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 life-threatening 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.