Diagnosis and Management of Influenza

1. Diagnosis and Managementof Influenza A/Prof. Michael Nissen Director of Infectious Diseases & Clinical Microbiologist Royal Children’s Hospital-Brisbane Queensland Children’s Medical Research Institute University of Queensland Herston, Qld. Australia http://www.uct.ac.za/deps/mmi/stannard/fluvirus.html

2. Overview • Influenza infection • Diagnosis of influenza • Clinical • Laboratory • Management of influenza • Infection Control • Antivirals • [Vaccines] http://www.uct.ac.za/depts/mmi/stannard/fluvirus.html

3. Influenza Orthomyxoviridae -ssRNA virus [8 segments], 14kb, enveloped, 80-120nm http://www.uq.edu.au/vdu/VDUInfluenza.htm

4. Influenza • Acute respiratory and systemic disease caused by infection with influenza type A, type B and influenza type C viruses. • Influenza A viruses sub grouped on the basis of their surface haemagglutinin (H) & neuraminidase (N) glycoproteins. • Influenza A subtypes currently circulating most widely in humans are A (H1N1) & A(H3N2). • Aquatic birds are primary reservoir for influenza A viruses but also circulate among other animals including pigs, horses & seals. • Humans are the primary reservoir for influenza B viruses.

5. Influenza type A • Subtype variation: • 16 different haemagglutinin(HA) types: H1-16 • 9 different neuraminidase (NA) types: N1-9 • Recombination of HA and NA possible. • H1N2 H3N8 H6N9 H11N1 • H2N1 H4N6 H7N2 H11N8 • H2N2 H4N8 H7N3 H11N9 • H2N9 H5N1 H7N7 H12N4 • H3N2 H5N3 H8N4 H13N6 • H3N3 H6N1 H9N2 H14N1 • H3N6 H6N2 H10N3 H15N2 • Strain variation: • Point mutations create variation within subtypes

6. Influenza • Influenza A and B viruses cause seasonal epidemics with winter peaks in temperate zones and year-round circulation in the tropics with rainy season and dry season peaks in activity. • A & B viruses continually evolve by accumulation of mutations leading to antigenic drift of the H and N glycoproteins. • A viruses also evolve by reassortment leading to novel influenza A viruses and potential influenza pandemics if the novel virus spreads in a sustained manner through largely susceptible populations.

7. Seasonal Distribution of Influenza A & B in Queensland 2005 2006 2007 2008 30.0 25.0 Influenza A % Positive of Total Tested Su Au Wi Sp Su Au Wi Sp Su Au Wi Sp Su Au Wi Sp S 12.0 Influenza B

8. Reassortment of Influenza A strains

9. Influenza • The spectrum of influenza infection is wide: • nonfebrile, mild upper respiratory tract illness, • febrile influenza-like illness (ILI) • severe & fatal complications. • Greatest burden of illness usually occurs among children. • Greatest severe disease [hospitalization & death]: • underlying medical conditions, infants-young children & elderly.

10. Fatal H1N1 Viral Pneumonia

11. Clinical diagnosis of Influenza • Influenza Like Illness [ILI] • Fever, cough, sore throat, rhinorrhea, headache, myalgia & malaise • NO shortness of breath, NO dyspnoea • Some or all symptoms • GIT symptoms without dehydration-especially children

12. Seasonal Distribution of Respiratory Viruses in Qld 2005 2006 IA IB PIV1 PIV 2 PIV 3 ADV RSV HMPV summer autumn winter spring summer autumn winter spring 2008 2007

13. Diagnosis of Influenza in Adults

14. Adults risk factors for influenza

15. When to test for Influenza in Adults

16. Influenza in children

17. Childhood Influenza Risk Factors

18. Diagnostic tests for Influenza

19. Specimen collection Nasopharyngeal aspirates are collected from patients and are still considered the specimen of choice

20. Diagnostic settings for Influenza WHO 2010

21. Impact of Molecular Testing @ PathQld 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 Number of Samples Increase = 12 to 43% per year • The introduction of real-time PCR for respiratory viruses has provided significant additional benefits to our organisation • Improved diagnosis (greater sensitivity & specificity) • Improved turn around times for results (3 – 24 hours) • Reduced costs; particularly labour component • Better patient care (positive diagnosis/limit use of antibiotics) • Changed barrier nursing practice

22. Testing Algorithm for Influenza Until April 2009, the influenza A testing protocol utilised primers and probes targeting the gene coding for the matrix protein* Assay was validated against: H1N1, H2N1, H2N2, H3N2, H4N6, H5N1(3)*, H5N3,H6N1, H7N7, H9N2, H11N1 * Vietnamese (2); Indonesian (1) strains Specimens for clinical diagnosis of Influenza are tested by the duplex real-time PCR assay for INF A & INF B Any Influenza A-positive samples are then screened further with a second H5N1-specific assay targeting the haemagglutinin gene. All positive specimens are forwarded to the QH Public Health Virology laboratory for Influenza typing and confirmation of any H5N1 result All positive isolates are forwarded to the WHO Collaborating Centre for Reference and Research on Influenza, Melbourne. *Whiley et al. Diagnostic Microbiology and Infectious Disease 53 (2005) 335–337

23. QPID matrix assay Previous matrix assay H3N2 H3N2 H5N1 H5N3 H7N7 H9N2 H5N1 H5N3 H7N7 H9N2

24. 24 April, 2009 The Australian National Incident Room (NIR) was notified by WHO on 24 April 2009 of outbreaks in Mexico & USA of a novel strain of A/H1N1 influenza (Swine flu). • H1N1 influenza 09 was a novel influenza A virus infecting humans. • H1N1 influenza 09 appeared to be formed through reassortment of human and swine-origin influenza strains, creating a virus against which humans have little or no immunity.

25. Friday 24 April Monday 27 April Wednesday 6 May Assay validated Transferred to PQ Assays designed Publication submitted

26. Friday 24 April Monday 27 April Wednesday 6 May Thursday (night) 7 May Saturday 9 May Assay validated Transferred to PQ PQ Detected First positive case in Australia Positive result confirmed by WHO, Melbourne Assays designed Publication submitted

27. Respiratory virus PCR Requests 2006 – 2009 at PQ Central 37,263 10832 H1N1 requests 27/04 – 15/09 Respiratory virus PCR requests

28. Management of Influenza • Infection Control • Antivirals • [Vaccines]

29. Infection Control • Appropriate infection control measures • (Standard plus Droplet Precautions) • should be adhered to at all times. • Whenever performing high risk • aerosol-generating procedures (e.g. • bronchoscopy or any procedure involving • aspiration of the respiratory tract) • use a particulate respirator (N95) • Eye protection, gowns, and gloves and carry out the procedure in an adequately ventilated room, either naturally or mechanically. • Don’t forget handwashing and cough etiquette! WHO 2009

30. Infection Control • The duration of isolation precautions for hospitalized patients with influenza: • 7 days after onset of illness or • 24 hours after the resolution of fever and respiratory symptoms, whichever is longer, while a patient is in a health-care facility. • For prolonged illness with complications (i.e. pneumonia), control measures should be used during the duration of acute illness (i.e. until the patient has improved clinically). • Special attention is needed in caring for immunosuppressed patients who may shed virus for a longer time period and are also at increased risk for development of • antiviral-resistant virus WHO 2009

31. Antiviral medications

32. Antivirals for Influenza

33. Mode of action

34. Neuramidase inhibitors

35. Oseltamivir

36. Oseltamivir

37. Oseltamivir

38. Antiviral medications

39. Conclusion • Influenza diagnosis is dependant on clinical findings supported by known epidemiology & laboratory identification during epidemics and pandemics. • Molecular techniques such as PCR have revolutionised approach to influenza epidemiology, diagnosis and treatment. • Antivirals assist in controlling complications of influenza in seasonal epidemics and pandemics.

40. Thank you for your attention Brisbane-Australia

42. Royal Children’s Hospital-Brisbane

43. Diagnostic tests for Influenza

45. RIDT Mode of action

46. Rapid Influenza Diagnostic Tests