Influenza virus growing

Fertile chicken eggs, 10-12 days old, have been used as a convenient cell system in which to grow a number of human pathogenic viruses. Figure 3.7 shows that viruses generally have preferences for particular tissues within the embryo. Influenza viruses. 

Burnat, Sir Frank Maefarlane (1899-1985) Australian virologist, who spent his working life at the Walter and Eliza Hall Institute in Melbourne. In the early 1930s he developed a method of growing influenza virus in chick embryos. He later discovered that immunological tolerance (failure of the immune response) required repeated exposure to the antigen. For this work he shared the 1960 Nobel Prize for physiology or medicine with Sir Peter Medawar. He dso proposed the clonal selection theory. 

Samples taken from a dead duck to be tested for the highly pathogenic avian influenza virus H5N1. Veterinary pathology, which studies disease and its process in animals, is an area of pathology that is growing quickly. (AP Photo)... 

The salient biochemical fact of phage multiplication is that infection of a rapidly growing cell by a virulent but metabolically inert virus particle produces a cessation of normal synthesis and an almost total diversion of the enzymatic apparatus of the cell to the production of the foreign agent. Actually this statement implies three points that must be demonstrated first, that phage has no metabolic activity, second, that the enzymes of the host cell are used for synthesis of the virus, and third, that only virus is produced after infection. The first of these is most widely accepted for reason of the fact that no virus has ever been shown to possess independent metabolic activity. For animal viruses this conclusion is based mainly on the detailed study of vaccinia and influenza, which Bauer (25) has concluded have no enzymatic activity apart from the questionable instance of mucinase in influenza virus. 

Viruses of vertebrates and man have not been studied nearly as well as those of the plants and bacteria mentioned. Many of them are considerably bigger The influenza virus (shown in Fig. 35 has a particle weight of 350 million the smallpox virus, several billion. These viruses contain components which are host specific and not virus specific. The introduction of tissue culture for growing virus and the use of the electron microscope for their characterization has permitted substantial progress in virus research. 

There is a set of two (or possibly three) strains of virus associated with the disease influenza. It is only these particular virus strains that the "so-called" flu shot is intended to be effective against. Note that the science journal that described this inoculation [27] was very meticulous in its choice of terminology. It deliberately never used the word flu . To the lay public, the word flu refers to any bad rhino virus, of which there are over 300 known such viruses today, as well as thousands of the larger class of all viruses. Moreover, these numbers are rapidly growing with new discoveries. To the scientists who designed, synthesized and analyzed these chemicals, the inoculation that they developed is intended to ward off only two viruses, not hundreds or thousands. The misinterpretation of these results by writers in the popular press, and even some, who should have known better, in science... 

The population balance model of Mohler et al. [4], which forms the basis for the presented approach, describes the replication of influenza A viruses in MDCK cells growing on microcarriers. It is rmstmctured and includes three concentrated state variables, which are the number concentrations of uninfected cells Uc, infected cells /<, and free virus particles V. 

Viral infection in the 21 century is still a leading cause ofhuman and animal disease. From historically well known scourges such as influenza to the growing list of emerging viruses and to the relatively recent intractable threat posed by human immunodeficiency virus (HIV), viruses continue to exercise the intellect of scientists, clinicians and public health experts. 

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