Covid 19 is a virus disease.its full name corona virus disease.
Scientists first identified a human coronavirus in 1965. It caused a common cold.
Later that decade, human and animal viruses and named them after their crown-like appearance. Seven coronaviruses can infect humans. The one that causes SARS emerged in southern China in 2002 and quickly spread to 28 other countries. More than 8,000 people were infected by July 2003, and 774 died. A small outbreak in 2004 involved only four more cases. This coronavirus causes fever, headache, and respiratory problems such as cough and shortness of breath. MERS started in Saudi Arabia in 2012. Almost all of the nearly 2,500 cases have been in people who live in or travel to the Middle East. This coronavirus is less contagious than its SARS cousin but more deadly, killing 858 people.
Again corona virus see in wuhan 31 December 2019.first case identified 1 December 2019. Who alerted 31 December 2019.
First death in china (wuhan) 9 January 2020.
Thailand report first case beyond china 13 January 2020.
Who admits no known effective treatment.
New corona virus to be called COVID-19 11 February 2020.
11 march 2020 official declaration of covid-19 as pandemic.
Coronaviruses are a big family of different viruses. Some of them cause the common cold in people. Others infect animals, including bats, camels, and cattle. SARS-CoV-2 made the jump to humans at one of Wuhan’s open-air “wet markets.” They’re where customers buy fresh meat and fish, including animals that are killed on the spot.
Causative agent-SARS COV-2
Median incubation period-5.1days
Mode of transmission-Droplets, contact,fomites Case fertility rate-2-3.7%(0.2-15%)
Figure 1. Epidemic Curve of the Confirmed Cases of Coronavirus Disease 2019 (COVID-19
Figure 2. Timeline Comparing the Severe Acute Respiratory Syndrome (SARS) and Coronavirus Disease 2019 (COVID-19) Outbreaks
its mainly effect lungs.
Diffuse alveolar damage ,platelet fibrin thrombosis embolism.
Increase D-Dimer levels
Spike surface glycoproteins of the virus binds to the host via receptor binding domains of the angiotensin converting enzyme 2(ACE2),which is most abundant in type2 alveolar cells.
10- 20 times higher binding affinity as compared with the SARS-CoV-1 virus. After a SARS-CoV-2 attaches to a target cell, the virion releases RNA into the cell, initiating replication of the virus
which further disseminates to infect more cells.
SARS COV-2 is a member of the order NIDOVIRALES family coronaviridae ,sub family Ortho -corona virinae.
Unsegmented ,single strand positive sense RNA-genome .
4 major protein major ,membrane,envelope,nucleocapsid.
Average time from exposure to symptom onset is 5 days .
97.5% of people who develop symptoms do so within 11.5 days.
Asymptomatic infection rate 46%
Rare in children, about 2 - 5% of confirmed cases, with milder symptoms, very low hospitalization rate < 7%
Common symptoms in hospitalized patients :-
Fever (70 - 90%)
Dry cough (60 - 86%)
Shortness of breath (53 - 80%)
Myalgias (15 - 44%)
Nausea / vomiting or diarrhea (15 - 39%)
Headache, weakness (25%)
Patients can present with nonclassical symptoms
Isolated gastrointestinal symptoms
Isolated anosmia or ageusia (3%)
COVID-19 can progress to severe acute respiratory syndrome and its major clinicopathological phenotypes include pneumonia and acute respiratory distress syndrome.
Distribution of severity
Mild or no disease: 81%
Severe disease: 14%
Critical disease: 5%
Overall case fatality rate: 2.3%
20 - 42% of hospitalized patients developed acute respiratory distress syndrome
Patients who required ICU supportive care presented with acute respiratory distress syndrome, acute cardiac injury, acute kidney injury and shock; up to 15% of them had fatal outcomes. Common complications among hospitalized patients
Acute respiratory distress syndrome (15%)
Acute liver injury (19%)
Cardiac injury (7 - 17%): troponin elevation, acute heart failure, dysrhythmias, myocarditis Prothrombotic coagulopathy resulting in venous and arterial thromboembolic events (10 - 25%) Acute kidney injury (9%)
Acute cerebrovascular disease (3%)
A rare multisystem inflammatory syndrome similar to Kawasaki disease has recently been described in children (2 per 100,000 persons aged < 21 years)
Nasopharyngeal swab is recommended for the specimen; oropharyngeal swab, sputum and bronchoalveolar lavage may be used alternatively .
Positive rates of SARS-CoV-2 PCR testing by specimen types: bronchoalveolar lavage fluid (93%), sputum (72%), nasal swabs (63%), pharyngeal swabs (32%)
Definite diagnosis is based on detection of viral RNA by real time RT-PCR via many available
False negative test results may occur in up to 20 - 67% of patients depending on the quality and timing of testing
A modeling study estimated sensitivity at 33% 4 days after exposure, 62% on the day of symptom onset and 80% 3 days after symptom onset.
Confirmation-nucleic acid sequencing viral genes targeted [N,E,S,RDRP]
Bilateral multi-lobar ground glass opacities.
Sub pleural dominance.
15% of CT and 40% of chest radiograph findings are normal early in the disease Evolution of abnormalities occurs in the first 2 weeks after onset
Meta analysis data
High C reactive protein
High lactate dehydrogenase (LDH) Lymphopenia
Chest CT images
High erythrocyte sedimentation rate (ESR) D dimer elevation
Risks of acute respiratory distress syndrome development include age (> 65 years), underlying
diseases (diabetes mellitus) and secondary infection.
Risk factors for disease progression: male, old age (> 65 years) and smoking. Risk factors for critical / mortal states, in order of strength of association Cardiovascular disease
Non specific- Symptomatic
Oxygen support Medication and devices Prone positioning
Antiviral drug- ribavirin ,favipiravir ,remdesivir Glucocorticoids -dexamethasone,pcm Other-Nsaids hydroxy chloroquine
(Minimum 20 sec)
Alcohol based sanitizer (more than 60%) Wearing mask