Ventricular Septal Defect Causes No one knows what causes ventricular septal defects, but they probably come from a malformation of the heart that occurs while the infant is developing in the womb. There may be just one hole or several holes in the septum.
Definition. Hepatitis B is a potentially serious form of liver inflammation due to infection by the hepatitis B virus (HBV). It occurs in both rapidly developing (acute) and long-lasting (chronic) forms, and is one of the most common chronic infectious diseases worldwide. Contact with infected blood is a common means of transmitting hepatitis B. 2  One way this may happen is by being stuck with a needle. 3  Both health care workers and those who inject drugs into their veins are at risk in this way. 4  Having sex with a person infected by HBV is an important risk factor (especially anal sex).
Hepatitis B virus (HBV), a member of the hepadnavirus group, double-stranded DNA viruses which replicate, unusually, by reverse transcription. Hepatitis B virus is endemic in the human population and hyperendemic in many parts of the world.epatitis B virus was originally recognized as the agent responsible for âserum hepatitisâ, the most common form of parenterally transmitted viral hepatitis, and an important cause of acute and chronic infection of the liver. The incubation period of hepatitis B is variable with a range of 1 to 6 months.