Frequently Asked Questions
Q. What is infectious diarrhea?
A. Infectious diarrhea is an alteration of normal bowel habits, usually characterized by increased stool frequency and liquid consistency, which is caused by infectious bacteria, viruses or protozoa that infect the intestinal tracts of humans and animals. The infectious organisms are normally contracted by ingestion of contaminated water or food. Some of the more well-known organisms causing infectious diarrhea include Campylobacter, enterotoxigenic or Shiga toxin-producing E. coli, Salmonella, Shigella, Clostridium, Cryptosporidium, Giardia, Cyclospora and rotavirus.
Q. How common are infectious diarrheal diseases?
A. Infectious diarrheal diseases are the second leading cause of morbidity and mortality worldwide. There are 3.1 million deaths worldwide due to diarrhea per year (more than 8,400 per day), mostly among children in developing areas. In the United States, an estimated 211- 357 million episodes of diarrheal illness occur each year resulting in 73 million physician consultations, 1.8 million hospitalizations and 3,100 deaths. The CDC issued a new study November 22, 2002 reporting that outbreaks of waterborne illnesses roughly doubled in the U.S. in a three-year period ending in 2000. Studies have shown that approximately 20 percent of children in the United States are exposed to Cryptosporidium by age 5-7 years. Approximately 9% of all hospitalizations of children younger than 5 years are due to diarrhea

Q. How do diarrheal illnesses affect those suffering from the infection?
A. Most cases of infectious diarrhea are self-limiting in nature resolving spontaneously after a few days. Acute cases of infectious diarrhea can, however, lead to dehydration and even death. Persistent or chronic diarrhea often associated with intestinal protozoan infections can also cause serious long-term consequences, including malnutrition and impairment of physical or cognitive development.
Q. Who is most at-risk of contracting infectious diarrhea?
A. Anyone who is exposed to the causative organism is susceptible to contracting infectious diarrhea. Young children, the elderly and people with weakened immune systems however, are particularly susceptible to infection with a variety of different pathogens and often are more likely to develop illness of greater severity.
Q. Is there a way to prevent or control exposure to these infections?
A. The risk of contracting infectious diarrheal diseases can be reduced by improved sanitary conditions, but they are very difficult to prevent. Efforts to guarantee clean water supplies and food have been successful in reducing the prevalence of infectious diarrhea in developed countries. Still, these organisms cause millions of cases of infectious diarrhea in the United States each year.
Q. What can be done to treat infectious diarrhea?
A. The first step in treating diarrhea of any origin is to initiate rehydration therapy, orally or intravenously if necessary. Then, a diagnosis of the causative organism should be made, and where appropriate, antimicrobial therapy should be administered to reduce the duration of diarrhea and prevent potential long-term consequences of the infection. The lack of a specific diagnosis is the most significant obstacle hindering appropriate management and treatment of many infections. For diarrhea lasting more than 7 days, standards of care call for consideration of Cryptosporidium or Giardia infection, especially if the patient is immunocompromised.
Q. Why is it difficult to determine the specific cause of infectious diarrhea?
A. Specific diagnosis of the cause of infectious diarrhea requires the collection of fecal samples (often 2 or 3 samples collected on consecutive days) for microscopic examination or cultures to grow bacteria. The time required to conduct these fecal tests can delay treatment of the patient for several days, and the accuracy of the tests is less than optimal. As a result, many physicians view fecal tests as an unnecessary expense and inconvenience, particularly if the physician believes the infection will ultimately resolve spontaneously. In such cases, the physician either treats empirically with an antimicrobial agent or recommends rehydration therapy until the infection resolves spontaneously.
By questioning a patient about his symptoms and epidemiological risks, a physician can obtain clues that might lead him to suspect a particular infection. Factors suggestive of a particular infection might include recent consumption of unsafe foods, daycare center attendance or employment, swimming in lakes or streams, contact with animals with diarrhea, recent use of certain medications, recent hospitalization, travel to a developing country, blood in the stool, fever, the duration of diarrhea and associated symptoms.