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Coronary Artery Disease Transcript The Causes Of Bird Flu Bird flu is caused by strains of the influenza virus that have evolved to be specially adapted to enteravian cells.
There are three main types of influenza: A, B, and C. The virus that causes bird flu is aninfluenza A type with eight RNA strands that make up its genome.
Influenza viruses are furtherclassified by analyzing two proteins on the surface of the virus. The proteins are called hemagglutinin H and neuraminidase N.
There are many different types of hemagglutinin and neuraminidaseproteins. The current highly pathogenic bird flu virus has type 5 hemagglutinin and type 1neuraminidase. Thus, it is a H5N1 influenza A virus.
There are many types of influenza viruses, and most prefer to live in a limited number of animals. Human influenza is best adapted to humans. A few cases may occur in an accidental host, such as when people who haveextensive contact with sick birds get the bird flu.
In addition to humans and birds, we know that pigs,tigers, leopards, ferrets, and domestic cats can sometimes be infected with avian influenza viruses. Influenza viruses mutate easily and often. These mutations can arise spontaneously in a single virusor can occur when two different influenza strains get close enough together to exchange geneticmaterial.
There are two major types of mutations in influenza viruses: The antigenic shifts are usually responsible for developing newstrains. For example, the swine flu pandemic was caused by a virus that included geneticmaterial from pig influenza, avian influenza, and human influenza strains.
New mutations can allowthe virus to evade the body's immune system and makes older vaccines ineffective. Inonestrain of the highly pathogenic avian influenza virus mutated in this way, making the existing vaccineused against avian flu ineffective against the new strain.
Sometimes a flu virus will mutate in a waythat makes it able to infect a new species. Serious pandemic influenza occurs when a relatively new strain of the influenza virus arises that ishighly contagious to humans.
The most deadly pandemic in modern history was the influenza,also known as the Spanish flu although it did not srcinate in Spain.
The virus spread rapidlyand killed tens of millions of people worldwide. Mortality was especially high in healthy youngadults. Although the virus was a human influenza virus it, had many genes that likely camefrom a strain of bird flu.
One reason that health officials carefully watch for and try to limit humancontact with birds that develop avian flu is to avoid chances for a new strain to arise that may preferto develop in human tissue.
Symptoms of Bird Flu Symptoms occur approximately two to eight days after exposure, on average. Bird Flu Effects The flu virus has existed in wild aquatic birds such as ducks. The virus does not necessarily affect thebirds. The viruses comein close to each other and exchange genetic material allowing the new virus to spread from pigs topeople.
This was thought the route that avian or bird flu spread to humans but about ten years agoit was discovered that bird flu skipped the pig step and infected humans directly.
This triggered thefear of a pandemic global scale non-seasonal epidemic. Fortunately for now, the virus can notspread effectively from human to human. This however is a matter of time, as the flu virus isconstantly changing. This why the health officials are constantly developing new vaccines yearly tocombat that particular years prevalent strain.
Bird Flu in the Human BodyOnce infected by the bird flu viruses infects the cells in the human lungs.Sep 01, · Biology form 4 chapter 8 essay >>> next page Montessori school observation essay Part three of the author’s roots of greatness, wings of light set about her grandparents this essay takes the form of an imagined letter from her paternal.
Sep 15, · Assalamualaikum and hello everyone, Here is the latest module that I managed to prepare. Just like the previous module, it consists of a collection of previous year trial papers.
But this time it is for form four essay questions. All questions are arranged according to chapter and each questions is followed by their answer scheme.
Physics form 4 chp 2(Essay Question) plombier-nemours.comm/plombier-nemours.com Answer. May 06, · Structures question must check and write the correct answer in the worksheet plombier-nemours.com, teacher allow u to print or photostat and read /highlight To give you all more time to do revision.
Then, put everything inside the file. 17/5/12 Pass up the file to Jack (Group 4,5,6) and Lim Wilson (group 1,2,3).
questions each chapter see sample ap biology questions below or go to p33 on the following link ? cambridge o level biology key stage 4 revision guide anthology and reproduction for the purposes of setting examination questionsap biology evolution essay questions and answers.
A. All living things are made of cells. B. All cells come from other preexisting cells. C.
Cells form through spontaneous generation. D. Cells are the basic structural and functional units of life.