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A V I A N
F L U
Ginny Codd Viruses Infection and Ecology
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Zoonotic DiseaseRapidly emerging viral infections

• Zoonosis Transmission to human from non-human
  vertebrate
• Examples in USA
• Monkey pox chimpanzee (importation as pets)
• Lyme disease deer, deer mice ticks (urban
  expansion proximity to deer population)
• Hanta virus - mice
• (recall Helens Four corners trailer tale)
• SARS corona virus quail human
• H5N1 oxym virus poultry human

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"Habitat" of influenza A viruses. Ecological and
phylogenetic studies suggest that wild waterfowl
are the principal reservoirs for influenza A
viruses, which occasionally are transmitted to
other host animals such as horses, pigs, and
chickens, leading to influenza outbreaks among
these species. Some of the viruses may become
established in these new hosts and cause
epidemics and epizootics. Viruses are transmitted
among these new host animals (e.g., between
humans and pigs or between chickens and humans,
as occurred in 1997 in Hong Kong).
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Potential for virulence and genetic mutation

• Determinants affecting pathogenicity of influenza
  virus
• -HA cleavability
• -PB2 amino acid at position 627 and others
• -NS1 protein

• SARS(corona virus) and H5N1both RNA viruses show
  ease of variation in
• mutation deletion reassortment
  recombination.
• Clusters isolated in Indochina ( Cambodia, Laos,
  Malaysia, Thailand and Vietnam genetically and
  antigenetically similar
• Clusters isolated in China, Indonesia, Japan and
  Sth Korea show greater genetic divergence.
• Rapid mutation of the virus in Vietnam.

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H5N1Public Health Threat

• Globalization
• Challenge in isolation of outbreaks
• Threat to global markets international commerce
• International trade livestock, birds
• 6 billion global Illegal trade exotic animal
  and plant species
• Population Density
• Increased expansion and concentration
• increased risk of zoonotic transmission
• greater proximity of human and non-human
  vertebrates.
• Agricultural methods
• Deforestation
• Weaponized virus
• Pathogens as biological weapon
• Deliberate or accidental release of genetically
  modified highly virulent strains

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Asian Wet Markets

• Wet markets
• Selling of live animals, vertebrate and
  invertebrate at market
• SARS ( corona virus)
• Live Himalayan palm civet in southern China
• H5N1
• Live quail
• Changes in practices
• Hong Kong aquatic birds eliminated/sold chilled
• quail eliminated
• introduction of two clean days per month
• inactivated vaccine on poultry markets
• improved sanitation
• Indochina peninsula greater challenge in
  implementing change
• geographical diversity

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Geographical Distribution ( Feb 2004)
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Vaccination

• Chicken
• 600,000 doses to chicken in Ho Chi Minh city (
  april 2005)
• Current practice in Hong Kong and parts of
  Mainland China that serve the HK market.

• Human
• Current methods
• Egg-based manufacture ( 300 million eggs needed
  annually for influenza)
• 6-9 months to develop
• Dedendant upon effective method for production
  and equitable distribution

Potential emerging practice Genetic engineering
of strains containing the correct prescription of
genes Reverse recombination
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Anti-virals

• Amantadine
• Rimantadine
• Neuraminidase inhibitors
• -Tamiflu (oseltamivir)
• Zanamivir

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So what if ?

• Pandemic of immense proportion
• 1968 pandemic China population 790 million
• Pig population 5.2 million
• Poultry population 12.3.million
• 2004 China population 1.3 billion
• Pig population 508 million
• Poultry population 13 billion
• If H5N1 were to mimic 98 pandemic predict 1.7
  million deaths U.S.
• 180 360 million deaths globally
• Halt to global economy
• Lack of medical resources
• Inadequacy of vaccines and anti-virals
• Production and availability.

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What are we doing about it?

• World health organization ( WHO)
• - meeting in Manila in May to address global
  concerns.
• - focus on increased surveillance
• - vaccine development
• - education and change of farming and market
  practices

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