Avian flu?

In humans?

Avian Influenza in Humans-2004

Silvio Pitlik, MD

Mar 17, 2004

Avian Influenza in Humans-2004

Silvio Pitlik, MD

Mar 17, 2004

Outline

– How Mother Nature ignites emerging infections

– Historical perspective– Clinician’s perspective– Back to the future

Influenza Virus• Highly unstable• Sloppy• Promiscuous• Completely unpredictable

Dr Anarfi Asamoa-Baah, Assistant Director-General, WHO Communicable Diseases

Opening address-Technical consultation on influenza pandemic preparedness- March 16, 2004

one small step for man, one giant leap for mankind

Neil Armstrong

Crossing the species barrier — one small step to man, one giant leap to mankind

NEJM, Mar 18, 2004

Emerging Infections-1990’s

• Andes virus• Banna virus• Bartonella henselae• Bayou virus• Cycloscopora cayetanensis• Ehrlichia chaffeensis• Ehrlichia equi• Equine morbillivirus• Fakeeh virus• Guanarito virus• Hendra virus• Hepatitis G virus• HIV-1• Picobirnavirus

• Influenza A H5N1• Influenza A H9N2• Juquitiba virus• Laguna Negra virus• Lechiguanas virus• New York virus• Nipah virus• Oran virus• Oscar virus• Prion protein• Rotavirus 116E P360• Sabia virus• Sin nombre virus

Current Opinion in ID, 2000

How Mother Nature Ignites an Emerging Infection

How Mother Nature Ignites an Emerging Infection

Wild-life reservoir

How Mother Nature Ignites an Emerging Infection

Wild-life reservoir

Man-made amplifier

How Mother Nature Ignites an Emerging Infection

Disease Wild-life reservoir

Man-made amplifier

AIDS Pan troglodites troglodites

Promiscuous sex, drug adiction, blood products

SARS Paguma larvata Restaurants, hotels, hospitals

WNV Wild birds Geese farms

Monkeypox Wild rodents in Africa Pet retailers and stores

How Mother Nature Ignites an Emerging Infection

Disease Wild-life reservoir

Man-made amplifier

AIDS Pan troglodites troglodites

Promiscuous sex, drug adiction, blood products

SARS Paguma larvata Restaurants, hotels, hospitals

WNV Wild birds Geese farms

Monkeypox Wild rodents in Africa Pet retailers and stores

Influenza Wild aquatic birds Poultry farms

Healthy aquatic birds

Healthy aquatic birds

H1 N1H2 N2H3 N3H4 N4H5 N5H6 N6H7 N7H8 N8H9 N9

H10H11H12H13H14H15

Natural hosts of influenza viruses

Haemagglutinin subtype Neuraminidase subtype

Bird-flu in humans

Year Place Strain # of cases # of deathsCase

fatality

1997 Hong Kong H5N1 18 6 0.33

1999 Hong Kong H9N2 2 0 0.00

2003 Hong Kong H5N1 2 1 0.50

2003 Netherlands H7N7 84 1 0.01

2003 Hong Kong H9N2 1 0 0.00

2004 Viet Nam H5N1 22 15 0.68

2004 Thailand H5N1 11 7 0.64

Total     140 30 0.21

Outbreak of influenza A (H5N1) in Hong Kong in 1997

Age and sex distribution of patients infected with influenza A (H5N1)

Geographical distribution of influenza A

(H5N1) infected cases in Hong Kong

Diagnostic algorithm for the rapid diagnosis of H5N1 infection.

Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of ARDS- Netherlands 2003

• Overall - 89 patients

• 78 - conjunctivitis

• 5 - conjunctivitis and influenza-like illness

• 2 - influenza-like illness

• 4 - did not fit the case definitions

• Illnesses were generally mild, except for a fatal case of pneumonia in combination with ARDS

Sickchicken

Sickchicken

Deadchicken

Deadchicken

Radiological Findings

Prerequisites for the Start of a Pandemic

• First, a novel virus must emerge to which the general population will have no or little immunity

• Second, the new virus must be able to replicate in humans and cause disease

• Third, the new virus must be efficiently transmitted from one human to another. Efficient transmission is expressed as sustained chains of transmission causing community-wide outbreaks

Life expectancy-USA, 1900-28

30

40

50

60

70

Life expectancy-USA, 1900-28

30

40

50

60

70

• Culling• Quarantine• Disinfection • Vaccination against

circulating flu• H5N1 vaccine

development• Stockpiling of

antivirals

Take-home messages

• The threat to public health will remain so long as the virus continues to cause disease in domestic poultry

• The outbreaks in poultry are likely to take a very long time to control

• Should the final prerequisite for a pandemic be met, the consequences for human health around the world could be devastating

• Regardless of how the present situation evolves, the world needs to be better prepared to respond to the next influenza pandemic

We have to preparefor the next pandemic!!!

Clinical features of mild and severe influenza A (H5N1)