Sever's disease or calcaneal apophysitis is usually considered to be due to damage or a disturbance in this area of growth. The two growth areas of the calcaneus can be seen on this x-ray. The smaller area to the back of the heel is normal.hat are the long term consequences of heel pain in the child (Severs disease or Calcaneal apophysitis): This condition is self limiting-it will go away when the two parts of bony growth join together-this is natural.
So, a virus must have a host cell (bacteria, plant or animal) in which to live and make more viruses. Outside of a host cell, viruses cannot function. For this reason, viruses tread the fine line that separates living things from nonliving things.
In order for a virus to infect a cell, it must bring its DNA or RNA into contact with the host cell. Therefore, infection requires that the virus get through the cellular membrane. Some viruses remain outside the cell. They attach to the membrane at specific receptor sites.Once attached the virus injects its DNA or RNA into the cell. Enveloped viruses are enclosed in a membrane similar to that of the host cell. The virus and the envelope fuse and the virus enters the cell through endocytosis.In the first example only the genetic material enters the cell.herefore, infection requires that the virus get through the cellular membrane. Some viruses remain outside the cell. They attach to the membrane at specific receptor sites. Once attached the virus injects its DNA or RNA into the cell. Enveloped viruses are enclosed in a membrane similar to that of the host cell.