Health · reviewed 2026-05-16

What are the odds of getting travelers' diarrhea on an international trip to a high-risk destination?

Evidence quality 4.25/5

Eight-dimension review score against the quality rubric . Each dimension scored 1–5.

D1 Source grounding: 4/5
D2 Source authority: 5/5
D3 Arithmetic: 4/5
D4 Uncertainty: 4/5
D5 Scope: 5/5
D6 Prose: 4/5
D7 Perception honesty: 3/5
D8 Caveat completeness: 5/5

Average 4.25/5

Direct evidence

Lifetime probability · lifetime, activity-specific

1 in 2.0

50% lifetime chance

range 1 in 3.3 to 1 in 1.4

lifetime, activity-specific each band = 10× rarer → zoomed to your factors See full scale →

1 in 1.1

1 in 5,681,818

certain 1 in 1K 1 in 1M 1 in 1B

1 in 1.0 1 in 6.7

● your factors — click this risk ▾ to reveal

≈ As likely as

A simplified world map with a heat-spot over South Asia and Africa, a water bottle and fork, flat vector illustration.

Perceived

Travelers to developing-country destinations widely know that gastrointestinal illness is a real risk, but many underestimate how probable it actually is for high-risk destinations like South Asia, Sub-Saharan Africa, and Mexico. Informal survey data from travel medicine clinics suggests most travelers heading to high-risk destinations estimate their per-trip risk at 10-20%, roughly half to one-third of the actual epidemiological range. The condition is also often dismissed as mild inconvenience, though a meaningful fraction of cases involve fever, bloody stools, or require antibiotic treatment.

Rough estimate: Most travelers to high-risk destinations guess 10-20% per trip

Source: editorial intuition, not polled

Actual

30-70% per 2-week trip to high-risk destinations

International travelers to high-risk destinations (South Asia, Sub-Saharan Africa, Mexico, Central America, parts of South America)

Show derivation

CDC Yellow Book 2024 states attack rates of 30-70% for travelers during a 2-week period to high-risk destinations (South/Central Asia, Sub-Saharan Africa, Mexico, Central and South America). The scope is activity_specific_lifetime: this figure represents the per-trip probability for a single 2-week trip to a high-risk destination, not a cumulative lifetime figure. The central estimate of 0.50 (50%) is the midpoint of the 30-70% published range. A Utah-based prospective study of international travelers (PMC9651512) found an incidence rate of 1.1 episodes per 100 travel-days in travelers departing for a mix of destinations, with Southeast Asian and African destinations associated with significantly higher odds. The lifetime_us_adult value here represents the per-trip probability (0.50) for a single high-risk-destination trip; it is not a conventional US adult lifetime accumulation. normalized.scope = activity_specific_lifetime documents this.

Caveats: The 30-70% attack rate is specifically for high-risk destinations (South/Central…

The 30-70% attack rate is specifically for high-risk destinations (South/Central Asia, Sub-Saharan Africa, Mexico, Central America) during a 2-week stay. Travelers to low-risk destinations (Western Europe, Japan, Australia, Canada) face rates below 5% per trip — essentially a different exposure category. The CDC definition of TD requires ≥3 unformed stools in 24 hours plus at least one enteric symptom; milder gastrointestinal disturbances are even more common. Most TD episodes are self-limiting within 1-5 days and require only rehydration; approximately 10% of cases involve fever, bloody stools, or require antibiotic treatment. Hemolytic uremic syndrome and post-infectious IBS are rare but real sequelae in a small fraction of cases. The entry does not cover food poisoning in the context of domestic US travel, which is addressed in other entries.

Risks at similar odds

Other risks with roughly the same likelihood — useful for calibration.

Health

Traveler's diarrhea (water)

What are the odds of getting seriously ill from drinking water while traveling to a developing country?

Health

Flying with cold

What are the odds of ear barotrauma or a ruptured eardrum from flying with a cold?

Health

Adventure sports

What are the odds of a serious injury from regular participation in surfing, mountain biking, or rock climbing?

Health

Alcohol use disorder

What are the odds of developing alcohol use disorder over a lifetime?

Health

Drug-resistant infection

What is the risk of developing a serious antibiotic-resistant infection?

Health

No marrow match

What are the odds of not finding a bone marrow donor match?

Health

Family caregiver probability

How likely am I to become an unpaid family caregiver — and what is the mental-health toll?

Health

Inheriting AUD risk

If a parent had alcohol use disorder, what are the odds you'll develop alcohol use disorder yourself?

More Travel risks: Mishandled luggage Flight cancellation Blood clot (flight) Chagas disease Child bike trailer +27 more

Compare to:

Travelers’ diarrhea is the most common travel-related illness and one of the most predictable adverse events in international travel. The CDC Yellow Book 2024 puts the attack rate at 30-70% per two-week trip to high-risk destinations — South Asia, Sub-Saharan Africa, Mexico, and Central and South America. The midpoint of that range, roughly 1 in 2 trips to a high-risk destination, is substantially higher than most travelers’ intuitive estimate of 10-20%. Intermediate-risk destinations (Southeast Asia, Middle East, parts of South America) run 10-20% per trip, and low-risk destinations (Western Europe, Japan, Australia) fall below 5%.

The condition’s clinical course varies more than its reputation suggests. Most episodes are self-limiting within one to five days and require only oral rehydration; the stereotype of a brief unpleasant inconvenience is accurate for roughly 90% of cases. The remaining 10% involve fever, bloody stools, or symptoms persistent enough to warrant antibiotic treatment — and a small fraction of cases result in post-infectious irritable bowel syndrome, a condition that can persist for months after the original infection resolves. Bacteria dominate the etiology, with enterotoxigenic E. coli (ETEC), Campylobacter, and Shigella accounting for the large majority of identifiable cases.

The attack-rate range reflects real and substantial heterogeneity in exposure. Behavioral precaution compliance is the strongest modifiable predictor: consistent avoidance of tap water (including ice), raw vegetables, and unpasteurized dairy reduces risk substantially. Budget travelers eating street food regularly face rates at the upper end of the range; travelers staying in international hotels with purified water throughout their stay face rates at the lower end or below it. Prophylactic rifaximin, used off-label by some travel medicine providers, demonstrates approximately 70% efficacy in controlled trials, though it is not universally recommended due to concerns about promoting antibiotic resistance.

Claim ledger

Every number below is what each source reported, with the verbatim quote we relied on and how we arrived at our figure. Click any link to verify directly.

[1] Centers for Disease Control and Prevention — Travelers' Diarrhea — CDC Yellow Book 2024 Government report

Travelers' Diarrhea — CDC Yellow Book 2024

Statistic

Attack rates 30-70% per 2-week trip to high-risk destinations (South/Central Asia, Sub-Saharan Africa, Mexico, Central and South America); 10-20% for intermediate-risk destinations (SE Asia, Middle East); <5% for low-risk destinations (Western Europe, Japan, Australia)

Excerpt

“"Attack rates range from 30%–70% of travelers during a 2-week period, depending on the destination and season of travel. The highest-risk destinations are in Asia (except for Japan and South Korea) as well as the Middle East, Africa, Mexico, and Central and South America." ”

Source data from

2024-01-01

Accessed

2026-05-14 · archived copy

Calculation

CDC Yellow Book attack-rate range: 30-70% per 2-week stay at high-risk destinations. Central estimate: 50% (midpoint). This is a per-trip figure, not a lifetime accumulation, and is used directly as normalized.lifetime_us_adult with scope: activity_specific_lifetime. The 10-20% range for intermediate-risk destinations is cited for context but not used in the primary calculation.

Independence

CDC Yellow Book is a government public health reference compiled by CDC travel medicine experts from peer-reviewed literature. It is the primary US clinical reference for travel medicine and is independent from pharmaceutical company prophylaxis studies and private travel insurer claims data.
[2] PMC / National Library of Medicine — Incidence Rate and Risk Factors Associated with Travelers' Diarrhea in International Travelers Departing from Utah, USA Peer-reviewed

Incidence Rate and Risk Factors Associated with Travelers' Diarrhea in International Travelers Departing from Utah, USA

Statistic

23% of 484 surveyed travelers reported TD; incidence rate 1.1 episodes per 100 travel-days; Southeast Asian and African regions associated with significantly increased odds

Excerpt

“"Of 571 travelers who completed posttravel surveys, 484 (85%) answered the TD question, of which 111 (23%) reported TD, for an incidence rate of 1.1 episodes per 100 travel-days. Visiting Southeast Asian and African WHO regions, longer trip duration, visiting both urban and rural destinations were statistically significantly associated with increased odds of reporting TD." ”

Source data from

2022-09-01

Accessed

2026-05-14 · archived copy

Calculation

The Utah study's 23% overall rate across mixed destinations (including low-risk destinations) is consistent with the CDC Yellow Book 30-70% high-risk range when accounting for the study population's destination mix. The 1.1 episodes per 100 travel-days translates to approximately 15 episodes per 100 travelers on a 14-day trip for the average study destination — below the CDC high-risk range because the study included many lower-risk destinations. Used to corroborate that the CDC range is epidemiologically supported; the CDC figure is used for the primary estimate.

Independence

This prospective cohort study surveyed travelers departing a single US university travel clinic, making it methodologically independent from CDC Yellow Book meta-analytic estimates. The study's population (Utah international travelers) may differ from the national average traveler in destination choice and demographic composition.
[3] Emerging Infectious Diseases (CDC) — Etiology and Epidemiology of Travelers' Diarrhea among US Military and Adult Travelers, 2018-2023 Peer-reviewed

Etiology and Epidemiology of Travelers' Diarrhea among US Military and Adult Travelers, 2018-2023

Statistic

Bacteria account for 80-90% of TD episodes; ETEC, Campylobacter, and Shigella dominate; antimicrobial-resistant ETEC increasing; rifaximin ~70% effective in Mexico trials

Excerpt

“"Bacteria are the predominant enteropathogens and are thought to account for ≥80%–90% of cases. ETEC (enterotoxigenic E. coli) remains the leading pathogen globally. Rifaximin demonstrated approximately 70% efficacy in prophylactic trials in Mexico. Antimicrobial resistance in TD pathogens has increased, complicating empirical treatment." ”

Source data from

2024-10-01

Accessed

2026-05-14 · archived copy

Calculation

Used for the prophylaxis efficacy estimate (rifaximin ~70% reduction) that informs the personal_factor_multipliers entry. Also documents that the disease burden is dominated by bacterial pathogens against which antibiotic prophylaxis and treatment are most effective.

Independence

Peer-reviewed CDC journal; data sources include US military surveillance and civilian travel clinic data, distinct from the CDC Yellow Book meta-analytic framework and the Utah cohort study.