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Understanding the Global Impact of Influenza Pandemics

Explore the devastating effects of historical influenza pandemics like the Spanish Flu and Hong Kong Incident, and the current impact of Influenza on morbidity rates, hospitalizations, and mortality. Learn about the demand for influenza vaccines, historical outbreaks in India, and the emergence of Bird Flu, a highly contagious disease affecting both birds and humans.

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Understanding the Global Impact of Influenza Pandemics

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  1. MAGNITUDE OF PROBLEMDr. SK Pradhan Module-4

  2. Five leading causes of death by the year 2020

  3. Reichelderfer PS, Kendal AP, Shortridge KF, Hampson A. et al. Influenza surveillance in the Pacific basin. In: Current topics in medical virology 1988:412-38 Seasonal occurrence of Influenza Summary of influenza activity and occurrence in different climates

  4. An iceberg of viral disease1 in 7 is diagnosed

  5. True picture over the centuries "Russian" flu 1977 1968 "Hong Kong" flu 1957 "Asian flu" 1933 First human influenza virus isolated Epidemic recorded by Hippocrates 1918 Spanish influenza" killed 20-40 million people    1781 & 1830 412 B.C Epidemics spread across Russia from Asia Middle ages Numerous episodes described "Flu spreads across the world and ages" Murphy B.R., Webster R.G., Virology, IInd edition, New York, 1990, 1091-2 Ghendon Y. Introduction to pandemic influenza through history Eur Jour of Epid, 1994;10: 451-453

  6. Pandemic Influenza & the Specter of the 1918 Spanish Influenza • Global Impact • Half of 2 billion people on earth became infected • 20 - 40 (m) died • US Impact • 25 (m) cases, 500,000 deaths • 43,000 deaths in US armed forces (80% of battle deaths) • Hospitals overflowing, lack of medical services, social disruption

  7. Spanish Flu: 1918-19 (H1N1) • >500,000 deaths US • 20-50 million worldwide • Asian Flu: 1957-58 (H2N2) • 70,000 deaths US • Hong Kong Flu: 1968-69 (H3N2) • 50,000 deaths US Global Impact of Influenza Pandemics

  8. Impact of Influenza • Highest rates of complications and hospitalization among young children and person >65 years • Average of 114,000 influenza-related excess hospitalizations per year since 1969 • 57% of all hospitalizations among persons <65 years of age • Greater number of hospitalizations during type A (H3N2) epidemics

  9. Morbidity Associated with Influenza Episodes Kavet J. Am J Public Health 1977; 67: 1063.

  10. Epidemic Influenza Has a Huge Annual ImpactEstimates for the US • Cases: 25 – 50+ million cases • Days of illness: 100 – 200 million days • Work loss: Tens of millions • Hospitalizations: 100,000 – 300,000 • Deaths: 35,000 – 50,000 + • Costs: Billions of dollars

  11. Impact of Pandemic Influenza • 200 million people could be affected • Up to 40 million require outpatient visits • Up to 700,000 hospitalized • 89,000 - 200,000 deaths

  12. Spanish Flu and the Hong Kong Incident • As their lungs filled … the patients became short of breath and increasingly cyanotic. After gasping for several hours they became delirious and incontinent, and many died struggling to clear their airways of a blood-tinged froth that sometimes gushed from their nose and mouth. It was a dreadful business. Isaac Starr, 3rd year medical student, University of Pennsylvania, 1918.

  13. Spit spreads Death……. 1918-19

  14. Emergency hospital, Camp Funston, Kansas 1918 Courtesy of National Museum of Health and Medicine

  15. Demand for Influenza Vaccine 1947 New York Times photograph Nancy J. Cox, Ph.D. Chief, Influenza Branch, Centers for Disease Control and Prevention

  16. INDIA & INFLUENZA “ First cases appeared in Bombay in June 1918” “Some Deaths in Karachi & Madras” Martin Gilbert , First World War, Influenza, WWW spartacus.school net.co.uk

  17. INDIA & INFLUENZA Historians claim: Between June 1918 & July 1919 Over 16,000,000 Indians died of the Virus Martin Gilbert , First World War, Influenza, WWW spartacus.school net.co.uk

  18. INFLUENZA – Indian Scenario More than 400 million Indians suffer from Flu every year 900 million working hour lost dailyexcelsior.com Jyotsana Pandit, Fight against FLU: A Long Battle Ahead

  19. Influenza virus isolation AIIMS • Total Isolates: 101/1961 (5%) • H1N1: 29 • H3N2 : 35 • Inf B : 26 • To be typed : 11

  20. 2 peaks seen for positive influenza virus isolates: • Months of July and August which coincide with • rainy season in new Delhi • 2) Months of February and March which coincide with • winter season • Humidity levels (both Morning and Evening ) • seem to have positive co-relation with spurts of • influenza cases

  21. 200 No. of isolates Rainfall (mm) Relative Humidity (%) 180 160 140 No of isolates, Humidity (%) & Rainfall (mm) 120 100 80 60 40 20 0 Rainy season Hot season Cool season J F M A M J J A S O N D Human Influenza Surveillance at NIV, Pune, 1976-2002

  22. Month wise distribution of Influenza viruses New Delhi

  23. Multi-centric influenza surveillance network in India AIIMS V P Chest RMRC, Dibrugarh New Delhi IGGMC,Nagpur NICED, Kolkata Haffkine Inst.Mumbai NIV, Pune Regional Centers New Regional Centers CMC,Vellore KIPM, Chennai Referral Center

  24. Thank you

  25. Bird Flu • Also known as avian (bird) influenza (flu) • Highly contagious disease • Bird flu virus occurs naturally among birds • Wild waterfowl are known reservoirs (i.e. they carry the virus but do not get infected) • Highly pathogenic form of virus – a major concern today.

  26. The highly pathogenic form of avian influenza A was first recognized in Italy in 1878 • It is extremely • contagious and • rapidly fatal in • birds with a mortality • approaching 100%.

  27. Spread of Infection • Highly pathogenic avian flu (A/H5N1) currently circulating in poultry in Asia & Europe • Infected wild birds (waterfowl) shed influenza virus in their saliva, nasal secretions,feaces. • Domesticated birds like chicken and duck become infected on coming in contact with these secretions.

  28. How did it all start ? • 1997- H5N1 appeared in poultry in Asia caused only minor disease in poultry Virus mutated – highly pathogenic form killing chickens in less than 24 hours • 1st human case in Hong Kong 18 cases with 6 deaths • 1.5 million chickens culled • epidemic prevented • Became quiescent till 2003

  29. 2003 – became highly and widely visible • Dec. 2003 – unexplained chicken deaths in Korea • Samples sent to Paris - H5N1 • Jan 2004 – High alert issued by WHO • 5th Jan – Vietnam reports 11 children affected (7 died) • Large poultry deaths also observed in Southern Province • 12th Jan – Japan reports H5N1 in poultry

  30. 14th Jan – WHO alerts Global Outbreak Alert & Response Network (GOARN) • 23rd Jan – Thailand reports first case in human and poultry • Subsequent reports from Cambodia, Laos, Indonesia and China • Became clear this type of infection was historically unprecedented

  31. With the onset of summer felt that infection would wane • July – fresh outbreaks reported in Cambodia, China, Indonesia, Thailand, Vietnam and Malaysia • Subsequently reported from Russia, Europe and Egypt • 18th Feb 2006 India reports first case in birds from Navapur, Maharastra

  32. Phase 1 SE Asia 1996–2005 • Very few wild bird deaths • Closely associated with outbreaks in poultry • Not migrants: mostly scavengers that feed at farms • Died close to source of infection

  33. Phase 2 Summer 2005 Spread west-central Asia • Outbreaks mainly in poultry • Did not follow migration route or occur at migration time • Followed major transport routes

  34. Phase 3 Autumn 2005 Eastern Europe • Major outbreaks in poultry around the Black Sea • Some continuation in Russia • Wild birds: mainly small numbers of Mute Swans, but hundreds died over short periods near Caspian and Black Seas, suggesting locally-acquired infection

  35. Phase 4 Jan-March 2006 Wild birds & poultry in Europe • Persistent poultry outbreaks in Turkey and Romania; fewer in Ukraine • Widely scattered deaths of small numbers wild birds (mainly Mute Swans & few ducks) • Bigger outbreaks Rügen Island, Germany; poultry in Ain, France • Suggests dispersal from freezing conditions around Black Sea, followed by a few secondary infections

  36. Phase 5 February 2006 Africa and India • Outbreaks in Africa and India/Pakistan • Poultry only • Nigerian government believes due to smuggling poultry • No evidence of wild bird involvement; not at migration time

  37. Avian Influenza in Humans (H5N1) * Till 2 October 2007 reported to WHO

  38. India • Feb. 18, 2006 • First reports of H5N1 in Domestic Poultry in 2 Districts of Maharashtra • July 26, 2007 • Epidemic in backyard poultry in East Imphal District of Manipur • No Human case reported so far

  39. H5N1 : Why the panic? • Highly pathogenic strain • Unique capacity to jump the species barrier • Transmission from one person to another is possible • Humans would have little or no immunity nor would the existing vaccine be effective • H5N1 replicates in a wide range of cell types resulting in disseminated disease

  40. Usually bird flu does not infect humans Current strain of Avian flu has shown ability to transmit from poultry to people More than 200 confirmed cases of human infection with avian flu virus since 1997 More than half of people infected have died. Implications to human health

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