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).
A retrovirus is a single-stranded positive-sense RNA virus with a DNA intermediate and, as an obligate parasite, targets a host cell. Once inside the host cell cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus.