March 12, 2007 2:46am CST
The size of bacteria varies from 0.4 to 1.5 microns. They are of different shapes: Round, rodlike and spiral. Sometimes, bacteria are found clinging to one another. Many of them, can move by themselves, and many are parasites. They live and propagate in different parts of human and animal bodies. Bacteria are responsible for many serious and not so serious diseases. For example: sore throat, sepsis (of wounds), pneumonia, cholera, tuberculosis, leprosy, sexually transmitted diseases, dysentery etc.