There are several infectious illnesses a traveller could experience, especially while visiting developing regions where health and sanitation conditions are different from North American standards. This article will focus on three conditions that affect the digestive system: travellers’ diarrhea, hepatitis A, and hepatitis B.
Travellers’ diarrhea (TD) afflicts 20-50% of people travelling from industrialized countries to high-risk developing ones. The most common mode of transmission is through ingesting food contaminated by feces that contains viruses, pathogenic bacteria, or parasites. These infectious organisms colonize the small and/or large intestine. Most of them produce toxins that increase the flow of water and electrolytes into the bowel (secretion). An infection-related fluid imbalance can cause large and uncomfortable increases in stool production (i.e., diarrhea).
Most TD cases occur within 2 weeks of arriving at a destination and could still occur within 2 weeks after returning home.1 The most common cause of travellers’ diarrhea is infection with enterotoxigenic Escherichia coli (ETEC), a pathogenic bacterium; however, other organisms can cause travellers’ diarrhea and most people never learn the specific contaminant that infected them. TD is a self-limiting disease usually lasting less than 7 days.2 However, 20% of TD sufferers are confined to bed, 8-15% remain unwell after a week, and at least 1% become hospitalized.3 In addition, an episode of TD does not provide protection against future attacks and an individual can experience more than one episode in a single trip.1
Mild travellers’ diarrhea involves the passage of three or more loose stools over a 24-hour period, with at least one other symptom: abdominal cramping, the sensation of having to go immediately (urgency), painful rectal spasms associated with the strong urge to pass stool even though little stool is present (tenesmus), and nausea or vomiting.
In 10% of effected travellers, fever and/or bloody stools may occur. These symptoms are associated with more severe infection.4 Some types of infectious organisms invade and damage the intestinal wall, which leads to inflammation and a reduction in fluid passing out of the bowel into the blood (absorption). These invasive pathogens typically cause a more severe set of clinical symptoms called dysentery, which involves fever, chills, or bloody stools, and they might not respond to certain antibiotics.
There are three key approaches for TD treatment:
Hydration: Adults and older children can usually drink water (only boiled, bottled, or disinfected water if still travelling) until they’re passing clear or light-colored urine. Younger children often need special oral rehydration solutions containing electrolytes. The Public Health Agency of Canada recommends that travellers include oral rehydration salts within first-aid kits they take with them.
Symptom control: Loperamide (Imodium®) can reduce the symptoms of TD by reducing the muscular contractions that propel stool through the intestine; however, it is not recommended in the early stages of infection when it is important for the offending organisms to evacuate the body. Loperamide is not for infants younger than two years old or travellers with fever or bloody stools.5
Antibiotics: Antibiotics kill the harmful bacteria and/or parasites causing the infection, reduce the amount of stool passed, and decrease the duration of symptoms by about half. Some studies suggest that antibiotics combined with loperamide are more effective than antibiotics alone.6
Although rare, TD can lead to serious complications or initiate chronic bowel problems. Studies indicate that post-infectious irritable bowel syndrome (PI-IBS) affects about 10% of those who experience TD. PI-IBS involves long-lasting abdominal discomfort or pain that is associated with a change in bowel habits. It usually involves prolonged diarrhea for at least three days out of every month, though it can also manifest as constipation. Symptoms typically persist for several years, slowly improving over time.
Guillain-Barré syndrome, a very rare complication of TD, is a neurologic disorder that causes weakness and sometimes numbness in the extremities; it can last from months to years. Another rare but serious complication is reactive arthritis, which involves mild to severe joint inflammation that typically affects the lower extremities and can persist for months.
Careful dining habits and good personal hygiene practices will help prevent infection. While travelling in high-risk areas:
- Drink only boiled, bottled, or carbonated beverages. Alcohol also presents a low risk of contamination. Do not mix any beverages with juice or ice, as these could be a source of contamination and freezing does not kill most microorganisms. Check that bottled beverages are factory-sealed.
- Avoid raw vegetables and fruit unless they have a skin that you can peel (apples, kiwi, etc.).
- Eat only thoroughly and recently cooked meat or fish.7 Food served by street vendors is at a high risk for contamination. Restaurant food is usually safer, but water used to clean food and cooking tools can be a source of contamination. Home-cooked meals are the safest, although nothing is foolproof.
- Wash hands with soap and water before eating. Waterless alcohol-based hand sanitizers might also be effective if hands are not visibly dirty.6
Even careful travellers occasionally make a mistake or a risky dietary choice, and some individuals (such as those with blood group O or certain genetic backgrounds) are more susceptible to infection with particular bacteria than the general population. Those who take stomach acid-suppressing medications, such as proton pump inhibitors (PPIs) for GERD, and travellers with chronic diseases, including kidney disease and diabetes, are a higher risk for TD or for more severe consequences.6 Fortunately, there are some prophylactic treatments available:
Vaccination: Dukoral® is an oral vaccine (taken by mouth) that helps prevent travellers’ diarrhea caused by ETEC in adults and children 2 years of age and older. It also protects against cholera, another bacterial infection that affects some developing regions. In a field trial, the Dukoral® vaccine demonstrated 67% protection against certain ETEC strains for three months. In a second trial of tourists from Finland visiting Morocco, efficacy against any ETEC diarrhea was 52%. Protective efficacy for all TD will vary depending on the prevalence of ETEC in the travel region or season.8
Bismuth subsalicylate: One trial found that this substance, the active ingredient in Pepto-Bismol®, reduced the rate of TD from 40% to 14%, a 65% rate of protection. The protective effects occur with frequent, regular doses (usually 2 tablets taken up to four times a day) for the duration of a trip. However, bismuth subsalicylate has a range of potential side effects and it is not recommended for everyone, including children and pregnant women.9
Probiotics: Probiotics are living microorganisms, typically bacteria or yeast, taken orally to maintain a healthy microbiome in the colon and prevent colonization by harmful microorganisms. They are effective in treating some diarrheal disorders and probiotic research is ongoing. In particular, a study of Saccharomyces boulardii (Florastor®), a probiotic yeast, showed that it has a protective effect against travellers’ diarrhea. Limited evidence supports the effectiveness of certain other probiotic strains against TD and suggests that probiotic efficacy varies widely depending on the travellers’ destination.10 If you do choose to use probiotics while travelling, look for ones that contain a sufficient quantity of microorganisms to confer a health benefit and that do not require refrigeration.
Evidence suggests that certain antibiotics also have a preventative effect against travellers’ diarrhea, but specialists in this area do not recommend prophylactic antibiotics unless an individual is at a higher risk of TD or its complications (e.g., individuals whose immune system is suppressed).
Book an appointment with your family physician or local travel clinic well in advance of travel to high-risk areas in order to obtain personalized advice, medications, or immunizations. Similarly, don’t wait until you’re travelling to buy prophylactic products as they might not be available in the country you’re visiting – prepare in advance to avoid disappointment.
Hepatitis A (HAV) spreads when a person ingests food or beverages, including water, contaminated with stool containing the virus. Obvious symptoms are more common in adults and older children, and they can be mistaken for the flu. These include fatigue, fever, abdominal pain, nausea, and loss of appetite.11 Other symptoms include dark urine and jaundice.
Most patients recover within two months of infection, but 10-15% of patients will experience a relapse within the first six months of their initial infection. HAV causes the liver to swell, but it does not become chronic or cause permanent liver damage.
If you suspect HAV, contact a physician for a proper diagnosis and avoid spreading the illness to others by taking careful hygiene precautions such as frequent hand-washing. Treatment usually involves rest, plenty of fluids (no alcohol), and regular meals. Once you have contracted HAV, your immune system makes antibodies so that you will never get it again.
Fortunately, you can avoid ever getting hepatitis A because there are vaccines available to prevent HAV infection. It is unusual for individuals to contract HAV in North America unless it is through a household member who is suffering from the illness after returning from travels to a high-risk area. Vaccination for hepatitis A is not part of the publicly funded immunization program in Canada, but you can purchase the vaccine at most travel clinics or through your family physician. Twinrix® is a vaccine that provides immunization against both hepatitis A and hepatitis B (see below). If you have already received vaccination for hepatitis B, there is also a vaccine for hepatitis A alone.
Hepatitis B affects more than 350 million people worldwide and is quite common in Asia, Africa, the South Pacific Islands, and much of the Middle East, Eastern Europe, and Central and South America.
After exposure to the hepatitis B virus, infection begins as acute hepatitis B. Less than 5% of adults who get acute hepatitis B develop chronic hepatitis, but up to 90% of infants and children infected with hepatitis B become chronically infected. Researchers estimate that 0.7-0.9% of Canadians have chronic hepatitis B. Worldwide, 500,000-700,000 people die from hepatitis B each year due to complications of severe scarring of the liver (cirrhosis) and/or liver cancer.
Symptoms and Spread
Some infected individuals experience nonspecific symptoms, such as mild fatigue or discomfort in the abdomen, but many people do not have any symptoms and may not know that they have the disease. Hepatitis B often does not manifest noticeable symptoms until it has advanced, so individuals could unknowingly live with hepatitis B for years, resulting in liver damage and the infection of others.
Hepatitis B spreads when blood or another bodily fluid (salivary, seminal, or vaginal) from a person infected with the virus enters the body of someone who is not infected. High-risk activities include sexual contact with an infected person, having multiple sexual partners, getting a tattoo or body piercing using unsterilized instruments, or sharing contaminated drug paraphernalia. Blood-to-blood contact may occur through sharing of personal hygiene items (such as razors and toothbrushes) and through contact with open wounds. Hepatitis B does not transmit through casual contact, such as coughing, sneezing, hugging, or sharing food.
While chronic hepatitis B is not curable, there are excellent treatments available, as well as clear strategies to prevent and decrease complications, and to avoid further spread of this disease.
If you were not vaccinated as a child or teenager through a routine vaccination program, visit your family physician or local travel clinic and receive a vaccination well in advance of travelling to any high-risk areas (at least three weeks prior to travelling). You may save some time and money by getting Twinrix®, a safe and effective vaccine that provides life-long immunity from both hepatitis A and B.