Organisms like bacteria and viruses are all over the environment.

Many of the most common diseases are caused by microorganisms called pathogens. 

Communicable diseases come from one infected person to another. 

Stomach ache is one symptom of a communicable disease. 

Viral hepatitis is caused by a virus that affects the liver 

Mortality is the being unhealthy for a particular state of situation, disease or Morbidity is the number of deaths that occur in a population.

Insomnia is a sickness caused by a carrier mosquito. 

Pinworms hatch and live primarily in the intestines of a person. 

Stagnant water is a reservoir for mosquitoes to multiply. 

It is the nature of pathogens to invade its host through certain points of entry to cause morbidity.