E. coli is a leading cause of bacteria-triggered diarrhea and it comes from food, the environment or the intestines of people and animals. But while the bug makes some people extremely ill, it has little to no effect on others, the researchers. Recently researchers found there were differences with the subjects that seemed to predict who would become sick. They interpreted those as signals that make an innate resistance to infection. There may be certain genetic traits that can increase or decrease your chances of being infected after exposure to a pathogen. The next step is to look at other types of infections, including viral and respiratory illnesses such as the flu. It clearly indicates how the expression of these genes imparts this resistance and susceptibility, it might be able to offer new ways to boost immune system to protect against prevalent infections such as E. coli or better predict who is at greatest risk of getting an infection. According to Disease Control and Prevention, E. coli illness usually appears within an average of three or four days after swallowing the germ. Illness can be severe and include diarrhea, often bloody, and abdominal cramps. Most people will recover within a week, but in some the illness can progress to kidney failure. Children under the age of 5, older adults and people with weakened immune systems are at highest risk from E. coli illness.