|
Variants Of SARS-CoV-2
There are many variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). Some are believed, or have been stated, to be of particular importance due to their potential for increased transmissibility, increased virulence, or reduced effectiveness of vaccines against them. These variants contribute to the continuation of the COVID-19 pandemic. only the Omicron variant is designated as a circulating variant of concern by the World Health Organization. Overview The emergence of SARS-CoV-2 may have resulted from recombination events between a bat SARS-like coronavirus and a pangolin coronavirus through cross-species transmission. The earliest available SARS-CoV-2 viral genomes were collected from patients in December 2019, and Chinese researchers compared these early genomes with bat and pangolin coronavirus strains to estimate the ancestral human coronavirus type; the identified ancestral genome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology Of SARS-CoV-2 – Evolution And Mutations
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments. Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations.Based on definition from: Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the scientific meth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confidence Interval
In frequentist statistics, a confidence interval (CI) is a range of estimates for an unknown parameter. A confidence interval is computed at a designated ''confidence level''; the 95% confidence level is most common, but other levels, such as 90% or 99%, are sometimes used. The confidence level represents the long-run proportion of corresponding CIs that contain the true value of the parameter. For example, out of all intervals computed at the 95% level, 95% of them should contain the parameter's true value. Factors affecting the width of the CI include the sample size, the variability in the sample, and the confidence level. All else being the same, a larger sample produces a narrower confidence interval, greater variability in the sample produces a wider confidence interval, and a higher confidence level produces a wider confidence interval. Definition Let be a random sample from a probability distribution with statistical parameter , which is a quantity to be estima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Case Fatality Rate
In epidemiology, case fatality rate (CFR) – or sometimes more accurately case-fatality risk – is the proportion of people diagnosed with a certain disease, who end up dying of it. Unlike a disease's mortality rate, the CFR does not take into account the time period between disease onset and death. A CFR is generally expressed as a percentage. It represents a measure of disease lethality and may change with different treatments. CFRs are most often used for with discrete, limited-time courses, such as acute infections. Terminology The ''mortality rate'' – often confused with the CFR – is a measure of the relative number of deaths (either in general, or due to a specific cause) within the entire population per unit of time. A CFR, in contrast, is the number of deaths among the number of diagnosed cases only, regardless of time or total population. From a mathematical point of view, by taking values between 0 and 1 or 0% and 100%, CFRs are actually a measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inpatient Care
Inpatient care is the care of patients whose condition requires admission to a hospital. Progress in modern medicine and the advent of comprehensive out-patient clinics ensure that patients are only admitted to a hospital when they are extremely ill or have severe physical trauma. Progress Patients enter inpatient care mainly from previous ambulatory care such as referral from a family doctor, or through emergency medicine departments. The patient formally becomes an " inpatient" at the writing of an admission note. Likewise, it is formally ended by writing a discharge note. Planning for patient discharge Health care professionals involved in rehabilitation are often involved in discharge planning for patients. When considering patient discharge, there are a number of factors to take into consideration: the patient's current state, their place of residence and the type of support available. When considering the patient's current state, although the patient may be eligible ... [...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 u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laboratory Diagnosis Of Viral Infections
In the diagnostic laboratory, virus infections can be confirmed by a myriad of methods. Diagnostic virology has changed rapidly due to the advent of molecular techniques and increased clinical sensitivity of serological assays. Sampling A wide variety of samples can be used for virological testing. The type of sample sent to the laboratory often depends on the type of viral infection being diagnosed and the test required. Proper sampling technique is essential to avoid potential pre-analytical errors. For example, different types of samples must be collected in appropriate tubes to maintain the integrity of the sample and stored at appropriate temperatures (usually 4 °C) to preserve the virus and prevent bacterial or fungal growth. Sometimes multiple sites may also be sampled. Types of samples include the following: * Nasopharyngeal swab * Blood * Skin * Sputum, gargles and bronchial washings * Urine * Semen * Faeces * Cerebrospinal fluid * Tissues (biopsies or post-m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disease Outbreak
In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire continent. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent. Outbreaks include many epidemics, which term is normally only for infectious diseases, as well as diseases with an environmental origin, such as a water or foodborne disease. They may affect a region in a country or a group of countries. Pandemics are near-global disease outbreaks when multiple and various countries around the Earth are soon infected. Definition The terms "outbreak" and "epidemic" have often been used interchangeably. Researchers Manfred S. Green and colleagues propose that the latter term be restricted to larger events, pointing out that '' Chambers Concise Dictionary'' and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nextstrain
Nextstrain is a collaboration between researchers in Seattle, United States and Basel, Switzerland which provides a collection of open-source tools for visualising the genetics behind the spread of viral outbreaks. Its aim is to support public health measures and surveillance by facilitating understanding of the spread and evolution of pathogens. The Nextstrain platform was begun in 2015. Code developed by Nextstrain is made publicly available, via, for example github.com and its data is available and viewable in accessible form via the pages at the website. Applications According to their website, the Nextstrain team maintains an up-to-date genomic analysis of each of the following pathogens: * Avian influenza * Dengue * Enterovirus D68 * Measles * Mumps * SARS-CoV-2 * Seasonal influenza * Tuberculosis * West Nile virus * West African Ebola 2013-16 * Zika * Monkeypox virus Covid-19 pandemic Nextstrain and its results have been widely quoted during the COVID-19 pandemic. Awar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lineage (genetic)
A genetic lineage, also known as genetic pedigree, is a series of mutations which connect an ancestral genetic type (allele, haplotype, or haplogroup) to derivative type. In cases where the genetic tree is very bushy the order of mutations in the lineage is mostly known, examples are the order of mutations between E1b1b and E1b1b1a1a for the human Y-chromosomesal L0 or L1 nodes. A genetic lineage can be contrasted with an evolutionary lineage in that a genetic lineage applies to a locus. An example of the difference is that an ancient African ape evolved into the gorilla-chimpanzee-human ancestor, which further evolved into the chimpanzee-human ancestor and then to humans. While most human lineages coalesce with chimpanzee lineages, which then converge with gorilla lineages, a few human lineages coalesce with gorilla lineages and then converge with chimpanzee lineages (or chimpanzee lineages that coalesce with gorilla lineages and then converge with human lineages). This occu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Assignment Of Named Global Outbreak Lineages
The Phylogenetic Assignment of Named Global Outbreak Lineages (PANGOLIN) is a software tool developed by Dr. Áine O'Toole and members of the Andrew Rambaut laboratory, with an associated web application developed by the Centre for Genomic Pathogen Surveillance in South Cambridgeshire. Its purpose is to implement a dynamic nomenclature (known as the PANGO nomenclature) to classify genetic lineages for SARS-CoV-2, the virus that causes COVID-19. A user with a full genome sequence of a sample of SARS-CoV-2 can use the tool to submit that sequence, which is then compared with other genome sequences, and assigned the most likely lineage (PANGO lineage). Single or multiple runs are possible, and the tool can return further information regarding the known history of the assigned lineage. Additionally, it interfaces with Microreact, to show a time sequence of the location of reports of sequenced samples of the same lineage. This latter feature draws on publicly available genomes obtaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Correlates Of Immunity
Correlates of immunity or correlates of protection to a virus or other infectious pathogen are measurable signs that a person (or other potential host) is immune, in the sense of being protected against becoming infected and/or developing disease. For many viruses, antibodies and especially neutralizing antibodies serve as a correlate of immunity. Pregnant women, for example, are routinely screened in the UK for rubella antibodies to confirm their immunity, which can cause serious congenital abnormalities in their children. In contrast, for HIV, the simple presence of antibodies is not a correlate of immunity/protection since infected individuals develop antibodies without protection against the disease. The fact that the correlates of immunity/protection remain unclear is a significant barrier to HIV vaccine research. There is evidence that some highly exposed individuals can develop resistance to HIV infection, suggesting that immunity and therefore a vaccine is possible. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
