II. Pathophysiology
- Paramyxovirus characteristics
- Single stranded, negative sense RNA virus
- Helical symmetry
- Fusion Protein (F Protein)
- Induces infected host cells to fuse together in multinucleated giant cells (syncytial cells)
- F Protein is also found in Herpesvirus and Retrovirus
- Paramyxovirus organisms are similar to Orthomyxovirus (Influenza)
- Both replicate in the upper respiratory tract, binding to 2 Glycoprotein receptors by 1 spike Protein (HN)
- Hemagglutinin Activity (HA)
- Neuraminidase Activity (NA)
- However and in contrast to Orthomyxovirus
- Paramyxovirus HA and NA Glycoproteins are on the same surface spikes (HN)
- Single stranded (non-segmented RNA), unlike Orthomyxovirus RNA (segmented into 8 bound strands)
- Fusion Protein is not found in Orthomyxovirus
- Both replicate in the upper respiratory tract, binding to 2 Glycoprotein receptors by 1 spike Protein (HN)
III. Types: Important Paramyxoviridae in Human Disease
- Systemic, hematogenous spread (viremia) AND Vaccine preventable diseases (MMR Vaccine)
- Measles
- Prodromal Upper Respiratory Infection (cough, Coryza, Conjunctivitis) and high fever
- Morbiliform rash spreading from head to trunk to extremities (inc. palms, soles), mouth Koplik Spots
- Complicated by Pneumonia, Myocarditis, Glomerulonephritis, Encephalitis (and death in 0.1%)
- Mumps
- Prodromal fever, malaise, myalgias, then Parotitis, Orchitis and variable maculopapular truncal rash
- Complicated by Male Infertility, Meningitis/Encephalitis, Deafness
- Measles
-
Bronchiolitis, Viral Pneumonia and croup in children (Upper Respiratory Infections in adults)
- Metapneumovirus
- Reclassified as of 2016 into the family Pneumoviridae
- Parainfluenza VIrus
- Respiratory Syncytial Virus
- Differs from other Paramyxoviridae, in that it lacks the HN Glycoproteins (HA, NA)
- Metapneumovirus
IV. References
- Gladwin, Trattler and Mahan (2014) Clinical Microbiology, Medmaster, Fl, 245-9
- Park (2023) Paramyxovirus, StatPearls +PMID: 33620863 [PubMed]