CDC Health Information for International Travelers Safe Food and Water

RISKS FROM FOOD AND WATER (DRINKING AND RECREATIONAL)
CREUTZFELDT-JAKOB DISEASE (VARIANT) AND BOVINE SPONGIFORM ENCEPHALOPATHY (PRION DISEASES)
TRAVELERS’ DIARRHEA

The following is general information concerning prevention of recognition and prevention of food borne illnesses. For more complete travel health information, view the CDC website at http://www.cdc.gov/travel/foodwater.htm

RISKS FROM FOOD AND WATER (DRINKING AND RECREATIONAL)

Contaminated food and water (drinking and recreational) are common sources for the introduction of pathogens 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, noroviruses, 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 infectious diseases transmitted through food consumption and drinking water can also be acquired directly through the fecal-oral route. Accidental consumption of recreational water from lakes, rivers, oceans, and inadequately treated swimming pools can spread these same diarrheal diseases as well as ear, eye, skin, respiratory, and neurologic infections.

Food

To avoid illness, travelers should be advised to select food with care. All raw food is subject to contamination. Particularly 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 washed in clean water and then 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 or be recontaminated by food-handling techniques so should be thoroughly reheated before serving. Consumption of food and beverages obtained from street vendors has been associated with an increased risk of illness. Travelers should be advised that these recommendations also include eating eggs that have been thoroughly cooked, alone or in sauces, and washing their own hands or using hand gel with more than 60% alcohol prior to eating, after using the bathroom or changing diapers and after direct contact with preschool children, animals or any feces.

The easiest way to guarantee a safe food source for an infant younger than 6 months of age is to have the infant breastfeed. 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.

Cholera cases have occurred in people who ate crab brought back from Latin America by travelers. Travelers should be advised not to bring perishable seafood with them when they return to the United States from high-risk areas. Moreover, travelers may assume incorrectly that food and water aboard commercial aircraft are safe. Food and water may be obtained in the country of departure, where items may be contaminated.

Water

Swimming

A variety of infections (e.g., skin, ear, eye, respiratory, neu-rologic, and diarrheal infections) have been linked to wading or swimming in the ocean, freshwater lakes and rivers, and swimming pools, particularly if the swimmer's head is submerged. Water may be contaminated by other swimmers and from sewage, animal waste, and wastewater runoff. Diarrhea and other serious waterborne infections can be spread when disease-causing organisms from human or animal feces are introduced into the water. Accidentally swallowing small amounts of fecally contaminated water can cause illness. Travelers should be warned to try to avoid swallowing water while engaging in aquatic activities. All travelers who have diarrhea should refrain from swimming to avoid contaminating recreational water.

Travelers who swim at freshwater or marine beaches should be advised to avoid swimming or wading 1) at beaches that may be contaminated with human sewage or animal feces (e.g., cattle, sheep, dogs); 2) near storm drains; 3) following heavy rainfall; 4) in freshwater streams, canals, and lakes in schistosomiasis-endemic areas of the Caribbean, South America, Africa, and Asia; 5) in bodies of water that may be contaminated with urine from animals infected with Leptospira; and 6) with open cuts or abrasions that might serve as entry points for pathogens.

In certain areas where fatal primary amebic meningoen-cephalitis has occurred after swimming in warm freshwater lakes or rivers, thermally polluted areas around industrial complexes, and hot springs, travelers should avoid submerging the head and should wear nose plugs when entering untreated water to prevent water containing the pathogen from getting up the nose and causing infection.

Generally, for infectious disease prevention, pools that contain chlorinated water can be considered safe places to swim if the disinfectant levels and pH are properly maintained. However, some organisms are moderately (e.g., Giardia, hepatitis A, norovirus) to highly (i.e., Cryptosporidium) resistant to chlorine levels commonly found in chlorinated swimming pools, so travelers also should avoid swallowing chlorinated swimming pool water. Poorly maintained swimming pools or spas may not only spread disease from fellow swimmers but may allow amplification of environmental contaminants, such as Pseudomonas or Legionella, to levels that may cause disease. Travelers may choose to take test kits or strips to check pool chlorine and pH levels when traveling.

Drinking

Water that has been adequately chlorinated according to the minimum recommended water treatment standards used in the United States will afford substantial protection against viral and bacterial waterborne diseases. However, chlorine treatment alone, as used in the routine disinfection of water, may 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 may be safe to drink: beverages, such as tea and coffee, made with boiled water, canned or unopened bottled beverages, including water, carbonated mineral water, 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 clean the containers thoroughly, 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 may 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 may be contaminated, travelers should be advised to avoid brushing their teeth with tap water and that locally prepared fruit juice may also contain tap water.

Treatment of Drinking Water

Travelers should be advised of the following methods for treating water to make it safe for drinking and other purposes.

Boiling

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 all common waterborne pathogens. 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

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 depending on the water quality (e.g., turbid water). In addition, some forms of chlorine disinfectant may not be stable through long-term storage or at high temperatures.

Chemical disinfection with iodine, which is not as sensitive as chlorine to pH shifts, is an alternative method of water treatment when it is not feasible to boil water. However, using iodine cannot be relied on to kill Cryptosporidium. Cloudy water should be strained through a clean cloth into a container to remove any sediment or floating matter, and then the water should be treated with iodine. 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 manufacturer's instructions should be followed. If water is cloudy, the number of tablets used should be doubled; if water is extremely cold (<41°F), an attempt should be made to warm the water, and the recommended contact time should be increased to achieve reliable disinfection. Iodine treatment of water is intended for short-term use only to avoid over exposure to iodine. When the only water available is iodine treated, it should be used for only a few weeks.

Water Filters

Portable filters currently on the market will provide various degrees of protection against microbes but are generally meant to be used in conjunction with disinfection for greatest protection from pathogens. Reverse-osmosis filters provide protection against viruses, bacteria, and protozoa, but they are expensive and larger than most filters used by backpackers, and the small pores on this type of filter are rapidly plugged by muddy or cloudy water. In addition, the membranes in some filters can be damaged by chlorine in water. Microstrainer filters with pore sizes in the 0.1-to 0.3-pm range can remove bacteria and protozoa from drinking water, but they do not remove viruses. To kill viruses, travelers using microstrainer filters should be advised to disinfect the water with iodine or chlorine after filtration, as described previously. Some filtration kits come with an additional filter effective against viruses. Protozoa can be highly (Cryptosporidium) to moderately (Giardia) resistant to halogen treatment, particularly in cold or turbid water. As a result, filtration or boiling should be considered as a safer alternative to chemical disinfection. A travelers’ guide to buying water filters for preventing cryptosporidiosis and giardiasis can be found http://wwwn.cdc.gov. Increased protection can be obtained by using a filter that removes Giardia and Cryptosporidium that is combined with an iodine-impregnated resin which is more effective against bacteria and some viruses.

Filters that are designed to remove Cryptosporidium and Giardia carry one of the four messages below—verbatim—on the package label.

• Reverse osmosis
• Absolute pore size of 1 micron
• Tested and certified by NSF International (formerly the National Sanitation Foundation) Standard 53 or NSF Standard 58 for cyst removal
• Tested and certified by NSF Standard 53 or NSF Standard 58 for cyst reduction

Filters may not be designed to remove Cryptosporidium and Giardia if they are labeled only with these words:

• Nominal pore size of 1 micron
• One-micron filter
• Effective against Giardia
• Effective against parasites
• Carbon filter
• Water purifier
• Environmental Protection Agency (EPA)-approved (Caution: EPA does not approve or test filters.)
• EPA-registered (Caution: EPA does not register filters for Cryptosporidium removal)
• Activated carbon
• Removes chlorine
• Ultraviolet light
• Pentiodide resins
• Water softener

Filters collect organisms from water. Anyone changing cartridges should wash hands afterwards. Filters may not remove Cryptosporidium as well as boiling does, because even good brands of filters may sometimes have manufacturing flaws that allow small numbers of organisms to pass through the filter. In addition, poor filter maintenance or failure to replace filter cartridges as recommended by the manufacturer can cause a filter to fail.

Proper selection, operation, care, and maintenance of water filters are essential to producing safe water. The manufacturers’ instructions should be followed. NSF International, an independent testing company, tests and certifies water filters for their ability to remove protozoa, but not for their ability to remove bacteria or viruses.

Few published scientific reports have evaluated the efficacy of specific brands or models of filters against bacteria and viruses in water (10). Until such information becomes available, CDC cannot identify which specific brands or models of filters are most likely to remove bacteria and viruses. To find out if a particular filter is certified to remove Cryptosporidium, contact NSF International by calling 1-877-867-3435; by fax to 313-769-0109; or by writing to 789 North Dixboro Road, P.O. Box 130140, Ann Arbor, Michigan 48113-0140; or online at http://www.NSF.org/certified/DWTU.

As a last resort, if no source of safe drinking water is available or can be obtained, tap water that is uncomfortably hot to touch might be safer than cold tap water; however, proper disinfection and filtering, or boiling is still advised.

CREUTZFELDT-JAKOB DISEASE (VARIANT) AND BOVINE SPONGIFORM ENCEPHALOPATHY (PRION DISEASES)

Description

Since 1996, strong evidence has accumulated for a causal relationship between ongoing outbreaks, primarily in Europe, of a disease in cattle called bovine spongiform encephalopathy (BSE, or “mad cow disease”) and a disease in humans called variant Creutzfeldt-Jakob disease (vCJD). Both disorders, which are caused by an unconventional transmissible agent, are invariably fatal brain diseases with incubation periods typically measured in years. Transmission of the BSE agent to humans, leading to vCJD, is believed to occur via ingestion of cattle products contaminated with the BSE agent; the specific foods associated with this transmission are unknown. However, a recently published case-control study involving 132 vCJD cases in the United Kingdom (UK) showed evidence of an increased risk for vCJD associated with the frequency of consuming beef products likely to contain mechanically recovered meat and head meat (such as burgers, meat pies, and sausages). Bioassays and molecular tests have enabled identification of what World Health Organization consultants have classified as “high-infectivit” and “lower infectivity” tissues of cattle with BSE. The high-infectivity tissues include the brain, spinal cord, retina, optic nerve, and dorsal root and trigeminal ganglia, suggesting that these tissues can pose a relatively high risk of transmission. The lower infectivity tissues include peripheral nerves (e.g., sciatic and facial nerves), tonsils, nictitating membrane (third eye lid), distal ileum, bone marrow, and possibly thigh muscle. The latter tissue from one cow with BSE transmitted disease to highly BSE-sensitive transgenic mice at a rate indicative of trace levels of infectivity.

Occurrence

Human

From 1995 through mid August 2006, a total of 195 human cases of vCJD were reported worldwide, 162 in the UK, 20 in France, 4 in Ireland, 2 in the United States (US), and 1 each in Canada, Italy, Japan, the Netherlands, Portugal, Saudi Arabia and Spain. Seven of the non-UK case-patients were most likely exposed to the BSE agent in the UK because of their having resided there during a key exposure period of the UK population to the BSE agent. These latter case-patients were those from Canada, Japan, the US, 1 of the 20 from France, and 2 of the 4 from Ireland. The median age at death from vCJD in the UK has been 28 years and almost all cases have been in persons under age 55 years. The reasons for this age distribution are not well understood but it suggests that older adults are much less susceptible to vCJD through the oral route of exposure than are children and young adults. By year of onset, the incidence of vCJD in the UK appears to have peaked in 1999 and to have been declining thereafter. In contrast, the number of reported cases in France has been increasing since the beginning of 2005. However, the future pattern of these ongoing epidemics remains uncertain. In 2004, a prevalence study of asymptomatic vCJD infections in the UK identified three positive appendices out of a sample of 12,674 surgically removed tonsils and appendices that were satisfactory for analysis. Genetic studies completed on two of the appendices regarded as positive for vCJD revealed that both had a different polymorphism at codon 129 of the prion protein gene than any of the patients with clinical vCJD tested to date, indicating that more people are genetically susceptible to vCJD infection, although not necessarily to the disease, than had been previously determined.

Transfusion of blood contaminated with the vCJD agent is believed to be responsible for at least three vCJD infections reported in the UK, including two blood recipients with clinical vCJD and one infected recipient who died without signs of neurologic disease. These three recipients indicate that the blood of asymptomatic, infected donors can contain infectivity 18 months to 3.5 years before the onset of vCJD disease. The possibility of transfusion transmission of vCJD had prompted the US Food and Drug Administration to publish guidance in 1999 and 2002 outlining a geography-based donor deferral policy to reduce the risk of such transmission in the United States. This guidance document included an appendix that listed European countries with BSE or a possible increased risk of BSE for use in determining blood donor deferrals.

Bovine

From 1986 through July 2006, >97% of BSE cases worldwide were reported from the UK, where the disease was first described. From 2003 through 2005, however, for the first time, Portugal rather than the UK reported the highest total country incidence of indigenous cases of BSE per million bovines aged over 24 months, reflecting the relatively more rapid decline of BSE cases in the UK. As of July 2006, the number of European countries that had ever reported an indigenous BSE case increased to 21. During 2001 through July 2006, four countries outside Europe (Canada, Israel, Japan, and the United States) reported their first indigenous BSE cases, and, except for Israel, other BSE cases in these countries followed.

The reported BSE incidence rates, by country and year, are available on the Internet website of the World Organization for Animal Health, and new information is being generated regularly. As of July 2006, of the countries with at least six reported BSE cases, only four reported that the incidence of BSE had risen in recent years (Canada, Czech Republic, Japan, and Poland).

The identification in 2003 of a BSE case in Canada and the subsequent identification later that year of a BSE case in the United States that had been imported from Canada led to the concern that indigenous transmission of BSE may be occurring in North America. During 2004 through August 2006, the evidence for such transmission in North America was strengthened by the confirmation of nine additional indigenous North American BSE cases (seven in Canada and two in the United States). In 2004, both countries had implemented new safeguards to reduce the risk for human exposure to BSE. In 2006, Canada also banned cattle tissues capable of transmitting BSE from all animal feeds, pet foods, and fertilizers to enhance its BSE-related feed controls; at least four of the seven Canadian BSE cases reported in 2004 through August 2006 had been born after the 1997 US and Canadian feed bans.

Risk for Travelers

The current risk of acquiring vCJD from eating beef (muscle meat) and beef products produced from cattle in countries with at least a possibly increased risk of BSE cannot be determined precisely. If public health measures are being well implemented, the current risk of acquiring vCJD from eating beef and beef products from these countries appears to be extremely small, although probably not zero. A rough estimate of this risk for the UK in the recent past, for example, was about 1 case per 10 billion servings. Among many uncertainties affecting such risk determinations are 1) the incubation period between exposure to the infective agent and onset of illness, 2) the appropriate interpretation and public health significance of the prevalence estimates of asymptomatic human vCJD infections, 3) the sensitivities of each country's surveillance for BSE and vCJD, 4) the compliance with and effectiveness of public health measures instituted in each country to prevent BSE contamination of human food, and 5) details about cattle products from one country distributed and consumed elsewhere. As of August 2006, despite the apparent exceedingly low risk of contracting vCJD through consumption of food in Europe, the US blood donor deferral criteria focuses on the time (cumulatively 5 years or more) that a person lived in continental Europe from 1980 through the present. In addition, these deferral criteria apply to persons who lived in the UK from 1980 through 1996.

Clinical Presentation

Patients with vCJD are typically much younger than those with sporadic disease. They may present with sensory disturbances and psychiatric problems. Paresthesias, dysar-thria, gait disturbances, depression and anxiety are common findings, especially as disease progresses. Tissue diagnosis is required.

Prevention

Public health control measures, such as surveillance, culling sick animals, or banning specified risk materials, have been instituted in many countries, particularly in those with indigenous cases of confirmed BSE, in order to prevent potentially BSE-infected tissues from entering the human food supply. The most stringent of these control measures, including a program that excluded all animals >30 months of age from the human food and animal feed supplies [the Over Thirty Month (OTM) rule], was applied in the UK and appeared to be highly effective. With the decrease in British BSE cases, the OTM rule was replaced in 2005 with a BSE testing regime, and in 2006, the ban on exports of British beef to other members of the European Union was lifted. In June 2000, the European Union Commission on Food Safety and Animal Welfare had strengthened the European Union's BSE control measures by requiring all member states to remove specified risk materials from animal feed and human food chains as of October 1, 2000; such bans had already been instituted in most member states. To reduce any risk of acquiring vCJD from food, concerned travelers to Europe or other areas with indigenous cases of BSE may consider either avoiding beef and beef products altogether or selecting beef or beef products, such as solid pieces of muscle meat (rather than brains or beef products like burgers and sausages), that might have a reduced opportunity for contamination with tissues that may harbor the BSE agent. These measures, however, should be taken with the knowledge of the very low risk of disease transmission, particularly to older persons, as discussed above. Milk and milk products from cows are not believed to pose any risk for transmitting the BSE agent.

Treatment

As of August 2006, treatment of prion diseases remains supportive; no specific therapy has been shown to stop the progression of these diseases.

TRAVELERS’ DIARRHEA

Who gets travelers’ diarrhea?

Travelers′ diarrhea (TD) is the most common illness affecting travelers. Each year between 20%-50% of international travelers, an estimated 10 million persons, 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.

What are common symptoms of travelers’ diarrhea?

Most TD cases begin abruptly. The illness usually results in increased frequency, volume, and weight of stool. Altered stool consistency also is common. Typically, a traveler experiences four to five loose or watery bowel movements each day. Other commonly associated symptoms are nausea, vomiting, diarrhea, abdominal cramping, bloating, fever, urgency, and malaise. Most cases are benign and resolve in 1–2 days without treatment. TD is rarely life-threatening. The natural history of TD is that 90% of cases resolve within 1 week, and 98% resolve within 1 month.

What causes travelers’ diarrhea?

Infectious agents are the primary cause of TD. Bacterial enteropathogens cause approximately 80% of TD cases. The most common causative agent isolated in countries surveyed has been enterotoxigenic Escherichia coli (ETEC). ETEC produce watery diarrhea with associated cramps and low-grade or no fever. Besides ETEC and other bacterial pathogens, a variety of viral and parasitic enteric pathogens also are potential causative agents.

What preventive measures are effective for travelers’ diarrhea?

Travelers can minimize their risk for TD by practicing the following effective preventive measures:

• Avoid eating foods or drinking beverages purchased from street vendors or other establishments where unhygienic conditions are present
• Avoid eating raw or undercooked meat and seafood
• Avoid eating raw fruits (e.g., oranges, bananas, avocados) and vegetables unless the traveler peels them.

If handled properly well-cooked and packaged foods usually are safe. Tap water, ice, unpasteurized milk, and dairy products are associated with increased risk for TD. Safe beverages include bottled carbonated beverages, hot tea or coffee, beer, wine, and water boiled or appropriately treated with iodine or chlorine.

Is prophylaxis of travelers’ diarrhea recommended?

CDC does not recommend antimicrobial drugs to prevent TD. Studies show a decrease in the incidence of TD with use of bismuth subsalicylate and with use of antimicrobial chemoprophylaxis. Several studies show that bismuth sub-salicylate taken as either 2 tablets 4 times daily or 2 fluid ounces 4 times daily reduces the incidence of travelers’ diarrhea. The mechanism of action appears to be both antibacterial and antisecretory. Use of bismuth subsalicylate should be avoided by persons who are allergic to aspirin, during pregnancy, and by persons taking certain other medications (e.g., anticoagulants, probenecid, or methotr-exate). In addition, persons should be informed about potential side effects, in particular about temporary blackening of the tongue and stool, and rarely ringing in the ears. Because of potential adverse side effects, prophylactic bismuth subsalicylate should not be used for more than 3 weeks.

Some antibiotics administered in a once-a-day dose are 90% effective at preventing travelers’ diarrhea; however, antibiotics are not recommended as prophylaxis. Routine antimicrobial prophylaxis increases the traveler′s risk for adverse reactions and for infections with resistant organisms. Because antimicrobials can increase a traveler ′s susceptibility to resistant bacterial pathogens and provide no protection against either viral or parasitic pathogens, they can give travelers a false sense of security. As a result, strict adherence to preventive measures is encouraged, and bismuth subsalicylate should be used as an adjunct if prophylaxis is needed.

What treatment measures are effective for travelers’ diarrhea?

TD usually is a self-limited disorder and often resolves without specific treatment; however, oral rehydration is often beneficial to replace lost fluids and electrolytes. Clear liquids are routinely recommended for adults. Travelers who develop three or more loose stools in an 8-hour period—especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in stools—may benefit from antimicrobial therapy. Antibiotics usually are given for 3–5 days. Currently, fluoroquinolones are the drugs of choice. Commonly prescribed regimens are 500 mg of ciprofloxacin twice a day or 400 mg of norfloxacin twice a day for 3-5 days.

Trimethoprim-sulfamethoxazole and doxycycline are no longer recommended because of the high level of resistance to these agents. Bismuth subsalicylate also may be used as treatment: 1 fluid ounce or 2 262 mg tablets every 30 minutes for up to eight doses in a 24-hour period, which can be repeated on a second day. If diarrhea persists despite therapy, travelers should be evaluated by a doctor and treated for possible parasitic infection.

When should antimotility agents not be used to treat travelers’ diarrhea?

Antimotility agents (loperamide, diphenoxylate, and paregoric) primarily reduce diarrhea by slowing transit time in the gut, and, thus, allows more time for absorption. Some persons believe diarrhea is the body's defense mechanism to minimize contact time between gut pathogens and intestinal mucosa. In several studies, antimotility agents have been useful in treating travelers’ diarrhea by decreasing the duration of diarrhea. However, these agents should never be used by persons with fever or bloody diarrhea, because they can increase the severity of disease by delaying clearance of causative organisms. Because antimotility agents are now available over the counter, their injudicious use is of concern. Adverse complications (toxic megacolon, sepsis, and disseminated intravascular coagulation) have been reported as a result of using these medications to treat diarrhea.

What is CDC doing to prevent travelers’ diarrhea?

CDC, in collaboration with the World Health Organization and several Ministries of Health, is working to improve food and water safety around the world. CDC also investigates risk factors associated with acquisition of TD, to assist in identifying more effective preventive measures. CDC continues to monitor antimicrobial resistance in other countries and in the United States. In addition, CDC, in collaboration with international agencies, is working to improve sanitary conditions in foreign accommodations (e.g., tourist resorts) and frequently consults with travel medicine specialists and local and state health departments. CDC is responsible for evaluating sanitation on cruise ships docking in US ports.

How can I learn more about travelers’ diarrhea?

Potential travelers should consult with a doctor or a travel medicine specialist before departing on a trip abroad. Information about TD is available from your local or state health departments or the World Health Organization (WHO).

Other information that may be of interest to travelers can be found at the CDC Travelers’ Health homepage at www.cdc.gov/travel.