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Explore the structure and impact of Rhinoviruses, known for causing the common cold. Learn about their replication process, transmission, and implications for cold weather infections.
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Medical Microbiology Chapter 57 Picornaviruses - Rhinoviruses
Rhinoviruses • Pico-rna-viruses • Rhinoviruses cause the common cold • Structure: • Naked virus • Single-stranded RNA genome (linear) • Plus-strand of RNA (essentially an mRNA) • Contains 7200-8450 bases with a poly-A tail • The genome alone is able to cause infection • Human Rhinoviruses consist of at least 100 different serotypes • Importance in cold recurrence • Vaccine?
Rhinoviruses • Infection may be initiated by as few as 1 virus • Attachment occurs through the ICAM-1 molecule on epithelial cells • Viral replication shuts down normal cellular RNA and protein synthesis • This is the primary cause of pathology • Infected cells release inflammatory chemicals which stimulate nasal secretions (“runny nose”) • Viruses are shed in nasal secretions (500-1000 viruses/ml)
Rhinoviruses • The viruses replicate poorly at above 33º C • Confined to upper respiratory tract • Implications for cold weather infections? • Transmission – virus can be passed by aerosols or contact with fomites (naked virus) • Hands seem to be the major mechanisms of transmission • Box 57-5 and 57-6 • Info. from other text