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| Forms/Documents |
Travelers
health: Prevention through water and food precautions
May 2004
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High-risk destinations are the developing countries of Latin America, Africa, the Middle East, and Asia. Persons at particular high-risk include young adults, infants, children, immunosuppressed persons, persons with inflammatory-bowel disease or diabetes. |
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Contaminated food and drink are common sources for the introduction of infection into the body. Consumption of food and beverages obtained from street food vendors has been associated with an increased risk of illness. |
As the summer and holidays approach millions of people travel abroad for vacation or to visit friends and relatives. Many people travel to developing countries, where the risk of contracting infectious diseases is increased.
According to some estimates, 50% of international travelers become ill as a result of their travels. The diseases contracted include traveler's diarrhea, common cold, malaria, typhoid fever, yellow fever and others.
Most international travel-related health problems are preventable. However, travelers are often unaware of health risks. Additionally there is a lack of understanding of the measures necessary to avoid them.
To prevent infectious diseases among international travelers, health-care providers and the public should be aware of the current health recommendations for international travel.
It is important to consider the regional risks for illness and recommended vaccinations, country-specific malaria prevention information, notification of disease outbreaks, measures to prevent mosquito bites. Vaccinations should be done in time prior to travel to destinations necessitating specific immunizations.
The Centers for Disease Control and Prevention recommend travelers to visit a health-care provider 4-6 weeks before their departure date to allow time for vaccinations to take effect.
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Travelers are reminded of other measures to stay healthy:
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Travelers' diarrhea (TD) is the most common illness affecting travelers. Each year between 20%-50% of international travelers, develop diarrhea.
The onset of TD usually occurs within the first week of travel but may occur at any time while traveling, and even after returning home. The most important determinant of risk is the traveler's destination.
High-risk destinations are the developing countries of Latin America, Africa, the Middle East, and Asia. Persons at particular high-risk include young adults, immunosuppressed persons, persons with inflammatory-bowel disease or diabetes, and persons taking H-2 blockers or antacids.
Attack rates are similar for men and women. The primary source of infection is ingestion of fecally contaminated food or water.
Contaminated food and drink are common sources for the introduction of infection into the body. Among the more common infections that travelers can acquire from contaminated food and drink are Escherichia coli infections, shigellosis or bacillary dysentery, giardiasis, cryptosporidiosis, Norwalk-like viruses, and hepatitis A.
Other less common infectious disease risks for travelers include typhoid fever and other salmonelloses, cholera, rotavirus infections, and a variety of protozoan and helminthic parasites (other than those that cause giardiasis and cryptosporidiosis). Many of the infectious diseases transmitted in food and water can also be acquired directly through the fecal-oral route.
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To avoid illness, travelers should be advised to select food with care. All raw food is subject to contamination. Special caution is warranted in areas where hygiene and sanitation are inadequate. The traveler should be advised to avoid salads, uncooked vegetables, and unpasteurized milk and milk products such as cheese, and to eat only food that has been cooked and is still hot or fruit that has been peeled by the traveler personally. Undercooked and raw meat, fish, and shellfish can carry various intestinal pathogens. Cooked food that has been allowed to stand for several hours at ambient temperature can provide a fertile medium for bacterial growth and should be thoroughly reheated before serving. |
Consumption of food and beverages obtained from street food vendors has been associated with an increased risk of illness. The easiest way to guarantee a safe food source for an infant <6 months of age is to have the infant breast feed. If the infant has already been weaned from the breast, formula prepared from commercial powder and boiled water is the safest and most practical food.
Water that has been adequately chlorinated, by using minimum recommended water treatment standards, will afford substantial protection against viral and bacterial waterborne diseases. However, chlorine treatment alone, as used in the routine disinfection of water, might not kill some enteric viruses and the parasitic organisms that cause giardiasis, amebiasis, and cryptosporidiosis.
In areas where chlorinated tap water is not available or where hygiene and sanitation are poor, travelers should be advised that only the following might be safe to drink:
- Beverages, such as tea and coffee, made with boiled
water
- Canned or bottled carbonated beverages, including
carbonated bottled water and soft drinks
- Beer and wine
Where water might be contaminated, travelers should be advised that ice should also be considered contaminated and should not be used in beverages. If ice has been in contact with containers used for drinking, travelers should be advised to thoroughly clean the containers, preferably with soap and hot water, after the ice has been discarded.
It is safer to drink a beverage directly from the can or bottle than from a questionable container. However, water on the outside of beverage cans or bottles might also be contaminated. Therefore, travelers should be advised to dry wet cans or bottles before they are opened and to wipe clean surfaces with which the mouth will have direct contact.
Where water might be contaminated, travelers should be advised to avoid brushing their teeth with tap water.
Travelers should be advised of the following methods for treating water to make it safe for drinking and other purposes.
- Boiling is by far the most reliable method to
make water of uncertain purity safe for drinking. Water should be brought
to a vigorous rolling boil for 1 minute and allowed to cool to room
temperature; ice should not be added. This procedure will kill bacterial
and parasitic causes of diarrhea at all altitudes and viruses at low
altitudes. To kill viruses at altitudes >2,000 m (6,562 ft), water should
be boiled for 3 minutes or chemical disinfection should be used after the
water has boiled for 1 minute. Adding a pinch of salt to each quart or
pouring the water several times from one clean container to another will
improve the taste
- Chemical disinfection with iodine is an alternative
method of water treatment when it is not feasible to boil water. However,
this method cannot be relied on to kill Cryptosporidium unless the
water is allowed to sit for 15 hours before it is drunk.
Two well-tested methods for disinfection with iodine are the use of tincture of iodine and tetraglycine hydroperiodide tablets (e.g., Globaline, Potable-Aqua, or Coghlan's). These tablets are available from pharmacies and sporting goods stores. The manufacturers' instructions should be followed
- Chlorine, in various forms, can also be used for
chemical disinfection. However, its germicidal activity varies greatly
with the pH, temperature, and organic content of the water to be purified;
therefore, it can produce less consistent levels of disinfection in many
types of water. Chemically treated water is intended for short-term use
only. If iodine-disinfected water is the only water available, it should
be used for only a few weeks
- Portable filters currently on the market will provide various degrees of protection against microbes. Reverse-osmosis filters provide protection against viruses, bacteria, and protozoa, but they are expensive andlarger
It is true that in modern times, people travel much more often to spicier and more exotic realms, from Kenya to China to Suriname. These destinations among with many others may often carry risk for infectious diseases.
The precautions taken before international traveling as well as learning what to do when in specific regions of the globe, can offer a great service and preserve a happy and pleasant stay or holiday.
Bibliography:
Centers for Disease Control and Prevention
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