Insects can often carry diseases with them. If they have a disease and they bite or sting a human they can transmit that disease to the person they have bitten or stung. Some examples of diseases that insects have transmitted include: Malaria, West Nile, and Yellow Fever. The West Nile Disease is one of the most common, present day diseases that mosquitos carry, and can infect humans in many different regions of the world. Insects can also infect fruit and vegetables with diseases. These diseases can destroy a lot of food that farmers are trying to grow.