Slow blood flow can occur if there is a narrowing of the blood vessel. This can obstruct the flow. One common cause is atherosclerosis. There are deposition of cholesterol or lipids in the wall of the arteries which can narrow it. Other causes can be an inflammation. In the veins there can be slow flow where there is difficulty in pumping blood from legs towards the heart. If you feel any symptom, you should get an examination you need to get it checked by doctor. Any query, please feel free to ask.
Retrovirus, any of a group of viruses that belong to the family Retroviridae and that characteristically carry their genetic blueprint in the form of ribonucleic acid (RNA).
Medical Definition of Coronavirus. Coronavirus: One of a group of RNA viruses, so named because they look like a corona or halo when viewed under the electron microscope. The corona or halo is due to an array of surface projections on the viral envelope. The coronavirus genome is a single strand of RNA 32 kilobases long and is the largest known RNA virus genome.