Influenza, commonly called "the flu," is an illness caused by RNA viruses that infect the respiratory tract of many animals, birds, and humans. Influenza viruses are found in body fluids such as saliva and mucous and commonly transmitted via tiny, air-born droplets created through sneezing and coughing. Depending on the conditions and temperature of the environment, the Influenza virus can remain infectious for up to one month. Transmission occurs as a new host comes into contact with viruses dispersed into the air or onto surfaces of objects. The main targets of the influenza virus are the columnar epithelial cells of the trachea, bronchi and bronchioles. HA binds to galactose-bound sialic acid on the surface of host cells. The HA binding …show more content…
Once tightly bound the virus is endocytosed via coated vesicles. The virus is transported into late endosomes which acidify their content and hence induce conformational rearrangement of HA exposing the fusiogenic peptide sequence. The loop region of the HA becomes a coiled coil that mediates membrane fusion. The release of viral genome into the cytoplasm also requires protons that are pumped from the acidic endosome into the virion interior via the matrix protein M2 that acts as a proton channel. Viral RNA dissociates from M1 and is then imported in an ATP-dependent manner into the nucleus for transcription and translation. In humans, the replication of the influenza virus is usually restricted to the airways epithelial cells due to the limited expression of a serine protease, produced by nonciliated bronchial epithelial cells and which cleaves the HA precursor in HA1 and HA2 polypeptides, rendering the virions infectious. Replication and virions production occurs within hours after virus entry. The viral ribonucleoprotein (vRNP) complexes are released from the endosomes into the cytoplasm and subsequently transported to the nucleus, where replication and transcription take …show more content…
Influenza type A viruses are divided into subtypes based on two proteins on the surface of the virus. These proteins are called hemagglutinin (HA) and neuraminidase (NA). There are 15 different HA subtypes and 9 different NA subtypes. There are three prominent subtypes of influenza A that are known to infect both birds and people. The first one is influenza A H5; there are nine known subtypes of H5 viruses (H5N1, H5N2, H5N3, H5N4, H5N5, H5N6, H5N7, H5N8, and H5N9). Most H5 viruses identified worldwide in wild birds and poultry are low pathogenic viruses, but occasionally highly pathogenic viruses have been detected. Sporadic H5 virus infection of humans, such as with Asian-origin highly pathogenic avian influenza A (H5N1) viruses currently circulating among poultry in Asia and the Middle East have been reported in 16 countries, often resulting in severe pneumonia with approximately 60% mortality worldwide. The second one is influenza A H7; there are nine known subtypes of H7 viruses (H7N1, H7N2, H7N3, H7N4, H7N5, H7N6, H7N7, H7N8, and H7N9). Most H7 viruses identified worldwide in wild birds and poultry are LPAI
There are there types of influenza A and C or the most severe types and B which is the most common, Luckily not the to severe. The virus works by first attaching to the outside of a host cell. It injects its RNA into the cell. Unfortunately our cells treat the RNA like they should. It translates the viral genes using the cell’s ribosomes and enzymes. Now the virus can take the cell over and use it to reproduce more viruses. Sooner or later it releases the new nauseating viruses and they search for another cell to raid.
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
According to History.com, a well-known historical record website, on March 11th 1918, a U.S. Army soldier reported cold-like symptoms consisting of sore throat, fever, and headache. By the noon of that same day, over 100 other soldiers reported the same symptoms. This would grow into the first-known outbreak of influenza in the world, infecting 500 million people worldwide, and killing over 20 million people. Robert Krulwich, a scientific correspondent for NPR, explains the process by which a virus enters your body and manifests into something much worse: The influenza virus first enters your respiratory system by inhalation or other, less-common methods. The virus is then expelled into your bloodstream where it latches onto a cell found there.
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 (flu) is an acute, contagious and fast-spreading respiratory infection caused by the influenza virus. Virus spread through the contact between persons, contact with contaminated items or the droplets in the air. Typical symptoms are high fever, chills, body aches, significant fatigue and mild respiratory infection. There is a high incidence of infection in autumn and winter, complications and mortality are very serious. This influenza viral disease can be classified into three types, A, B and C which cause the annual influenza epidemics that have up to 20% of the population sniffling, aching, coughing, and running high fevers. This disease is self-limiting, but serious complications such as pneumonia in infants, children, elderly
There are different ways a molecule can be endocytosed into cell. Rust and colleagues focused on two different mechanisms: clathrin-mediated endocytosis and clathrin- and caveolin-independent endocytosis. Using real-time visualization of the influenza virus, Rust and colleagues were able to observe these two pathways in action. They hypothesized that without inhibiting endogenous endocytic mechanisms of the cell, the influenza virus would use both types of pathways to enter a cell.
Influenza, commonly called the fu, is a viral infection that attacks the respiratory system. 5 to 20 percent of Americans will be infected by the flu virus every year, causing about 200,000 hospitalizations and 36,000 deaths (Colds/Flu, National center for complementary and integrative health, nccih.nih.gov). The influenza virus enters the cell, injects its nucleic acid, transcribes the RNA, assembles the new virion, and begins lysis of the cell.
Unlike DNA viruses, the RNA influenza virus lacks the proofreading mechanism to self-repair arising errors during its replication. Thus two forms of genetic variations representing a hallmark feature of influenza viruses. The antigenic drift occurred in influenza type A and influenza type B. The accumulation of changes in surface glycoproteins, hemagglutinin and neuraminidase, by gene sequence mutations of virus RNA segments causing the antigenic drift. These mutations cause minor changes in HA and NA antibody-binding sites generating novel strains of influenza virus that responsible for the seasonal epidemics. As these novel strains are not detectable by host antibodies that were generated against previous strains, they can infect both vaccinated
A virus is “snippet of nucleic acid, either DNA or RNA” (YouTube, Dr. Tony Fauci, H1N1 Influenza a Virus, 2009) that is able to replicate itself only in other cells. Unlike bacteria, a virus cannot thrive on its own. A virus has to break into a cell and take control of the cell functions in order to replicate, often causing disease. Some viruses are benign, and others cause diseases like polio, smallpox, and measles. There are be three types of influenza: A, B, and C, which are all found in humans. Influenza A is found in “birds, pigs, whales, horses, and seals” (Microbiology: An Introduction, 2016, pp. 364) and also humans. It has the ability to attack the respiratory system, nose, throat, and lungs. Influenza A can also cause fever, chills, sore throat, runny nose, cough, muscle aches, and fatigue. The swine flu (influenza a virus) is an acute virus. The infected person shows the symptom of
Virions consist of a lipid membrane (envelope) derived from the host cell with glycoproteins (spikes) on the top of it. There are two types of glycoproteins in Influenza A and Influenza B viruses – neuraminidase (NA) and hemagglutinin (HA). These spikes can reach the
An influenza is a highly contagious viral infection of the respiratory passages causing fever, severe aching, and catarrh, and often occurring in epidemics. Because it is a viral infection, it cannot be treated with antibiotics. Antiviral agents can reduce the severity and duration of infection, but these are
What is influenza? According to Flu Guide, “influenza is a respiratory infection. It is caused by the influenza virus. It typically spreads by air or by direct contact from one person to another. Influenza virus can be highly contagious” (1). Worldwide, the majority of people commonly come in contact with this virus during the colder months. The symptoms of this illness are commonly, “chills, moderate to high fever, muscle aches, headaches, fatigue, cough, vomiting, sore throat, runny nose, diarrhea and dizziness” (Flu Guide 1). According to Flu Causes, “you can spread the flu 7 days after these symptoms start. The virus can live in your mucus and spit up to 24 hours before you start to feel bad. This means you might give it to someone else
The influenza virus is an RNA virus has an envelope that included members of the family Orthomyxoviridae. Its genome is a single negative strand segmented RNA. This virus consists of three types: A, B, and C. Influenza types A and B has eight segments of RNA, but the influenza virus type C only has 7
Influenza also known as the flu will be the next virus of discussion. Like Ebola and HIV; Influenza is characterized as an enveloped virus but consist of eight segments of single-stranded RNA. The shape of the Influenza virus is as that of HIV, round. Structurally the round influenza cell is covered in an envelope that is made of a lipid bilayer with spikes of glycoproteins that are called hemagglutinin and neuraminidase. With those types of proteins, the virus is able to bind with a host cell.
The flu, properly called influenza, is an amazingly widespread and widely known disease. There are many variations of the influenza virus, differing in severity, but not significantly different in function. The influenza virus infects epithelial cells in the respiratory tract, taking over the cell’s production mechanisms so more viruses are produced, eventually causing the host cells to burst. The body’s immune system tries to combat the infection from succeeding. This internal battle produces many outward symptoms including a fever and dry cough, among others. Influenza is not usually a fatal disease, but its high mutation rate insures its continuing import by allowing it to return in