Influenza Virus Essay

For long before the 1918 pandemic, doctors had been trying to isolate the microorganism that causes influenza. In 1892, one man, Dr. Friedrich Johann Pfeiffer, believed he had the answer. His discovery, Pfeiffer’s

Viruses are microscopic particles that invade and take over both eukaryotic and prokaryotic cells. They consist of two structures, which are the nucleic acid and capsid. The nucleic acid contains all genetic material in the form of DNA or RNA, and is enclosed in the capsid, which is the protein coating that helps the virus attach to and penetrate the host cell. In some cases, certain viruses have a membrane surrounding the capsid, called an envelope. This structure allows viruses to become more stealthy and protected. There are two cycles in which a virus can go into: lytic and lysogenic. The lytic cycle consists of the virus attaching to a cell, injecting its DNA, and creating more viruses, which proceed to destroy the host. On the other hand, the lysogenic cycle includes the virus attaching to the cell, injecting its DNA, which combines with the cell’s DNA in order for it to become provirus. Then, the provirus DNA may eventually switch to the lytic cycle and destroy the host.

Every year, millions of people start talking about the influenza virus and getting their vaccines as the flu season approaches, which starts around the October-November period and reaches its peak between December and March. Therefore, public health officials around the world- and in the U.S in particular- are constantly challenged by properly preparing for the annual influenza dilemma, given that this viruses, and other respiratory viruses, are a serious health threat to the U.S population and the world as a whole. Furthermore, what makes the influenza virus even more challenging to control is that it can mutate rapidly and reassort to form new strains, having the ability to reside in multiple animal hosts. In fact, many scientists and researchers have been doing in-depth intensive research so as to understand the mechanism behind this unique characteristic of the virus, try to find new ways to control it, and explore different areas of protection and vaccination.

Hemagglutinin is very important for the virus to bind to animal cells, for example, a human red blood cell. This causes agglutination which is the clumping of the red blood cells. Tests based on this simple clumping of the red blood cells is useful to determine if one has influenza. The neuraminidase is used to cut off the viruses hemagglutinin receptors when new viruses are produced and start budding off. It also degrades the mucosal surfaces of the lungs and the throat to prevent being ejected. This hampers the ability of the antibodies of getting into the lungs.

Influenza is a highly contagious flu that is a viral infectious virus of the respiratory organ. Orthomyxoviridae is the scientific name of the Influenza virus. Some examples of the influenza virus are Influenza A, Influenzavirus B, Influenzavirus C, Bourbon virus, and Isa Virus. The types of flu A, B, and C are responsible for nearly all the Influenza disease that occurs almost every winter. Infection with type C influenza usually causes either a very mild respiratory illness or no symptoms at all. Infection with type C Influenza are usually caused by either a very mild respiratory illness, or there would be no symptoms at all. The most common host for Influenza is any ages in any lifetime. The symptoms of Influenza are fever, cough, and

7 Influenza transmit through respiratory droplet from an infect individual. When we come into contact with infections, our symptoms can be caused by two sources: the particular pathogen we are victim to and our immune response against the pathogen. The specific pathogens that enter our bodies can directly cause damage to our tissues and organs; certain pathogens can even affect various parts of our body, causing systemic infections. Systemic infections are caused by our own immune response, designed to destroy the pathogen, such as cytotoxic T-cells action cause Cell death in respiratory track. Our immune system reacts to the presence of the pathogen, and inflammatory response that causes collateral damage to our own tissues while

(Silverstein: 13) There are three types of influenza, depending on their activity: type A, which is usually the cause of outbreaks; type B, which is linked to sporadic cases, and type C, which rarely causes disease reactions. (Silverstein: 54) The virus which causes influenza enters the host through the respiratory tract, and binds itself to epithelial cells. The virus causes the cell to engulf it by endocytosis, and then fuses to the wall of the endocytic vesicle, injecting the contents of the virus into the cytosol of the cell. The RNA of the virus enter the nucleus of the cell, and spur the creation of new copies of the genes. These genes, as well as new viral proteins that are created in the cell, leave the cell as fresh viruses, budding off the plasma membrane of the cell.

Influenza or flu is a contagious viral infection that attacks nose, throat, and lungs. It can cause fever, chills, runny nose, sore throat, cough, muscle ache, and fatigue. The flu virus is extremely small and only visible through electron microscopes. Inside the virus genetic material contains the information to make more copies of the same virus. A protein shell provides hard protective enclosures for the genetic material as the virus travels between the people or animals it infects. And outer envelope allows the virus to infect cells by merging with the cell’s outer membrane projecting from the envelope or spikes of protein molecules. The flu virus uses its H spikes like a key to get inside cells. And N spikes allows copies of the virus to break away from infected cells to infect more cells. There are 17 known types of H spikes and 9 types of N spikes that scientist uses to name different flu viruses such as virus H5N1.

Influenza viruses are unique. They have the ability to avoid host immunity, therefore causing annual reoccurring epidemics of disease, and sometimes, major worldwide pandemics. The recognition of the variability in antigenic characteristics of influenza strains led to the establishment of a global Influenza Surveillance Network by the World Health Organization. The network monitors changes in viruses that cause outbreaks of influenza throughout the year all around the world. This article aims to explain the difference in epidemiology between influenza strains A and B, and how they are related to previous viruses.

This intricate virus contains many structures that allow it to survive and be pathogenic. Constructed by lipids, the cells

Industrialization and urbanization make people live and work in indoors, and some studies found that people in industrialized countries spend around 90% of their lifetime in the inside of the building [1, 2]. Therefore, it is important to recognize that, indoor air quality is an important determinant of public health [3]. In indoor air, the microbial fraction of aerosols present is of fundamental environmental and public health importance. This fraction is commonly termed “bioaerosols” and is a mixture of viable and nonviable microorganisms. The definition of bioaerosol includes airborne fungi, bacteria and viruses. Influenza viruses are one of bioaerosol in indoor environment and are among the most common causes of human respiratory infections. Influenza viruses are among the most significant because they cause high morbidity and mortality [4]. Influenza viruses are spreaded with different ways such as; direct contact, indirect contact, large respiratory droplets and aerosols that are left behind by the evaporation of larger droplets [5]. Also, Virus aerosols may be released into air when infected

The characteristics of it are that it is small, microscopic, and has a sphere like form with spikes surrounding the outside covering. It has a lipid envelope. The diameter of it is approximately 80-120 nanometers. Only about 80% of the spikes are hemagglutinin, a protein that functions as an attachment to the host cell. The other 20% of the spikes contains neuraminidase, is involved in the releasing of the newly produced virus from the host cell. On the inner side of the envelope there is an antigenic matrix protein lining. Inside of it contains the genome influenza; it is organized into 8 pieces of single RNA strands. Sometimes there are also mutations that can occur when reproducing. The top 2 types of mutations that

the macromolecular synthesis of the host cell is not shut off, and virus purification is difficult

essential for the entry of the viruses into the host cell by attaching to its cell surface (10). GP is a

The protective capsid helps the virus escape detection and destruction during the invasion of the host. When the virus reaches the target cell, biochemical reactions between the capsid and cell wall allow the virus to latch on and inject its genome into the cell’s interior. Once inside, the viral genetic material insinuates itself into the host’s DNA or RNA. In an efficient feat of natural bioengineering, the host cell’s genetic machinery now does the rest of the work for the virus. The cell, which had already been making copies of its own genome, now also replicates that of the virus. Coded within the viral material is the blueprint for making more copies of the viral genome. Further instructions command the production of capsids and directions for assembly of new viruses. After the host cell becomes engorged with viruses, it explodes, sending the new