Transmission & Staging (H1N1)v Pandemic

1. www.drsarma.in H1N1v Transmission & Staging (H1N1)v Pandemic Dr. R V S N Sarma., MD., MSc. (Canada), FIMSA Consultant Physician & Chest Specialist

2. Acknowledgement • To compile this comprehensive presentation many resources on the internet are reviewed and relevant material like text, pictures, images, diagrams etc., are incorporated. • The main objective is to share the wide knowledge, at this hour of need, with all the physicians I come across and in turn help the patients and the community at large. • Scientific information from CDC, WHO, NIH, ECDC, BMJ, NEJM, Flu watch, SEARO, MOHFW, NCDC (NICD) is invaluable. • I record my sincere thanks and acknowledge using these resources. The references are listed at the end.

3. What Should be Our Approach? Essential – Positive – Constructive Approach • Adequate awareness in general public – preventive measures • Comprehensive knowledge for the healthcare providers • Appropriate planning and responsibility of all involved Unwarranted – Misleading – Dangerous – Negative reactions • Fear, minute to minute monitoring of deaths, rumors • Media hype, Anxiety about infection and death by this flu • Panic, mania of mask use by one and all, and worry

4. Types of Human Flu • Influenza A • Common, More Severe, Several Sub-types • Epidemics, Pandemics,  Mortality, High Mutagenicity • Influenza B • Less Severe, Less Frequent, No Sub types, Faithfully Human • Influenza C • Mild, Rare, No Sub types, Non fatal, Mild Illness in Children • Common Cold – Coryza & Other Viruses – Not Flu

5. Influenza v/s Common Cold

6. Influenza A Virus Types Neuraminidase (N) For Detachment Hemagglutinin (H) for Attachment • Orthomyxoviridae Family • Single stranded RNA virus • High mutagenicity, 8 proteins • H Ag types are 16 • N Ag types are 09 • So, 16 x 9 = 144 types possible • But only 3 types infect Humans • H1N1, H2N2 and H3N2 • Avian Flu Virus is H5N1 • Virus H1N1 - ‘Swine Flu’ Misnomer • Present Pandemic – (H1N1)v

7. Seasonal v/s Pandemic Flu

8. Avian, Swine and Human Flu Viruses

9. The Novel H1N1 Virus • Orthomyxoviridae Family • Single Stranded RNA virus • High mutagenicity • Two viruses co-infect the same cell • New virus with segments of both • A mix of Avian, Swine and Human • This is genetic reassortment • Doesn’t require pigs as intermediary • ‘Swine Flu’ is now named H1N1v • Present Pandemic – (H1N1)v • This is less virulent than H5N1

10. Antigenic Shift Antigenic Drift

11. Seasonal Epidemic Flu v/s Pandemic H1N1

12. Influenza Pandemics

13. How Serious is the Current pandemic ? • We’re still learning about the severity of the novel H1N1 • At this time, there is not enough information to predict how severe this novel H1N1 flu outbreak will be in terms of illness and death or • It compares very similar to seasonal influenza. • Luckily most cases have been mild. Only few fatal cases • Most people recover without hospitalization or Tamiflu • It may mutate eventually and become more / less serious.

14. Clinical Attack Rate

15. Idealized National Curve For Planning Second Wave

16. Global Scenario of the Current Pandemic CFR = (6260 ÷ 5,03,536) x 100 = 1.243%

17. Global Picture of the Pandemic

18. H1N1 in India As on 08thNovember 2009

19. Natural History of H1N1v Mortality Rate = 150 ÷1,00,000 = 0.15% 1,00,000 50,000 Clinical Attack Rate = 10,000 ÷ 50,000 = 20% 10,000 1,000 CFR = 150 ÷ 10,000 or 1.5% 150

20. Influenza A H1N1 Status as on 11th November 09 CFR = (508 ÷ 14851) x 100 = 3.42 %

21. Symptoms of H1N1 Pandemic Flu • Very Similar to the Seasonal Flu and Not like Common Cold • Moderate to high fever • aches, muscle and joint pains • chills and fatigue • sore throat, head ache • cough • sneezing and running nose • shortness of breath, chest pain on breathing • diarrheas and vomiting (possible), loss of appetite

22. When to Suspect H1N1 ? • Onset of acute febrile respiratory illness within 7 days of close contact with a person who has a confirmed case of H1N1 influenza A virus infection, or • Onset of acute febrile respiratory illness within 7 days of travel to a community (within the United States or internationally) where one or more H1N1 influenza A cases have been confirmed, or • Acute febrile respiratory illness in a person who resides in a community where at least one H1N1 influenza case has been confirmed.

23. Clinical Presentations(in non-fatal cases)

24. Age and Gender Distribution

25. Epidemiological Parameters

26. Global Experience of the Pandemic • Secondary attack rate in household contacts: 12 %. • Overall proportion of hospitalizations: 8 %. • Overall case fatality: 0.15 % or 1.5 per every 1000 cases • Most cases (58 %) highest incidence in 5–24 years age group, • Second highest incidence in children < 5 years • Most hospitalizations (34 %) in 5–24 years age group, • Highest age-specific hospitalization rate in children < 5 years • Most deaths in 5–24 years age group • The old are generally spared > 65

27. The Current H1N1 Virus • Cocktail mix of Porcine, Avian and Human Influenza A Virus • Direct Airborne, No other routes so far • Fine droplets expelled during coughing and sneezing • Expectorated sputum and the dried secretion • Indirect - All items that have been in contact with a patient (Fomite) • Incubation Period (IP) – 3 to 7 days – Median 2-3 days • Contagious period – One day before symptoms to 7 days • Asymptomatic carrier state – None • Immunity – Life time for this type; No protection by seasonal flu

28. Isolation and Quaranteen Isolation • Separation and restricted movement of ill persons with contagious disease, often in a hospital setting • Primarily individual level; Can be voluntary or mandated Quarantine • Separation and restriction of movement or activities of persons who are, not yet ill, have been exposed • Often at home, or residential facility or hospital Individual or community level; Can be voluntary or legally mandated

29. Transmission

30. Transmission

31. Transmission

32. The Aaa-chooh – (Sneezing)

33. High Risk Groups for H1N1 • Diabetes • Pregnancy • Chronic Respiratory Illnesses , Neuromuscular disorders • Chronic cardio-vascular disease (? hypertension) • Seizure disorder and other neurodegenerative disease • Chronic renal disease stages III and IV • Cancer and immuno suppression including HIV • Morbid Obesity • More deaths in people <18 years of age

34. Who are the High Risk Groups ? • Children < 5 years old; Persons aged 65 years or older • Children and adolescents (< 18 years) who are receiving long-term aspirin therapy and at risk for Reye syndrome • Pregnant women • Adults and children who have asthma, chronic pulmonary, cardiovascular, hepatic, hematological, neurologic, neuromuscular, or metabolic disorders such as diabetes; • Adults and children who have immuno-suppression (either due to medications or by HIV) • Residents of nursing homes and other chronic-care facilities.

35. Diagnostic Testing • rRT-PCR Swine Flu assay– reverse transcriptase real time PCR • Highly specific test, 24 to 48 hours, costly Rs. 4,000, detects viral multiplication, can identify the novel H1N1 correctly • Confirmatory test, sensitivity is also quite high 85%, Quantitative • RIDT (Rapid Influenza Diagnostic Test) – Not Recommended • point of care, 1 hour, less cost (Rs 700), card test, detects viral protein • Sensitivity low 10 to 70% - A negative result can’t exclude Influenza • Can not distinguish between Influenza B or A or A sub types • Specificity – 80% - can confirm Influenza infection – not the type • If positive – needs a confirmatory test to identify the type

36. This is the best way to contain H1N1 Namaskaar