Epidemiology of travelers' diarrhea

Long-Term Sentinel Surveillance for Enterotoxigenic Escherichia coli and Non-O157 Shiga Toxin-Producing E. coli in Minnesota

Sentinel surveillance in Minnesota revealed that enterotoxigenic E. coli (ETEC) and non-O157 Shiga toxin-producing E. coli are common enteric pathogens; ETEC was the second leading bacterial pathogen in an urban site; 39% of ETEC were domestically acquired.

Background. Enterotoxigenic Escherichia coli (ETEC) and non-O157 Shiga toxin-producing E. coli (STEC) are not detected by conventional culture methods. The prevalence of ETEC infections in the United States is unknown, and recognized cases are primarily associated with foreign travel. Gaps remain in our understanding of STEC epidemiology.

Methods. Two sentinel surveillance sites were enrolled: an urban health maintenance organization laboratory (Laboratory A) and a rural hospital laboratory (Laboratory B). Residual sorbitol MacConkey (SMAC) plates from stool cultures performed at Laboratory A (1996–2006) and Laboratory B (2000–2008) were collected. Colony sweeps from SMAC plates were tested for genes encoding STEC toxins stx1 and stx2 (1996–2008) and ETEC heat-labile and heat-stable toxins eltB, estA 1, 2 and 3 (2000–2008) by polymerase chain reaction (PCR)-based assays.

Results. In Laboratory A, a bacterial pathogen was identified in 7.0% of 21 970 specimens. During 1996–2006, Campylobacter was the most common bacterial pathogen (2.7% of cultures), followed by Salmonella (1.2%), Shigella (1.0%), and STEC (0.9%). Among STEC (n = 196), O157 was the most common serogroup (31%). During 2000–2006, ETEC (1.9%) was the second most common bacterial pathogen after Campylobacter (2.6%). In Laboratory B, of 19 293 specimens tested, a bacterial pathogen was identified for 5.5%, including Campylobacter (2.1%), STEC (1.3%), Salmonella (1.0%), and ETEC (0.8%). Among STEC (n = 253), O157 was the leading serogroup (35%). Among ETEC cases, 61% traveled internationally.

Conclusions. Enterotoxigenic E. coli and STEC infections were as common as most other enteric bacterial pathogens, and ETEC may be detected more frequently by culture-independent multiplex PCR diagnostic methods. A high proportion of ETEC cases were domestically acquired.

Diarrheal illness among US residents providing medical services in Haiti during the cholera epidemic, 2010 to 2011

Although nosocomial transmission of cholera is rare, two US healthcare workers (HCW) became ill with cholera after providing medical services during the Haiti cholera epidemic. To assess the incidence of diarrheal illness and explore preventive health behaviors practiced by US residents who provided medical services in Haiti, we conducted a cross-sectional, anonymous, web-based survey. We e-mailed 896 participants from 50 US-based, health-focused non-governmental organizations (NGOs), of whom 381 (43%) completed the survey. Fifty-six percent of respondents (n = 215) reported providing some care for patients with cholera. Diarrhea was reported by 31 (8%) respondents. One person was diagnosed with cholera by serologic testing. NGOs responding to international emergencies should ensure ample access to basic hygiene supplies and should promote their use to reduce the incidence of diarrheal illness among HCW working overseas.

Health hazards and medical treatment of volunteers aged 18-30 years working in international social projects of non-governmental organizations (NGO)

The specific health risk profile and diversity of treatments sought by young volunteers participating in international social projects should differ from those of their older colleagues. In the absence of any data to identify whether this was correct, a retrospective analysis was performed using a standardized questionnaire. Questions included what diseases occurred, and details of the frequency and types of treatment sought during their stay - (e.g. self-treatment, medical/dental intervention, or local healer). The 153 participants were aged 18-30 years and worked in a non-governmental organization for >6 months. The participants were: 53% female, mean age 20 years, and mean duration of stay was 11.2 months. Their NGO placement abroad was in Latin America 65.4%, 14.4% in Africa, and 9.8% in Asia. 83% of the young volunteers had received some advice regarding travel medicine before their departure. However, they suffered from more injuries compared to private travellers, and febrile infections were more common when compared to older studies. 21.2% suffered from dental problems and 50% of them sought medical treatment. This study highlights a previously unreported higher risk profile of specific health problems occurring in young NGO volunteers, including some potentially life-threatening diagnoses that differed from their older colleagues and normal travellers. It is recommended that young volunteers should receive age specific, comprehensive pre-departure training in health and safety, first aid, and management of common health problems. A medical check-up upon returning home should be mandatory. The provision of a basic first aid kit to each volunteer before departure is also recommended.

GeoSentinel surveillance of illness in returned travelers, 2007-2011

BACKGROUND

International travel continues to increase, particularly to Asia and Africa. Clinicians are increasingly likely to be consulted for advice before travel or by ill returned travelers.

OBJECTIVE

To describe typical diseases in returned travelers according to region, travel reason, and patient demographic characteristics; describe the pattern of low-frequency travel-associated diseases; and refine key messages for care before and after travel.

DESIGN

Descriptive, using GeoSentinel records.

SETTING

53 tropical or travel disease units in 24 countries.

PATIENTS

42 173 ill returned travelers seen between 2007 and 2011.

MEASUREMENTS

Frequencies of demographic characteristics, regions visited, and illnesses reported.

RESULTS

Asia (32.6%) and sub-Saharan Africa (26.7%) were the most common regions where illnesses were acquired. Three quarters of travel-related illness was due to gastrointestinal (34.0%), febrile (23.3%), and dermatologic (19.5%) diseases. Only 40.5% of all ill travelers reported pretravel medical visits. The relative frequency of many diseases varied with both travel destination and reason for travel, with travelers visiting friends and relatives in their country of origin having both a disproportionately high burden of serious febrile illness and very low rates of advice before travel (18.3%). Life-threatening diseases, such as Plasmodium falciparum malaria, melioidosis, and African trypanosomiasis, were reported.

LIMITATIONS

Sentinel surveillance data collected by specialist clinics do not reflect healthy returning travelers or those with mild or self-limited illness. Data cannot be used to infer quantitative risk for illness.

CONCLUSION

Many illnesses may have been preventable with appropriate advice, chemoprophylaxis, or vaccination. Clinicians can use these 5-year GeoSentinel data to help tailor more efficient pretravel preparation strategies and evaluate possible differential diagnoses of ill returned travelers according to destination and reason for travel.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

Diarrhea outbreak during U.S. military training in El Salvador

Infectious diarrhea remains a major risk to deployed military units worldwide in addition to their impact on travelers and populations living in the developing world. This report describes an outbreak of diarrheal illness in the U.S. military’s 130^th Maneuver Enhancement Brigade deployed in San Vicente, El Salvador during a training and humanitarian assistance mission. An outbreak investigation team from U.S. Naval Medical Research Unit – Six conducted an epidemiologic survey and environmental assessment, patient interviews, and collected stool samples for analysis in an at risk population of 287 personnel from May 31^st to June 3^rd, 2011. Personnel (n = 241) completed an epidemiological survey (87% response rate) and 67 (27%) reported diarrhea and/or vomiting during the past two weeks. The median duration of illness was reported to be 3 days (IQR 2–4 days) and abdominal pain was reported among 30 (49%) individuals. Presentation to the medical aid station was sought by (62%) individuals and 9 (15%) had to stop or significantly reduce work for at least one day. Microscopy and PCR analysis of 14 stool samples collected from previously symptomatic patients, Shigella (7), Cryptosporidium (5), and Cyclospora (4) were the most prevalent pathogens detected. Consumption of food from on-base local vendors (RR = 4.01, 95% CI = 1.53–10.5, p-value <0.001) and arriving on base within the past two weeks (RR = 2.79, 95% confidence [CI] = 1.35–5.76, p-value = 0.001) were associated with increased risk of developing diarrheal disease. The risk of infectious diarrhea is great among reserve military personnel during two week training exercises. The consumption of local food, prepared without proper monitoring, is a risk factor for deployed personnel developing diarrheal illness. Additional information is needed to better understand disease risks to personnel conducting humanitarian assistance activities in the Latin America Region.

Clinical characteristics and etiology of travelers' diarrhea among Korean travelers visiting South-East Asia

The morbidity of travelers' diarrhea (TD) is still high. This study examined the incidence of common pathogens and characteristics of TD among Korean travelers who visited South-East Asian countries. We performed a prospective study involving 479 Korean travelers with diarrheal disease from February 2009 to April 2009 and stool samples were examined and questionnaire surveys were done after arrival. Enterotoxigenic Escherichia coli (ETEC) was found in 36.0% of TD cases, as were the following: Enteroaggregative Escherichia coli (EAEC) in 27.0%, Vibrio parahaemolyticus in 13.1%, and Norovirus in 11.5%. The detected rate of classic TD was higher in men (P = 0.007), in patients who had a shorter duration trip (P = 0.023) and in patients who drank more than 1 liter of water per day (P = 0.037). Positive stool culture rates were higher in men (P = 0.005), in hospitalized patients (P = 0.013). and in those who consumed impure water or raw foods (P = 0.033). A higher severity of disease corresponded to a significantly higher culture positivity rate (P = 0.029). We should consider the possibility of other pathogens in addition to ETEC in patients with TD who visit South-East Asia. Travelers need to educate about risk factors associated with TD.

Ekbom syndrome: the challenge of "invisible bug" infestations

Ekbom Syndrome is synonymous with delusory parasitosis, a belief that one's body is infested by invisible bugs. Persons suffering from this syndrome often claim to feel dermal sensations and to visualize the bugs, although no one else can see them. Ekbom Syndrome is a delusional condition; it is intractable and cannot be corrected by argument or evidence. Ekbom Syndrome sufferers exhibit a range of predictable behaviors in their attempts to eliminate their infestations, including seeking identifications and treatment from physicians and entomologists. Frequently they also experience comorbid psychological conditions. Because this is a delusional affliction, successful treatment typically requires neuroleptic medications, necessitating intervention by medical professionals.

Defining infections in international travellers through the GeoSentinel surveillance network

International travellers are often exposed to a wide range of infections, most of which are a reflection of common diseases in the destination country. The consequences of acquiring such infections are serious and can be associated with substantial morbidity and mortality. Attempting to define the range of infections and the risk factors that are associated with acquiring them during travel to different regions worldwide will provide an evidence base for the development and implementation of effective preventative interventions. This Science and Society article focuses on the valuable function served by the GeoSentinel surveillance network in defining the range of infections in travellers.

Delusional infestation

This papers aims at familiarizing psychiatric and nonpsychiatric readers with delusional infestation (DI), also known as delusional parasitosis. It is characterized by the fixed belief of being infested with pathogens against all medical evidence. DI is no single disorder but can occur as a delusional disorder of the somatic type (primary DI) or secondary to numerous other conditions. A set of minimal diagnostic criteria and a classification are provided. Patients with DI pose a truly interdisciplinary problem to the medical system. They avoid psychiatrists and consult dermatologists, microbiologists, or general practitioners but often lose faith in professional medicine. Epidemiology and history suggest that the imaginary pathogens change constantly, while the delusional theme "infestation" is stable and ubiquitous. Patients with self-diagnosed "Morgellons disease" can be seen as a variation of this delusional theme. For clinicians, clinical pathways for efficient diagnostics and etiology-specific treatment are provided. Specialized outpatient clinics in dermatology with a liaison psychiatrist are theoretically best placed to provide care. The most intricate problem is to engage patients in psychiatric therapy. In primary DI, antipsychotics are the treatment of choice, according to limited but sufficient evidence. Pimozide is no longer the treatment of choice for reasons of drug safety. Future research should focus on pathophysiology and the neural basis of DI, as well as on conclusive clinical trials, which are widely lacking. Innovative approaches will be needed, since otherwise patients are unlikely to adhere to any study protocol.

Gastrointestinal infection among international travelers globally

BACKGROUND

Data on relative rates of acquisition of gastrointestinal infections by travelers are incomplete. The objective of this study was to analyze infections associated with oral ingestion of pathogens in international travelers in relation to place of exposure.

METHODS

We performed a multicenter, retrospective observational analysis of 6,086 travelers ill enough with any gastrointestinal infection to seek medical care at a GeoSentinel clinic after completion of travel during 2000 to 2005. We determined regional and country-specific reporting rate ratios (RRRs) in comparison to risk in northern and western Europe.

RESULTS

Travel to sub-Saharan Africa (RRR = 282), South America (RRR = 203), and South Asia (RRR = 890) was associated with the greatest rate of gastrointestinal infections. RRRs were moderate (25-142) for travel to Oceania, the Middle East, North Africa, Central America, the Caribbean, and Southeast Asia. RRRs were least (<28) following travel to southern, central, and eastern Europe; North America; Northeast Asia; and Australasia. Income level of the country visited was inversely proportional to the RRR for gastrointestinal infection. For bacterial and parasitic infections examined separately, the regions group in the same way. RRRs could be estimated for 28 individual countries and together with regional data were used to derive a global RRR map for travel-related gastrointestinal infection.

CONCLUSIONS

This analysis of morbidity associated with oral ingestion of pathogens abroad determines which parts of the world currently are high-risk destinations.

Antimicrobial prevention and therapy for travelers' infection

International journeys are increasing and more than 70 million people from industrialized countries cross the borders of tropical countries every year. More than 50% of them will suffer from some form of infectious illness, ranging from mild travelers' diarrhea to severe dengue fever to fatal malaria, with a wide spectrum of microbiological entities. Travel-related respiratory infections, including TB, and sexually transmitted infections are also increasingly reported. Awareness of travel-related risk is not always adequate among international travelers. Specific training on travel medicine-related issues, as well as better diagnostic facilities for imported diseases, is crucial for physicians and nurses in industrialized countries.

Current perceptions of travelers' diarrhea treatments and vaccines: results from a postal questionnaire survey and physician interviews

BACKGROUND

Travelers' diarrhea (TD) occurs at high frequency in individuals from industrialized countries visiting destinations in nonindustrialized countries and may result in chronic complications such as Guillain-Barré syndrome.

METHODS

We distributed a questionnaire requesting information on physicians' perceptions of currently available TD products, hypothesized TD vaccines, and aspects of travelers' behavior. Some physicians also were interviewed by telephone.

RESULTS

We obtained completed questionnaires from named individuals at 68 UK/US clinics. These individuals reported seeing a total of approximately 76,500 travelers per year, and estimated that 61% (UK) and 77% (US) of travelers present 2 weeks or more predeparture. More US (92%) than UK (43%) travelers are advised to purchase TD products. In both countries, 85% of travelers would be prescribed an ideal TD vaccine, but only approximately 47% (UK) and approximately 65% (US) would purchase this vaccine. About 80% of physicians would recommend an hypothesized 100% effective Campylobacter vaccine for travelers visiting regions where 30% of TD cases are caused by Campylobacter.

CONCLUSIONS

Physicians support the concept of TD vaccines, including campylobacteriosis vaccines. An ideal TD vaccine might be purchased by up to 16% (UK) and 28% (US) of relevant travelers. A 100% effective Campylobacter vaccine might be purchased by over 2 million UK/US travelers per year.

Trends in antimicrobial resistance in Campylobacter spp. causing traveler's diarrhea

The aim of this study was to analyze the evolution of the levels of resistance to nine antimicrobial agents in clinical isolates of Campylobacter spp. causing traveler's diarrhea during the period from 1993 to 2003. The antimicrobial resistance levels to ampicillin, amoxicillin plus clavulanic acid, chloramphenicol, tetracycline, erythromycin, gentamicin, clindamicin, nalidixic acid and ciprofloxacin were established by the method of Kirby-Bauer. Two subperiods (1993-1998 and 1999-2003) were chosen to compare the evolution of the levels of antimicrobial resistance. Mantel-Haenszel or Fisher's exact test was performed to determine statistical significance. High levels of resistance to four out of nine antimicrobial agents tested were detected: ampicillin (66.3%), nalidixic acid (52.2%), ciprofloxacin (46.7%), and tetracycline (42.4%). In addition, resistance levels of 20.6% to amoxicillin plus clavulanic acid were detected. An increase in the resistance levels between the two subperiods analyzed for those five antimicrobial agents was observed. This increase was statistically significant for ampicillin, nalidixic acid, and ciprofloxacin. Two cases of therapeutic failure during treatment with ciprofloxacin were detected. The level of resistance to the most commonly used antibacterial agents in the developing world is increasing in Campylobacter spp., the increase in the resistance to quinolones being of special concern.

Diarrhea and respiratory symptoms among travelers to Asia, Africa, and South and Central America from Scotland

Surveillance using admissions to hospital, while being useful, is a poor indicator of the real incidence of disease encountered by travelers. An alternative is self-reported illness among those who attended at a pretravel clinic prior to their travels. Estimates of incidence and risk factors were determined for attendees at a travel clinic in Scotland using a questionnaire. Analysis for risk factors was carried out for those travelers visiting countries in Africa, Asia, or South and Central America, who had traveled for 1 week or more and had returned between 1997 and 2001 (N= 4,856). Multivariate logistic regression was used to test the hypotheses that time abroad and age-group would be significant for both respiratory and diarrheal symptoms regardless of which of the three geographical areas are visited. From 2006 returned questionnaires (response rate = 41.3%), diarrhea and respiratory symptoms were reported by 44.2 and 16.8% of respondents, respectively; the incidence was significantly greater among travelers to Asia for both diarrheal (55.5%) and respiratory (23.7%) symptoms than among travelers to Africa (36.6 and 12.2%, respectively) or South and Central America (39.5 and 16.2%, respectively). For diarrhea, age was a highly significant risk factor for travelers to Asia, South and Central America, and Africa. Being a self-organized tourist/backpacker, traveling to Asia was associated with increased risk, while for Africa and South and Central America visiting family or friends was associated with a lower risk. For travelers to Asia, traveling to the Indian subcontinent was significantly associated with increased risk. The majority of travelers had an adverse event while traveling abroad, with diarrhea and respiratory conditions being especially common despite attending a travel clinic for advice prior to departure. However, the limitations of this surveillance-based strategy have highlighted the requirement for more research to understand more fully the issues of risk and incidence among travelers to high-risk destinations from Scotland.

The impact of the Catholic Jubilee in 2000 on infectious diseases. A case-control study of giardiasis, Rome, Italy 2000-2001

Mass gatherings are believed to increase the transmission of infectious diseases although surveillance systems have shown a low impact. The Catholic Jubilee was held in Rome, Italy in 2000. We conducted a case-control study to analyse the risk factors of giardiasis among residents. All diseases reported to the laboratory surveillance system from January 2000 to May 2001 were compared with hospital controls concurrently selected in the same season as cases and frequency-matched for age and birth country. Fifty-two cases (44.1%) and 72 controls were enrolled. In the multivariable analysis factors associated with giardiasis among adults were: travelling abroad (OR 24.2, P>0.01), exposure to surface water (OR 4.80, P=0.05), high educational level (OR 3.8, P=0.03). Having a maid from a high-prevalence country was independently associated (OR 2.3) although not statistically significant. This is the only exposure that changed during the Jubilee.

Rifaximin: a review of its use in the management of traveller's diarrhoea

Oral rifaximin, a semisynthetic rifamycin derivative, is an effective and well tolerated antibacterial for the management of adults with non-invasive traveller's diarrhoea. Rifaximin was significantly more effective than placebo and no less effective than ciprofloxacin in reducing the duration of diarrhoea after treatment initiation for illness contracted during travel to diverse geographic locations. While rifaximin is effective in patients with Escherichia coli-predominant traveller's diarrhoea, it appears ineffective in patients infected with inflammatory or invasive enteropathogens. Rifaximin has a broad spectrum of antibacterial activity in vitro and undergoes negligible systemic absorption (<0.4%). In contrast to systemically absorbed antibacterials, such as the fluoroquinolones and macrolides, the acquisition of resistance to rifaximin would have limited consequences for global public health, as rifaximin has no role in the management of systemic infections. Rifaximin shows promise as chemoprophylaxis against traveller's diarrhoea and is a valuable new option for the management of traveller's diarrhoea caused by non-invasive bacterial strains.

Correlation between adherence to precautions issued by the WHO and diarrhea among long-term travelers to India

BACKGROUND

Travelers' diarrhea is the most common infectious disease afflicting travelers to developing countries. Most studies investigating the benefits of recommendations regarding the consumption of food and water have focused on short-term travelers. We investigated the benefits of adherence to the precautions from the World Health Organization (WHO) among long-term travelers.

METHODS

We asked 140 incidental travelers in India traveling for at least 2 months to complete a questionnaire about their adherence to the WHO precautions and the occurrence of diarrhea. Adherence was graded on a scale of 1 to 6 (least to most).

RESULTS

The mean age of the 114 travelers whose questionnaires were eligible was 26.6 +/- 5.7 years, and the median duration of their trip was 5 months. None of them adhered strictly to the entire set of rules. The mean individual adherence was 3.4 (range 1.2-5.8). The vast majority of the travelers (83%) suffered from diarrhea. Most travelers (60%) had diarrhea for up to 3% of their journey time. Diarrhea was accompanied by fever among 18% and necessitated hospitalization in 3%. Forty-five percent indicated that they had lost traveling days due to diarrhea, for an average of 0.7% of the traveling time. We found no correlation between the percentage of traveling time with diarrhea and the following variables: adherence to the WHO recommendations, receipt of advice regarding prevention, duration of the trip, age, sex, and nationality of the travelers.

CONCLUSIONS

Dietary self-restraint of travelers as proposed by the WHO is both difficult to comply with and lacks a proven value for the long-term traveler to a developing country.

Travel and health status: a survey follow-up study

BACKGROUND

To date there is little sound knowledge on the relationship between travel and health status as perceived by the traveller. Our aim was to investigate the frequency and risk factors of travel-associated illnesses and injuries and identify potential protective factors.

METHODS

All adults enrolled in a health insurance scheme who planned to travel in 2002 were eligible for participation in a baseline survey. Pre-travel written questionnaires and post-travel telephone interviews were conducted with responders. We analysed travel-associated health problems using descriptive methods and multivariate logistic regression.

RESULTS

From 8316 persons who returned a pre-travel questionnaire, a sample of 2384 were chosen, of whom 1471 completed post-travel interviews. 10.1% of all travellers reported travel-associated illnesses, and 1.8% suffered from injuries during travel. Among travellers to European destinations, 6.0% reported an illness as opposed to 16.2% of travellers to overseas destinations. Predictors for travel-associated illness were age <30 years (OR 1.48), duration of travel >4 weeks (OR 3.35) and travel destination. Perceived health status as scored by the travellers improved after travel. The frequency of medical consultations and personal health-related expenses decreased significantly shortly after travel.

CONCLUSIONS

In this study, travel had a positive effect on the perceived health status of the traveller. The positive effects of travel seemed to outweigh the impact of health problems. Travel did not lead to increased health-related costs, neither in individual health expenses nor indirectly through increased medical consultation rates.

Medical conditions affecting well-accommodated travelers in Lebanon

There are no data on the prevalence of common diseases affecting travelers to Lebanon. Between 2001 and 2002, one among nine physicians was consulted on guests who needed medical attention in a five-star Beirut hotel. Physicians were consulted 114 times. The mean age of the patients was 36.6 years. Gastroenteritis (50.9%) followed by respiratory problems (25.4%) were the leading causes for consultation.

Severe acute diarrhea

Acute diarrhea is commonly caused by an infection. Severe acute diarrhea warrants immediate medical evaluation and hospitalization. Indications for stool studies include fever; bloody diarrhea; recent travel to an endemic area; recent antibiotics; immunosuppression; and occupational risks, such as food handlers. Noninfectious causes include inflammatory bowel disease, radiation enteritis, and intestinal ischemia. Management of severe acute diarrhea includes intravenous fluid rehydration and empiric antibiotics. Use of antidiarrheal agents is controversial when invasive pathogens are suspected.

Diagnosis and treatment of bacterial diarrhea

Diarrheal illness caused by bacterial pathogens is a global health problem and remains one of the most common complaints prompting patients to seek medical care. Strategies to increase the yield of stool culture and new rapid diagnostic tests can improve diagnostic ability. Emerging antimicrobial resistance among the common bacterial causes of diarrhea has made treatment more challenging. Emerging fluoroquinolone resistance is a particular concern. Recent studies of rifaximin, a nonabsorbed antibiotic for the treatment of bacterial diarrhea, have shown favorable results. Rifaximin may represent a much-needed addition to the armamentarium against bacterial agents.