19-1 Introduction

19-2 Helicobacter pylori Is the Cause of Many Ulcers

19-3 Some Escherichia coli Strains Cause Diarrheal Diseases by Colonizing the Intestine, while Others Are Capable of Extraintestinal Infections.

19-4 Salmonella enterica Causes a Common Form of Gastroenteritis

19-5 Vibrio cholerae Is the Cause of Cholera

19-6 Infections with protozoa

19-7 Infections with Helminths

19-8 The hepatitis viruses

19-9 Summary