Coronavirus: Structure, Transmission, and Symptoms Quiz

Coronavirus: Structure, Transmission, and Symptoms

The coronavirus is a family of viruses characterized by their spiky surface proteins called peplomers. These virions have a positive-sense single-stranded RNA strand encased within an envelope formed from host cell membranes. This section will discuss the structure, transmission routes, and primary symptoms associated with different strains of the coronavirus, including SARS-CoV, MERS-CoV, and SARS-CoV-2.

Virus Structure

Coronaviruses share common structural features but differ in genetic makeup. They possess a lipid bilayer that surrounds the genomic material, which is composed of a segmented, single-stranded (ss) RNA. This naked nucleocapsid is covered by a protein shell called the capsid. Additionally, each virus sports one or more glycoprotein spikes embedded in its outer layer. These spike proteins play a vital role in the attachment of the virus to the target cell's receptors, allowing entry into the host cell.

Transmission

Transmission occurs when the virus enters the body through bodily fluids such as saliva, nasal secretions, mucous, sweat, feces, urine, semen, and blood that contain infectious particles. Common routes of infection include respiratory droplets (coughing), contact with contaminated surfaces, and airborne spread.

Respiratory Droplets

Respiratory droplets originate from infected individuals during coughing, sneezing, talking, breathing, singing, and aerosol-generating procedures like suctioning. These larger respiratory droplets transmit the virus primarily through direct contact with the mucosae of the nose, mouth, and eyes.

Contact with Contaminated Surfaces

Contamination can also occur by touching fomites - objects or materials capable of harboring pathogens - and subsequently transferring the virus to the face or other susceptible areas. Survival rates vary depending on factors such as environmental conditions like temperature and humidity, persistence of the virus, and the effectiveness of cleaning and disinfection procedures.

Airborne Spread

Airborne transmission involves the dispersion of smaller particles, typically smaller than 5 μm, which can remain suspended in the air for extended periods. These particles can be generated by a wide range of activities, including coughing, sneezing, talking, and singing. Airborne transmission is particularly relevant in enclosed spaces with poor ventilation.

Symptoms

The clinical presentation of coronavirus infection varies depending on the virus strain and individual host factors. Common symptoms include fever, cough, fatigue, body aches, and loss of appetite. Severe cases may progress to pneumonia, respiratory failure, and death.

SARS-CoV-2

SARS-CoV-2, the virus responsible for COVID-19, causes a range of symptoms. Some individuals experience mild or no symptoms, while others develop severe respiratory complications. Symptoms may include fever, cough, shortness of breath, fatigue, body aches, headache, sore throat, runny nose, congestion, hoarseness, and new loss of taste or smell.

SARS-CoV

SARS-CoV and SARS-CoV-2 share similar symptoms, such as fever, cough, loss of appetite, and shortness of breath. In some cases, SARS-CoV infections may progress to pneumonia, respiratory failure, and death.

MERS-CoV

MERS-CoV infections often cause severe respiratory symptoms, including fever, cough, and shortness of breath. Other symptoms include gastrointestinal disturbances, such as diarrhea and vomiting, as well as kidney failure.

In conclusion, coronaviruses are RNA viruses that possess a lipid bilayer and a nucleocapsid shell. They are primarily transmitted via respiratory droplets, contact with contaminated surfaces, and airborne spread. Common symptoms include fever, cough, fatigue, and loss of appetite, with complications like respiratory failure and death in severe cases.