A travel memento that's hard to stomach

By Laurie Sullivan

One-in-3 people who travel overseas can expect a tummy bug.
For most healthy adults, travellers’ diarrhoea is rarely serious or life-threatening, but it can make for an unpleasant episode during or just after your dream holiday. 
But, what if the effects of this nasty travel memento were to linger for more than 6 YEARS?
It’s possible with the parasitic disease, giardiasis, one of the most common causes of gastrointestinal infections (GIs) among travellers.
Scientists recently published the results of a long-term study of 1252 people with giardiasis infected during an outbreak in Canada in 2004. When the researchers interviewed the group 3 years later in 2007, they found that 39% had irritable bowel syndrome while 30% were suffering from chronic fatigue.
Six years later in 2010, the incidence of irritable bowel had decreased only marginally from 39% to 32% of those originally infected, while the incidence of chronic fatigue dropped by half from 30% to 15%.


The study concluded that not only was exposure to giardia (pron. gee-ar-dia) a ‘significant risk factor’ for persistent irritable bowel and chronic fatigue, but that increasing age heightened the risk of persistent chronic fatigue for people infected with the parasite.
The researchers noted that both conditions do disappear over time, but that complete recovery may be very slow.
Past studies of illnesses among people who’ve returned from overseas travel have found that gastrointestinal infections are THE most common cause of sickness. At least 1-in-3 travellers will experience a GI, with symptoms ranging from mild and brief, to severe and debilitating.
One major international study published in 2013 collected data on 42,173 people treated for illness following overseas travel between 2007 and 2011. They consulted doctors at 53 specialists travel medicine clinics in 24 countries.


The data revealed that more than 40% of the returned travellers who reported gastrointestinal symptoms lasting more than 2 weeks had chronic diarrhoea or ongoing irritable bowel syndrome.
The study showed that:
- Giardia was the most common cause of GIs.
- Most cases of travel-related giardiasis occurred in South and Central Asian countries, particularly India. (Perhaps not surprising considering 597 million Indians practise open defecation – 10 times the number of any other single country, according to another recent report.)
(As for gastro infections caused by bacteria, CampylobacterSalmonella, and Shigella top the list of causes. These are mainly seen among travellers who visited Southeast Asia, North Africa, sub-Saharan Africa, and the Middle East.)


Giardiasis is a zoonotic disease (one passed from animals to humans) caused by a flagellate protozoan, Giardia lamblia. Encased in a hard, shell-like cyst, the organism is found in the digestive tract of humans and many animals (domestic and wild).


People can only become infected with giardia by swallowing the parasite, but it takes as few as 10 cysts to cause infection. Anything that comes into contact with faeces from infected humans or animals can become contaminated with giardia, but it is usually spread by:
- Touching contaminated surfaces such as bathrooms taps or door handles, nappy changing tables, or even toys that contain faeces from an infected person or animal.
- Drinking water (or using ice) made from water containing the parasite, such as untreated or improperly treated water from lakes, streams, or wells. 
- Accidentally swallowing infected water while swimming.
- Eating uncooked food that contains the parasite.
- Contact with someone who has giardiasis.
Once inside their host, the microscopic cysts rapidly multiply. An infected person can shed millions of cysts a day in their faeces.


Giardia occurs worldwide, particularly during the summer months. People are particularly prone to infection when travelling in countries where the parasite is common in its human and animal populations. 
As mentioned, the highest incidence is in South and Central Asian countries, where it’s estimated that 1-in-3 people have or have had giardia, along with the Middle East and South America.
But, as the large Canadian study shows, giardiasis also occurs in developed countries. In fact, it’s the most common internal parasitic disease affecting humans worldwide.


Symptoms of giardiasis normally appear 1 – 2 weeks after infection, but can occur as quickly 2 days. In otherwise healthy people, symptoms of giardiasis may last 2 to 4 weeks – occasionally longer. For those with few or no symptoms, giardia infection can clear up completely without treatment in a fortnight.
However, giardia can result in diarrhoea (often with foul-smelling, greasy stools), abdominal cramps, bloating, flatulence, fatigue, and nausea. Typically, there is a gradual onset of 2–5 loose stools per day and increasing fatigue. Sometimes upper gastrointestinal symptoms are more prominent and weight loss may occur over time, although fever and vomiting are uncommon.
Some sufferers, particularly infants and pregnant women are at higher risk of dehydration.


Medication containing tinidazole, metronidazole, nitazoxanide, paromomycin, furazolidone, or quinacrine can reduce the symptoms of giardiasis and speed up recovery.


Following the safe food and water guidelines is the best way to prevent giardia.
If you are uncertain if water you intend to drink is safe, first boil it for one minute and allow it to cool before drinking. Chemical disinfectants or filters are also effective.
One of the most important ways of avoiding illness is regular hand washing – especially before handling food.

For more about avoiding water- and food-borne travel health risks, call Travelvax Australia’s free travel health advisory service on 1300 360 164 (toll-free from landlines). You can also book a pre-travel medical consultation for recommended or required vaccinations at your nearest Travelvax Australia clinic.