Seasonal Influenza and Pandemic Influenza A (H1N1, H5N1) Virus Dr. Alaa kuttar musa Department of Medicine College of Medicine/ Basra University

Circulating Influenza Strains and Pandemics in The 20 th Century H1N1 H2N2 H3N2 1918: “Spanish Flu”1957: “Asian Flu” 1968: “Hong Kong Flu” million deaths1-4 million deaths

3 Influenza Virus Types A and B Type A (Seasonal, avian, swine influenza,….) Type B (Seasonal influenza) Can cause significant disease Generally causes milder disease but may also cause severe disease Infects humans and other species (e.g., birds; H5N1) Limited to humans Can cause epidemics and pandemics (worldwide epidemics) Generally causes milder epidemics

The InfluenzaVirus is an acute systemic viral infection that primarily affects the respiratory tract; it carries a significant mortality

Avian influenza is caused by transmission of avian influenza A H5N1 from poultary. Infections with H5N1 viruses have been severe, with enteric features and respiratory failure. Swine influenza H1N1 transmitted from pigs to humans. Re-assortment of swine, avian and human influenza strains can occur in pigs. Sometimes this can lead to an outbreak of swine ‘flu’ in humans( Maxico 2009)

Viral Re-assortment Reassortment in pigs Reassortment in humans Pandemic Influenza Virus

Influenza Transmission Routes Infectious 1 day before and up to 7 days –Fever, cough, headache, muscle aches –Sometimes lower respiratory Transmission of influenza viruses –Air droplet from coughing or sneezing * Person-to-person (H1N1) * Poultry to human ( H5 N1) –Contact orally or MM with animal or animal products (meat, egg, discharges) 8

Isolation Precautions

Big droplets fall on people surfaces bed clothes Courtesy of CDC Clinical features -incubation period of 1–3 days, -fever, malaise and cough. May followed by Viral pneumonia. - superinfection with Strep. pneumoniae, Staph. aureus or other bacteria

Complications extrapulmonary manifestations include: 1. myositis, myocarditis, pericarditis 2. neurological complications (Reye’s syndrome in children, encephalitis or transverse myelitis, fit). 3.Mortality is greatest in the elderly, those with medical comorbidities and pregnant women.

Seasonal Flu  Occurs every year during the winter.  Affects up to 10% of the population.  Looks ill, but not life-threatening in most cases.  May complicated by pneumonia but not early  Very young, very old, and people with certain chronic illnesses most at risk.  Vaccines are available to prevent seasonal flu.  Antiviral drugs available to treat those at special risk. How Do Pandemic Flu and Seasonal Flu Differ?

1.Droplet precautions: Surgical Masks 2.Personal Protective Equipment (PPE) 3.Ovoid contact with infected patients 4.hand hygiene and preventing dissemination of infection by coughing and sneezing 5.seasonal vaccination Prevention

Antivirals- Oseltamivir 1.Administration of neuraminidase inhibitor, oral oseltamivir (75 mg twice daily) or inhaled zanamivir (10 mg twice daily) for 5 days 2.Prophylaxis is 75 mg once a day for 7 days after last exposure

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