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Simple Risk Assessment
Models for Oahu
by David Duffy and
Stephanie Saephan
The simple avian influenza risk maps
for Oahu (below) were created based on proximity of poultry/pig
farms to wetlands with "risky" water bird species. Two of the “chicken farms” located
downtown are likely to be retail outlets, the others, based on other
information, do appear to have commercial rearing operations. We
drew three-km cordons around them to mark the areas that would be
culled under international response plans, were avian influenza
detected at such a site.
Next we chose mallards, pintails and ruddy turnstones as three bird
species likely to be involved in avian influenza transmission.
Pintails and turnstones migrate from Alaska to Hawaii and thus could
bring the disease to Hawaii. Mallards in Hawaii are introduced and
non-migratory. They tend to be tamer than the migratory species and
are often fed by the public. Mallards could thus be a “bridge”
species from migratory species to humans.
Where both mallards and pintails occurred within the three-km of a
chicken or pig farm, we suggest there is an elevated risk of avian
influenza becoming established. However, our analysis ignores two
major environmental factors. We were not able to find any data on
the distribution and abundance of backyard or feral chickens. Feral
chickens could provide a bridge between waterfowl in wetlands and
human areas while backyard poultry could provide an immediate source
of infection to homeowners throughout Oahu.
We would appreciate further data or corrections if available (dduffy@hawaii.edu
or saephan@hawaii.edu).
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