Medical Microbiology Department of Microbiology HMU n n
Medical Microbiology Department of Microbiology, HMU
n n 80 -120 nm -ss. RNA，分节段 甲、乙型8个节段 丙型7个节段 n 8 Structural proteins: u Glycoproteins v v u u M 1, M 2 8 nucleocapsid segments v n n HA (H 1 -H 15) NA (N 1 -N 9) RNA, NP, PB 1, PB 2, PA HA-attachment to receptors, initiation NA-degradation of receptors, release
Influenza pandemics associated with antigenic shift
Influenza pathogenesis n n n Transmission Aerosoles Infection Epithelial cells Replication cycle 4 – 6 h Cell death Necrosis, apoptosi s Incubation 18 – 72 h PBMC Non-productive
Influenza natural course
Primary influenza pneumonia
Influenza - diagnosis • Specimens: throat swabs, NPS, nasal aspirates, sputum • Culture: conventional, rapid • Direct detection (EIA, IF, PCR) • Serologic response: 4 -fold or greater rise in Ig. G titers
Treatment: Amantadine n bind M 2 protein, inhibit uncoating n selective – influenza A n reduce symptom score n Disadvantages : u side effects – CNS u drug-resistance
NA Inhibitor n zanamivir, oseltamivir Sialic acid analogues, Inhibit influenza A, B n Highly effective if started early, effective in prophylaxis
SARS Genome
Summary: Respiratory Infected Viruses n Orthomyxoviruses u Influenza n viruse n Rubella virus n Coronavirus and SARS Coronavirus n Adenoviruses Paraomyxoviruses u Measles virus u Parainfluenza u Respiratory syncytial virus u Mumps virus
Influenza Viruses n Orthomyxoviruses: Influenza Viruses n A middle-sized enveloped virus with fragmented RNA genome
Variation n There two surface proteins in the surface of the envelope. HA is the main neutralizing antigen u Hemagglutinin u neuaminidase n Since the highly variation of the genome, Influenza happens frequently due to people have no immunity to the mutated viruses
Other Respiratory Infected Viruses n Paraomyxoviruses u Measles virus u Parainfluenza u Respiratory u Mumps virus syncytial virus n Rubella virus n Coronavirus and SARS Coronavirus n Adenoviruses
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