Cryptosporidium sp 0 to less than 20% Rotavirus 0-36% 0-10%
Infectious agents are the primary cause of travelers' diarrhea. Bacterial enteropathogens cause approximately 80% of cases. Viruses and protozoans account for most of the rest.
The most common causative agent isolated in countries surveyed has been enterotoxigenic Escherichia coli (ETEC). Enteroaggregative E. coli is increasingly recognized and many studies do not look for this important bacterium.Shigella spp. and Salmonella spp. are other common bacterial pathogens. Campylobacter, Yersinia, Aeromonas, and Plesiomonas spp. are less frequently found. Some bacteria release toxins which bind to the intestinal wall and cause diarrhea; others damage the intestines themselves by their direct presence.
While viruses are associated with less than 20% of adult cases of traveler's diarrhea, they may be responsible for nearly 70% of cases in infants and children. Diarrhea due to viral agents is unaffected by antibiotic therapy, but is usually self-
limited. Protozoans such as Giardia lamblia and Cryptosporidium can also cause diarrhea.
Pathogens implicated in travelers' diarrhea appear in the table at right.
A sub-type of traveler's diarrhea afflicting hikers and campers, sometimes known as wilderness diarrhea, may have a somewhat different frequency distribution of pathogens.
Traveler's Diarrhea Causes
You can become infected by eating or drinking food or water that has come in contact with feces. Food and water become contaminated when they are handled by people with fecal content on their hands—not in direct contact with feces. Restaurants are common sites for exposure to this type of food poisoning. Food from street vendors is even more risky. Eating in a private home is the safest food source.
High-risk food and drink: Certain items are considered high risk for transmission and include the following:
Raw or undercooked meats
Raw leafy vegetables
Unpasteurized dairy products
Tap water (A common mistake travelers make is to avoid tap water but to place ice cubes in a beverage. Contaminated ice is still able to transmit disease. Do not use ice cubes.)
Safe products to eat and drink
Bottled carbonated beverages
Hot coffee or tea
Water boiled or treated appropriately with chlorine Specific bacterial causes: Up to 85% of traveler's diarrhea is caused by bacteria. The remaining cases are caused by viruses and protozoa. The most common organism causing traveler’s diarrhea is Escherichia coli accounting for up to 72% of cases in some regions. Other bacterial causes
Subtypes of E coli
Vibrio species Protozoa causing traveler's diarrhea
Giardia duodenalis, known as giardiasis
Cryptosporidium parvum Viral causes
Enteroviruses PATOFISIOLOGI The pathogenesis of diarrhea in food poisoning is classified broadly into either noninflammatory or inflammatory types.
Noninflammatory diarrhea is caused by the action of enterotoxins on the secretory mechanisms of the mucosa of the small intestine, without invasion. This leads to large volume watery stools in the absence of blood, pus, or severe abdominal pain. Occasionally, profound dehydration may result. The enterotoxins may be either preformed before ingestion or produced in the gut after ingestion. Examples include Vibrio cholerae, enterotoxic Escherichia coli, Clostridium perfringens, Bacillus cereus, Staphylococcus organisms , Giardia lamblia, Cryptosporidium,rotavirus, norovirus (genus Norovirus, previously called Norwalk virus), and adenovirus.
Inflammatory diarrhea is caused by the action of cytotoxin on the mucosa, leading to invasion and destruction. The colon or the distal small bowel commonly is involved. The diarrhea usually is bloody; mucoid and leukocytes are present. Patients are usually febrile and may appear toxic. Dehydration is less likely than with noninflammatory diarrhea because of smaller stool volumes. Fecal leukocytes or a positive stool lactoferrin test indicates an inflammatory process, and sheets of leukocytes indicate colitis.
Sometimes, the organisms penetrate the mucosa and proliferate in the local lymphatic tissue, followed by systemic dissemination. Examples include Campylobacter jejuni, Vibrio parahaemolyticus, enterohemorrhagic and enteroinvasive E coli, Yersinia enterocolitica, Clostridium difficile, Entamoeba histolytica, and Salmonella and Shigella species.
In some types of food poisoning (eg, staphylococci, B cereus), vomiting is caused by a toxin acting on the central nervous system. The clinical syndrome of botulism results from the inhibition of acetylcholine release in nerve endings by the botulinum.
The pathophysiological mechanisms that result in acute gastrointestinal symptoms produced by some of the noninfectious causes of food poisoning (naturally occurring substances [eg, mushrooms, toadstools] and heavy metals [eg, arsenic, mercury, lead]) are not well known