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Avian
Influenza: Interim Recommendations for Persons with Possible Exposure
to Avian Influenza During Outbreaks Among Poultry in the United
States
This is an official CDC Health Update
Distributed
via Health Alert Network
February
24, 2004, 21:45
EST (9:45 PM EST)
CDCHAN-00186-04-02-24-UPD-N
February 24, 2004
Outbreaks
of avian influenza A occur among U.S. poultry flocks from time to
time. Since early February 2004, avian influenza outbreaks have
been reported in several locations in the United States, most recently
in Texas. This document briefly describes the current outbreak in
Texas and provides interim guidance for persons who might be exposed
to avian influenza; healthcare professionals; and consumers of poultry.
Background
The state of Texas
has reported an outbreak of highly pathogenic avian
influenza A (H5N2) among poultry on one farm in Gonzales County,
in south-central Texas. This is the first outbreak of highly
pathogenic avian influenza in the United States in 20 years and
was detected by routine state monitoring for avian influenza.
Birds on this farm were sold to live bird markets in the Houston
area. Preliminary testing of birds at two of these markets
found evidence of avian influenza. The farm and the two live
bird markets have been quarantined, cleaned, and disinfected following
the culling of affected poultry. In addition, extensive surveillance
measures have been instituted around the affected premises.
CDC and the U.S. Department of Agriculture (USDA) are working with
the Texas Department of Health and the Texas Animal Health Commission
on both the human health and animal/veterinary aspects to contain
this outbreak in poultry and minimize risk to humans.
The health risk to humans from the H5N2 influenza outbreak in Texas
is considered low at this time.
The
H5N2 strain in Texas is a different subtype of influenza A than
the virus affecting parts of Asia. The H5N1 outbreaks among poultry
in Asia have been associated with human cases in Thailand and Vietnam.
There is no epidemiologic link between the H5N1 virus in Asia and
the H5N2 virus in Texas.
Avian
influenza viruses typically do not infect humans; however,
several instances of human infections and outbreaks of avian influenza
have been reported since 1997 (for more information, see “Basic
Information About Avian Influenza”).
It is believed that most cases of avian influenza infection in humans
have resulted from contact with infected poultry or contaminated
surfaces. Other means of transmission also are possible, such as
the virus becoming aerosolized and landing on exposed surfaces of
the mouth, nose, or eyes, or being inhaled into the lungs.
Interim CDC Recommendations
Because it is
possible that
avian influenza could be transmitted to humans, CDC is issuing the
following interim U.S. guidance for 1) individuals who may be exposed
to avian influenza, 2) healthcare professionals, and 3) consumers
of poultry. Guidance for individuals who may be exposed to avian
influenza is based on the degree of risk associated with various
levels and types of exposures.
This document also contains interim guidance for healthcare professionals
who may need to evaluate, test, and diagnose potentially exposed
individuals. Additionally, food safety information for consumers
is provided to address concerns surrounding avian influenza outbreaks
and poultry. The recommendations will be updated as necessary.
Individuals
Participating in Avian Influenza Outbreak Control
and Eradication Activities
Persons involved
in outbreak control and eradication activities (e.g., euthanasia,
carcass disposal, and cleaning and disinfection of premises affected
by avian influenza) on poultry farms or live bird markets are at
increased risk for exposure to avian influenza. Such persons
often have prolonged, direct contact with infected birds and/or
contaminated surfaces in an enclosed setting.
CDC and USDA have developed interim guidance to reduce these risks,
including recommendations about personal protective equipment, vaccination
with seasonal influenza vaccine, administration of antiviral drugs
for prophylaxis, surveillance and monitoring of workers, and evaluation
of workers who develop a febrile respiratory illness within 7 days
of their last exposure.
Other
Individuals with Possible Exposure to Avian Influenza
The risks for exposure
to avian influenza viruses and the possibility of viral reassortment
would be expected to be lower for persons with more routine (i.e.,
less intense and prolonged) occupational or other
types of contact with poultry or contaminated surfaces or equipment
on affected farms or in live bird markets.
Individuals who develop a febrile respiratory illness within a week
after their last exposure to avian-infected or exposed birds or
potentially contaminated surfaces should consult a healthcare provider. Before
visiting a health-care setting, tell the provider about symptoms
and recent possible exposures to avian influenza.
HealthCare
Professionals: Evaluation of Ill Persons
Healthcare providers
should be alert for respiratory illness among persons who may have
been exposed to infected poultry. The following section provides
recommendations for health-care professionals who may need to evaluate
symptomatic persons with possible avian influenza exposure.
-
Persons who develop
a febrile respiratory illness should have a respiratory sample
(e.g., nasopharyngeal swab or aspirate) collected.
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The respiratory
sample should be tested by RT-PCR for influenza A, and if possible
for H1 and H3. If such capacity is not available in the state,
or if the result of local testing is positive, then CDC should
be contacted and the specimen should be sent to CDC for testing.
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Virus isolation
should not be attempted unless a biosafety level 3+ facility
is available to receive and culture specimens.
-
Optimally, an acute-
(within 1 week of illness onset) and convalescent-phase (after
3 weeks of illness onset) serum sample should be collected and
stored locally in case testing for antibody to the avian influenza
virus should be needed.
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Requests for testing
should come through the state and local health departments,
which should contact the CDC Director’s Emergency Operations
Center at 770-488-7100 before sending specimens for testing.
Consumers:
Food Safety Guidance
There is no evidence
that any human cases of avian influenza have been acquired by eating
poultry products. Influenza viruses such as H5N2, H7N2, and H5N1
are destroyed by adequate heat, as are other foodborne pathogens.
Consumers are reminded to follow proper food preparation and handling
practices, including:
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Cook all poultry
and poultry products (including eggs) thoroughly before eating.
(This means that chicken should be cooked until it reaches a
temperature of 180 degrees Fahrenheit, throughout each piece
of chicken.)
-
Raw poultry always
should be handled hygienically because it can be associated
with many infections, including salmonella. Therefore, all utensils
and surfaces (including hands) that come in contact with raw
poultry should be cleaned carefully with water and soap immediately
afterwards. The World Health Organization has developed food
safety guidance for the current situation in Asia. This is available
at www.who.int/foodsafety/micro/avian/en/ .
For
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