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Issued as Health Alert Network message on 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; health-care 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) health-care 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 health-care
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 (available at http://www.cdc.gov/flu/avian/protectionguid.htm).
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 health-care provider. Before
visiting a health-care setting, tell the provider about symptoms
and recent possible exposures to avian influenza.
Health-Care Professionals: Evaluation of Ill Persons
Health-care 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.
- 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.
- 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.
- 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:
- 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 http://www.who.int/foodsafety/micro/avian/en/ .
More Information for People Who May be Exposed to Avian
Influenza
"WHO interim recommendations for the protection of
persons involved in the mass slaughter of animals potentially
infected with highly pathogenic influenza viruses" and "Guidelines
for the use of seasonal influenza vaccine in humans at
risk of H5N1 infection" are available online.
The Occupational Safety & Health Administration's (OSHA) "Guidance
for Protecting Workers Against Avian Flu" is
available online.
For More Information
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