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Traveler's diarrhea [keywords]
- Epidemiology and clinical manifestations of enteroaggregative Escherichia coli. [Journal Article, Research Support, Non-U.S. Gov't]
- Clin Microbiol Rev 2014 Jul; 27(3):614-30.
Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission, reservoirs, and symptoms. Manifestations associated with EAEC infection include watery diarrhea, mucoid diarrhea, low-grade fever, nausea, tenesmus, and borborygmi. In early studies, EAEC was considered to be an opportunistic pathogen associated with diarrhea in HIV patients and in malnourished children in developing countries. In recent studies, associations with traveler's diarrhea, the occurrence of diarrhea cases in industrialized countries, and outbreaks of diarrhea in Europe and Asia have been reported. In the spring of 2011, a large outbreak of hemolytic-uremic syndrome (HUS) and hemorrhagic colitis occurred in Germany due to an EAEC O104:H4 strain, causing 54 deaths and 855 cases of HUS. This strain produces the potent Shiga toxin along with the aggregative fimbriae. An outbreak of urinary tract infection associated with EAEC in Copenhagen, Denmark, occurred in 1991; this involved extensive production of biofilm, an important characteristic of the pathogenicity of EAEC. However, the heterogeneity of EAEC continues to complicate diagnostics and also our understanding of pathogenicity.
- Cyclospora cayetanensis in a pediatric hospital in Morelia, México. [Journal Article]
- Am J Trop Med Hyg 2014 Sep; 91(3):537-40.
Cyclospora cayetanensis, a coccidian parasite, can cause gastrointestinal illness in humans and is characterized by watery and persistent diarrhea and abdominal pain. Cyclosporiasis has been associated with traveler's diarrhea. The infection is acquired through food and waterborne transmission, particularly by consumption of contaminated fresh fruits and vegetables. In the present study, stool samples from 8,877 children were examined for ova and parasites at the Pediatric Hospital of Morelia in Michoacán, Mexico, during 2000-2009. Sixty children (0.67%) had Cyclospora in their stools. Diarrhea (45.8%), abdominal pain (39.6%), and vomiting (18.8%) were the most frequent symptoms of cases with cyclosporiasis. Most of the cases (93.3%) were observed during June-August, the rainy season. In 45 children, Cyclospora was the only parasitic pathogen detected (75%); 15 children were co-infected with commensal, pathogenic, or both groups of parasites. Our findings suggest that C. cayetanensis is endemic to Michoacán and shows characteristically temporal patterns.
- Enteroaggregative coli: A Pathogen Bridging the North and South. [JOURNAL ARTICLE]
- Curr Trop Med Rep 2014 Jun 1; 1(2):88-96.
Enteroaggregative Escherichia coli (EAEC) is a heterogeneous emerging enteric pathogen. Identified during the 1980's when EAEC strains where isolated from cases of acute and persistent diarrhea among infants from developing countries and of traveler's diarrhea. Subsequently, EAEC strains were linked with foodborne outbreaks and diarrhea illness in adults and children from industrialized countries, HIV-infected subjects and stunting of malnourished poor children. Nowadays, EAEC is increasingly recognized as a major cause of acute diarrhea in children recurring hospitalization and of traveler's diarrhea worldwide. EAEC strains defining phenotype is the aggregative adherence (AA) pattern on epithelial cells. AggR a transcriptional regulator of several EAEC virulence genes has been a key factor in both understanding EAEC pathogenesis and defining typical EAEC (tEAEC) strains. EAEC virulence genes distribution among these strains is highly variable. Present challenges are the identification of key virulence genes and how they coordinately function in the setting of enteric disease.
- Oral cholera vaccine for traveler's diarrhea prophylaxis. [Journal Article]
- Can Fam Physician 2014 May; 60(5):451.
Should the oral cholera vaccine be routinely recommended to prevent traveler's diarrhea (TD)?Randomized controlled trials evaluating oral cholera vaccine for TD did not show a benefit and routine use is not recommended.
- The 2014 FIFA World Cup: communicable disease risks and advice for visitors to Brazil--a review from the Latin American Society for Travel Medicine (SLAMVI). [Journal Article]
- Travel Med Infect Dis 2014 May-Jun; 12(3):208-18.
The next FIFA World Cup will be held in Brazil in June-July 2014. Around 600,000 international visitors and participants (as well over 3 million domestic travelers) are expected. This event will take place in twelve cities. This event poses specific challenges, given its size and the diversity of attendees, including the potential for the transmission of imported or endemic communicable diseases, especially those that have an increased transmission rate as a result of close human proximity, eg, seasonal influenza, measles but also tropical endemic diseases. In anticipation of increased travel, a panel of experts from the Latin American Society for Travel Medicine (SLAMVI) developed the current recommendations regarding the epidemiology and risks of the main communicable diseases in the major potential destinations, recommended immunizations and other preventives measures to be used as a basis for advice for travelers and travel medicine practitioners. Mosquito-borne infections also pose a challenge. Dengue poses a significant risk in all states, including the host cities. Vaccination against yellow fever is recommended except for travelers who will only visit coastal areas. Travelers visiting high-risk areas for malaria (Amazon) should be assessed regarding the need for chemoprophylaxis. Chikunguya fever may be a threat for Brazil, given the presence of Aedes aegypti, vector of dengue, and the possibility of travelers bringing the virus with them when attending the event. Advice on the correct timing and use of repellents and other personal protection measures is key to preventing these vector-borne infections. Other important recommendations for travelers should focus on preventing water and food-borne diseases such as hepatitis A, typhoid fever, giardiasis and traveler's diarrhea. Sexually transmitted diseases (STD) should be also mentioned and the use of condoms advocated. This review addresses pre-travel, preventive strategies to reduce the risk of acquiring communicable diseases during a mass gathering such as the World Cup and also reviews the spectrum of endemic infections in Brazil to facilitate the recognition and management of infectious diseases in travelers returning to their countries of origin.
- Morbidity and outcomes of foreign travelers in Zakynthos island, Greece: a retrospective study. [Journal Article]
- PLoS One 2014; 9(4):e94416.
Although there is satisfactory recording of diseases affecting travelers visiting developing countries, little is known regarding morbidity of travelers when visiting developed countries. We sought to evaluate the morbidity of foreign travelers in Zakynthos, a popular Greek island attracting large number of foreign tourists every summer.Data from foreign travelers that accommodated in Zakynthos and sought medical services from the private offices of Zante Medical Care from May 1 to October 30 2012 were retrospectively analyzed.Two thousand six hundred and eighty-eight patients were included in the study. The mean age (± SD) of the patients whom the age was recorded was 29.6 (± 18.3) and 51.5% of them were from 18 to 40 years old. Disorders of the respiratory tract (32.7%), dermatologic conditions (21.1%), musculoskeletal injuries (16.4%), and gastrointestinal disorders (16.3%) were the four most prevalent clinical categories among patients. Ear disorder was the most common syndromic description (14.5%) among which 81.2% were ear infections; otitis externa and otitis media were diagnosed in 8.5% and 3.3% patients in total. The most common specific diagnosis was gastroenteritis (14.3%). Insect bite and sunburn were the most common diagnosis (6.5% and 3.8%, respectively) among patients with a dermatologic condition. Ear infection was the most common diagnosis in pediatric patients.Disorders mainly of the upper respiratory tract were the predominant causes of illness among foreign travelers in Zakynthos. Traveler's diarrhea was the most common specific diagnosis but the prevalence within the total population was not very high.
- Does Tropheryma whipplei contribute to travelers' diarrhea?: A PCR analysis of paired stool samples in French travelers to Senegal. [Journal Article]
- Travel Med Infect Dis 2014 May-Jun; 12(3):264-7.
Tropheryma whipplei was recently associated with acute infections as gastroenteritis in children. We hypothesize that T. whipplei may be a contributing microbe in traveler's diarrhea.The presence of T. whipplei was investigated by using a specific PCR on stool samples of travelers to Senegal before and after traveling, independently of the occurrence of diarrhea.A total of 59 travelers returned both stool samples before and after travel and 16 (27%) experienced diarrhea during travel. Fifty-three patients (89.8%) were negative for T. whipplei before and after travel. Two patients (3.4%) were negative before and positive after travel. Two patients (3.4%) were positive before travel and negative after travel. Finally, two patients (3.4%) were positive before and after travel. There were no carriage differences of T. whipplei, visiting Senegal or staying in France. We found no significant association of T. whipplei carriage and travel-associated diarrhea but this may have been impacted by the use of doxycycline.This is the first report of T. whipplei carriage acquired during travel to tropical area. Further study addressing this issue in larger cohorts of travelers to Senegal, including individuals visiting friends and relatives in their country of origin and the protective role of doxycycline malaria chemoprophylaxis may help to understand the potential contribution of T. whipplei to travelers' diarrhea.
- Arginine deiminase pathway is far more important than urease for acid resistance and intracellular survival in Laribacter hongkongensis: a possible result of arc gene cassette duplication. [Journal Article, Research Support, Non-U.S. Gov't]
- BMC Microbiol 2014.:42.
Laribacter hongkongensis is a Gram-negative, urease-positive bacillus associated with invasive bacteremic infections in liver cirrhosis patients and fish-borne community-acquired gastroenteritis and traveler's diarrhea. Its mechanisms of adaptation to various environmental niches and host defense evasion are largely unknown. During the process of analyzing the L. hongkongensis genome, a complete urease cassette and two adjacent arc gene cassettes were found. We hypothesize that the urease cassette and/or the arc gene cassettes are important for L. hongkongensis to survive in acidic environment and macrophages. In this study, we tested this hypothesis by constructing single, double and triple non-polar deletion mutants of the urease and two arc gene cassettes of L. hongkongensis using the conjugation-mediated gene deletion system and examining their effects in acidic environment in vitro, in macrophages and in a mouse model.HLHK9∆ureA, HLHK9∆ureC, HLHK9∆ureD and HLHK9∆ureE all exhibited no urease activity. HLHK9∆arcA1 and HLHK9∆arcA2 both exhibited arginine deiminase (ADI) activities, but HLHK9∆arcA1/arcA2 double deletion mutant exhibited no ADI activity. At pH 2 and 3, survival of HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 were markedly decreased (p < 0.001) but that of HLHK9∆ureA was slightly decreased (p < 0.05), compared to wild type L. hongkongensis HLHK9. Survival of HLHK9∆ureA/arcA1/arcA2 and HLHK9∆arcA1/arcA2 in macrophages were also markedly decreased (p < 0.001 and p < 0.01 respectively) but that of HLHK9∆ureA was slightly decreased (p < 0.05), compared to HLHK9, although expression of arcA1, arcA2 and ureA genes were all upregulated. Using a mouse model, HLHK9∆ureA exhibited similar survival compared to HLHK9 after passing through the murine stomach, but survival of HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 were markedly reduced (p < 0.01).In contrast to other important gastrointestinal tract pathogens, ADI pathway is far more important than urease for acid resistance and intracellular survival in L. hongkongensis. The gene duplication of the arc gene cassettes could be a result of their functional importance in L. hongkongensis.
- Acute diarrhea. [Journal Article]
- Am Fam Physician 2014 Feb 1; 89(3):180-9.
Acute diarrhea in adults is a common problem encountered by family physicians. The most common etiology is viral gastroenteritis, a self-limited disease. Increases in travel, comorbidities, and foodborne illness lead to more bacteria-related cases of acute diarrhea. A history and physical examination evaluating for risk factors and signs of inflammatory diarrhea and/or severe dehydration can direct any needed testing and treatment. Most patients do not require laboratory workup, and routine stool cultures are not recommended. Treatment focuses on preventing and treating dehydration. Diagnostic investigation should be reserved for patients with severe dehydration or illness, persistent fever, bloody stool, or immunosuppression, and for cases of suspected nosocomial infection or outbreak. Oral rehydration therapy with early refeeding is the preferred treatment for dehydration. Antimotility agents should be avoided in patients with bloody diarrhea, but loperamide/simethicone may improve symptoms in patients with watery diarrhea. Probiotic use may shorten the duration of illness. When used appropriately, antibiotics are effective in the treatment of shigellosis, campylobacteriosis, Clostridium difficile, traveler's diarrhea, and protozoal infections. Prevention of acute diarrhea is promoted through adequate hand washing, safe food preparation, access to clean water, and vaccinations.
- Commercializing diarrhea vaccines for travelers. [Journal Article]
- Hum Vaccin Immunother 2014; 10(6):1557-67.
Continued growth in international travel and forecasts for a great increase in the number of people who travel from industrialized to emerging and developing countries make it necessary to develop and improve the capacity to provide health protection to travelers. Measures available to prevent some diseases include a currently limited number of marketed vaccines which represent extremely useful tools to protect travelers. Travelers very often experience diarrheal and gastrointestinal diseases for which some vaccines are available. Use of these vaccines should be evaluated based on traveler and travel destination and characteristics. Vaccines available include those against cholera, typhoid fever, hepatitis A, hepatitis E (only available in China), and rotavirus. The aim of this review is to provide an updated summary about each of the abovementioned vaccines that may be useful for making decisions regarding their use and assessing their indications in recommendations for travelers.