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24 Cards in this Set
- Front
- Back
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Influenzaviruses
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3 of 5 genera in Orthomyxoviridae, Class V. Enveloped icosahedral. Influenzavirus A in all animals, B in humans and seals, C in humans and pigs.
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Influenzavirus Surface Antigens
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Hemagluttinin (H) allows virus to bind - 16 types. Neuraminidase (N) keeps viruses from sticking - 9 types.
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Classifying Influenza Viruses
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Based on surface proteins. Evolution: drift and shift. All major pandemics from A. Virus ecology allows strains to exchange adaptations.
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Influenza Targets at Risk
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Infants, elderly, and people with cancer, diabetes, kidney, heart, lung problems.
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Influenza Transmission
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Mainly airborne droplets. Fomites secondary, important in children. Infectious day before symptoms until 3 days after recovery. Spreads quickly in crowded areas, therefore in winter.
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Influenza Symptoms
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High fever*, malaise, myalgia, headache, cough, sore throat, rhinitis (nose congestion).
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Influenza Treatment
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Early treatment most effective. Usually self-resolving (treat symptoms & rest). Severe cases: amantadine and rimantadine (Type A viral entry blockers), Relenza and Tamiflu (Types A&B release inhibitors), antibiotics (prevent 2ndary infection), and life support systems.
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Influenza Prevention & Control
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Personal hygiene. Vaccines (everchanging based on circulating strains): typically trivalent including 1 of A/H1N1, 1 of A/H3N2, & 1 of B. Injected (inactivated) or nasal spray (killed).
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Rhinoviruses
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Picornaviridae Class IV. Naked icosahedral. Low temperature preference keeps the virus in upper resp. tract.
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Rhinitis Transmission
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Contact with mucus membranes thru airborne particles, droplets, or fomites. Mainly in winter.
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Rhinitis Symptoms
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Incubation 2-3 days. Inflammation of the nose: rhinorrhea (runny nose, transmitter), sneezing (transmitter), stuffiness, edema (swelling), general inflammation (heat, redness, swelling, pain). Sore throat.
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Rhinovirus Secondary Bacterial Infections
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Bronchitis, laryngitis, otitis media, sinusitis, tracheitis. Development changes symptoms slightly: headache, myalgia, worsening sore throat, discolored exudate.
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Rhinitis Treatment
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Palliative, rest, fluids. NO antipyretics (fever reducers make environment more favorable). Antibiotics (prevent 2ndary infection).
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Rhinitis Prevention & Control
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Personal hygiene: handwashing, kleenex, redirected sneezing. Vaccine: impractical.
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Cold vs. Flu
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Rhinovirus: mild aches & pains, fatigue, and cough; common stuffy nose, sneezing, and sore throat. Influenzavirus: common fever, headache, aches & pains, fatigue, exhaustion, and cough; uncommon stuffy nose, sneezing, & sore throat.
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Polio
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Picornaviridae Class IV Genus Enterovirus A (historically devastating), B (least important), C (emerging).
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Polio in the Early 20th Century
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Improved hygiene & sanitation standards. Shift from children to adolescents & adults. Roosevelt's "March of Dimes" 1940s.
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Polio Vaccine History
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Salk IPV (inactivated polio vaccine), formalin-inactived injection. Sabin OPV (oral polio vaccine), live attenuated. New version of Salk used today.
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Polio Transmission
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Requires direct contact. Incubation 1-2 weeks. Fecal-oral route. Shed from feces 2-6 weeks post-infection.
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Polio Infection Process
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First multiplies in pharynx and small intestine. Tonsils and Peyer's patches (lymph nodes) lead to viremia. CNS infection rare.
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Polio Symptoms
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90% asymptomatic. 9% Abortive Poliomyeltis: temporary fever, malaise, sore throat, headache vomiting. 1% paralysis: spinal poliomyelitis (muscle func.), bulbar poliomyelitis (respiratory), Late Postpolio Muscle Atrophy.
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Polio Symptoms
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90% asymptomatic, 9% Abortive Poliomyelitis: temporary fever, malaise, sore throat, headache vomiting. 1% paralysis: spinal poliomyelitis, bulbar poliomyelitis, Late Postpolio Muscle Atrophy.
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Polio Treatment
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No treatment. Analgesics (pain-relievers). "Iron lung" for Bulbar Poliomyelitis. Physical therapy for spinal Poliomyelitis.
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Polio Prevention & Control
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Vaccine starts at 2 months. Eradicated from North and South America. Monitoring travelers.
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