Detection of viral infections currently relies on two major methodologies: Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) and serological immunoassays that detect viral-specific antibodies (IgM and IgG) or antigens. Rapid IgG/IgM detection provides an easy, cheap, and fast method to find COVID-19 infection but how much is this serological test is reliable?
Coronavirus is a pathogenic viral infection and is highly transmittable. Coronaviruses genomes are enveloped single-stranded RNA, and with a size range of 26-32 kilobases, which is the largest genome of viral RNA. Genotypically coronavirus subfamily is categorized into four groups which are α-alpha, β-beta, ɣ-gamma, and δ-delta. Α-alpha and β-beta coronavirus cause infections in humans.
These viral infections cause upper respiratory tract infections with signs of fever, cough, and headache, and other signs of a symptom similar to influenza.
The immune system is the major player when any foreign body enters the human body. The immune system of humans is a complex system protecting against invading bodies. The coronavirus was caused by a new strain of virus SARS-CoV2 in December 2019 which produces pneumonia-like symptoms. The pathophysiology of this virus includes entry into the lungs through respiration. The viral infection initiates the inflammatory responses because of inflammatory chemotactic factors like cytokines (IL-6 and TNF-alpha). These cytokines produce physiological changes including an increase in body temperature resulting in fever. This also causes accumulation of fluid in the lungs and produces difficulty in breathing.
There are 4 types of structural proteins of this novel virus which are S-spike surface glycoprotein, M-matric protein, N-nucleocapsid protein, and E-envelop protein. The S protein act as an adhesion factor to help in getting the entry to the human epithelial cells through the dipeptidyl peptidase-4 receptor. This receptor plays a major role in the activation and initiation of the immune response in the body.