Avian influenza: Public health readiness and surveillance

Hector Valtierra and Thomas Arminio
11/23/05

As you read this, many organizations are working to keep a watchful eye on
the abundance of information being gathered on avian influenza from
countries around the world. Organizations ranging from the international
World Health Organization and the Food and Agriculture Organization of the
United Nations, to the U.S.-based Centers for Disease Control and
Prevention and the Department of Agriculture, are tracking the disease
across countries. Numerous specialists ranging from veterinarians to
wildlife biologists to infectious disease specialists are gathering data,
trying to predict when avian influenza will shift from being a disease that
is transmitted between birds and become a disease that can be transmitted
between humans. This surveillance of avian influenza, subtype H5N1, allows
public health specialists to immediately spring into action to keep the
disease from spreading like wildfire from country to country should an
outbreak occur.

The human cases of avian influenza, as of this writing, have mostly been
limited to people coming into direct contact with infected poultry -- with
the exception of a few notable cases, the most prominent being the case of
an 11-year-old girl who most likely passed avian influenza to her mother
and aunt in September of 2004.

Influenza virus, or "the flu," is caused by a more-or-less spherical virus.
Inside are eight separate pieces of genetic material, each made of RNA (a
molecule resembling the DNA in our own chromosomes). Because RNA is less
stable than DNA, it undergoes changes at a very high rate from generation
to generation as it replicates within the respiratory system; the result is
that the outside surface of the virus takes on a slightly different shape
every time it replicates and produces a new virus. This makes it seem like
a brand-new germ each time our immune systems encounters it. Due to this
change in the virus from year to year, the CDC has to formulate a new flu
vaccine every year. Just before every flu season (from November to March),
a new batch of flu vaccine is made specifically to prevent the most
probable types of influenza that are predicted to circulate in the United
States for that year.

Pandemics are diseases which have the ability to infect most of the people
on this planet and wreak havoc on the health systems in place. History has
shown that the flu has the capability to become a pandemic, causing deaths
on a global scale such as the 1918 Spanish flu pandemic and other flu
pandemics in 1957 and 1968.

From November 2002 through September 2003, keeping the virus that caused
Severe Acute Respiratory Syndrome from becoming a pandemic was a difficult
task that took a concerted international effort. In that real-life
scenario, public health officials contained the spread of disease by acting
quickly and decisively to isolate infected people from others whenever a
suspected case of SARS occurred. Similarly, computer models have predicted
the onset of a pandemic and have indicated that the critical component of
halting the spread of a pandemic is isolation and treatment of cases in the
very beginning: before they are allowed to spread to other people or
communities.

No one knows exactly when a pandemic caused by the flu or some other virus
will occur, but preparation at both the local and national level is a very
good approach toward decreasing the potentially devastating effects of a
pandemic. As in most things, practice decreases the response time to such
an outbreak.

Community disaster drills and simulated exercises help public health
officials determine how well their emergency preparedness programs work.
Coordination of the response among participating emergency medical
facilities such as hospitals, paramedics and infectious disease experts is
paramount in keeping such health systems operating efficiently. Preparing
for natural disasters should be a key concern for any community's and
country's preparedness plan.

No place is completely immune to pandemics. In 1918, the Spanish flu killed
5,000 people in New Mexico, many of them American Indians. The goal of
preparedness is to have a medical system that works together as a team
during a disaster, combining resources and manpower. In Indian country,
communities are supported by an IHS hospital or clinic, either of which may
possibly combine efforts with a local community hospital. There was a time
when these two important resources did not interact closely. Now, however,
working together with emergency medical services, IHS hospitals and
community hospitals plan drills to simulate disease outbreaks and test how
health service agencies respond to an outbreak.

In a disaster, the rules change: and the goal needs to be helping the most
people with the resources you have. The saying "the whole is greater than
the sum of its parts" is especially true with regards to agencies planning
for disasters. A coordinated effort among health care and emergency medical
service agencies is much more effective than each agency acting alone.

Health care agencies assess their ability to recognize and respond
appropriately to a disease outbreak and a large influx of patients,
answering such critical questions as how do the triage system, patient
registration and medical response team work together during an emergency?
More importantly, can these departments communicate effectively with
community resources and other hospitals to coordinate patient care?
Community disaster drills like this show where changes need to be made to
improve patient care during a crisis, while keeping health care providers
alert for clues that might prevent a pandemic from occurring.

The combined efforts of medical, public health services and community
emergency response services personnel (such as fire and police departments)
work with wildlife biologists to make up an interdisciplinary group of
professionals, a group that is necessary for the control of the infectious
disease. Predicting the spread of avian influenza relies on understanding
man's relationship to nature. The fact that humans can contract avian
influenza from birds makes it a zoonosis, a disease that is transmitted
from animals to man. The expertise and research of wildlife biologists and
ornithologists are currently being utilized to track how avian influenza is
spread throughout various bird species' migration and behavior patterns.
The interfaces between wild animals and domestic animals, as well as
domestic animals and people, are the key phases in understanding how
zoonoses are spread.

Dr. David E. Swayne, laboratory director of the Southeast Poultry Research
Laboratory at the Agricultural Research Service of the Department of
Agriculture, said: "The USDA, through its National Poultry Improvement
Plan, conducts 1.6 million tests per year for avian influenza in commercial
poultry and avian influenza is very rare. We should be able to detect any
incursion from Asia of H5N1. Surveillance in wild birds for H5N1 is ongoing
by several institutions including the USDA, [the] universities of Georgia
and Alaska, and Ohio State University. No Asian H5N1 has been found in
North America. This is good news for ... animal agriculture [in the United
States]. Our biggest risk is importation of the virus by illegal commerce
in poultry products and live birds which are banned from the infected Asian
countries."

Effective public health strategies include keeping the public informed on
the spread of infectious diseases such as avian influenza. Because
pneumonia and influenza are among the top 10 leading causes of death in
American Indian communities, tracking the disease is important in keeping a
community safe and ready. It is incumbent upon local medical and public
health personnel to keep readiness plans in place and make sure they work
through periodic drills and assessments.

Although there is currently no human vaccine against avian influenza,
laboratories in the WHO Global Influenza Network are in the process of
producing one. However, it is important to realize that influenza during
any year in the United States causes, on average, more than 200,000 people
to be hospitalized from flu complications but, more importantly, each year
about 36,000 people die from the flu.

The young, elderly and people with already-weakened immune systems are most
vulnerable to influenza. It is recommended that these people who are most
at risk receive an annual immunization (vaccine) against the current
circulating flu. With continued vigilance and EMS practice drills, along
with the combined efforts of many different types of health officials and
scientists, it is hoped that community and global epidemics can be averted.

Hector Valtierra is a graduate student at Tulane University's School of
Public Health and Tropical Medicine and currently works at the National
Institutes of Health in Bethesda, Md. He may be reached at
valtiehe@mail.nih.gov.

Cmdr. Thomas Arminio is a registered nurse with the U.S. Public Health
Service. He is currently the Safety and Infection Control Manager at Santa
Fe Indian Hospital in Santa Fe, N.M. He received his R.N. from The College
of St. Catherine in St. Paul, Minn., and his Master of Public Health from
Johns Hopkins University in Baltimore, Md.

You need to be logged in in order to post comments
Please use the log in option at the bottom of this page