History of COVID19

                    THE CORONA  VIRUS 

On 30 December 2019, three bronchoalveolar lavage samples were collected from a patient 

with pneumonia of unknown etiology – a surveillance definition established following the 

SARS outbreak of 2002-2003 – in Wuhan Jinyintan Hospital. Real-time PCR (RT-PCR) assays

on these samples were positive for pan-Betacoronavirus. 
Using Illumina and nanopore 

sequencing, the whole genome sequences of the virus were acquired. Bioinformatic 

analyses indicated that the virus had features typical of the corona virus family and belonged 

to the Betacoronavirus 2B lineage.
 Alignment of the full-length genome sequence of the 

COVID-19 virus and other available genomes of Betacoronavirus showed the closest 

relationship was with the bat SARS-like coronavirus strain BatCov RaTG13, identity 96%.

Virus isolation was conducted with various cell lines, such as human airway epithelial cells, 

Vero E6, and Huh-7.
 Cytopathic effects (CPE) were observed 96 hours after inoculation. 

Typical crown-like particles were observed under transmission electron microscope (TEM) 

with negative staining. The cellular infectivity of the isolated viruses could be completely 

neutralized by the sera collected from convalescent patients. Transgenic human ACE2 mice 

and Rhesus monkey intranasally challenged by this virus . The COVID-19 virus was subsequently detected 

and isolated in the lung and intestinal tissues of the challenged animals.

Whole genome sequencing analysis of 104 strains of the COVID-19 virus isolated from 

patients in different localities with symptom onset between the end of December 2019 and 

mid-February 2020 showed 99.9% homology, without significant mutation .

Outbreak

Post-mortem samples from a 50-year old male patient from Wuhan were taken from the

lung, liver, and heart. Histological examination showed bilateral diffuse alveolar damage 

with cellular fibromyxoid exudates.
 The lung showed evident desquamation of 

pneumocytes and hyaline membrane formation, indicating acute respiratory distress 

syndrome (ARDS). Lung tissue also displayed cellular and fibromyxoid education,

desquamation of pneumocytes and pulmonary oedema. Interstitial mono nuclear 

inflammatory infiltrates, dominated by lymphocytes , were seen in both lungs.

Multinucleated syncytial cells with atypical enlarged pneumocytes characterized by large 

nuclei, amphophilic granular cytoplasm, and prominent nucleoli were identified in the intra-

alveolar spaces, showing viral cytopathic-like changes. 
No obvious intranuclear or 

intracytoplasmic viral inclusions were identified.

The outbreak

As of 20 February 2020, a cumulative total of 75,465 COVID-19 cases were reported in 

China. Reported cases are based on the National Reporting System (NRS) between the

National and Provincial Health Commissions. 

The NRS issues daily reports of newly 

recorded confirmed cases, deaths, suspected cases, and contacts. A daily report is provided 

by each province at 0300hr in which they report cases from the previous day. 

The epidemic curves presented in Figures 2 and 3 are generated using China’s National 

Infectious Disease Information System (IDIS), which requires each COVID-19 case to be 

reported electronically by the responsible doctor as soon as a case has been diagnosed. 
It 

includes cases that are reported as asymptomatic and data are updated in real time. 

Individual case reporting forms are downloaded after 2400hr daily. Epidemiologic curves 

for Wuhan, Hubei (outside of Wuhan), China (outside Hubei) and China by symptom onset.

The signs, symptoms, disease progression and severity

Based on  laboratory confirmed cases, typical signs and symptoms include: fever 

, dry cough , fatigue ,sputum production, shortness of breath 

, sore throat , headache , myalgia or arthralgia, chills ,

nausea or vomiting, nasal congestion , diarrhea, and hemoptysis , 

and conjunctival congestion.

Also some other people with COVID-19 generally develop signs and symptoms, including mild respiratory 

symptoms and fever, on an average of 5-6 days after infection (mean incubation period 5-6 

days, range 1-14 days). 

Approximately 

80% of laboratory confirmed patients have had mild to moderate disease, which includes some pneumonia and non pneumonia cases and other cases like dyspnea

Asymptomatic infection has been reported, but the majority of the relatively rare cases who are asymptomatic on the date of identification/report went on to develop disease. The proportion of truly asymptomatic infections is unclear but appears to be relatively rare and does not appear to 

be a major driver of transmission. 

The people of age group over 60 years are at high risk for severe disease and death cases.The patients with the problem of diabetes,hypertension or cardiovascular diseases are also found to be more prone to the pandemic. 

The individuals of under 19 years age are also reported to be infected that is about 2.4 percent. Among these 2.4 percents are reported to severe cases while 0.2 percents are reported to be of critical cases.
These were some of the importances on the topic of covid 19.
Hope you liked the article.
Please do visit our article too link is given below

symptoms of corona virus

what-are-importance-of-yoga

__________
Stay safe
Keep social distance.