respiratory viruses 2 Flashcards
- List the viruses that commonly cause disease in the respiratory tract and describe each of them and the diseases they cause.
- Rhinovirus- plus stranded ssRNA, naked. 2. parainfluenza viruses 1-4: minus ssRNA, enveloped. 3. respiratory syncytial virus: minus ssRNA, enveloped. 4. Metapneumovirus: minus ssRNA, enveloped. 5. Corona viruses (SARS and MERS): plus ssRNA, enveloped. 6. adenovirus: dsDNA, naked. 7. Parvovirus (boca): ssDNA, naked. 8. Polyomavirus: dsDNA, naked
- Describe the availability of vaccines or drugs against these respiratory viruses.
Influenza A and B: live attenuated vaccine. RSV: new vaccine coming. Adenovirus: yes for some strains (military)
describe a cold
Infection of epithelial cells only. Short incubation (1-2 days). Many viruses block interferons. Induces cytokines, then secretory IgA. Reinfections are common and often many virus serotypes
Rhinovirus structure/ characteristics
Picornaviruses. Small, + strand RNA, Icosohedral capsid, Temperature sensitive, Acid labile, >100 serotypes
Rhinovirus hallmarks
single open reading frame. Polyprotein. Protease processed to give capsid and polymerase proteins. All rhinoviruses use either of only 3 receptors
ICAM-1 or LDL-R or carbohydratesingle open reading frame. Polyprotein. Protease processed to give capsid and polymerase proteins. All rhinoviruses use either of only 3 receptors
ICAM-1 or LDL-R or carbohydratesingle open reading frame. Polyprotein. Protease processed to give capsid and polymerase proteins. All rhinoviruses use either of only 3 receptors
ICAM-1 or LDL-R or carbohydrate
Rhinovirus clinical features
Group A and B rhinoviruses are heat sensitive and inactivated by acid pH, so they grow only in upper respiratory tract. Group C can grow in lower respiratory tract Can cause common colds, bronchiolitis, influenza like illness, bronchopneumonia in infants and exacerbation of asthma (human rhinovirus-C)
Rhinovirus treatment
Symptomatic treatment with antihistamines. Inhibitors of 3C protease that processes polyprotein. Inhibitors of receptor-induced conformation change in capsid
List the members of the paramyxoviridae group
parainfluenza virus, Pneumovirus (RSV), metapneumovirus (HMPV), morbillivirus (measles), rubulavirus (mumps) and henipavirus
Structure of paramyxovirus
helical nucleocapsid. ssRNA (minus sense). Hemagglutinin and Fusion proteins.
Describe trxn of viral minus strand RNA
minus strand RNA > template RNA (+) and mRNA. Template (+) RNA gets converted back into minus strand RNA. mRNA gets translated
parainfluenza virus structure
large, enveloped ssRNA (minus sense) with helical nucleocapsid. Hemagglutinin mediates entry and destroys virus receptor from cell membranes. Fusion proteins mediate membrane fusion of respiratory cells to cause syncytia formation (giant cells) and virus infection.
Parainfluenza virus clinical features
Parainfluenza viruses 1 and 2 can cause croup, laryngotracheitis, in infants and young children, but usually just colds in adults. Parainfluenza virus 3 causes colds in adults and can cause bronchopneumonia in infants and young children. Therefore it is an important goal to develop a
PIV3 vaccine. Parainfluenza virus 4 (subtypes a and b) is associated with mild upper respiratory disease, but is less common than PIV1 and 3.Parainfluenza viruses 1 and 2 can cause croup, laryngotracheitis, in infants and young children, but usually just colds in adults. Parainfluenza virus 3 causes colds in adults and can cause bronchopneumonia in infants and young children. Therefore it is an important goal to develop a
PIV3 vaccine. Parainfluenza virus 4 (subtypes a and b) is associated with mild upper respiratory disease, but is less common than PIV1 and 3.Parainfluenza viruses 1 and 2 can cause croup, laryngotracheitis, in infants and young children, but usually just colds in adults. Parainfluenza virus 3 causes colds in adults and can cause bronchopneumonia in infants and young children. Therefore it is an important goal to develop a
PIV3 vaccine. Parainfluenza virus 4 (subtypes a and b) is associated with mild upper respiratory disease, but is less common than PIV1 and 3.
List the viruses that cause bronchiolitis, bronchopneumonia and croup in young kids
bronchiolitis: RSV. Bronchopneumonia: parainfluenza virus 3, RSV. Croup: parainfluenza virus 1 and 2
vaccines for paramyxoviridae
Measles and mumps: live attenuated virus. Parainfluenza virus 3: clinical trials. RSV: prophylactic passive immunization with RSV neutralizing monoclonal ab against F glycoprotein. New active vaccine in trials
RSV clinical features
colds in adults and older kids. Bronchiolitis and bronchopneumonia in infants <1 yr. Can predispose to asthma.
RSV pathogensis
Fusion proteins on viral surfaces causes membranes of nearby cells to fuse, forming syncytia
RSV risk factors for death
prematurity, bronchopulmonary dysplasia, cardiac abnormalities
Metapneumovirus clinical features
Interstitial pneumonia in adults. Wheezing and asthma may follow
Structure of coronaviruses
Large, enveloped ssRNA (positive sense) with helical nucleocapsids.
List the types of coronaviruses
alpha: 229E and NL63. Beta: OC43 and HKU1 in lineage a, zoonotic SARS-CoV in lineage b and zoonotic MERS-CoV in lineage C
Coronavirus clinical features
URIs in children. LRIs in elderly/immunocompromised.
- Describe SARS coronavirus and the disease it caused in 2002-3, its epidemiology, global spread and mortality rate.
SARS caused severe lower respiratory tract disease/ acute interstitial pneumonia with 50% fatality in people > 65 yrs and case/fatality ratio of 10%. It came from bats and spread from southern China to 29 countries. It was spred via respiratory drops and fecal
- Explain the likely source of the SARS coronavirus and what was done to prevent the virus from becoming established as a common human respiratory pathogen worldwide.
It came from himalayan palm civets or raccoon-dogs, originally from a bat It was eliminated from human population by une 2003 due to coordinated global survellance and quarantine/ isolation of all victims and exposed persons
describe MERS
is currently causing sporadic infections and
hospital-acquired infections of fever, cough and shortness of breath, particularly in elderly people with underlying clinical conditions such as diabetes, obesity etc. Primary case in Arabian peninsula. secondary cases on every continent. High case fatality rate.is currently causing sporadic infections and
hospital-acquired infections of fever, cough and shortness of breath, particularly in elderly people with underlying clinical conditions such as diabetes, obesity etc. Primary case in Arabian peninsula. secondary cases on every continent. High case fatality rate.
