Influenza A Virus Lab Report

Additionally, as many as 500,000 chicken eggs per day are needed for the process. Influenza viruses are injected into chicken egg embryos, where they are allowed to incubate and multiply for several days. A machine extracts the virus from the egg, which is then purified and chemically killed and made into the vaccine. (Tenpenny, 2008, Davidson, 2007-2009, Offit, 2008).

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.

Influenza is not a deadly virus and does have a vaccination. One of the three types of influenza, type C, “type C infections cause a mild respiratory illness and are not thought to cause epidemics” (Types of Influenza Viruses). The other two types of influenza viruses type“ A and B viruses cause seasonal epidemics” and happen mostly when winter hits (Types of Influenza

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.

Seasonal Influenza is the monitored acquisition of the current avian influenza affecting a patient in that particular season, it commonly presents itself as a common cold but then advances to show more serious symptoms, in addition the seasonal influenza can mutate if not treated properly creating yet another strand of the attenuated virus. A primary health care physician can only diagnose seasonal influenza because some symptoms mimic those of the common cold, however the seasonal influenza is often misdiagnosed- one of the many reasons attempts of retention struggle. However there is a solution in the prevention of these epidemics and they include the proper implementation on the influenza vaccines. There are two different types of vaccines the Intramuscular injection is applied to the forearm and the LAIV (live

The FDA approved in 2003 the commercialization of FluMist® (MedImmune) the first influenza vaccine with attenuated virus. This trivalent vaccine is administrated via intranasal spray because the virus replicates in cells lining the nasopharynx [21–23]. Use of live-attenuated vaccine has been limited to individuals two through forty-nine years of age based on a failed efficacy to prevent febrile illness in adults fifty through sixty five years of age [22]. As in the TIV the first step for the vaccine production is the generation of the viral seeds that presents the circulating HA and NA and six internal segments (PA, PB1, PB2, NS, NP, M) from the cold-adapted (ca) A/Ann Arbor/6/60 or ca B/Ann Arbor/1/66 (the master donor virus for LAIV (MDV)) [24, 25]. The manufacture of approved FluMist® is also based on the injection in embryonated eggs of the reassortant virus and the recovery of the allantoic fluid with the screening of the reassortant that grows well at 25ºC (cold-adapted) and present restricted growth (ta) at 37-39ºC and is attenuated (att). The vaccine is tested in the ferret model [22].

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 remains as a significant global threat to public health. In United States alone, a typical influenza epidemic results in over 25 million infections, 300,000 hospitalizations and 13,000 deaths every year (1). The virus evolves antigenically from one year to the next, requiring annual reformulation of the vaccine and leading to variable vaccine efficacy. Exacerbating this natural antigenic evolution, adaptation to the chicken eggs may occur during the manufacture of virus used to produce the inactivated vaccine (2). This year such adaptation has reduced the vaccine efficacy against H3N2 strain (3). Low vaccine efficacy is expected to generate higher attack rates, as has already occured in Australia (3, 4). Compounding the effects of low vaccine efficacy, public perception following the widespread media attention may depress vaccine uptake for a given year. The combination of low vaccine efficacy and low coverage has the potential to reduce herd immunity, putting the population at risk of elevated infection incidence and ultimately high rates of infections and mortality. Consequently, optimizing epidemiological effectiveness of vaccination given vaccine efficacy is imperative to minimize the annual mortality and morbidity of influenza.

The influenza virus is transmitted from human to human mainly by droplet, although there are cases of animal to human transmission. The incubation

Every year, many people get influenza all over the world and sometime this disease causes death. Medical care has been improved, but it is difficult to prevent influenza. People get it easily. According to Mortada, during the ful season of 2012 to 2013, the disease has caused 111 deaths (Mortada, 16). We have to prevent ourselves from the disease as much as we can. Otherwise, it would be infect to other people 　including family, friends, classmates, coworkers, and more. To prevent influenza, we must have strong immune system and get vaccinations that are suited for each person.

There are two important proteins used in the determination of the type of influenza; haemagglutinin (HA) and neuraminidase (NA). There are 18 known variations of the haemagglutinin protein and 11 of the neuraminidase protein, giving hundreds of possible variations in the subtypes of the virus . These subtypes are further divided into different strains that have a divergent molecular makeup, giving rise to viruses that differ in virulence, ease of transmission and severity of symptoms. Not all strains of influenza can cause disease in humans; influenza D subtypes cannot infect humans and influenza C infections are rare and usually very minor. Influenza A and B are the subtypes that are responsible for the common infections and the epidemics and pandemics that occur periodically, with influenza A causing the majority of these infections. The virus is transmitted through the inhalation of droplets which are expelled when an infected person coughs or sneezes, through contact with a contaminated surface and through the exchange of saliva . The infected person becomes infectious to others around 12 hours after first contact with the virus and remains contagious for around the next five days; this can vary as the immunocompromised can take longer to subdue the virus and children tend to be more infectious than adults . The virus incubates in the respiratory tract by invading cells through the cleavage of the viral protein haemagglutinin by human proteases . The pathogenicity of a certain strain is determined by the spread of proteases in the respiratory tract that can cleave the proteins of the virus; a strain is typically milder if the proteases that reside in the lungs and throat are the only ones capable of cleaving the virus, causing an upper respiratory tract (URT)

potential pathogens and their particular tissue location. Rapid influenza antigen testing is completed by swabbing the nose, mouth or throat obtaining secretions for staining with fluorescent antibodies to identify the virus. This usually takes 1 to 3 hours for the determination of results whether a bacteria is positive or negative, so that the correct antibiotics can be prescribed. First a thin smear of bacteria on a clean slide that is covered with crystal violet stain for 1 minute. A wash is completed and iodine solution is added to the smear to enhance staining for 1 minute. Being rinsed again in water and then 95% ethanol for one minute. Washing the violet stain off will differentiate between the two types of bacteria. If the bacteria

The incubation period of Influenza virus is reported to be average 2 days (range 1–4 days). The shedding of the influenza virus is detectable 24 to 48 hours before the clinical onset. The shedding reaches peak during the first 24 hours of illness due to virus. The virus shedding generally declines over next 5 days which may be longer in children (Carrat et

The influenza virus looks like a sphere covered with spike like proteins for grip ready to latch on to a healthy human cell. The virus holds RNA in the very center of the virus. The outside layer is called the envelope. “The H spike (hem agglutinin) and the N spike (neuraminidase) are called proteins and exist in the envelope and they are used for antigenic typing” (Pearson 2004). These proteins allow the virus to enter and exit the host (our cells). Once the virus is inside the cell, the virus can begin reproducing. Soon, each infected cell is filled with thousands of new viruses, each of them looking to leave the cell to find a new home in another cell and begin

With a huge number of victims, 80 to 100 million, since 1918, the influenza is considered as one of the most pandemic diseases ever. There are three types of influenza virus: influenza virus A, influenza virus B, and influenza virus c. These are a subtypes of the virus family orthomyx-oviride. The types B and C do not cause pandemic diseases while type A does. The type A classified into three main subtype H1.N1, H1.N2, and H3.N2. The (H.N) refers to the two kinds of proteins on the surface of the virus (hemagglutinin and neuraminidase). The difference in numbers is due to the difference in protein variability. A H1.N1 virus which is widely known as Spanish flu is the only type that can transmit from human to human. The H5.N1, or “bird flu”