Antigen
An antigen is a substance which stimulates an immune response. Influenza A subtypes are distinguished by two antigens, the proteins hemagglutin and neuroaminidase, which occur on the surface of the virus.

Antigenic drift
Antigenic drift is the process of cumulative genetic variation within a virus; specifically, the mutation of genes recognised by the immune system. Antigenic drift in the influenza A and influenza B viruses allows new variations of the virus to infect people or animals with immunity to older strains. It is one of two possible mechanisms that could produce a pandemic influenza strain.

Antigenic shift
In influenza viruses, antigenic shift is the mixing of genetic material from two strains infecting a single cell to produce a new strain. Antigenic shift is one of two possible mechanisms that could produce a pandemic influenza strain.

Avian influenza
Avian influenza refers to any influenza strain which is well adapted to birds. Only influenza A viruses are known to have adapted to birds.

Biohazard
A biohazard is a biological organism, or substance produced by an organism, which poses a risk to human or animal health. Influenza viruses are classifed as a Level 2 biohazard by the US Centers for Disease Control and Prevention.

Bird flu
Bird flu is a term commonly used to refer to the highly pathogenic avian influenza strain H5N1.

Business continuity management
Business continuity management is the overall process of identifying a businesses critical objectives and processes and planning to ensure that these can be maintained or restored in the event of a significant disruption

Business continuity plan
A business continuity plan is a written document which details the information required and procedures to be followed for the business to respond to and recover from a significant disruption.

Containment
The word containment is used by the Australian Government to describe strategies to prevent or delay the widespread occurrence of pandemic influenza within Australia. It can also be used to describe safe methods for the handling of infectious materials.

Epidemic
The term epidemic refers to an incidence of a specific infectious disease, within a given human population, that is significantly greater than would normally be expected.

Epizootic
The term epizootic is equivalent to epidemic, but applies only to the occurrence of disease within an animal population. Outbreaks of avian influenza within domestic poultry are correctly referred to as an epizootic rather than an epidemic.

Hemagglutinin
Hemagglutinin (“H”) is a protein which occurs on the surface of the influenza A virus. Hemagglutin is one of two antigens which are used to distinguish subtypes of influenza A.

H5N1
H5N1 is a subtype of influenza A. H5 stands for the fifth of several known types of the protein hemagglutinin. N1 stands for the first of several known types of the protein neuraminidase.

Isolation
Isolation is the seperation of people with an infectious disease from others to prevent the spread of illness.

Outbreak
An outbreak is a small concentration of people or animals infected by a common disease in a particular area.

M2 inhibitors
M2 inhibitors are a class of antiviral drug that have been used to treat and prevent influenza infection. M2 inhibitors have been associated with the rapid emergence of resistant influenza strains and are therefore unlikely to have broad clinical application during a pandemic.

Maintenance of social functioning
The Australian Government uses the term “maintenance of social functioning” to describe measures which would be used if outbreaks of pandemic influenza in Australia cannot be contained.

Mortality
Mortality (or “mortality rate”) is the measure of the number of deaths in a given population.

Mutation
Mutations are changes in genetic material that can occur through natural processes or when cells are exposed to radiation, chemical agents or viruses.

Neuraminidase inhibitors
Neuraminidase inhibitors are a class of antiviral drug that have been used to treat and prevent influenza infection. Neuraminidase inhibitors are considered less likely to give rise to resistant strains than M2 inhibitors, an older class of antiviral drug. Neuraminidase inhibitors are preferred over M2 inhibitors for treatment during an influenza pandemic, according to WHO.

Pandemic
A pandemic is an epidemic which occurs across a wide geographic area. The term is often used to decribe the occurrence of an epidemic across many countries, or globally.

Panzootic
The term epizootic is equivalent to pandemic, but applies only to the occurrence of disease within an animal population.

Pathogenic
A pathogenic organism is one which has the ability to cause disease.

Personal protective equipment
Personal protective equipment (PPE) is equipment used or worn by an individual to reduce exposure to specific hazards. In the workplace, appropriate PPE may be used where it is not practical to completely remove a health and safety risk from the workplace.

Prophylaxis
Prophylaxis refers to any medical procedure designed to prevent rather than treat or cure disease.

Quarantine
Quarantine is the seperation of people or animals with a suspected infectious disease from others to minimise the risk of disease spreading through a population. It is commonly used to describe the detention of people, animals or materials to prevent infectious disease from entering a country.

Reassortment
Reassortment is the mixing of genetic material from two viruses infecting the same cell. In influenza viruses, this process is known as antigenic shift.

Respirator
A respirator is a device designed to protect the wearer from inhaling harmful gases, vapours or particles. Particle filter respirators work by forcing inhaled air to pass through a filtering medium which traps particles. Filter respirators are only effective if a proper facial seal is achieved. They should not be confused with simple surgical masks, which permit the inhalation of unfiltered air.

Social distancing
Social distancing refers to personal or public health measures to prevent the spread of infection by limiting close contact between people. Social distancing measures range from individuals sitting or standing back from others to the closure of workplaces or schools.

Surgical mask
Surgical masks are commonly worn by health care workers to protect the wearer from splashes of infectious material and protect patients by redirecting airflow and catching some of the wearer’s respiratory secretions. They perform a similar function when worn by people with symptoms of respiratory illness.

Surgical masks do not provide protection against inhalation of small particles or aerosols. They should not be confused with particle filter respirators, which work by forcing inhaled air to pass through a filter medium.

Vaccine
A vaccine is a substance which confers immunity against a specific disease. The seasonal influenza vaccine contains inactivated (killed) viruses that stimulate an immune response but cannot cause infection.