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PRRSV Genome Organization
Porcine reproductive and respiratory syndrome virus (PRRSV), is a virus that causes a disease of pigs, called porcine reproductive and respiratory syndrome (PRRS), also known as blue-ear pig disease (in Chinese, ''zhū láněr bìng'' 豬藍耳病). This economically important, panzootic disease causes reproductive failure in breeding stock and respiratory tract illness in young pigs. History PRRS earlier known as "mystery swine disease" and "blue ear disease" during 1987–1988 in the United States and Canada caused first undiagnosed outbreaks, characterized by reproductive losses combined with respiratory signs. In 1990-1991, a similar disease was reported in several European countries such as Germany, The Netherlands, Belgium, Denmark, France, the United Kingdom, and Spain. The emergence of PRRS in Japan, Taiwan and mainland China was reported in 1987, 1991 and 1996, respectively. According to the WOAH, the disease is now present throughout the world, especially in countri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panzootic
A panzootic (from Greek παν all + ζόιον animal) is an epizootic (an outbreak of an infectious disease of non-human animals) that spreads across a large region (for example a continent), or even worldwide. The equivalent in human populations is called a pandemic. A panzootic can start when three conditions have been met: * the emergence of a disease new to the population. * the agent infects a species and causes serious illness. * the agent spreads easily and sustainably among animals. A disease or condition is not a panzootic merely because it is widespread or kills a large number of animals; it must also be infectious. For example, cancer is responsible for a large number of deaths but is not considered a panzootic because the disease is, generally speaking, not infectious. Unlike an epizootic, a panzootic covers all or nearly all species over a large surface area (ex. rabies, anthrax). Typically an enzootic or an epizootic, or their cause, may act as a potential prepa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PRRSV Genome Organization
Porcine reproductive and respiratory syndrome virus (PRRSV), is a virus that causes a disease of pigs, called porcine reproductive and respiratory syndrome (PRRS), also known as blue-ear pig disease (in Chinese, ''zhū láněr bìng'' 豬藍耳病). This economically important, panzootic disease causes reproductive failure in breeding stock and respiratory tract illness in young pigs. History PRRS earlier known as "mystery swine disease" and "blue ear disease" during 1987–1988 in the United States and Canada caused first undiagnosed outbreaks, characterized by reproductive losses combined with respiratory signs. In 1990-1991, a similar disease was reported in several European countries such as Germany, The Netherlands, Belgium, Denmark, France, the United Kingdom, and Spain. The emergence of PRRS in Japan, Taiwan and mainland China was reported in 1987, 1991 and 1996, respectively. According to the WOAH, the disease is now present throughout the world, especially in countri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Reproduction Number
In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted R_0 (pronounced ''R nought'' or ''R zero''), of an infection is the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection. The definition assumes that no other individuals are infected or immunized (naturally or through vaccination). Some definitions, such as that of the Australian Department of Health, add the absence of "any deliberate intervention in disease transmission". The basic reproduction number is not necessarily the same as the effective reproduction number R (usually written R_t 't'' for "time" sometimes R_e), which is the number of cases generated in the current state of a population, which does not have to be the uninfected state. R_0 is a dimensionless number (persons infected per person infecting) and not a time rate, which would have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog to be present. Humidity depends on the temperature and pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 8 g of water per cubic metre of air at , and 28 g of water per cubic metre of air at Three primary measurements of humidity are widely employed: abso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCID50
Virus quantification is counting or calculating the number of virus particles (virions) in a sample to determine the virus concentration. It is used in both research and development (R&D) in academic and commercial laboratories as well as in production situations where the quantity of virus at various steps is an important variable that must be monitored. For example, the production of virus-based vaccines, recombinant proteins using viral vectors, and viral antigens all require virus quantification to continually monitor and/or modify the process in order to optimize product quality and production yields and to respond to ever changing demands and applications. Other examples of specific instances where viruses need to be quantified include clone screening, multiplicity of infection (MOI) optimization, and adaptation of methods to cell culture. There are many ways to categorize virus quantification methods. Here, the methods are grouped according to what is being measured and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study. PCR was invented in 1983 by American biochemist Kary Mullis at Cetus Corporation. Mullis and biochemist Michael Smith (chemist), 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 DNA, 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 and forensic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotypes
The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a specific gene depends on the number of copies of each chromosome found in that species, also referred to as ploidy. In diploid species like humans, two full sets of chromosomes are present, meaning each individual has two alleles for any given gene. If both alleles are the same, the genotype is referred to as Zygosity, homozygous. If the alleles are different, the genotype is referred to as heterozygous. Genotype contributes to phenotype, the observable traits and characteristics in an individual or organism. The degree to which genotype affects phenotype depends on the trait. For example, the petal color in a pea plant is exclusively determined by genotype. The petals can be purple or white depending on the alleles present in the pea plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porcine Reproductive And Respiratory Syndrome Virus 2
Porcine reproductive and respiratory syndrome virus 2 (''Betaarterivirus americense'') is a species of enveloped, positive-strand RNA viruses which infect domestic pigs. It is one of two porcine reproductive and respiratory syndrome viruses (PRRSV). The two types of PRRSV are distinguished by which genomic cluster they are associated with. Type 1 is associated with a LV cluster. Type 2 is associated with a VR2332 cluster. PRRSV is in the '' Arteriviridae'' family and the order ''Nidovirales''. It has a positive sense RNA genome that is 15 kb long. This genome consists of ten open reading frames (ORFs) with a 5' untranslated region (UTR) and a 3' UTR. PRRSV causes porcine reproductive and respiratory syndrome in swine. This syndrome results in failure during breeding and respiratory problems. Type 2 PRRSV was first seen in the United States in 1987. However, it has now spread worldwide to commercial swine facilities. Within the swine industry, porcine reproductive and respirator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Phylogenetic Tree Of PRRSV
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, '' a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest known ancestor of A is ''aleph''—the first letter of the Phoenician ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleocapsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The proteins making up the capsid are called capsid proteins or viral coat proteins (VCP). The virus genomic component inside the capsid, along with occasionally present virus core protein, is called the virus core. The capsid and core together are referred to as a nucleocapsid (cf. also virion). Capsids are broadly classified according to their structure. The majority of the viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Structural Protein
A viral structural protein is a viral protein that is a structural component of the mature virus. Examples include the SARS coronavirus 3a and 7a accessory proteins. Bacteriophage T4 structural proteins During assembly of the bacteriophage (phage) T4 virion, the structural proteins encoded by the phage genes interact with each other in a characteristic sequence. Maintaining an appropriate balance in the amounts of each of these structural proteins produced during viral infection appears to be critical for normal phage T4 morphogenesis. Phage T4 encoded proteins that determine virion structure include major structural components, minor structural components and non-structural proteins that catalyze specific steps in the morphogenesis sequence. Phage T4 morphogenesis is divided into three independent pathways: the head, the tail and the long tail fibres as detailed by Yap and Rossman.Yap ML, Rossmann MG. Structure and function of bacteriophage T4. Future Microbiol. 2014;9(12):131 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA-dependent RNA Polymerase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the self-replication, replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand Complementarity (molecular biology), complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription (genetics), transcription of RNA from a DNA template. RdRp is an essential protein encoded in the genomes of most RNA-containing viruses that lack a DNA stage, including SARS-CoV-2. Some eukaryotes also contain RdRps, which are involved in RNA interference and differ structurally from viral RdRps. History Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested the action of a virus-specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
