Topic: bacteria, viruses, and health order description please do not work with the multiple choice question part just proceed working with the 7 page essay final exam for biol 302 bacteria, viruses, and health summer 2016 this is an open-book take-home final exam. Influenza viruses have been divided into three types, ( a, b and c ) and this based on their nucleoprotein antigen fluctuation type a grippe viruses are exposed to decelerate mutants ( antigenic impetus ) and disconnected alterations in their surface protein ( antigenic displacement ). The hemagglutination assay (or haemagglutination assay ha) and the hemagglutination inhibition assay (hi or hai) were developed in 1941–42 by american virologist george hirst as methods for quantifying the relative concentration of viruses, bacteria, or antibodies.
Influenza was chosen due to the prevalence of the numerous influenza viruses that have circulated globally over the last few decades and the presence of community health nurses on the frontlines of dealing with the diseases. The neuraminidase protein present on influenza viruses acts to break virus-cell bonds and may eventually begin to break apart the lattice formed by the virus and erythrocytes some virus strains have very high neuraminidase activity and may not allow proper hemagglutination. Influenza a viruses are very hard to control because they undergo changes, making it harder for human's immune systems to detect them there are two types of changes the first is a series of mutations that occur over time and cause a gradual change in the virus.
Influenza viruses onslaught chiefly to epithelial cells of the respiratory piece of land the virus receptor at ha adhering site is required to adhere with galactose bound sialic acid on the host cells surface, followed by merger of the viron in the cell and let go of viral rna. There are many subtypes of avian influenza viruses, but only some strains of four subtypes have been highly pathogenic in humans these are types h5n1, h7n3, h7n7, and h9n2 once domesticated birds such as chickens or turkeys are infected, it could become much more deadly because the birds are often within close contact of one another. Influenza a h1n1 virus is a subtype of influenza virus a and the most cause of influenza/flu in humans viruses are considered non-living because of their prodigious reproductive abilities viruses are considered non-living because of their prodigious reproductive abilities. Many viruses that infect only animals, such as influenza, have an exterior viral envelope ii in many cases, the viral envelope is composed of a lipid bilayer derived from the membrane of the host cell d.
The presumed influenza anamnesis of the human population born before 1956—the year when a(h1ni) influenza viruses came out of circulation—is modelled on sixty male white rats the model is an essay to clarify why these people demonstrated higher resistance to influenza a(h1n1) during its. Influenza, commonly referred to as the flu, is an infectious disease caused by rna viruses of the family orthomyxoviridae (the influenza viruses), that affects birds and mammals the most common symptoms of the disease are chills, fever, sore throat, muscle pains, severe headache, coughing, weakness/fatigue and general discomfort. Influenza also undergoes antigenic drift, where one strain of the virus mutates within itself this gradual evolution is very common, but occurs much more slowly, thus the name drift dr robert webster, a renowned virologist warns us “all the genes of all influenza viruses in the world are being maintained in aquatic birds, and periodically.
Much like other influenza a viruses, the virion of the h5n1 virus is enveloped and is either spherical or filamentous as to its formation and in clinical isolates, the virus has been shown to be more filamentous, while in some laboratory strains, it appears more spherical (eigel, et al, 1379. Influenza virus – essay sample adaptive and mutated strains of the influenza virus have provided emergence of a new strain called h1n1(2009) this potentially leading towards pandemic conditions that can spread amongst the human population. Avian influenza, also known as bird flu, is a zoonotic disease with several different subtypes that affect mostly other birds, but few can be transmitted to humans the most prevalent avian influenza virus in humans is the highly pathogenic avian influenza a (h5n1) virus, which has caused over 380 confirmed cases in 15 countries (rabinowitz, [. Influenza viruses are important pathogens that can cause sporadic respiratory diseases, annual epidemics and (in case of influenza a virus) periodic pandemics thus innovative and continuous.
Influenza pandemics are caused by type a viruses, and therefore these are the most feared type of influenza virus neither types b or c have caused pandemics type a influenza is classified into subtypes depending on which versions of two different proteins are present on the surface of the virus. Influenza a viruses can be broken down into sub-types depending on the genes that make up the surface proteins over the course of a flu season, different types (a & b) and subtypes (influenza a) of influenza circulate and cause illness.
Recommendation covering two influenza a viruses (h1n1 and h3n2) and an influenza b virus, had also recommended further research on inclusion of a fourth strain (another influenza b virus of different linage) background+paper+on+influenza+vaccines+and+immunization+. The influenza or the flu is caused by rna viruses which belong to orthomyxoviridae family of viruses there are three types of flu viruses infect humans are influenza a, influenza b and influenza c influenza a viruses only infect nonhuman hosts, and a reassortment of genes can happen between those subtypes. 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 viruses h7 virus infection in humans is uncommon. Influenza influenza, commonly known as the flu, is an infectious disease of birds and mammals caused by rna viruses of the family orthomyxoviridae, the influenza viruses the most common symptoms are chills, fever, sore throat, muscle pains, headache (often severe), coughing, weakness/fatigue and general discomfort.