Some viral infections can spread throughout
the body. One example is HIV, the human
immunodeficiency virus. Over the course of several
years, this viral infection eventually develops into
AIDS (Acquired Immunodeficiency Syndrome), at
'which point symptoms appear. Since HIV destroys
the body's immune system, people suffering
from AIDS are at risk of catching a wide
variety of infections that lead to death,
including cancer and pneumonia. To date, there is no cure for or vaccine against this particular virus.