I give credit to Dr. Gene Allred for the information that I’ve learned and posted here. He is an expert in Wilderness and Travel Medicine.
I enjoy travelling, but I am always concerned the possibility of developing diarrhea when I go the backcountry or remote areas. The majority of cases of traveler’s diarrhea (TD) occur in the first 2 weeks of travel.
Symptoms: The “typical” symptoms are either 4 loose stools in 24 hours or 3+ loose stools per day x 4-5 days plus at least one of the following: nausea, vomiting, abdominal pain, fever (10%), blood in the stools (15%). Symptoms can begin as early as 8-10 hours after exposure to contaminated food or water. With persistent diarrhea (>14 days) we usually consider a parasitic infection with Giardia, E. histolytica, Crypto, or Cyclospora more likely.
The majority of diarrheal diseases improve on their own and specific tests to identify the pathogen may not be necessary. Treatment typically involves ensuring adequate fluid replacement, and empiric antibiotic treatment. If there is fever along with abdominal pain and dysentery we will obtain a stool culture to look for Salmonella, Shigella and Campylobacter as well for ova and parasites.
We used to think that water contaminated with bacteria was the way the infection was spread from person-to-person but we now know that the flies spread the disease very effectively. The travel from fecal samples and then land on food that’s been sitting out.
Diarrhea can be caused from viruses, bacteria or protozoan. The most common pathogen that causes diarrhea in travellers is E-Coli. Bacteria cause 50-75% of TD with E-Coli causing 25-40%, Campylobacter – 0-30%, Salmonella 0-15%, and Shigella 0-15%. Protozoan cause 0-5% of TD, and viruses cause 0-20%.
I try to take meticulous drinking water precautions (including ice) but it’s often very challenging. When I go out in the backcountry or to remote areas I take along water purification tablets such as chlorine dioxide. Boiling water for at least 1 minute can be helpful, as can chemical disinfection, filtration and use of UV devices. Remember to cook your food well, and peel all your fruits and vegetables – it’s easy to remember but impossible to do. As the saying goes “Boil it, cook it, peel it, or forget it!”
Diagnosis: I’m not sure if there is any hard and fast rule for diagnosing traveler’s diarrhea when out in the field without access to a laboratory, but if I’m with a group of people in a developing country and one of the group members has at least one loose stool, I treat them for traveler’s diarrhea. In the clinic, we can check the stool cultures and for ova & parasites, but we usually only need to do this if there are symptoms of fever, bloody stools or persistent abdominal pain.
Treatment: There is increasing resistance of campylobacter to the fluroquinolone medications such as Cipro. Azithromycin has been found to be a better choice – 1000mg taken daily for 2-3 days usually works well. Rifaximin is a newer antibiotic with few side effects and has a broad spectrum of coverage – the dose is 200mg three times a day for three days. PeptoBismol often improves diarrhea and cramps (2 tablets every 30 minutes for up to 8 doses). If there is no fever, vomiting or blood in the stool, loperamide can help reduce the frequency of diarrhea and can be invaluable for long bus rides.
If there is persistent infection, even after treatment with antibiotics we think about the cause being a protozoa. Giardia is a protozoan that can be detected by a immunoassay and causes diarrhea that lasts for 10 days or longer. Nitazoxanide (Alinia) 500mg twice a day for three days or Tinidazole (Tiniba) 2 grams in a single dose for adults.
Cryptosporidiosis can be a concern, however it is very sensitive to heat. Even 65 degrees C will kill it, so just boil the water.
In third world countries, we wary of swimming in fresh water or going barefooted because there are infectious agents that can get through the skin and cause serious infections (Schistosomiasis, Leptospirosis and Crytopsoridium).
Prevention when travelling: Here are a few of my recommendations about preventing traveler’s diarrhea with water precautions:
1) Drink carbonated water from a sealed container – the carbonation process kills many pathogens – beer is also acceptable
2) If non-carbonated, bring beverages to a boil – you can bring them just up to boiling temperature
3) Avoid ice cubes in your beverages unless you prepared them
If you are interested in learning more about wilderness medicine, a great resource for information is the wilderness medical society: http://www.wms.org/
This document is for informational purposes only, and should not be considered medical advice for any individual patient. If you have questions please contact your medical provider.
Stay safe, and happy travels,
Scott Rennie, DO