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Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

Viruses causing respiratory infections. Influenza viruses. Paramyxoviruses. Measles and mumps viruses. Vinnitsa National Pirogov Memorial Medical University / Department of microbiology. Classification of an Orthomyxoviridae.

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Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

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  1. Viruses causing respiratory infections. Influenza viruses. Paramyxoviruses. Measles and mumps viruses. Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

  2. Classification of an Orthomyxoviridae Family Orthomyxoviridae includes three pathogenic for human species: • Influenza virus A • Influenza virus B • Influenza virus C

  3. Influenza virus

  4. Antigenic structure of influenza virus Internal antigens (S-antigen) • Ribonucleoprotein (RNP) • M-protein from inner layer of envelope External antigens (V-antigen) • Hemagglutinin (HA) • Neuraminidase (N)

  5. Antigenic variation of influenza virus • Antigenic variability may be of two different types: • Antigenic drift • Antigenic shift

  6. Epidemiology of the flu • The source of infection may be: • Infected person • Wild and domestic birds • Domestic animals • Characteristics of the viruses have caused the most famous pandemics: • In 1917-1919 “Spanish flu” was caused by A (H1N1) virus • In 1957 “Asian flu” was caused by A (H2N2) virus • In 1968 “Hong Kong flu” was caused by A/Hong Kong (H3N2) • In 1977 “Red flu” was caused by A (H1N1) • From 1968 and 1977 pandemics both types (H1N1 and H3N2) have been circulated together

  7. Endemic influenza annually in the US1 • 5% to 20% of the population gets the flu • More than 200,000 people are hospitalized from flu complications • About 36,000 people die from flu • Avian Influenza, cumulative data2 • 379 cases reported, 239 deaths (63%) • 2008: 28 cases / 22 deaths • 1http://www.cdc.gov/flu/keyfacts.htm • 2APR 08, WHO

  8. Avian Influenza, cumulative data2 379 cases reported, 239 deaths (63%) 2008: 28 cases / 22 deaths

  9. Laboratory diagnostics • Collected samples are nasal or throat swabs, nasal or throat washing, sputum, nasal prints • Rapid tests are based on the demonstration of the virus antigens in the collected material. They include: • Direct immunofluorescence • Reversed indirect hemagglutination test (RIHA) • FLU OIA and QUICKVUE Influenza Test are based on detection of the viral antigens with monoclonal antibody • ZSTATFLU is based on detection of viral neuraminidase with colored substrate of the enzyme

  10. Laboratory diagnostics • Microscopy • Isolation of the virus (culture or virological method) • Serology (serological method)

  11. Laboratory diagnostics of the flu Immunofluorescence Virus inoculation into chicken embryo

  12. Specific prophylaxis • Specific prophylaxis is immunization with subunit influenza vaccines 3-4 weeks before predictable onset of epidemic (Fluarix, Influvac, Vaxigrippe, Grippol and others).

  13. Paramyxoviruses • Family Paramyxoviridae • Subfamily Paramyxovirinae includes three genera: • Respirovirus (four serotypes of parainfluenza viruses) • Morbillivirus (measles virus) • Rubulavirus (mumps virus) • Subfamily Pneumovirinae contains one genus Pneumovirus (respiratory syncytial virus)

  14. Structure of a paramyxovirus

  15. Antigenic structure and biological features Outer antigens:HN and F Inner antigens:RNP and M-protein

  16. Epidemiology and pathogenesity Parainfluenza viruses cause croup (acute laryngotracheo-bronchitis), laryngitis, brochiolitis and pneumonia in children and a disease resembling the common cold in adults. They are responsible for 50-80% of respiratory tract infections Measles virus causes measles Mumps virus causes mumps The source of infection is an ill person Paramyxoviruses are transmitted via respiratory droplets (airborne diseases)

  17. Maculopapular rash (measles)

  18. Laboratory diagnostics • Rapid tests: • Immunofluorescence test • Cytoscopy • Culture method • Serological investigation

  19. Treatment and prophylaxis Prophylaxis is made by immunization with alive attenuated vaccine For current prophylaxis in pregnant women, children with immunodeficiency anti-measles and normal human immunoglobulin are used

  20. Mumps: clinical findings and immunity • Mumps is acute infectious disease commonly affecting children and characterized by nonsuppurative enlargement of parotid glands

  21. Laboratory diagnostics • Virus isolation (culture method) • Serological tests Prevention of mumps may be done with alive attenuated vaccine Current prophylaxis is possible with either alone vaccine (active immunization) or normal human immunoglobulin (passive immunization)

  22. Parainfluenza virus • Type 1 and type 2 cause croup ( acute laryngotracheobronchitis) in children • Type 3 cause tracheobronchitis, bronchiolitis and pneumonia in children before 5 years. • Type 4 provokes mild respiratory infections Laboratory diagnosis is based on virus isolation from throat and nasal swabs. Serological tests with paired sera can confirm diagnosis by 4-fold and greater rising of antibody titer

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