Why do epidemiologist study health concerns as diverse as salmonella and aids?

This nutrient found in fruits and vegetables strengthens the bodys immune system? What are the 4 steps in the path to addiction? What are the benefits of using Biotene dental products? What was the root cause of the rise of civilizations? Is it ok to take nurofen when pregnant? Why do you have large painless swollen lymph nodes in your neck and a very very itchy scalp if your 14 years old and apparently not fighting off infection? Are bone jealous of bizzy bone? Would it be difficult to live in Georgia with copd? Could I be pregnant if I was due to have my period had it for a day stopped and now I'm spotting brown Pregnancy test was negative but have all physical pregnancy symptoms.? What is a brown spot that appears between the index finger and the thumb? How do you know your unborn baby is alive? Is peeing inside a woman too dangerous during pregnancy? What is the color jonquil? What happens when someone catches a grenade? Can income support still be claimed if your partner works but only earns 8000 a year and you are pregnant? Does discharge from chlamydia change with your period? What are syndrome excuses? How many people died from the flu? Is jungle rot contagious? Was diabetes curable in the 1860s?