Coronaviruses Notes

NOTES NOTES CORONAVIRUSES MICROBE OVERVIEW ▪ Causes respiratory infections ▪ OC43, NL63: most common strains of human coronaviruses (HCoV) ▪ Associated clinical syndromes: common cold, pneumonia, bronchitis, Middle East respiratory syndrome (MERS-CoV), severe acute respiratory syndrome (SARS-CoV) Genetic material ▪ Positive-stranded RNA viruses Taxonomy ▪ Corona: crown; named after spiked appearance in electron microscopy ▪ Genera: alpha, beta (human pathogens), gamma, delta 364 OSMOSIS.ORG Morphology ▪ Helical capsid; enveloped (outer lipid membrane) ▪ Structural proteins ▫ Small envelope protein (E) → viral assembly ▫ Hemagglutinin esterase protein (HE) → binds to cell membrane (beta coronaviruses only) ▫ Membrane protein (M) → viral assembly ▫ Nucleocapsid protein (N) → forms nucleocapsid ▫ Spike protein (S) → binds, fuses with host cell membrane

Chapter 66 Coronaviruses CORONAVIRUS (SARS) osms.it/coronavirus-SARS PATHOLOGY & CAUSES ▪ Causes severe respiratory syndrome (SARS) ▪ B-beta coronavirus: viral pulmonary disease ▪ Viral inoculation of respiratory tract mucosa → cell damage → release of cytokines (interferon-gamma, IL-1, IL-6, IL-12) → inflammation, ↑ secretions ▪ Incubation period: 2–7 days CAUSES ▪ Direct contact, airborne droplets, fomites RISK FACTORS ▪ Immunosuppression, healthcare-related occupation, comorbid conditions COMPLICATIONS ▪ Acute respiratory distress syndrome, multiorgan failure SIGNS & SYMPTOMS ▪ Prodrome: fever, malaise, headaches, myalgia, chills ▪ Non-productive cough, dyspnea, chest pain ▪ Diarrhea, rhinorrhea, sore throat ▪ Interstitial pulmonary infiltrates LAB RESULTS Histologic pulmonary tissue observation ▪ Hyaline membranes, edema, fibroblast proliferation Reverse-transcriptase polymerase chain reaction (RT-PCR) ▪ Nasopharyngeal, oropharyngeal, stool, serum samples Serologic tests ▪ Enzyme-linked immunosorbent assays (ELISA) ▪ Fluorescence antigen detection assays Lab tests ▪ Lymphopenia, thrombocytopenia, ↑ lactate dehydrogenase (LDH), ↑ alanine aminotransferase (ALT) TREATMENT OTHER INTERVENTIONS ▪ Mechanical ventilation in respiratory failure Prevention ▪ Hand washing ▪ Proper disposal of infected materials (e.g. used tissues) ▪ Mask use within healthcare environment DIAGNOSIS ▪ Center for Disease Control and Prevention (CDC) ▫ No alternative diagnosis after 72 hours of clinical evaluation ▫ Individual at risk DIAGNOSTIC IMAGING Chest X-ray OSMOSIS.ORG 365