Transcript Avian Influenza – The Bird Flu

Avian Influenza – The Bird
Flu
Andrew Ullom
The Bird Flu
• The Avian Influenza is a flu virus that occurs in the bird
population.
• The virus has no real origin but has its roots in the areas
of Asia, Europe, Africa, and is beginning to spread
throughout the world.
• Also called the Influenza A H5N1 virus.
• There are two basic forms of the Bird Flu: the actual
“avian influenza” speaks specifically about the flu strain
found in birds and other forms of poultry.
• The other form of the virus is a more mutated version
that humans that resembles the common seasonal flu.
The Bird Flu…continued
• The form of the virus that is contracted by
humans is split up into two protein forms of the
virus: hemagglutinin [HA] and neuraminidase
[NA] proteins.
• There are 16 different subtypes within the [HA]
strand and 9 subtypes within the [NA] strand.
• These two strains of avian influenza will be able
to be combined into numerous different forms to
cause many different flu – like infections.
Other forms virus…
• Avian influenza A H5 and H7
viruses can be distinguished as
“low pathogenic” and “high
pathogenic” forms on the basis of
genetic features of the virus and
the severity of the illness they
cause in poultry; influenza H9 virus
has been identified only in a “low
pathogenicity” form. Each of these
three avian influenza A viruses
(H5, H7, and H9) theoretically can
be partnered with any one of nine
neuraminidase surface proteins;
thus, there are potentially nine
different forms of each subtype
(e.g., H5N1, H5N2, H5N3, H5N9).
(www.cdc.com)
Risks…
• The Bird Flu in the general form that birds
pass on is a basic form found primarily in
birds only.
• This “bird” form of the virus is of no real
threat to humans because even if it is
passed on the effects are “limited,
inefficient, and often un-sustained.”
Seasonal Flu and risks…
• There are currently three types of the seasonal
flu that are currently circulating among humans:
H1N1, H1N2, and H3N2.
• It is possible that the Human Influenza virus
spawned from birds and has evolved to attack
only humans.
• The H5N1 virus has the possibility to be able to
adapt over time to be able to be spread among
the human population and cause widespread
fatalities across the world.
How it spreads…
• The naturally occurring disease found
in most birds, ducks, and fowls passes
the disease through their excretions on
the ground.
• Since the disease is highly contagious
among birds it is then passed to
domestic birds such as turkeys and
chickens.
• The virus is then passed to mammals
and humans who are in contact with
these birds.
• And among humans the disease will
either die off there or it could fuse with
the human flu virus to form some
genetic mutant form of the virus that is
contagious to humans.
Symptoms…
• The reported symptoms of avian influenza
in humans have ranged from typical
influenza-like symptoms (e.g., fever,
cough, sore throat, and muscle aches) to
eye infections (conjunctivitis), pneumonia,
acute respiratory distress, viral
pneumonia, and other severe and lifethreatening complications.
Outbreaks
• Avian influenza outbreaks among poultry occur
worldwide from time to time. Avian influenza viruses can
be classified into low pathogenicity (LPAI) and highly
pathogenic (HPAI) forms based on the severity of the
illness they cause in poultry.
• LPAI poses no known serious threat to human health,
however some strains of HPAI viruses can be infectious
to people. Most recently, outbreaks of highly pathogenic
avian influenza A (H5N1) among poultry have been
associated with illness and death in humans in Asia,
Europe, and the Near East.
• In the United States, from 1997 to 2005, there were 16
outbreaks of low pathogenic avian influenza A viruses
(H5 and H7 subtype) and one outbreak of highly
pathogenic avian influenza A (H5N2) in poultry.
Antibodies…
• Genetic sequencing of influenza A (H5N1)
viruses from human cases in Vietnam and
Thailand shows resistance to the antiviral
medications amantadine and rimantadine,
two of the medications commonly used for
treatment of influenza.
• Because these viruses do not commonly
infect humans, there is little or no immune
protection against them in the human
population and an influenza pandemic could
begin. Experts from around the world are
watching the H5N1 situation very closely
and are preparing for the possibility that the
virus may begin to spread more easily from
person to person.