Avian Influenza / Pandemic Influenza

Neyla Gargouri Darwaza, M.D.

Surveillance Department

Directorate of Disease Control

Ministry of Health, Jordan

Outline

• Influenza virus

• Avian influenza

• Influenza pandemic

Influenza viruses

• Orthomyxoviruses

• Influenza virus   A, B, C  

– A: birds, pigs, humans

– B & C: humans

Influenza virus type A

• 16 different HA and 9 NA

• All subtypes found in birds

• Only H5 and H7 caused

severe disease in birds

• Human disease caused by

H1, H2, H3, N1, N2

Hemagglutinin (HA)Neuraminidase (NA)

Influenza virus type A

• 24–48 hours or hard non porous surfaces

• 8–12 hours on cloth, paper, tissue

• 5 min on hands

• 4 days in water 22ºC

• 30 days at 0ºC

• 30 min at 60ºC

• Inactivated by 70% alcohol, chlorine and disinfectants

Genetic reassortment

Migratory water birds

Pandemic influenza strain

Understanding pandemic influenza

• Pandemics* occur when a novel influenza strain emerges that has the following features:– readily transmitted between humans– genetically unique (i.e., lack of preexisting

immunity in the human population)– increased virulence

* Very widespread epidemic that affects a whole region, a continent or the world.

Previous pandemics

YearFluStrainDeath

million

1918SpanishH1N150

1957AsianH2N22

1968Hong Kong

H3N21

Avian influenza H5N1

• Since mid-2003, H5N1 virus has caused the

largest and most severe outbreaks in poultry

on record.

H5N1 among poultry or wild birds

• Cambodia• China• Croatia• Indonesia• Japan• Kazakhstan • Laos• Malaysia

• Mongolia • Romania • Russia• South Korea • Turkey• Thailand • Ukraine • Vietnam

Global risk of avian influenza outbreaks

Epidemic Pandemic risk Endemic High Risk At-Risk

Category 1 Category 2 Category 3 Category 4

Why is H5N1 very dangerous?

• Present in healthy waterfowl (e.g. ducks), shed in feces

• Very lethal to poultry and other animals including humans

• Big impact on trade and economics

• Crossed species barrier in 1997 in Hong Kong, caused 18 human cases & 6 deaths

Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO

Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO

10 January 2006

Total number of cases includes number of deaths.WHO reports only laboratory-confirmed cases.

Pandemic alert

• H5N1 currently lacks ability for efficient spread among humans

• But, continual H5N1 transmission in animals (and humans):– increases viruses in environment and

chances of humans being infected– increases chances of

mutations/reassortments to create pandemic virus

Present situation

Interpandemic Pandemic alert PandemicPhase 1: Phase 2: Phase 3: Phase 4: Phase 5: Phase 6:

No new virus in humans

Animal viruses

low risk to humans

No new virus in humans

Animal viruses high risk

to humans

New virus in humans

Little/no spread among humans

Small clusters, localized

limited spread among humans

Larger cluster,

localized

limited spread among humans

Increased and

sustained spread in general human

population

Current status of H5N1

?

Influenza pandemic

• “Once a fully contagious virus emerges, its global spread is inevitable”

• “Given the speed and volume of international travel today, the disease could reach all continents in less than 3 months”

• 2 waves of 6 weeks each

Influenza pandemic

• Worldwide– 30-50% human population– 2 to 7.4 million deaths (conservative

estimates, based on 1957 pandemic)

• In Jordan– 1.75 million cases (AR* 35%)– 10,000 deaths (CFR† 0.6%)

* Attack rate † Case fatality rate

Influenza pandemic

• Recent studies1,2 suggest that 1918 H1N1 and H5N1 are similar

– macrophage activities with high levels of cytokine production maybe a factor in the lung and other organ damage (cytokine storm)

1Kobasa et al; Nature 2004;431:7032Peiris et al; Lancet 2004;363:617

If influenza pandemic takes place…

• It will take several months before any vaccine becomes available

• Vaccines, antiviral agents and antibiotics will be in short supply & unequally distributed

• Medical facilities will be overwhelmed

• It will affect essential community services

• It will cause social and political disruption and considerable economic losses

Can a pandemic be prevented?

• Theory:

– antiviral drugs can contain/eliminate pandemic virus

– soon after it develops ability to spread human to human

– WHO antiviral stockpiles for rapid deployment in initially affected countries

Can a pandemic be prevented?

• Requirements:

– good surveillance and rapid reporting

– rapid response teams

– stockpile of antiviral drugs, PPE*, etc.

* Personal protective equipment

Can a pandemic be prevented?

• Challenges:

– limited money

– limited staff and training

– limited planning, coordination, cooperation within government and with other countries

Which antiviral?

• M2 protein inhibitor: amantadine, rimantadine– up to 30% resistance, one passage in cell culture– not effective against H5N1

• Neuraminidase inhibitors: oseltamivir*, zanamivir†

– multiple passages in cell culture required to produce resistance – effective against H5N1

• Susceptibility or resistance to antivirals of the new strain of influenza virus???

* Tamiflu, † Relenza

Suspected case of H5N1

• Symptoms:– Flu illness or respiratory illness

AND

• History within 10 days of onset :– Travel to a country with documented H5N1 in

poultry or humans, and/or– Contact with poultry or domestic birds, or known or

suspected patient with influenza H5N1

How to reduce risk of infection?

• Thorough cooking of all foods from poultry, including eggs

• Avoiding contact with poultry and any surfaces that may have been contaminated by poultry or their feces/secretions

How to reduce risk of infection?

• Frequent hand washing with soap & water

– after touching birds

– after cooking food involving poultry or eggs

• Simple etiquette like covering nose & mouth when sneezing & coughing

Conclusion

• “The next pandemic is just a matter of time”

• “For the first time in human history we have a chance to prepare ourselves for a pandemic before it arrives”

• Pray, plan and practice

References

• http://www.who.int/csr/disease/avian_influenza/en/index.html

• http://www.cdc.gov/flu/avian/outbreaks/asia.htm

Contact

• MOH/ Disease Control– Tel 5607144– Fax 5686965– epijor@wanadoo.jo – neylagd@yahoo.com

• MOH– Tel 5200230

• MOA/ Hotline– Tel 5657756