Influenza

Influenza is a word derived from Italian word, which means influence.

The flu is a contagious infection of nose, throat, and lungs caused by influenza virus.

Influenza is virus that occurs infectious disease. This virus is RNA virus that belongs to Orthomyxoviridae virus.

In Orthomyxociridae virus, there are 5 genus(influenza A, influenza B, influenza C, isavirus, thogovirus) that usually infects vertebrate, but the ones that infect human are influenza A,B, and C.

Caused By

Influenza A

In temperate climates, influenza A usually arrives between early winter and early spring.

Influenza B

Influenza B can appear at any time of the year.

The most common way

The most common ways to catch the flu is by breathing in droplet from coughs or sneezes. Less often, it is spread when you touch a surface such as faucet handle or phone that has the virus on it, and then touch your own mouth, nose, or eyes.

Influenza virus A

In influenza A there are only one species of virus, type A. This virus only infect portion of aves and mammals. This virus causes fatal problems to aves and unfortunately to mammals include human, too. Also, this causes serious pandemic because this virus is most toxic and critical among influenza A,B, and C.

Also, this virus is belong to negative sense, single standard, segmented RNA virus, according to characteristic of RNA virus. However, people should know this virus as HxNx(H1N1) virus commonly.

Viruses are surrounded by protein coat called capsid. Around capsid, lipid tunicate envelopes it and spine shaped glycoprotein on the surface of this envelop, plays important role to virus to survive. Two different type of glycoprotein which are called Neuraminidase and Hemagglutinin, categorize the viruses.

Hemagglutinin It helps virus to penetrate to host cells.

Neuraminidase 1. It helps virus to get out of the host cell.

2. It consist relenza and tamiflu (the cure of influenza)

Nowadays, there are only 16 of HA and 9 of NA found and H1, H2, H3, N1, N2 is most common.

Furthermore, there are more names of virus than naming it in subtype. The official name is A/Fujian/411/2002/H3N2

Influenza Virus B

Influenza virus Bs host cell is only human and seals. Because of these restricted species of host cell, infectivity is a lot more weaker than type A and it doesnt issue big problems.

Even though, it shaped similar to influenza virus A, it takes 2~3 more times on being mutate. As influenza virus A, it is negative sense single standard RNA virus and has 14648 of RNA consisted by nucleotides. Influenza virus A and B are consisting by 8 segments which encode 11 proteins.

Influenza Virus C

Influenza virus C is rare and not often occurs, but it has one of the strongest pathogenicity.

T

Host cell of this influenza is human and pig. These viruses dont infect, and also it is negative sense single standard RNA virus and consists by 7 segments which encode 9 proteins.

Shape

Influenza viruses (A,B,C) are 80~120 nanometers(mm) ball shaped virus.

Inside of viral core, there are 7~8 pieced RNA (A/B has 8, C has 7). In this RNA there are 9~11 of information which makes proteins (A/B has 11, C has 9). (Influenza A has HA, NA, NP, M1, M2, NS1, NS2(NEP), PA, PB1, PB1-F2, PB2.)

Symptoms

Influenza is hard to figure out whether it is influenza. When infected by this virus, they show symptoms. It shows a lot of symptoms and even non mostly the former one is cold or fever.

For the symptoms of this virus, it shows signs of fever that increase up to 38~40 degrees, sore throat and arthralgia. To the children, diarrhea, stomachache, and gastroenteritis show. Also, these symptoms show more clearly in influenza virus B.

Sometimes people confuse cold and flu, which share the same symptoms and typically occur at the same time of the year. However, the two diseases are different. Most people get a cold several times each year, and the flu only once every year.

Influenzas infection routes are getting into eyes or mouth by sneezing and coughing. Therefore, washing hands or wearing a mask helps to prevent

Epidemic and Pandemic

Pandemic

Pandemic occurs usually during the winter. The reason why pandemic of infuenza can cause serious problems although, modern medical science has developed a lot, is because this virus is very strong but also it mutate a lot.

Epidemic

The mutation can be occurred by hemagglutinin and neuraminidase, which are the vaccine of virus. This mutation is called antigenic drift that occurs by random mutation can have immunity on vaccine and also this cause epidemic.

Vaccine

Vaccines are usually collected by eggs. They collect the antigens which egg produced and inject those antigens to people, so that people can get memory cells.

History

Spanish Flu, 1918 Flu Pandemic

Spanish Flu is the diseases that killed the largest number of people in shortest period. This virus that occurred in Spain is H1N1 which are extreme virulent.

Even scientist doesnt know the birthplace of this virus. This virus killed five hundred million of humans which is 33.3% of population of the earth.

This virus occurred in 3 times.

- Spanish Flu-

2009 Pandemic, Swine Influenza

This swine influenza first occurred in Mexico, and first it only infected humans, pigs and birds. However, it was not very virulent. However, when influenza mutated by pig and added infect human again and caused serious problems. This had been found out that it is one of the H1N1 virus which are one of the Spanish Flu.