Post by on Sunday, March 29, 2020
Coronavirus disease 2019 (COVID-19) is an infectious horrific disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak was first identified in Wuhan, the Capital of China’s Hubei province in December 2019 and has since spread globally, therefore, it was recognized as pandemic by the World Health Organization (WHO) on 11 March 2020.
Health authorities in Wuhan, reported many pneumonia cases of unknown cause on 31 December 2019, and an investigation was launched in early January 2020. The cases mostly were linked to the Huanan Seafood Wholesale Market and so the virus is thought to have a zoonotic origin. The virus that caused the outbreak is SARS-CoV-2, a newly discovered virus closely related to bat coronaviruses, pangolin coronaviruses and SARS-CoV.
The earliest known person with symptoms was later traced back to 1 December 2019, someone who did not have visible connections with the later wet market's cluster. Of the early number of cases reported in December 2019, two-thirds were found to have a link with the market. On 13 March 2020, an unverified report from South China Morning Post suggested that a 55-year-old from Hubei province may have been the first case identified on 17 November 2019.
The WHO on 26 February, 2020 reported that, as new cases reportedly dropped in China but suddenly increased in Italy, Iran, and South Korea. There may be substantial underreporting of cases, particularly those with milder symptoms. Some governments have had an official policy of not testing those with only mild symptoms, including Switzerland and Italy. By 26 February, relatively few cases have been reported among youth, with those 19 and under making up 2.4% of cases worldwide.
The COVID-19 infected one’s may either be asymptomatic or develop symptoms such as fever, cough, fatigue, shortness of breath, muscle pain, diarrhoea, headache, sputum production, sore throat and loss of smell or taste. The U.S. Centres for Disease Control and Prevention (CDC) lists emergency symptoms including difficulty breathing, persistent chest pain or pressure, sudden confusion, difficulty waking, and bluish face or lips; immediate medical attention is advised if these symptoms are present.
Complications can lead to severe pneumonia, acute respiratory distress syndrome, sepsis, septic shock and death. Some of those infected may be asymptomatic (test results confirming infection but showing no clinical symptoms), therefore, researchers have advised that those with close contact to confirmed infected people should be closely monitored and examined to rule out infection. Incubation period (the time between infection and symptom onset) ranges from one to 14 days; it is most commonly five days.
The World Health Organization and Centre for Disease Control stages that the virus mainly spreads during close contact and via respiratory droplets discharged when people cough or sneeze. Respiratory droplets may be produced during breathing but the virus is not considered airborne. While there are concerns it may spread via faeces this risk is believed to be low. People may also catch COVID-19 by touching a contaminated surface and then their face. It is most contagious when people are symptomatic, although spread may be possible before symptoms appear. The virus can live on surfaces up to 72 hours.
Recommended measures to prevent the virus spreading include frequent hand washing, social distancing, covering coughs and sneezes with a tissue, keeping unwashed hands away from the face, travel restrictions and quarantines. There is no vaccine or specific antiviral treatment for COVID-19. Management involves treatment of symptoms, supportive care, isolation, and experimental measures.
To prevent the spread of the disease, frequent hand washing is recommended. The CDC recommends that people wash hands often with soap and water for at least 20 seconds, especially after going to the toilet or when hands are visibly dirty; before eating; and after blowing one's nose, coughing, or sneezing. Using an alcohol-based hand sanitizer with at least 60% alcohol by volume must be used when soap and water are not readily available. However, in some other countries, like Lebanon, they recommended a hand wash for at least 30 seconds while avoiding using alcohol-based hand sanitizer. The WHO advises people to avoid touching the eyes, nose, or mouth with unwashed hands.
China has specifically recommended the use of disposable medical masks by healthy members of the public. Hong Kong recommends wearing a surgical mask when taking public transport or staying in crowded places. Thailand's health officials are encouraging people to make face masks at home out of cloth and wash them daily. The Czech Republic banned going out in public without wearing a mask or covering one's nose and mouth.
Social distancing includes infection control actions intended to slow the spread of disease by minimizing close contact between individuals. Methods include quarantines; travel restrictions; and the closing of schools, workplaces, stadiums, theatres, or shopping centres. Individuals may apply physical distancing methods by staying at home, limiting travel, avoiding crowded areas, using no-contact greetings, and physically distancing themselves from others. On 22 March 2020, Germany banned public gatherings of more than two people.
Older ones and those with underlying medical conditions such as diabetes, heart disease, respiratory disease, hypertension, and compromised immune systems face increased risk of serious illness and complications and have been advised by the US CDC to stay home as much as possible in areas of community outbreak.
In late March 2020, the WHO and other health bodies began to replace the use of the term "social distancing" with "physical distancing", to clarify that the aim is to reduce physical contact while maintaining social connections, either virtually or at a distance. The use of the term "social distancing" had led to implications that people should engage in complete social isolation, rather than encouraging them to stay in contact with others via alternative means.
SARS-CoV-2 is closely related to the original SARS-CoV. It is thought to have a zoonotic origin. Genetic analysis has revealed that the coronavirus genetically clusters with the genus Betacoronavirus, in subgenus Sarbecovirus (lineage B) together with two bat-derived strains. It is 96% identical at the whole genome level to other bat coronavirus samples (BatCov RaTG13). In February 2020, Chinese researchers found that there is only one amino acid difference in certain parts of the genome sequences between the viruses from pangolins and those from humans, however, whole-genome comparison to date found at most 92% of genetic material shared between pangolin coronavirus and SARS-CoV-2, which is insufficient to prove pangolins to be the intermediate host.
The standard method of diagnosis is by reverse transcription polymerase chain reaction (rRT-PCR) from a nasopharyngeal swab. The infection can also be diagnosed from a combination of symptoms, risk factors and a chest CT scan showing features of pneumonia.
There is no vaccine or specific antiviral treatment for COVID-19, but research into developing a vaccine has been undertaken by various agencies including testing of existing medications. Depending on the severity, oxygen therapy, intravenous fluids and breathing support may be required. The use of steroids may worsen outcomes. Several compounds, which were previously approved for treatment of other viral diseases, are being investigated.
Author is a research scholar at Gene Expression Lab, Department of Bio-sciences, JamiaMilliaIslamia, New Delhi