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Egg Drop Syndrome
Egg drop syndrome '76 (EDS '76) is a viral disease that affects birds, notably chickens, ducks, geese and swans. It is characterised by a sudden drop in production of eggs as well as its eggshell quality in apparent healthy laying birds. Previously, this disease was commonly named as merely "egg drop syndrome"; however, it is now recommended that full name, egg drop syndrome '76 (EDS '76), should be used to distinguish the name discrepancy from the recently identified disease in ducks caused by a flavivirus, which is confusingly called "egg drop syndrome in ducks" or "duck egg drop syndrome". Incidence EDS '76 was first identified in Netherlands in 1974 and the virus was first isolated in Northern Ireland in 1976. It became a problem in European countries such as Ireland, the Netherlands, France, and the United Kingdom. Other places which have had outbreaks include India, Bangladesh, South America, Indonesia, Japan, and Africa. Since then, EDS '76 has been recognised as a global ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemagglutination Assay
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. HA and HI apply the process of hemagglutination, in which sialic acid receptors on the surface of red blood cells (RBCs) bind to the hemagglutinin glycoprotein found on the surface of influenza virus (and several other viruses) and create a network, or lattice structure, of interconnected RBCs and virus particles. The agglutinated lattice maintains the RBCs in a suspended distribution, typically viewed as a diffuse reddish solution. The formation of the lattice depends on the concentrations of the virus and RBCs, and when the relative virus concentration is too low, the RBCs are not constrained by the lattice and settle to the bottom of the well. Hemagglutination is observed in the presence of staphylococci, vibrios, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virotherapy
Virotherapy is a treatment using biotechnology to convert viruses into therapeutic agents by reprogramming viruses to treat diseases. There are three main branches of virotherapy: anti-cancer oncolytic viruses, viral vectors for gene therapy and viral immunotherapy. These branches use three different types of treatment methods: gene overexpression, gene knockout, and suicide gene delivery. Gene overexpression adds genetic sequences that compensate for low to zero levels of needed gene expression. Gene knockout uses RNA methods to silence or reduce expression of disease-causing genes. Suicide gene delivery introduces genetic sequences that induce an apoptotic response in cells, usually to kill cancerous growths. In a slightly different context, virotherapy can also refer more broadly to the use of viruses to treat certain medical conditions by killing pathogens. History Chester M. Southam, a researcher at Memorial Sloan Kettering Cancer Center, pioneered the study of viruses as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Viral Diseases
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes, containing animals such as nematodes, arthropods, flatworms, annelids and molluscs, and the deuterostomes, containing the echi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poultry Diseases
Poultry diseases occur in poultry, which are domesticated birds kept for their meat, eggs or feathers. Poultry species include the chicken, turkey, duck, goose and ostrich. Viral diseases * Avian infectious bronchitis, caused by a strain of Avian coronavirus previously known as infectious bronchitis virus * Avian infectious laryngotracheitis, caused by Gallid alphaherpesvirus 1 * Avian influenza, caused by Avian influenza virus * Duck plague, caused by Anatid alphaherpesvirus 1 * Chicken infectious anemia, caused by Chicken anaemia virus * Epidemic tremor, caused by Tremovirus * Fowlpox, caused by viruses in the genus ''Avipoxvirus'' * Infectious bursal disease (IBD), also known Gumboro disease, caused by Infectious bursal disease virus * Lymphoid leukosis caused by avian sarcoma leukosis virus * Marek's disease * Newcastle disease * Viral arthritis, caused by Avian reovirus Parasitic diseases * Scaly leg, caused by the mite ''Knemidocoptes mutans'' * Infestation by ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail. PCR was invented in 1983 by the American biochemist Kary Mullis at Cetus Corporation; Mullis and biochemist Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plaque Reduction Neutralization Test
The plaque reduction neutralization test is used to quantify the titer of neutralizing antibody for a virus. The serum sample or solution of antibody to be tested is diluted and mixed with a viral suspension. This is incubated to allow the antibody to react with the virus. This is poured over a confluent monolayer of host cells. The surface of the cell layer is covered in a layer of agar or carboxymethyl cellulose to prevent the virus from spreading indiscriminately. The concentration of plaque forming units can be estimated by the number of plaques (regions of infected cells) formed after a few days. Depending on the virus, the plaque forming units are measured by microscopic observation, fluorescent antibodies or specific dyes that react with infected cells. The concentration of serum to reduce the number of plaques by 50% compared to the serum free virus gives the measure of how much antibody is present or how effective it is. This measurement is denoted as the PRNT50 value. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ELISA
The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence of a ligand (commonly a protein) in a liquid sample using antibodies directed against the protein to be measured. ELISA has been used as a diagnostic tool in medicine, plant pathology, and biotechnology, as well as a quality control check in various industries. In the most simple form of an ELISA, antigens from the sample to be tested are attached to a surface. Then, a matching antibody is applied over the surface so it can bind the antigen. This antibody is linked to an enzyme and then any unbound antibodies are removed. In the final step, a substance containing the enzyme's substrate is added. If there was binding, the subsequent reaction produces a detectable signal, most commonly a color change. Performing an ELISA involves at le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newcastle Disease
Virulent Newcastle disease (VND), formerly exotic Newcastle disease, is a contagious viral avian disease affecting many domestic and wild bird species; it is transmissible to humans. Though it can infect humans, most cases are non-symptomatic; rarely it can cause a mild fever and influenza-like symptoms and/or conjunctivitis in humans. Its effects are most notable in domestic poultry due to their high susceptibility and the potential for severe impacts of an epizootic on the poultry industries. It is endemic to many countries. No treatment for VND is known, but the use of prophylactic vaccines and sanitary measures reduces the likelihood of outbreaks. The disease is caused by Newcastle disease virus (NDV), an avulavirus. Strains of Newcastle disease virus have been used to treat cancer in humans, since the virus appears to preferentially infect and kill cancerous cells. Strains of Newcastle disease virus have also been used to create viral vector vaccine candidates against Ebo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavivirus
''Flavivirus'' is a genus of positive-strand RNA viruses in the family ''Flaviviridae''. The genus includes the West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, Zika virus and several other viruses which may cause encephalitis, as well as insect-specific flaviviruses (ISFs) such as cell fusing agent virus (CFAV), Palm Creek virus (PCV), and Parramatta River virus (PaRV). While dual-host flaviviruses can infect vertebrates as well as arthropods, insect-specific flaviviruses are restricted to their competent arthropods. The means by which flaviviruses establish persistent infection in their competent vectors and cause disease in humans depends upon several virus-host interactions, including the intricate interplay between flavivirus-encoded immune antagonists and the host antiviral innate immune effector molecules. Flaviviruses are named for the yellow fever virus; the word ''flavus'' means 'yellow' in Latin, and yellow fever in turn is named from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avian Infectious Bronchitis Virus
''Avian coronavirus'' is a species of virus from the genus ''Gammacoronavirus'' that infects birds; since 2018, all gammacoronaviruses which infect birds have been classified as this single species. The strain of avian coronavirus previously known as infectious bronchitis virus (IBV) is the only coronavirus that infects chickens. It causes avian infectious bronchitis, a highly infectious disease that affects the respiratory tract, gut, kidney and reproductive system. IBV affects the performance of both meat-producing and egg-producing chickens and is responsible for substantial economic loss within the poultry industry. The strain of avian coronavirus previously classified as Turkey coronavirus causes gastrointestinal disease in turkeys. Classification IBV is in the genus ''Gammacoronavirus'', or group 3, with a non-segmented, positive-sense single-stranded RNA genome. It was previously the type species of its genus '' Igacovirus''. When there was only one genus of coronavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avian Influenza
Avian influenza, known informally as avian flu or bird flu, is a variety of influenza caused by viruses adapted to birds.Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner in ''Influenza Report 2006'' CDC has a showing the relationship between dozens of highly pathogenic varieties of the Z genotype of avian flu virus H5N1 and ancestral strains. The type with the greatest risk is highly pathogenic av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
