{"id":4847,"date":"2020-04-04T08:59:02","date_gmt":"2020-04-04T08:59:02","guid":{"rendered":"http:\/\/pokharasamachar.com\/?p=4847"},"modified":"2020-04-04T08:59:07","modified_gmt":"2020-04-04T08:59:07","slug":"a-research-on-corona-virus-disease-2019-covid-2019","status":"publish","type":"post","link":"http:\/\/pokharasamachar.com\/?p=4847","title":{"rendered":"A RESEARCH ON CORONA VIRUS DISEASE 2019 (COVID-2019"},"content":{"rendered":"\n

A RESEARCH ON CORONA VIRUS DISEASE 2019(COVID -19)<\/strong><\/p>\n\n\n\n

REVIEW – Dayasagar Parajuli <\/strong>4th\u00a0 <\/sup>April 2020, <\/p>\n\n\n\n

Corona virus disease 2019 (COVID -19) is an infectious disease<\/a>\u00a0caused by\u00a0severe acute respiratory syndrome corona virus 2<\/a>\u00a0(SARS-CoV-2).\u00a0The disease was first identified in December 2019 in\u00a0Wuhan<\/a>, the capital of China’s\u00a0Hubei<\/a>\u00a0province, and has since spread globally, resulting in the ongoing\u00a02019\u201320 corona virus pandemic<\/a>.\u00a0Common\u00a0symptoms<\/a>\u00a0include\u00a0fever<\/a>,\u00a0cough<\/a>, and\u00a0shortness of breath<\/a>.\u00a0Other symptoms may include\u00a0muscle pain<\/a>,\u00a0sputum<\/a>\u00a0production,\u00a0diarrhea<\/a>,\u00a0sore throat<\/a>,\u00a0loss of smell<\/a>, and abdominal pain.\u00a0While the majority of cases result in mild symptoms, some progress to viral\u00a0pneumonia<\/a>\u00a0and\u00a0multi-organ failure<\/a>.\u00a0As of 3 April 2020, more than 1,010,000\u00a0cases of COVID-19 have been reported in more than two hundred countries and territories,\u00a0resulting in over 53,000 deaths.\u00a0More than 211,000 people have recovered. <\/p>\n\n\n\n

The virus is mainly spread<\/a> during close\ncontact, and by small\ndroplets<\/a> produced\nwhen people cough, sneeze, or talk. Respiratory droplets may be produced\nduring breathing but the virus is not generally airborne<\/a>. People may\nalso contract COVID-19 by touching a contaminated surface and then their\nface. It is most contagious when people are symptomatic, although spread\nmay be possible before symptoms appear. The virus can survive on surfaces\nup to 72 hours. Time from exposure to onset of symptoms is generally\nbetween two and fourteen days, with an average of five days. The standard\nmethod of diagnosis<\/a> is by reverse transcription polymerase chain\nreaction<\/a> (rRT-PCR)\nfrom a nasopharyngeal\nswab<\/a>.\nThe infection can also be diagnosed from a combination of symptoms, risk factors<\/a> and a\nchest CT\nscan<\/a> showing\nfeatures of pneumonia.<\/p>\n\n\n\n

Recommended measures to prevent infection\ninclude frequent hand washing<\/a>, social distancing<\/a> (maintaining\nphysical distance from others, especially from those with symptoms), covering\ncoughs and sneezes with a tissue or inner elbow, and keeping unwashed hands\naway from the face. The use of masks<\/a> is recommended\nfor those who suspect they have the virus and their\ncaregivers. Recommendations for mask use by the general public vary, with\nsome authorities recommending against their use, some recommending their use,\nand others requiring their use. Currently, there is no vaccine<\/a> or\nspecific antiviral\ntreatment<\/a> for\nCOVID-19. Management involves treatment of symptoms<\/a>, supportive care<\/a>, isolation<\/a>, and experimental measures<\/a>.<\/p>\n\n\n\n

The World Health Organization<\/a> (WHO) declared\nthe 2019\u201320 coronavirus outbreak<\/a> a Public Health\nEmergency of International Concern<\/a> (PHEIC) on 30 January 2020, and\na pandemic<\/a> on 11 March\n2020. Local\ntransmission<\/a> of\nthe disease has been recorded in many countries across all six WHO regions<\/a>.<\/p>\n\n\n\n

SIGNS AND SYMPTOMS <\/strong><\/p>\n\n\n\n

Those infected with the virus may be asymptomatic<\/a> or\ndevelop flu-like symptoms,<\/a> including\nfever, cough, fatigue, and shortness of breath. Emergency symptoms include\ndifficulty breathing, persistent chest pain or pressure, confusion, difficulty\nwaking, and bluish face or lips; immediate medical attention is advised if\nthese symptoms are present. Less commonly, upper respiratory<\/a> symptoms, such\nas sneezing<\/a>, runny nose<\/a>, or sore throat<\/a> may be seen.\nSymptoms such as nausea<\/a>, vomiting<\/a>, and diarrhea<\/a> have been\nobserved in varying percentages. Some cases in China initially presented\nonly with chest tightness<\/a> and palpitations<\/a>. In March 2020\nthere were reports indicating that loss of the sense of smell<\/a> (anosmia) may\nbe a common symptom among those who have mild disease, although not as common\nas initially reported. In some, the disease may progress to pneumonia<\/a>, multi-organ failure<\/a>, and death<\/a>. In those who develop severe symptoms, time from symptom\nonset to needing mechanical ventilation is typically eight days.<\/strong><\/p>\n\n\n\n

As is common with infections, there is a delay between the\nmoment when a person is infected with the virus and the time when they develop\nsymptoms. This is called the incubation\nperiod<\/a>. The incubation period for COVID-19\nis typically five to six days but may range from two to 14 days. 97.5% of\npeople who develop symptoms will do so within 11.5 days of infection.<\/p>\n\n\n\n

Reports indicate that not all who are infected develop\nsymptoms, but their role in transmission is unknown. Preliminary evidence\nsuggests asymptomatic cases may contribute to the spread of the\ndisease. The proportion of infected people who do not display symptoms is\ncurrently unknown and being studied, with South Korea’s CDC reporting that 20%\nof all confirmed cases remained asymptomatic during their hospital stay.<\/p>\n\n\n\n

TRANSMISSION<\/strong><\/p>\n\n\n\n\n\n

<\/a><\/sup><\/p>\n\n\n\n

Respiratory droplets may also be produced\nduring breathing out, including when talking. Though the virus is not\ngenerally airborne<\/a>, The National\nAcademy of Science has suggested that bioaerosol<\/a> transmission\nmay be possible and air collectors positioned in the hallway outside of\npeople’s rooms yielded samples positive for viral RNA. The droplets can land in\nthe mouths or noses of people who are nearby or possibly be inhaled into the\nlungs. Some medical procedures such as intubation and cardiopulmonary resuscitation<\/a> (CPR) may cause\nrespiratory secretions to be aerosolised and thus result in airborne\nspread. It may also spread when one touches a contaminated surface, known\nas fomite<\/a> transmission,\nand then touches their eyes, nose, or mouth. While there are concerns it\nmay spread by feces<\/a>, this risk is\nbelieved to be low. <\/p>\n\n\n\n

The virus is most contagious when people are\nsymptomatic; while spread may be possible before symptoms appear, this risk is\nlow. The European Centre for\nDisease Prevention and Control<\/a> (ECDC) states that while it is not\nentirely clear how easily the disease spreads, one person generally infects two\nto three others. <\/p>\n\n\n\n

The virus survives\nfor hours to days on surfaces. Specifically, the virus was found to be\ndetectable for one day on cardboard, for up to three days on plastic and\nstainless steel, and for up to four hours on copper. This, however, varies\nbased on the humidity and temperature. Surfaces may be decontaminated with\na number of solutions (within one minute of exposure to the disinfectant for a\nstainless steel surface), including 62\u201371% ethanol<\/a>, 50\u2013100% isopropanol<\/a>, 0.1% sodium\nhypochlorite<\/a>,\n0.5% hydrogen\nperoxide<\/a>,\nand 0.2\u20137.5% povidone-iodine<\/a>. Other solutions,\nsuch as benzalkonium\nchloride<\/a> and chrohexidine\ngluconate<\/a>,\nare less effective.<\/p>\n\n\n\n

VIROLOGY<\/strong><\/p>\n\n\n\n\n\n

<\/a><\/p>\n\n\n\n

Severe acute respiratory syndrome coronavirus\n2 (SARS-CoV-2) is a novel<\/a> severe acute\nrespiratory syndrome coronavirus, first isolated from three people with\npneumonia connected to the cluster<\/a> of acute\nrespiratory illness cases in Wuhan. All features of the novel SARS-CoV-2\nvirus occur in related coronaviruses in nature.<\/p>\n\n\n\n

Outside the human body, the virus is killed\nby household soap<\/a>, which bursts its\nprotective bubble.<\/p>\n\n\n\n

SARS-CoV-2 is closely related to the original\nSARS-CoV. It is thought to have a zoonotic<\/a> origin. Genetic\nanalysis has revealed that the coronavirus genetically clusters with the\ngenus Betacoronavirus<\/em><\/a>, in subgenus Sarbecovirus<\/em><\/a> (lineage B)\ntogether with two bat-derived strains. It is 96% identical at the whole genome<\/a> level to other\nbat coronavirus samples (BatCov RaTG13). In February 2020, Chinese\nresearchers found that there is only one amino acid<\/a> difference in\ncertain parts of the genome sequences between the viruses from pangolins<\/a> and those from\nhumans, however, whole-genome comparison to date found at most 92% of genetic\nmaterial shared between pangolin coronavirus and SARS-CoV-2, which is\ninsufficient to prove pangolins to be the intermediate host<\/a>.<\/p>\n\n\n\n

The WHO<\/a> has published several testing protocols for the\ndisease. The standard method of testing is real-time reverse transcription polymerase chain\nreaction<\/a> (rRT-PCR). The\ntest is typically done on respiratory samples obtained by a nasopharyngeal\nswab<\/a>,\nhowever a nasal swab or sputum<\/a> sample may also\nbe used. Results are generally available within a few hours to two\ndays. Blood tests can be used, but these require two blood samples taken\ntwo weeks apart and the results have little immediate value. Chinese scientists\nwere able to isolate a strain of the coronavirus and publish the genetic\nsequence<\/a> so\nlaboratories across the world could independently develop polymerase chain reaction<\/a> (PCR) tests to\ndetect infection by the virus. As of 19 March 2020. there were no antibody\ntests though efforts to develop them are ongoing. The FDA approved the\nfirst point-of-care\ntest<\/a> on\n21 March 2020 for use at the end of that month. <\/p>\n\n\n\n

Diagnostic guidelines released by Zhongnan\nHospital of Wuhan\nUniversity<\/a> suggested\nmethods for detecting infections based upon clinical features and\nepidemiological risk. These involved identifying people who had at least two of\nthe following symptoms in addition to a history of travel to Wuhan<\/a> or contact with\nother infected people: fever, imaging features of pneumonia, normal or reduced\nwhite blood cell count, or reduced lymphocyte<\/a> count. <\/p>\n\n\n\n

A March 2020 review concluded that chest X-rays<\/a> are of little\nvalue in early stages, whereas CT scans of the chest are useful even before\nsymptoms occur. Typical features on CT include bilateral multilobar ground-glass\nopacificities<\/a> with\na peripheral, asymmetric and posterior distribution. Subpleural dominance<\/a>, crazy paving<\/a> and consolidation<\/a> develop as the\ndisease evolves. As of March 2020, the American College of Radiology<\/a> recommends that\n“CT should not be used to screen for or as a first-line test to diagnose\nCOVID-19”.<\/p>\n\n\n\n\n\n