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76-433: An epidemic (from Greek ἐπί epi "upon or above" and δῆμος demos "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infections , an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic. Epidemics of infectious disease are generally caused by several factors including

152-553: A P. falciparum parasite. Fluorescent in situ hybridization analysis has shown that activation of var alleles is linked to altered positioning of the genetic material to distinct "transcriptionally permissive" areas. Different virus families have different levels of ability to alter their genomes and trick the immune system into not recognizing. Some viruses have relatively unchanging genomes like paramyxoviruses while others like influenza have rapidly changing genomes that inhibit our ability to create long lasting vaccines against

228-543: A pitch accent . In Modern Greek, all vowels and consonants are short. Many vowels and diphthongs once pronounced distinctly are pronounced as /i/ ( iotacism ). Some of the stops and glides in diphthongs have become fricatives , and the pitch accent has changed to a stress accent . Many of the changes took place in the Koine Greek period. The writing system of Modern Greek, however, does not reflect all pronunciation changes. The examples below represent Attic Greek in

304-422: A change in the ecology of the host population (e.g., increased stress or increase in the density of a vector species), a genetic change in the pathogen reservoir or the introduction of an emerging pathogen to a host population (by movement of pathogen or host). Generally, an epidemic occurs when host immunity to either an established pathogen or newly emerging novel pathogen is suddenly reduced below that found in

380-425: A common source exposure or an environmental vector may spread a zoonotic diseases agent. Preparations for an epidemic include having a disease surveillance system; the ability to quickly dispatch emergency workers, especially local-based emergency workers; and a legitimate way to guarantee the safety and health of health workers. Effective preparations for a response to a pandemic are multi-layered. The first layer

456-491: A compensatory mutation in NA can result leading to NA antigenic variation. As a consequence, drug resistance develops to NA inhibitors. Such a phenomenon can mask the evolution of NA evolution in nature because the resistance to NA inhibitors could be due to antibody-driven, HA escape. The major challenge in controlling HIV-1 infection in the long term is immune escape. The extent and frequency to which an epitope will be targeted by

532-589: A disease above what is normally expected in that population in that area." The term "outbreak" can also apply, but is usually restricted to smaller events. Any sudden increase in disease prevalence may generally be termed an epidemic. This may include contagious disease (i.e. easily spread between persons) such as influenza ; vector-borne diseases such as malaria ; water-borne diseases such as cholera ; and sexually transmitted diseases such as HIV/AIDS . The term can also be used for non-communicable health issues such as obesity . The term epidemic derives from

608-447: A disease epidemic. By the early 17th century, the terms endemic and epidemic referred to contrasting conditions of population-level disease, with the endemic condition a " common sicknesse " and the epidemic " hapning in some region, or countrey, at a certaine time, ....... producing in all sorts of people, one and the same kind of sicknesse ". The term "epidemic" is often applied to diseases in non-human animals, although " epizootic "

684-597: A fast-spreading pandemic may easily exceed and overwhelm existing health-care resources. Consequently, early and aggressive mitigation efforts, aimed at the so-called "epidemic curve flattening" need to be taken. Such measures usually consist on non-pharmacological interventions such as social/physical distancing, aggressive contact tracing, "stay-at-home" orders, as well as appropriate personal protective equipment (i.e., masks, gloves, and other physical barriers to spread). Moreover, India has taken significant strides in its efforts to prepare for future respiratory pandemics through

760-400: A hierarchical order: telomeric VSGs are activated first, followed by array VSGs, and finally pseudogene VSGs. Only one VSG is expressed at any given time. Each new gene is switched in turn into a VSG expression site (ES). This process is partially dependent on homologous recombination of DNA, which is mediated in part by the interaction of the T. brucei BRCA2 gene with RAD51 (however, this

836-477: A lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period. They have the same general outline but differ in some of the detail. The only attested dialect from this period is Mycenaean Greek , but its relationship to the historical dialects and

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912-419: A lesser degree. Pamphylian Greek , spoken in a small area on the southwestern coast of Anatolia and little preserved in inscriptions, may be either a fifth major dialect group, or it is Mycenaean Greek overlaid by Doric, with a non-Greek native influence. Regarding the speech of the ancient Macedonians diverse theories have been put forward, but the epigraphic activity and the archaeological discoveries in

988-475: A mechanism for checking for mistakes in translation but recent work by Duffy et al. shows that some DNA viruses have the same high rates of antigenic variation as their RNA counterparts. Antigenic variation within viruses can be categorized into 6 different categories called antigenic drift , shift , rift, lift, sift, and gift The antigenic properties of influenza viruses are determined by both hemagglutinin and neuraminidase . Specific host proteases cleave

1064-478: A particular HLA allele differs from person-to-person. Moreover, as a consequence of immunodominance, an individual's CTL response is limited to a few epitopes of a specific HLA allele although six HLA class 1 alleles are expressed. Although the CTL response in the acute phase is directed against limited number of epitopes, the epitopic repertoire increases with time due to viral escape. Additionally amino acid co-evolution

1140-440: A period of time; an evolutionary change which increases survival time will result in increased virulence. Another possibility, although rare, is that a pathogen may adapt to take advantage of a new mode of transmission Seasonal diseases arise due to the change in the environmental conditions, especially such as humidity and temperature, during different seasons. Many diseases display seasonality , This may be due to one or more of

1216-410: A plasmid that contains fifteen silent vls cassettes and one functional copy of vlsE . Segments of the silent cassettes recombine with the vlsE gene, generating variants of the surface lipoprotein antigen. Antigenic variation is employed by a number of different protozoan parasites. Trypanosoma brucei and Plasmodium falciparum are some of the best studied examples. Trypanosoma brucei ,

1292-550: A prefix /e-/, called the augment . This was probably originally a separate word, meaning something like "then", added because tenses in PIE had primarily aspectual meaning. The augment is added to the indicative of the aorist, imperfect, and pluperfect, but not to any of the other forms of the aorist (no other forms of the imperfect and pluperfect exist). The two kinds of augment in Greek are syllabic and quantitative. The syllabic augment

1368-471: A role in binding to receptor and could play a role in evading the host immune system. It has three major antigenic domains namely A, B and C that correspond to the three structural domains II, III and I. Structural domain III is a putative receptor binding domain and antibodies against it neutralize the infectivity of flaviviruses. Mutations that lead to antigenic differences can be traced to the biochemical nature of

1444-608: A separate historical stage, though its earliest form closely resembles Attic Greek , and its latest form approaches Medieval Greek . There were several regional dialects of Ancient Greek; Attic Greek developed into Koine. Ancient Greek was a pluricentric language , divided into many dialects. The main dialect groups are Attic and Ionic , Aeolic , Arcadocypriot , and Doric , many of them with several subdivisions. Some dialects are found in standardized literary forms in literature , while others are attested only in inscriptions. There are also several historical forms. Homeric Greek

1520-630: A standard subject of study in educational institutions of the Western world since the Renaissance . This article primarily contains information about the Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period ( c.  300 BC ), Ancient Greek was followed by Koine Greek , which is regarded as

1596-503: A two-dimensional map using a process called antigenic cartography so that antigenic evolution can be visualized. These maps can show how changes in amino acids can alter the binding of an antibody to virus particle and help to analyze the pattern of genetic and antigenic evolution. Recent findings show that as a result of antibody-driven antigenic variation in one domain of the H1 hemagglutinin Sa site,

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1672-420: A very rare disease may be classified as an epidemic, while many cases of a common disease (such as the common cold ) would not. An epidemic can cause enormous damage through financial and economic losses in addition to impaired health and loss of life. The United States Centers for Disease Control and Prevention defines epidemic broadly: "Epidemic refers to an increase, often sudden, in the number of cases of

1748-510: A vowel or /n s r/ ; final stops were lost, as in γάλα "milk", compared with γάλακτος "of milk" (genitive). Ancient Greek of the classical period also differed in both the inventory and distribution of original PIE phonemes due to numerous sound changes, notably the following: The pronunciation of Ancient Greek was very different from that of Modern Greek . Ancient Greek had long and short vowels ; many diphthongs ; double and single consonants; voiced, voiceless, and aspirated stops ; and

1824-510: A word form attributed to Homer 's Odyssey , which later took its medical meaning from the Epidemics , a treatise by Hippocrates . Before Hippocrates, epidemios , epidemeo , epidamos , and other variants had meanings similar to the current definitions of " indigenous " or " endemic ". Thucydides ' description of the Plague of Athens is considered one of the earliest accounts of

1900-510: Is a challenging issue that needs to be addressed. For example, a substitution in a particular site results in a secondary or compensatory mutation in another site. An invaluable discovery was that when a selective pressure is applied, the pattern of HIV-1 evolution can be predicted. In individuals who express a protective HLA B*27 allele, the first mutation that occurs in the Gag epitope KK10 is at position 6 from an L to an M and after several years there

1976-438: Is a change in position 2 from a R to a K. Therefore, the knowledge of the predictability of the escape pathways can be utilized to design immunogens. The region gp120 of HIV-1 Env which contacts CD4 , its primary receptor, is functionally conserved and vulnerable to neutralizing antibodies such as monoclonal antibody b12. Recent findings show that resistance to neutralization by b12 was an outcome of substitutions that resided in

2052-426: Is a disease surveillance system. Tanzania , for example, runs a national lab that runs testing for 200 health sites and tracks the spread of infectious diseases. The next layer is the actual response to an emergency. According to U.S.-based columnist Michael Gerson in 2015, only the U.S. military and NATO have the global capability to respond to such an emergency. Still, despite the most extensive preparatory measures,

2128-570: Is a literary form of Archaic Greek (derived primarily from Ionic and Aeolic) used in the epic poems , the Iliad and the Odyssey , and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic and other Classical-era dialects. The origins, early form and development of the Hellenic language family are not well understood because of

2204-709: Is abrupt - in this, two or more different strains of a virus , coinfecting a single host, combine to form a new subtype having a mixture of characteristics of the original strains. The best known and best documented example of both processes is influenza . SARS-CoV2 has demonstrated antigenic drift and possibly shift as well. Antibiotic resistance applies specifically to bacteria that become resistant to antibiotics . Resistance in bacteria can arise naturally by genetic mutation , or by one species acquiring resistance from another through horizontal gene transfer . Extended use of antibiotics appears to encourage selection for mutations which can render antibiotics ineffective. This

2280-418: Is added to stems beginning with consonants, and simply prefixes e (stems beginning with r , however, add er ). The quantitative augment is added to stems beginning with vowels, and involves lengthening the vowel: Some verbs augment irregularly; the most common variation is e → ei . The irregularity can be explained diachronically by the loss of s between vowels, or that of the letter w , which affected

2356-666: Is called 'East Greek'. Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian Greek had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, as exemplified in the poems of the Boeotian poet Pindar who wrote in Doric with a small Aeolic admixture. Thessalian likewise had come under Northwest Greek influence, though to

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2432-448: Is considered by some linguists to have been closely related to Greek . Among Indo-European branches with living descendants, Greek is often argued to have the closest genetic ties with Armenian (see also Graeco-Armenian ) and Indo-Iranian languages (see Graeco-Aryan ). Ancient Greek differs from Proto-Indo-European (PIE) and other Indo-European languages in certain ways. In phonotactics , ancient Greek words could end only in

2508-428: Is encoded by the diverse family of genes known as the var family of genes (approximately 60 genes in all). The diversity of the gene family is further increased via a number of different mechanisms including exchange of genetic information at telomeric loci, as well as meiotic recombination. The PfEMP1 protein serves to sequester infected erythrocytes from splenic destruction via adhesion to the endothelium . Moreover,

2584-418: Is especially true of tuberculosis , with increasing occurrence of multiple drug-resistant tuberculosis (MDR-TB) worldwide. Pathogen transmission is a term used to describe the mechanisms by which a disease-causing agent (virus, bacterium, or parasite) spreads from one host to another. Common modes of transmission include: - The first three of these require that pathogen must survive away from its host for

2660-416: Is not immune. An example of this was the introduction European diseases such as smallpox into indigenous populations during the 16th century. A zoonosis is an infectious disease of humans caused by a pathogen that can jump from a non-human host to a human. Major diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in the early part of

2736-479: Is not the only possible mechanism, as BRCA2 variants still display some VSG switching). In addition to homologous recombination, transcriptional regulation is also important in antigen switching, since T. brucei has multiple potential expression sites. A new VSG can either be selected by transcriptional activation of a previously silent ES, or by recombination of a VSG sequence into the active ES (see figure, "Mechanisms of VSG Switching in T. brucei "). Although

2812-632: Is singular and all of the affected individuals develop the disease over a single exposure and incubation course, it can be termed as a point source outbreak. If the exposure was continuous or variable, it can be termed as a continuous outbreak or intermittent outbreak, respectively. In a propagated outbreak, the disease spreads person-to-person. Affected individuals may become independent reservoirs leading to further exposures.Many epidemics will have characteristics of both common source and propagated outbreaks (sometimes referred to as mixed outbreak ). For example, secondary person-to-person spread may occur after

2888-413: Is technically preferable. There are several factors that may contribute (individually or in combination) to causing an epidemic. There may be changes in a pathogen , in the population that it can infect, in the environment, or in the interaction between all three. Factors include the following: An antigen is a protein on the virus ' surface that host antibodies can recognize and attack. Changes in

2964-759: The Greek region of Macedonia during the last decades has brought to light documents, among which the first texts written in Macedonian , such as the Pella curse tablet , as Hatzopoulos and other scholars note. Based on the conclusions drawn by several studies and findings such as Pella curse tablet , Emilio Crespo and other scholars suggest that ancient Macedonian was a Northwest Doric dialect , which shares isoglosses with its neighboring Thessalian dialects spoken in northeastern Thessaly . Some have also suggested an Aeolic Greek classification. The Lesbian dialect

3040-463: The antigenic characteristics of the agent make it easier for the changed virus to spread throughout a previously immune population. There are two natural mechanisms for change - antigenic drift and antigenic shift . Antigenic drift arises over a period of time as an accumulation of mutations in the virus genes , possibly through a series of hosts, and eventually gives rise to a new strain of virus which can evade existing immunity. Antigenic shift

3116-506: The endemic equilibrium and the transmission threshold is exceeded. An epidemic may be restricted to one location; however, if it spreads to other countries or continents and affects a substantial number of people, it may be termed as a pandemic . The declaration of an epidemic usually requires a good understanding of a baseline rate of incidence ; epidemics for certain diseases, such as influenza , are defined as reaching some defined increase in incidence above this baseline. A few cases of

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3192-501: The present , future , and imperfect are imperfective in aspect; the aorist , present perfect , pluperfect and future perfect are perfective in aspect. Most tenses display all four moods and three voices, although there is no future subjunctive or imperative. Also, there is no imperfect subjunctive, optative or imperative. The infinitives and participles correspond to the finite combinations of tense, aspect, and voice. The indicative of past tenses adds (conceptually, at least)

3268-401: The 20th century, though it has now evolved into a separate human-only disease. Some strains of bird flu and swine flu are zoonoses; these viruses occasionally recombine with human strains of the flu and can cause pandemics such as the 1918 Spanish flu or the 2009 swine flu . In a common source outbreak epidemic, the affected individuals had an exposure to a common agent. If the exposure

3344-1031: The 5th century BC. Ancient pronunciation cannot be reconstructed with certainty, but Greek from the period is well documented, and there is little disagreement among linguists as to the general nature of the sounds that the letters represent. /oː/ raised to [uː] , probably by the 4th century BC. Greek, like all of the older Indo-European languages , is highly inflected. It is highly archaic in its preservation of Proto-Indo-European forms. In ancient Greek, nouns (including proper nouns) have five cases ( nominative , genitive , dative , accusative , and vocative ), three genders ( masculine , feminine , and neuter ), and three numbers (singular, dual , and plural ). Verbs have four moods ( indicative , imperative , subjunctive , and optative ) and three voices (active, middle, and passive ), as well as three persons (first, second, and third) and various other forms. Verbs are conjugated through seven combinations of tenses and aspect (generally simply called "tenses"):

3420-495: The Archaic period of ancient Greek (see Homeric Greek for more details): Μῆνιν ἄειδε, θεά, Πηληϊάδεω Ἀχιλῆος οὐλομένην, ἣ μυρί' Ἀχαιοῖς ἄλγε' ἔθηκε, πολλὰς δ' ἰφθίμους ψυχὰς Ἄϊδι προΐαψεν ἡρώων, αὐτοὺς δὲ ἑλώρια τεῦχε κύνεσσιν οἰωνοῖσί τε πᾶσι· Διὸς δ' ἐτελείετο βουλή· ἐξ οὗ δὴ τὰ πρῶτα διαστήτην ἐρίσαντε Ἀτρεΐδης τε ἄναξ ἀνδρῶν καὶ δῖος Ἀχιλλεύς. The beginning of Apology by Plato exemplifies Attic Greek from

3496-608: The Classical period of ancient Greek. (The second line is the IPA , the third is transliterated into the Latin alphabet using a modern version of the Erasmian scheme .) Ὅτι [hóti Hóti μὲν men mèn ὑμεῖς, hyːmêːs hūmeîs,   Antigenic variation Antigenic variation in bacteria is best demonstrated by species of the genus Neisseria (most notably, Neisseria meningitidis and Neisseria gonorrhoeae ,

3572-472: The amino acid substitutions as well as the location of the mutation in the domain III. For example, substitutions at different amino acids results in varying levels of neutralization by antibodies. If mutation in a critical amino acid can dramatically alter neutralization by antibodies then WNV vaccines and diagnostic assays becomes difficult to rely on. Other flaviviruses that cause dengue, louping ill and yellow fever escape antibody neutralization via mutations in

3648-550: The aorist. Following Homer 's practice, the augment is sometimes not made in poetry , especially epic poetry. The augment sometimes substitutes for reduplication; see below. Almost all forms of the perfect, pluperfect, and future perfect reduplicate the initial syllable of the verb stem. (A few irregular forms of perfect do not reduplicate, whereas a handful of irregular aorists reduplicate.) The three types of reduplication are: Irregular duplication can be understood diachronically. For example, lambanō (root lab ) has

3724-419: The augment when it was word-initial. In verbs with a preposition as a prefix, the augment is placed not at the start of the word, but between the preposition and the original verb. For example, προσ(-)βάλλω (I attack) goes to προσ έ βαλoν in the aorist. However compound verbs consisting of a prefix that is not a preposition retain the augment at the start of the word: αὐτο(-)μολῶ goes to ηὐ τομόλησα in

3800-521: The biological triggers that result in VSG switching are not fully known, mathematical modeling suggests that the ordered appearance of different VSG variants is controlled by at least two key parasite-derived factors: differential activation rates of parasite VSG and density-dependent parasite differentiation. Plasmodium falciparum , the major etiologic agent of human malaria, has a very complex life cycle that occurs in both humans and mosquitoes. While in

3876-438: The center of Greek scholarship, this division of people and language is quite similar to the results of modern archaeological-linguistic investigation. One standard formulation for the dialects is: West vs. non-West Greek is the strongest-marked and earliest division, with non-West in subsets of Ionic-Attic (or Attic-Ionic) and Aeolic vs. Arcadocypriot, or Aeolic and Arcado-Cypriot vs. Ionic-Attic. Often non-West

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3952-482: The circulating human strains. Another example comes from the 1968 Hong Kong flu which acquired 2 genes by reassortment from Eurasian avian viruses with the 6 gene segments from circulating human strains. After vaccination, IgG+ antibody-secreting plasma cells (ASCs) increase rapidly and reaches a maximum level at day 7 before returning to a minimum level at day 14. The influenza-specific memory B-cells reach their maxima at day 14–21. The secreted antibodies are specific to

4028-618: The development of the National Pandemic Preparedness Plan for Respiratory Viruses using a multisectoral approach. Preceding this national effort, a regional workshop on the Preparedness and Resilience for Emerging Threats (PRET) initiative was organized by WHO's South-East Asia Regional Office on October 12-13, 2023. Recognizing that the same capacities and capabilities can be leveraged and applied for groups of pathogens based on their mode of transmission,

4104-615: The dialect of Sparta ), and Northern Peloponnesus Doric (including Corinthian ). All the groups were represented by colonies beyond Greece proper as well, and these colonies generally developed local characteristics, often under the influence of settlers or neighbors speaking different Greek dialects. After the conquests of Alexander the Great in the late 4th century BC, a new international dialect known as Koine or Common Greek developed, largely based on Attic Greek , but with influence from other dialects. This dialect slowly replaced most of

4180-421: The disease. Viruses in general have much faster rate of mutation of their genomes than human or bacterial cells. In general viruses with shorter genomes have faster rates of mutation than longer genomes since they have a faster rate of replication . It was classically thought that viruses with an RNA genome always had a faster rate of antigenic variation than those with a DNA genome because RNA polymerase lacks

4256-461: The early stages of invasion, the VSG coat is sufficient to protect the parasite from immune detection. The host eventually identifies the VSG as a foreign antigen and mounts an attack against the microbe. However, the parasite's genome has over 1,000 genes that code for different variants of the VSG protein, located on the subtelomeric portion of large chromosomes , or on intermediate chromosomes. These VSG genes become activated by gene conversion in

4332-401: The following underlying factors: - Changes in behaviour can affect the likelihood or severity of epidemics. The classic example is the 1854 Broad Street cholera outbreak , in which a cholera outbreak was mitigated by removing a supply of contaminated water - an event now regarded as the foundation of the science of epidemiology . Urbanisation and overcrowding (e.g. in refugee camps ) increase

4408-403: The following years, immunity will decline, both within individuals and in the population as a whole as older individuals die and new individuals are born. Eventually, unless there is another vaccination campaign, an outbreak or epidemic will recur. It's also possible for disease which is endemic in one population to become epidemic if it is introduced into a novel setting where the host population

4484-673: The forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek ( c.  1400–1200 BC ), Dark Ages ( c.  1200–800 BC ), the Archaic or Epic period ( c.  800–500 BC ), and the Classical period ( c.  500–300 BC ). Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers . It has contributed many words to English vocabulary and has been

4560-500: The genes for structural proteins are acquired from other animal hosts resulting in a sudden dramatic change in viral genome. Recombination between segments that encode for hemagglutinin and neuraminidase of avian and human influenza virus segments have resulted in worldwide influenza epidemics called pandemics such as the Asian flu of 1957 when 3 genes from Eurasian avian viruses were acquired and underwent reassortment with 5 gene segments of

4636-671: The gonococcus); species of the genus Streptococcus and the Mycoplasma . The Neisseria species vary their pili (protein polymers made up of subunits called pilin which play a critical role in bacterial adhesion , and stimulate a vigorous host immune response) and the Streptococci vary their M-protein. In the bacterium Borrelia burgdorferi , the cause of Lyme disease , the surface lipoprotein VlsE can undergo recombination which results in antigenic diversity. The bacterium carries

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4712-561: The historical Dorians . The invasion is known to have displaced population to the later Attic-Ionic regions, who regarded themselves as descendants of the population displaced by or contending with the Dorians. The Greeks of this period believed there were three major divisions of all Greek people – Dorians, Aeolians, and Ionians (including Athenians), each with their own defining and distinctive dialects. Allowing for their oversight of Arcadian, an obscure mountain dialect, and Cypriot, far from

4788-476: The historical circumstances of the times imply that the overall groups already existed in some form. Scholars assume that major Ancient Greek period dialect groups developed not later than 1120 BC, at the time of the Dorian invasions —and that their first appearances as precise alphabetic writing began in the 8th century BC. The invasion would not be "Dorian" unless the invaders had some cultural relationship to

4864-475: The human host, the parasite spends most of its life cycle within hepatic cells and erythrocytes (in contrast to T. brucei which remains extracellular). As a result of its mainly intracellular niche, parasitized host cells which display parasite proteins must be modified to prevent destruction by the host immune defenses. In the case of Plasmodium , this is accomplished via the dual purpose Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). PfEMP1

4940-412: The likelihood of disease outbreaks. A factor which contributed to the initial rapid increase in the 2014 Ebola virus epidemic was ritual bathing of (infective) corpses; one of the control measures was an education campaign to change behaviour around funeral rites. The level of immunity to a disease in a population - herd immunity - is at its peak after a disease outbreak or a vaccination campaign. In

5016-508: The older dialects, although the Doric dialect has survived in the Tsakonian language , which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek . By about the 6th century AD, the Koine had slowly metamorphosed into Medieval Greek . Phrygian is an extinct Indo-European language of West and Central Anatolia , which

5092-399: The organism that causes sleeping sickness , replicates extracellularly in the bloodstream of infected mammals and is subjected to numerous host defense mechanisms including the complement system , and the innate and adaptive immune systems. To protect itself, the parasite decorates itself with a dense, homogeneous coat (~10^7 molecules) of the variant surface glycoprotein (VSG). In

5168-483: The parasite is able to evade host defense mechanisms by changing which var allele is used to code the PfEMP1 protein. Like T. brucei , each parasite expresses multiple copies of one identical protein. However, unlike T. brucei , the mechanism by which var switching occurs in P. falciparum is thought to be purely transcriptional. Var switching has been shown to take place soon after invasion of an erythrocyte by

5244-487: The perfect stem eilēpha (not * lelēpha ) because it was originally slambanō , with perfect seslēpha , becoming eilēpha through compensatory lengthening. Reduplication is also visible in the present tense stems of certain verbs. These stems add a syllable consisting of the root's initial consonant followed by i . A nasal stop appears after the reduplication in some verbs. The earliest extant examples of ancient Greek writing ( c.  1450 BC ) are in

5320-420: The region proximal to CD4 contact surface. In this way the virus evades neutralization by b12 without affecting its binding to CD4. Flaviviridae is a family of viruses that encompasses well known viruses such as West Nile virus and Dengue virus . The genus Flavivirus has a prototypical envelope protein (E-protein) on its surface which serves as the target for virus neutralizing antibodies. E protein plays

5396-409: The single peptide HA into two subunits HA1 and HA2. The virus becomes highly virulent if the amino acids at the cleavage sites are lipophilic. Selection pressure in the environment selects for antigenic changes in the antigen determinants of HA, that includes places undergoing adaptive evolution and in antigenic locations undergoing substitutions, which ultimately results in changes in the antigenicity of

5472-517: The syllabic script Linear B . Beginning in the 8th century BC, however, the Greek alphabet became standard, albeit with some variation among dialects. Early texts are written in boustrophedon style, but left-to-right became standard during the classic period. Modern editions of ancient Greek texts are usually written with accents and breathing marks , interword spacing , modern punctuation , and sometimes mixed case , but these were all introduced later. The beginning of Homer 's Iliad exemplifies

5548-611: The vaccine virus. Further, most of the monoclonal antibodies isolated have binding affinities against HA and the remaining demonstrate affinity against NA, nucleoprotein (NP) and other antigens. These high affinity human monoclonal antibodies can be produced within a month after vaccination and because of their human origin, they will have very little, if any, antibody-related side-effects in humans. They can potentially be used to develop passive antibody therapy against influenza virus transmission. The ability of an antiviral antibody to inhibit hemagglutination can be measured and used to generate

5624-451: The virus. Glycosylation of HA does not correlate with either the antigenicity or the selection pressure. Antigenic variation may be classified into two types, antigenic drift that results from a change in few amino acids and antigenic shift which is the outcome of acquiring new structural proteins. A new vaccine is required every year because influenza virus has the ability to undergo antigenic drift. Antigenic shift occurs periodically when

5700-417: The workshop aimed to facilitate pandemic planning efficiency for countries in the region. The participating countries, in the aftermath of the workshop, outlined their immediate next steps and sought support from WHO and its partners to bolster regional preparedness against respiratory pathogen pandemics. Ancient Greek Ancient Greek ( Ἑλληνῐκή , Hellēnikḗ ; [hellɛːnikɛ́ː] ) includes

5776-480: Was Aeolic. For example, fragments of the works of the poet Sappho from the island of Lesbos are in Aeolian. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, or to an island. Doric notably had several intermediate divisions as well, into Island Doric (including Cretan Doric ), Southern Peloponnesus Doric (including Laconian ,

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