Question

1. What are the causes of the common cold?
2. How does a virus cause a disease?

Answer 1

1.Ans: Common cold is the upper respiratory tract infection caused by the virus. These viruses primarily affect the nose, larynx, Thorat and sinuses. Human Rhinovirus causes the common cold and it is also known as Cold, viral rhinitis, nasopharyngitis. Human Rhinovirus has the ability to grow at 33°C to 35°C temperature. This is the temperature of the nose in our body. The normal body temperature of a human is 37°C. So the virus grows and proliferates in the nose. Rhinovirus spread through Direct contact with the infected person and also through the aerosols of the respiratory droplets. The symptoms of the common cold are running nose, sore throat, headache, malaise, nasal congestion, fatigue, cough and sneezing.

2. Ans: Pathophysiology of Rhinovirus in the common cold are: The Rhinovirus has three types Rhinovirus A and Rhinovirus B. Both viruses have a higher affinity for binding with epithelial cell. When the virus enters the human body through mouth or nose, it is bind to epithelial cell receptor ie, intercellular adhesion molecules 1 (ICAM-1) and it is also known as Cluster of Differentiation 54 (CD54). And these viruses also bind with minor receptor ie, LDL receptor. Rhinovirus C bind with the Cadherin related family member 3 (CDHR3) protein and enter in the epithelial cell. Within the infected cell, these viruses grow and replicate. After replication, the Rhinovirus spread and causes the secretion of cytokines and chemokines which causes the activation of inflammatory mediators. These inflammatory mediators cause the symptoms and these mediators don't cause the damage of the epithelial cell.