Corona virus

 Corona virus is an infectious disease cause by the SARS-CoV-2 virus( severe acute respiratory syndrome). The disease was spread world wide resulting in COVID-19 pandemic. COVID-19 transmission was originated from China and was slowly spread to all the countries. COVID-19 has head Protein health, social, economic impacts globally.

Morphology of COVID-19

1. Shape – spherical to pleomorphic.
2. Size – Approx 60-140 nm in diameter.
3. Envelope – a lipid bilayer derived from the host cell membrane surrounds the virus.
4. Spike (s) protein – forms crown- like spikes (~20nm long) on the viral surface.
5. Membrane ( M) protein – determine the shape, most abundant protein in the vision.
6. Nucleocapsid (N) protein – encapsulates the single - stranded, positive - sense RNA genome.
7. Genome – ~30kb in length, encodes non- structural proteins like RNA- dependent RNA polymerase ( RdRp), essential for viral replication.
8. Surface features – Glycoproteins protrude from envelope, forming spikes " crown"( hence name corona virus).

Pathogenesis of corona virus 

1. Viral Entry – SARS–CoV–2 enters the body through the respiratory tracts, binding to ACE2 receptors and host cells, primarily in the lungs and other organs.
2. Viral Replication – The virus replicates inside host cells, producing new viral particles and spreading to nearby cells.
3. Immune Response – The body's immune responds, leading to inflammation. In some cases, an overactive immune response ( cytokine storm) causes tissue damage.
4. Tissue damage – Viral replication and inflammation damage the lungs ( causing pneumonia, ARDS) and can affect other organs like the heart kidneys and gastrointestinal system. 
5. Clinical Manifestation – symptoms range from mild ( fever, cough) to severe ( difficulty breathing, organ failure) some people develope " long COVID" with persistent symptoms after recovery.

Clinical systems of Corona virus.

1. Fever – A common symptom indicating infection.
2. Cough – usually dry and persistent.
3. Difficulty Breathing – can range from mild to severe.
4. Fatigue – feeling tired or weak.
5. Loss of taste or smell – A unique symptom for many patients.
6. Muscle or body achese – general discomfort and pain.
7. Sore throat – Irritation in the throat.
8. Headache – common among infected individuals.
9. Gastrointestinal symptoms – such a diarrhea or nausea in some cases.

Lab diagnosis of corona virus 

1. Specimen collection:-

Nasopharyngeal swab, oropharyngeal swab, sputum , saliva, bronchoalveolar lavage ( fluid in severe cases).

2. Rapid Antigen Test:-

• Detects viral proteins ( antigens) in respiratory sample.
• It glued quick result in is to 30 minutes.
• It has lower sensitivity compare to RT-PCR .

3. Serological test:-

• Detects antibodies like IgM, IgG, IgA produced in response to the virus.
• Specimen blood ( serum or plasma).

4. RT - PCR

5. Viral culture:-

Mainly the virus is grown in the host, model animals in a controlled laboratory setting.

6. Chest imaging :- CT scan or X- ray.

Prevention 

1. Vaccination :- Covishield & Covaxin.
2. Hygeine practices :- wash hand frequently with soap and water.
3. Masking :-were mask in crowed or properly ventilated area.
4. Social distance :- minimum to 2 meter physical distance was maintained from other good ventilation.
5. Avoiding close content with sick people.

Treatment 

Antiviral medication, rest proper hydration, proper diet.