Understanding Bird Flu

• Avian (Bird) Flu—what it is
• The realistic connection between bird flu and a pandemic
• Previous influenza pandemics: Learning from history
• How fast could a pandemic spread?
• The work of the World Health Organization (WHO)
• Preparing for an outbreak
• Vaccines and antiviral medications

Avian (Bird) Flu—what it is

Avian influenza, commonly called “bird flu,” is a contagious viral illness that usually targets birds and sometimes pigs. There are a number of different subtypes and on rare occasions, one of these is able to mutate, cross the species barrier, and infect humans who have little or no immunity to it.

The current bird flu is caused by the H5N1 virus. Wild fowl, acting as resistant carriers, are taking the disease to more susceptible domestic stock along their migratory routes, passing the virus on in their saliva, nasal secretions and feces. The disease can be so mild that it is undetected or so severe that it kills whole flocks within 48 hours. The spread is difficult to control except through immunization and/or the culling of birds. Presently bird to human transmission of the disease is not common. Those who have contracted it have been in close contact with poultry.

The realistic connection between bird flu and a pandemic

In the best-case scenario, the immunization and culling of millions of birds will stop the spread of the virus and prevent further human infection and death (217 reported cases, 123 deaths between 2003 and May 19, 2006: WHO). This action has caused enormous economic loss to farmers and householders who raise poultry for a living and to their governments. The concerns are that:

• more humans in more countries will be infected by diseased birds
• a mutated (adapted) virus will develop with the capacity of spreading from person to person
• people will then take the infection rapidly around the world (the worst-case scenario)

At first the virus was confined to Asia. It has now spread to parts of Europe and Africa, specifically, Nigeria.

Previous influenza pandemics: Learning from history

There were three influenza pandemics in the last century and many lessons have been learned from them about preventing and containing infectious disease.

• Hong Kong Flu (1968-1969) that killed an estimated 1 million people
• Asian Flu (1957-1958) that killed 1-2 million people
• Spanish Flu (1918-1919) that killed 40-50 million people

People have varying degrees of immunity and it is highly likely that many cases of illness are unreported. What appears to be an extremely high mortality rate in each pandemic and with this subtype of avian flu is likely to be drastically reduced if all cases were reported.

How fast could a pandemic spread?

The pandemics of the 20th century encircled the globe in six to nine months, however the spread of a future pandemic is impossible to predict because of several unknown factors like

• The number of people initially infected with the new virus
• The incubation period of the virus – the length of time people may be infected and infectious without having any symptoms or taking precautions not to pass on the illness
• The virility or strength of the virus
• The size of the vulnerable population. In the Spanish Flu Pandemic, the age group 15-35 were most vulnerable but with most types flu, it is the young, elderly and those in poor health
• The geographical and cross border movements of people in affected areas
• The effectiveness of preventive measures, the development of a vaccine and the containment of the virus

The work of the World Health Organization (WHO)

The WHO is responsible for worldwide surveillance and has regional laboratories for testing tissue for the bird flu virus to confirm cases of infection. They monitor the spread of the virus with a six-phase Pandemic Alert Protocol. At present the world is at Phase 3.

Pandemic Alert Protocol
Period	Phase	Characteristics
Inter Pandemic	1	No new influenza virus subtypes have been detected in humans. An influenza virus subtype that has caused human infection may be present in animals. If present in animals, the risk of human infection or disease is considered to be low.
	2	No new influenza virus subtypes have been detected in humans. However a circulating animal influenza virus subtype poses a substantial risk of human disease.
Pandemic Alert	3	Human infections with a new subtype, but no human-to-human spread, or at most rare instances of spread, to a close contact.
	4	Small cluster(s) with limited human-to-human transmission but spread is highly localized, suggesting that a virus is not well adapted to humans.
	5	Larger cluster(s) with limited human-to-human spread still localized, suggesting that the virus is becoming increasingly better adapted to humans, but may not yet be fully transmissible.
Pandemic	6	Pandemic increased and sustained transmission in general population.

Preparing for an outbreak

We have created three basic resources to help you prepare.  They focus on the following three areas:
Individuals
Churches
Organizations

WHO and other groups have global means to monitor the migration routes of birds and the spread of the virus among birds, between birds and other animals, between birds and humans, and to act on any possibility of human-to-human contact.

These organizations also work with governments on the immunization and the culling of birds and plans for responding to and containing a pandemic. Governments will be prepared to stop imports of poultry, to close borders and change budget priorities in order to contain and treat the infection their own region.

Federal and local governments are also preparing for an outbreak even though it may not happen. Service and general organizations, businesses and churches should also be ready with plans to best serve their employees, their target communities and neighbors, if that is possible. Responsibility for preparation also lies with individuals and their families.

Vaccines and antiviral medications

Vaccines are not expected to be widely available until several months after an outbreak of the pandemic because a vaccine:

• needs to match the exact virus
• be produced in huge amounts
• be administered to millions of people

Two antiviral medications are available that may affect the severity and duration of bird flu: Tamiflu and Relenza. They need to be given within 48 hours of the onset of symptoms but cannot be obtained as over-the-counter medications. The WHO and certain governments have stockpiled these to contain the first wave of an outbreak and to treat health workers and other essential staff who are likely to be more intensely exposed.