constant bleeding - Yellow = progressive liver failure - yellow from jaundice - West Nile = causes cell-death induced jaundice, liver failure |
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Dengue fever overview
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- Flavivirus - Spread by mosquito - mostly warm areas (south/central america, S. Africa, SE Asia, etc.)
- Symptoms = flu-like = fever, headache, eye pain, joint/mm aches, RASH - Complications = can progress to hemorrhagic form (1-2% cases) - Confirmation = RT-PCR, immunochemistry - Treatment = mostly supportive, transfusions if hemorrhagic - No vaccine - not usually serious enough... |
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Dengue hemorrhagic fever
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- Progression from Dengue fever in 1-2% of cases
- Bleeding from gums, nose, subcutaneous - low platelet count |
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Dengue Shock Syndrome
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- Hypotension and death
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Yellow fever overview
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- Flavivirus - spread by mosquito
- Named for associated jaundice - Symptoms = Jaundice, fever, headache, vomiting, red eyes, bleeding eyes/nose/mouth, muscle ache, hepatomegaly - Complications = liver failure, hemorrhage - Diagnostic - RT-PCR, immunochemistry - Treatment - supportive (vaccine for travelers!) |
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Lassa fever overview
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- Arena virus - carried by African rats (not in US)
- Symptoms = hemorrhagic fever, highly lethal! - Transmission = droppings/aerosols from rodents, human-human (no mosquitoes/tick vectors) - Treatment = mostly supportive, Ribavirin if necessary - Diagnosis = RT-PCR (dangerous to culture) - Patients in US with this will have traveled... |
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Hantavirus pulmonary syndrome overview
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Bunyavirus - carried by US domestic mouse
- Symptoms = initially flu-like, pulmonary edema, respiratory failure, can be lethal (not quite as bad as Lassa) - Transmission = mouse droppings/urine/aerosols (not really human-human) - Treatment = supportive, sometimes ribavirin (can give inhaled form - avoid complications with liver, etc.) - Diagnosis = RT-PCR - Patients usually exposed to wild mice or have infested home |
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Lymphocytic choriomeningitis virus (LCM) overview
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Aseptic meningitis from mice - much less severe than Lassa fever, Hantavirus
- Symptoms = flu-like, headache, fever, Stiff neck, photophobia - Transmission = mouse droppings/aerosols (little/no human-human) - Diagnosis = RT-PCR of CSF - Treatment = Cell-mediated immunity (cytotoxic T-cells, etc.) usually take care of this |
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Other associated minor viruses
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Many have exotic names - geography of discovery
- Rift Valley fever = mosquito, no human-human - treatment is just supportive - Chikungunya virus = mosquito - febrile disease, crippling joint pain - treatment just supportive - Semliki forest virus = mosquito - flu-like - treatment just supportive - Also sandfly fever, toscana virus disease, Japanese encephalitis, Punta toro virus disease, etc. - BOTTOM LINE = ALL are enveloped RNA viruses with animal reservoirs, spread by arthropods or aerosols |
