The traveler’s diarrhea

by Marilisa F.

If you have ever suffered from diarrhea while traveling, you know very well what we are talking about! It’s not some sort of evil eye thing, don’t blame your envious friends forced to stay at home to put a spell on you!

This disorder manifests by an increased frequency of intestinal peristalsis, leading to three or more defecation per day with loose stools, generally during a trip abroad, often in developing countries.

What is the cause?

In 40-70% of cases there are not further investigation because the symptoms disappear before the end of holidays, exactly when you have to go back home. When the problem is better analysed, the following bacteria are almost always found:

  • Enterotoxigenic Escherichia coli is the most common bacterium responsible for traveler’s diarrhea (in 12-34% of confirmed cases) whose infection occurs with abdominal cramps, almost never febrile.
  • The enteroaggregating Escherichia coli is also frequent.

Campilobacter jejuni infection manifest by watery and bloody diarrhea, abdominal cramps and fever.

Salmonellas are responsible for acute diarrhea, fever, vomiting and abdominal cramps.

Shigella presents with acute diarrhea, abdominal cramps, blood stools, tenesmus and fever.

In few cases, viruses, such as noroviruses and rotaviruses, and protozoa such as Giardia lamblia may also be involved. Other parasites causing diarrhea are Cryptosporidium spp, Entamoeba histolytica and Cyclospora catayensis.


Risk map for travellers’ diarrhea

The most dangerous countries are those in the south and south-east Asia, northern, eastern and western Africa, South America and Central America. At intermediate risk are considered South Africa, the Caribbean, Russia and China.

Who risks more?

Children under 6 years old, immunosuppressed, people with inflammatory bowel disease or diabetes, patients undertaking H2 blockers or antacids. In addition, some situations are more exposed to risk, such as camping or cruising, whereas epidemics of viral and bacterial gastroenteritis are frequent. There is also a genetic predisposition: subjects with blood group 0 are more exposed to shigellosis and to severe forms of cholera.

How we can prevent it?

We suggest to follow these guidelines:

1- avoid foods from vendors that do not guarantee hygiene standards;

2- consume water and drinks in sealed bottles on purchase and avoid the addition of ice;

3- do not eat raw or undercooked meat or fish;

4- avoid eating raw vegetables and fruits without having peeled them.

It is always advisable to wash hands with soap and water to reduce the risk.


Regarding subjects in good health, the administration of antibiotics as a prophylaxis is not only not recommended, but actually exposes people to the risk of developing Candida infections or Clostridium difficile diarrhea.

In the case of subjects with impaired immune defenses or having other pathologies, antibiotic prophylaxis should be evaluated with the attending physician.


Usually the problem will be solved without specific treatments, however rehydration is often useful to restore the fluid loss. In mild forms (1-2 diarrheal faeces discharges in 24 hours) the BMJ experts recommend taking loperamide.

Travelers who experience three or more episodes of diarrhea over an 8-hour period, especially if associated with nausea, vomiting, abdominal cramps, fever or blood in the stool, may benefit from antimicrobial therapy. In any case, a doctor should be consulted.

Have a good trip, for those who can!




Mammoth and saber-toothed tiger: the secrets of the “La Brea” tar pits

Riccardo L.

Nowadays, we keep talking about the climate problems and the damage that oil derivatives do to the entire ecosystem in various ways. But in America there is a place where black gold has claimed victims for thousands of years, long before men started working on it. The place is called “La Brea” and is located in a quiet suburb of Los Angeles, California.

The “La Brea” tar pits are in fact a natural trap composed of an accumulation of oil, which form pools from a few tens of centimeters to a few meters deep: but do not be fooled by the little depth!

In these ponds, remains of large mammals have been found, such as saber-toothed tigers, bears, and even mammoths! races of alteration on their bones confirm that even just a few centimeters of height of this treacherous fluid were sufficient to trap large mammals, whom remained entangled there until starved to death.

This so called “infernal trap” is generated by a natural process of oil filtration from the ground, which, rising through faults and fractures, gets to accumulate on the surface. Here the most “light” and gaseous components evaporate, leaving only the heaviest fraction of hydrocarbons, called bitumen (essentially composed of asphaltenes).

Artistic reconstruction at “La Brea” museum

The “La Brea” tar pits, however, represent today a precious  mine of fossils from the previous ice ages!

One of the properties of bitumen is to perfectly incorporate and preserve the skeletons of animals that were trapped in it. This ability, besides being so unfortunate for the animals ending up fatally trapped , allowed us to find thousands of complete skeletons of mammals, birds, and reptiles from the Early Pleistocene (in this area, around 40,000 years ago) to the present day.

The site is home to a museum of natural sciences and, representing a geological window on the ice ages, is the subject of specific studies on climate change and palaeoenvironmental changes.

From now on, watch out  where you put your feet!


tanslation courtesy of Irene F.




Credits pic:

Creative Commons: Bone Clones image of Saber-toothed Cat

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