Because it is in an environment suitable for the larvae of pathogens and pests as food for human kind. Can cause fever, malaria, cholera is easily gatherers.
Because it is in an appropriate environment for incubation of germs and pests as some types of human food may cause disease, cholera, dengue fever, blisters easily maleria.
Because it is in the environment that is suitable for the breeding of germs and pests that it is the food of man some may cause disease, Maria respect fever diarrhea.