Viruses are tiny organisms that rely on human or animal cells for their survival, so they cannot last very long outside the body²⁷. They cause illnesses by invading healthy cells and multiplying.

Bacteria are single cell organisms usually found in and on our bodies²⁷. Some bacteria are harmless – and can even be good for us – and some cause infections²⁷.

Viruses are tiny organisms that rely on human or animal cells for their survival, so they cannot last very long outside the body²⁷. They cause illnesses by invading healthy cells and multiplying.

Bacteria are single cell organisms usually found in and on our bodies²⁷. Some bacteria are harmless – and can even be good for us – and some cause infections²⁷.