Life style risk factors such as aging, poor nutrition, infection and exposure to toxicants can also increase susceptibility to illnesses. These life style factors can therefore be considered to cause acquired susceptibility for increased risk for environmental disease.
A susceptible person is someone who is not vaccinated or otherwise immune, or a person with a weakened immune system who has a way for the germs to enter the body. For an infection to occur, germs must enter a susceptible person’s body and invade tissues, multiply, and cause a reaction.
