Epidemics+!


 * Attack of a lethal virus! **

__** Virus is a term which comes from latin //virus// (that means poison). A virus is a simple organism which cannot considered alive because it is not exactly a cell (the minimum structure for exist life). It is composed by a capsid (a membrane constituted basically of proteins) and a core with genetical information. This core would contain DNA (like current cells) or RNA, both coiled. The RNA material has a huge advantage: give to virus the capacity of changing. With these changes, viruses have the possibility of resist the attack of immune system of animals, humans or plants. Since viruses always parasites, it is very important to know if they have the capability of change multiplied. In nature, there are several types of viruses but in general they infect another organism and they cause destruction in cells and organs. When a virus is outside of an organism, it has not metabolism: it is, in fact, an inert particle. Is when virus is inside the body when it has "life". They exist two forms of classificate the virus: paying attention on their forms or on their genetic material. The classification for their external form it is very simply. There are three types of viruses   [|Helical viruses] : they have the form of a cylinder like tobacco (the virus of Tobacco mosaic has this form).    [|Polyedrical viruses] __:__ they have the form of a geometrical object like icosahedra or something like this.The virus of varicella has this structure.
 * __What is a virus and which type of viruses have? 

<span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;"> [|Mixed form viruses] : <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">they have a polyedrical <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">head and a helical tail. Another form to classificate viruses is according to genethycal material. Even though this classification is more complicated, I am going to metion some types of viruses like Herpesvirus, Picornavirus, Paramyxovirus, Orthomyxovirus and finally Retrovirus (the most dangerous viruses). <span style="font-size: 10pt; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES;"><span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">Until discover of first virus (Tobacco mosaic) scientists have found more than five thousand types. These investigations have permitted to reveal their mechanisms of action. It is very similar in all because firstly they must enter to cells. When they are inside, they use the enzymes of cell to create new virus (replicating her genetic material) so as to invader other cells. Finally, they live of the hosts and parasite another cells. <span style="font-size: 10pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;"><span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">When investigators study viruses, they must do this on high security labs where they work on extremely conditions of disinfection and hygiene. There are four levels of security in crescent order. On labs of 4th level there are viruses which if they would leave of lab, they would cause a global epidemic and it would be impossible fight in order to preserve the health of population. <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">Here you can see several photographs of viruses which have done with an electronic microscope or computer design:

Images of viruses

<span style="font-size: 14pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">**__What are the most violent viruses nowadays?__** <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">

HIV, Virus of Bird flu and influenza virus are the most important viruses on 21th century. I am going to explain each virus so as to learn their mechanisms of action.


 * HIV (Human immunodeficiency virus):** It causes Aids (Acquired immunodeficiency syndrome), a disease which affects the immune system. It destroys this system infecting their main cells (like leucocytes, or white blood cells). This devastation in the system of defence causes an infection of several diseases named opportunistic diseases. These diseases can be any type of Hepatitis (A, B or C), Influenza or flu and some others.



<span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">**Virus of Bird Flu (H5N1):** <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA; mso-bidi-font-weight: bold;"> It causes a disease seemed at Influenza or Common Flu but the effects on populations are more negatives because it is a virus with a high mutation capability. Although the virus is much studied (thanks to the recent epidemics of China), the virion (a viral particle) changes frequently and it prevents to make an absolute vaccine. The disease mainly affects to birds but the problem is that also can affect humans and other mammals. The symptoms are very similar to Common Flu but in a long time, Bird Flu is possible that will cause the death.



<span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">**Common Flu (Influenza virus):** It is a virus of same family of Bird Flu but it is less virulent. This virus changes every year and it is for that reason that people are vaccinated once a year. The vaccine is not 100% effective but in cases, can helps to immune system for fight against virus. Since population with a immune system more weak are old people and kids, the vaccine only is administrated to old people because kids must establish contact with the virus in order to reinforcing their immune system. Nowadays anybody have death for this disease, yet it is important because when Influenza changes, generates diseases like Spanish Flu (an epidemic which caused millions of deaths in Europe on 1918, immediately after of First Mundial War) or the Bird Flu which I have explained.

<span style="font-size: 10pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB;"><span style="font-size: 14pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">**__How would able to act a virus on population?__** <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;"> When a virus infect a numerous group of people, becomes aggressive because of its change and mutation. In particular cases of the explained viruses, they have a destruction potential increased because our immune system not have the capacity of fight against them. According to the book, once a virus has infected us, we would have antigens which will secrete antibodies, which would erase any virus of our bodies. But, in fact, it is not true because of the mutation. It causes that our body is protected during a period of time but, when this period finalized, virus can reinfects the same person who had have previously the disease. On top of that, there are thousands of types of viruses and we cannot vaccine for all of them and all people. To top it all, there are people who live in countries undeveloped (the Third world) who have not the economical sources for buy the vaccines or medicines necessaries to heal them. Anyhow, a virus affects of same form any country because there are three forms of infection: Endemic: On epidemiology (science which studies the infectious diseases) the mean of this term is a disease that affects a high number of people but in a little or medium geographic zone like a country in a long period of time. Epidemic: the term is used when a disease infects a big number of people but only in a short and transitory period of time. An example of epidemic is the Flu of which I have told previously. Pandemic: It is an epidemic that it is extended to other countries and remains there for a long time. The Spanish Flu, for example, was an epidemic and endemic disease in origin but after it becomes a pandemic. When it has a pandemic on the world, it established several degrees of danger from 1 (minor dangerous) to 5 (most dangerous). According to each level of pandemic disease, we obtain some recommendations for ill people:

<span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;"> <span style="font-size: 14pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;">**__What can we do in order to put brake at infections? It is possible any treatment?__** <span style="font-size: 12pt; line-height: 115%; font-family: 'Arial','sans-serif'; mso-ansi-language: EN-GB; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA;"> To avoid the propagation of the virus we can do different things. These security measures includes the personal security but also the country security. One of these measures of control can be a campaign of vaccination. The vaccine always contains viral particles (virions) inactivated which they are introduced in human body so as to cause a induced immune reponse. These campaign of vaccination would be very beneficial on devoloped countries (if we supposes that it is easy make a vaccine for the virus), yet on undevoloped countries, people not have the economical mediums for buying it. As I have shown, almost all population would be protected of virus with this method but the other part of people would death quickly. With vaccination it is not assured the survival of population because of the reasons that I told. Another solution is the close of borders of different countries. If each country it would be occuped by their own inhabitants, the contagion between people will decreases. As far as I can judge, these measures become more effective when they are combined. In addition, we would isolate the families that are reported one case of the disease caused by the virus. This treatment is utopian because it is possible that we can't treat all ill people. In all cases above it is very important to detect the virus as far in advance as possible in order to preserve the health of everyone.

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