RT Book, Section A1 Oberhelman, Richard A. A2 Rudolph, Colin D. A2 Rudolph, Abraham M. A2 Lister, George E. A2 First, Lewis R. A2 Gershon, Anne A. SR Print(0) ID 7031742 T1 Chapter 349. Giardiasis T2 Rudolph's Pediatrics, 22e YR 2011 FD 2011 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-149723-7 LK accesspediatrics.mhmedical.com/content.aspx?aid=7031742 RD 2024/04/19 AB Giardia lamblia or Giardia intestinalis is a protozoan flagellate that is among the most common disease-causing parasites in the United States and the most frequently identified agent of waterborne diarrhea.1 Cases are especially common in areas with inadequate water and sanitation facilities. Humans are the major reservoir of infection, although other mammals, such as dogs, cats, and beavers, may be colonized and excrete cysts. Massive epidemics have occurred after the contamination of reservoirs, lakes, and streams, especially when community water supplies are not adequately filtered.