A B or C. The RNA codes for five structural proteins and three nonstructural proteins.
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A pandemic can occur when a new and very different influenza A virus emerges that both infects people and has the ability to spread efficiently between people.
Etiology of influenza. Viral etiology of influenza-like illnesses in Antananarivo Madagascar July 2008 to June 2009. These viruses spread when people with flu cough sneeze or talk sending droplets with the virus into the air and potentially into the mouths or noses of people who are nearby. Influenza virus affects the respiratory tract by direct viral infection or by damage from the immune system response.
The flu spreads READ MORE. You can inhale the droplets directly or you can pick up the germs from an object such as a telephone or computer keyboard and then transfer them to. Influenza A is generally more pathogenic than influenza.
The 3 types of human influenza virus show similar biochemical and biological properties. Influenza A is virulent B is mild and C is nonvirulent. Influenza is contagious which means it can be spread easily from person to person.
The flu or influenza is a contagious respiratory illness caused by viruses that infect the nose throat and sometimes the lungs. THE ETIOLOGY OF INFLUENZA Semantic Scholar. The word influenza comes from the Italian word influenza from medieval Latin influentia originally meaning visitation or influence of the stars.
Seasonal influenza virus is a member of the orthomyxovirus family. The first case of Influenza AH1N1 in the United States was definitively diagnosed by laboratory tests on Apr. Influenza viruses travel through the air in droplets when someone with the infection coughs sneezes or talks.
The best way to prevent flu is by getting a flu vaccine each year. It has a segmented single-stranded RNA genome that can be classified into influenza A B and C based on antigenic differences. Influenza results from infection with 1 of 3 basic types of influenza virus.
Human influenza virus is an enveloped single stranded RNA virus belonging to the family of Orthomyxoviridae and can be typed into type A B and C. Influenza A viruses are the only influenza viruses known to cause flu pandemics ie global epidemics of flu disease. It can cause mild to severe illness and at times can lead to death.
The influenza bacillus was described by Pfeiffier and others in 1892 not long after the severe European epidemic in 188990 and for some considerable time this germ was thought to be the sole originating cause of the disease producing conditions in the respiratory tract favourable to the development of the micro-organisms of pneumonia. The virus is spherical or filamentous in shape with a diameter of 80120 nm. One of the earliest reports of an influenza-like illness comes from Hippocrates who.
Other people inhale the airborne virus and can become infected. 1Virology Unit National Influenza Centre Institut Pasteur de Madagascar Antananarivo Madagascar. Differences in the morphology and antigen patterns for these viruses account for the differences in virulence and immunity.
Its use in the disease sense is first attested in 1504 when it meant a visitation or outbreak of any disease affecting many people in a single. Viruses that cause influenza spread from person to person mainly by droplets of respiratory fluids sent through the air when someone infected with the virus coughs or sneezes. Influenza an acute contagious respiratory infection caused by orthomyxoviruses A B and C occurs in local outbreaks epidemics and pandemics.
Razanajatovo NH1 Richard V Hoffmann J Reynes JM Razafitrimo GM Randremanana RV Heraud JM. Etiology of Influenza A H1N1 SpringerLink Skip to main content. Influenza has likely been around for millennia though its cause was only identified relatively recently.
In humans the respiratory epithelium is the only site where the hemagglutinin HA molecule is effectively cleaved generating infectious virus particles. The flu is caused by influenza viruses that infect the nose throat and lungs. This referred to the diseases cause which at the time was ascribed by some to unfavorable astrological conditions.
Flu is a contagious respiratory illness caused by influenza viruses that infect the nose throat and sometimes the lungs. SINCE th1e results of otur pLelilminary experimenits weire reported in the B131ZITISu MIEDICAL JOURNAL of December 14tlh 19181 in anarticle entitled A Filtrable Virus as tlhe Cauise of tlhe Early Stage of thbe Presenit Epidemic of Influenza further work lias beeni carried out which.
