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9 Cards in this Set
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1. Differentiate the various Paramyxoviruses that cause respiratory infections
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1. (-) RNA genome, enveloped, unsegmented, helical capsid
2. Genome ~ 15 kb, encodes 6-10 genes 3. Common pathogen of humans, ungulates, dogs, birds 4. Parainfluenza virus 5. RSV 6. Metapneumovirus 7. Entry into cell by membrane fusion or endocytosis 8. Nucleocapsid uncoats 9. Viral RNA polymerase (packaged inside virus) copies (-) RNA into (+) mRNA 10. Protein synthesis, (-) RNA genome replication 11. Virus assembly and budding
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1. Recognize the importance in seasonal trends for clinical diagnosis
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1. HPIV-1: fall; biannual
2. HPIV-3: spring-summer; annual 3. HPIV-2: fall; annual 4. HPIV-4: sporadic; low level 5. Circulates annually; late fall to early spring |
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What is the parainfluenza virus |
1. Four major serotypes (PIV 1-4)
2. PIV1: fall trend, every other year (odd numbered years) 3. PIV2: more erratic, usually fall (annual) 4. PIV 3 prolonged seasonal occurrence (spring/early summer) 5. Among most frequent cause of hospitalizations in children every year 6. Virtually all children infected with PIV 7. Main cause of acute laryngotracheitis (croup) 8. PIV1: associated with ~ 40% of cases 9. Symptoms 10. Main tropism/replication in ciliated epithelial cells 11. 2-7 day incubation period 12. Fever, runny nose, cough; can be PIV 1-4 13. Croup (most often PIV1, 2) 14. Pneumonia, bronchitis/bronchiolitis (most often PIV3) 15. Ear infection, irritability, decreased appetite 16. Young children more susceptible to severe illness |
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What is RSV (Respiratory Syncytial Virus) |
1. Prototype member of pneumovirus genus (another Paramyxovirus)
2. (-) RNA genome, unsegmented, helical capsid, enveloped 3. Strains A & B, based on viral G protein (A seems to be more severe) 4. Severe lower respiratory tract infection in infants 5. Mild upper respiratory tract infection in adults 6. Spread by aerosol droplets, close contact 7. Replication in URT and spreads to LRT 8. Infects through eyes, nose, mouth 9. Leading cause of viral bronchiolitis in infants 10. Leading cause of infant hospitalization 11. Symptoms 12. Can cause otitis media during infection 13. Severe disease in infancy is associated with cardiovascular disease, asthma and wheezing later in life 14. 30-40% of cases in children will show pneumonia/bronchiolitis 15. More dangerous for premature infants (immunosuppressed) 16. Adult infections typically mild URTI 17. Allows for reinfection throughout life 18. Increased Risk Groups 19. Infants < 6 months old 20. Children < 1 year born prematurely or with underlying CV conditions 21. Infants in crowded child care 22. Older adults, especially with asthma, CHF, COPD 23. Immunocompromised (child or adult) 24. Also can make more susceptible to middle ear infection (otitis media) 25. May be a link between severe RSV infection and asthma later in life |
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What is the metapneumovirus |
1. Newly recognized Paramyxovirus
2. 1st seen in 2001, Netherlands 3. Identified by RT-PCR sequencing 4. Ubiquitous, almost all children seropositive by age 5 5. Often causes dual infection with other respiratory pathogens 6. Causes asymptomatic infection, common cold type symptoms, bronchiolitis, pneumonia 7. Seronegative children, elderly, immunocompromised at risk groups |
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What is the Hendra virus |
1. First isolated in 1994, Brisbane, Australia (Hendra suburbs)
2. Outbreak of respiratory and neurologic disease in horses and humans 3. Reservoir: flying foxes (bats) which infected horses 4. Next spread to a couple workers who cared for sick animals 5. 7 human cases, 4 dead |
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What is the Nipah virus |
1. First isolated in 1999; Sungai Nipah village, Malaysia 2. Outbreak of respiratory illness and encephalitis in pigs and farmers 3. Reservoir: flying foxes (bats) on neighboring farm 4. Infected pigs and then to humans 5. 2001 outbreak in Bangladesh and India |
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Identify modes of virus transmission and how to best prevent infection for PIV |
1. Very contagious, especially in settings with children in close contact
2. Aerosol fomites from cough/sneeze, close personal contact 3. Followed by touching eyes, nose, mouth 4. PIV can stay airborne for over an hour, on surfaces for a few hours and remain infectious 5. Hand washing, avoiding contact with infected individuals, not touching eyes/nose/mouth most effective preventative measures 6. Direct detection of genomes by PCR 7. Collected within one week of symptom onset 8. Using immunofluorescence/ELISA 9. Isolation of virus in cell culture 10. Demonstrate rise in PIV specific IgG/IgM 11. No specific treatments |
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Identify modes of virus transmission and how to best prevent infection for RSV |
1. Replication in URT and spreads to LRT
2. Infects through eyes, nose, mouth 3. Another Paramyxovirus that infects virtually everyone the first few years of life 4. Leading cause of infant hospitalization 5. Results in ~ 1,500 deaths per year in U.S. 6. Clinical ID in infants relatively accurate; winter months 7. Older children/adults must confirm by lab testing 8. Most cases use only supportive care 9. No currently licensed vaccine 10. Killed vaccine (Salk-type 1960’s), discontinued 11. Several live-attenuated RSV vaccines being developed 12. Best prophylaxis: hand washing, avoidance |
