In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.
Cytomegalovirus (CMV) is a common virus that can infect almost anyone. Most people don't know they have CMV because it rarely causes symptoms. However, if you're pregnant or have a weakened immune system, CMV is cause for concern.Once infected with CMV, your body retains the virus for life.However, CMV usually remains dormant if you're healthy. CMV spreads from person to person through body fluids, such as blood, saliva, urine, semen and breast milk. CMV spread through breast milk usually doesn't make the baby sick.owever, if you're pregnant or have a weakened immune system, CMV is cause for concern. Once infected with CMV, your body retains the virus for life. However, CMV usually remains dormant if you're healthy. CMV spreads from person to person through body fluids, such as blood, saliva, urine, semen and breast milk.
Tobacco mosaic virus (TMV) is a positive-sense single stranded RNA virus that infects a wide range of plants, especially tobacco and other members of the family Solanaceae.The infection causes characteristic patterns, such as  mosaic -like mottling and discoloration on the leaves (hence the name).TMV was the first virus ever to be discovered.Although it was known from the late 19th century that an infectious disease was damaging tobacco crops, it was not until 1930 that the infectious agent was determined to be a virus.he infection causes characteristic patterns, such as  mosaic -like mottling and discoloration on the leaves (hence the name). TMV was the first virus ever to be discovered.