Risk Of Salmonellosis Research Articles

Analysis of German nutrition brochures for pregnant women with evidence-based patient information criteria

ObjectiveTo evaluate nutrition brochures for pregnant women in Germany based on evidence-based patient information (EBPI) criteria. MethodsNutrition brochures for pregnant women in Germany were collected. Brochures addressing the risk of salmonellosis, toxoplasmosis or listeriosis were analyzed by two researchers independently. ResultsFifty brochures reporting any information on the risk of infection were analyzed. Most brochures did not include literature citations and only few brochures gave a risk description, predominantly verbally, which usually leads to an overestimation of the actual risk. Advertisement was present in 22% of the brochures. ConclusionGerman nutrition brochures for pregnant women should be adapted to comply with evidence-based patient information (EBPI) criteria for achieving a better quality of the disseminated information. Practice implicationsThe findings highlight the need of high quality nutrition brochures for pregnant women, which are relevant not only for pregnant women, but also to those responsible for creating brochures, and to physicians in charge of patient information.

Induction of an innate immune response and pathogenesis following ex vivo infection of human decidual tissues with human cytomegalovirus

Induction of an innate immune response and pathogenesis following ex vivo infection of human decidual tissues with human cytomegalovirus

Assessment of the risk of salmonellosis from internally contaminated shell eggs following initial storage at 18 °C (65 °F), compared with 7 °C (45 °F)

In the U.S., chicken-breeder farms that supply hatcheries typically store and transport eggs intended for broiler production at a temperature of 18.3 °C (65 °F). However, in case of surplus, some of these eggs may be diverted to human consumption. According to the U.S. Food and Drug Administration's ‘Egg Safety Final Rule,’ shell eggs intended for human consumption are required to be held or transported at or below 7.2 °C (45 °F) ambient temperature beginning 36 h after time of lay. We adapted a risk assessment model developed by the U.S. Department of Agriculture's Food Safety Inspection Service, to quantify human exposure to Salmonella Enteritidis and the risk of human salmonellosis if eggs are held and transported at 18.3 °C for up to 5.5 days after time of lay, as has been observed when hatchery eggs are diverted to human consumption, rather than held and transported at 7.2 °C within 36 h after time of lay. Storage at 18.3 °C leads to considerable bacterial growth in internally contaminated eggs. The model predicted that more than 10% of internally contaminated eggs would remain contaminated after in-shell pasteurization resulting in a 5-log10 reduction, and that some bacteria would survive after home-cooking. The model predicted that, alternatively, eggs stored at 7.2 °C after lay would have limited bacterial growth prior to pasteurization, and Salmonella would be very unlikely to be present after pasteurization. The predicted risk of salmonellosis from the consumption of eggs held and transported at 18.3 °C and subsequently diverted to human consumption is 25 times higher than the risk when eggs are held and transported at 7.2 °C.

Prevalence and quantification of Salmonella contamination in raw chicken carcasses at the retail in China

The quantitative contamination load of Salmonella in raw chicken carcasses at the retail level in six provinces and cities of China was determined within 1595 carcasses over 12 consecutive months. The overall Salmonella contamination rate was 41.6% and the median load of those contaminated was 4.6 MPN/100 g with 1.8 MPN/100 g as the 25th percentile and 18.0 MPN/100 g as the 75th percentile. There were significant variations in prevalence among carcasses sampled either in different provinces or sampling months. Carcasses collected in August had not only the highest prevalence of contamination (55.8%), but also the highest median (14.0 MPN/100 g) and 75th percentile load (120.0 MPN/100 g) values compared to January with lowest prevalence (26.5%), median (1.5 MPN/100 g) and 75th percentile load (7.6 MPN/100 g). The chilled (55.1%) stored carcasses was significantly higher in prevalence than those frozen (33.5%) and those freshly slaughtered (28.3%), those unpackaged (45.1%) was more likely to be contaminated with Salmonella than those packaged (37.4%). The present study revealed the widely prevalent Salmonella contamination among retail carcasses, indicating a strong potential of the cross-contamination occurred before and/or at the retail level. The study also provided quantitative data for a risk assessment evaluating potential intervention methods to reduce the risk of salmonellosis by consuming chicken meat of Chinese origin.

Prevalence of salmonella infection in dogs in maiduguri, northeastern Nigeria.

The prevalence and antimicrobial sensitivity of Salmonella from dogs in Maiduguri Metropolis were determined using standard bacteriological methods to assess the risk of possible transmission of Salmonella infection from dogs to humans. Of 119 samples, Salmonella was isolated from 52 (43.7%). Males had higher prevalence of 50.0% compared with 34.7% in females (P < 0.05). Dogs older than 24 months had higher prevalence of 61.0% and the lowest was seen in dogs aged 13–24 months (P < 0.05). The prevalence of 31.8%, 41.2%, and 58.8% was observed in dogs aged 3–6, 10–12, and 7–9 months, respectively. High prevalence of 49.5% was observed in Mongrels, while Terrier and Alsatian breeds had 30.0% and 8.3%, respectively. Salmonella isolates from Alsatian and Terrier breeds showed about 100% susceptibility to all the tested antimicrobials. Higher percentage of the Salmonella isolates from Mongrels also showed susceptibility to ciprofloxacin (89.7%), amoxicillin (87.6%), vancomycin (86.6%), and chloramphenicol (84.5%). However about 50% of these isolates showed resistance to ofloxacin. The carrier status of Salmonella is high among dogs especially Mongrels. Therefore good environmental hygiene, discouraging straying coupled with feeding of dogs with properly cooked and uncontaminated feeds was recommended to mitigate risk of human salmonellosis.

NADPH Oxidase Deficient Mice Develop Colitis and Bacteremia upon Infection with Normally Avirulent, TTSS-1- and TTSS-2-Deficient Salmonella Typhimurium

Infections, microbe sampling and occasional leakage of commensal microbiota and their products across the intestinal epithelial cell layer represent a permanent challenge to the intestinal immune system. The production of reactive oxygen species by NADPH oxidase is thought to be a key element of defense. Patients suffering from chronic granulomatous disease are deficient in one of the subunits of NADPH oxidase. They display a high incidence of Crohn’s disease-like intestinal inflammation and are hyper-susceptible to infection with fungi and bacteria, including a 10-fold increased risk of Salmonellosis. It is not completely understood which steps of the infection process are affected by the NADPH oxidase deficiency. We employed a mouse model for Salmonella diarrhea to study how NADPH oxidase deficiency (Cybb −/−) affects microbe handling by the large intestinal mucosa. In this animal model, wild type S. Typhimurium causes pronounced enteropathy in wild type mice. In contrast, an avirulent S. Typhimurium mutant (S.Tmavir; invGsseD), which lacks virulence factors boosting trans-epithelial penetration and growth in the lamina propria, cannot cause enteropathy in wild type mice. We found that Cybb −/− mice are efficiently infected by S.Tmavir and develop enteropathy by day 4 post infection. Cell depletion experiments and infections in Cybb −/− Myd88 −/− mice indicated that the S.Tmavir-inflicted disease in Cybb −/− mice hinges on CD11c+CX3CR1+ monocytic phagocytes mediating colonization of the cecal lamina propria and on Myd88-dependent proinflammatory immune responses. Interestingly, in mixed bone marrow chimeras a partial reconstitution of Cybb-proficiency in the bone marrow derived compartment was sufficient to ameliorate disease severity. Our data indicate that NADPH oxidase expression is of key importance for restricting the growth of S.Tmavir in the mucosal lamina propria. This provides important insights into microbe handling by the large intestinal mucosa and the role of NADPH oxidase in maintaining microbe-host mutualism at this exposed body surface.

Environmental Salmonella in Agricultural Fair Poultry Exhibits in Colorado

Salmonella enterica is a common zoonotic pathogen in humans. Transmission typically occurs through consumption of contaminated food products or contact with infected animals, including poultry or their environment. The objective of this study was to estimate the frequency of Salmonella contamination in the environment in poultry exhibits at agricultural fairs. Samples were collected from cages, feed, floors and tables in the exhibit and cultured for Salmonella. At least one environmental sample was positive for Salmonella in 10 of 11 fairs (91%), and Salmonella was isolated from 28 of 55 environmental samples (50.9%). Eleven different serotypes were detected. Results of this study demonstrate that environmental surfaces at agricultural fairs can be contaminated with Salmonella and could potentially serve as a route of transmission to bird owners and the general public. Poultry owners and the general public should be educated about the risks of Salmonella infection from the poultry exhibit environment. Agricultural fairs should consider instituting policies and practices to improve hygiene and mitigate the risk of zoonotic salmonellosis.

Preventing Foodborne Illness: Salmonellosis

In 2007, there were over 1 million cases and some 400 deaths associated with Salmonella-contaminated food. In 2004, it was estimated that the total economic burden caused by Salmonella infection in the United States was $1.6–$5.3 billion. Food handlers, processors, and retailers can minimize the risk of salmonellosis by using good food handling practices. This 6-page fact sheet was written by Keith R. Schneider, Renée Goodrich Schneider, Michael A. Hubbard, and Susanna Richardson, and published by the UF Department of Food Science and Human Nutrition, March 2013.&#x0D; http://edis.ifas.ufl.edu/fs096

Risk assessment strategies as a tool in the application of the Appropriate Level of Protection (ALOP) and Food Safety Objective (FSO) by risk managers

In the course of the last decade, the Appropriate Level of Protection (ALOP), the Food Safety Objective (FSO) and their associated metrics have been proposed by the World Trade Organization and Codex Alimentarius as a means for competent authorities to ultimately translate governmental public health policy regarding food safety into risk-based targets for the food industry. The industry needs to meet these targets through the effective choice of control measures that are part of its operational food safety management system. The aim of this study was to put the practical application of ALOP and FSO to the test in the case of Salmonella in chicken meat in the Netherlands. Two different risk assessment approaches were applied to derive potential ALOP and FSO values, a ‘top-down’ approach based on epidemiological data and a ‘bottom-up’ approach based on food supply chain data. To this end, two stochastic models specific to the Dutch situation were built. Comparisons between 23 countries in Europe were also made using the top-down model. The mean estimated current Level Of Protection values were similar for the two approaches applied, with the bottom-up model yielding 87 cases per 100,000 inhabitants per year (95% CI: 0.03, 904) and the top-down model 71 (95% CI: 9.9, 155). The estimated FSO values on the other hand were considerably different with the mean ‘top down’ FSO being −4.6 log CFU/g (95% CI: −5.4, −4.1) and the mean ‘bottom-up’ FSO −6.0 log CFU/g (95% CI: −8.1, −2.9) reflecting major differences in the output distributions of this parameter obtained with the two approaches. Significant differences were observed between current LOP values for different EU countries, although it was not clear whether this was due to actual differences in the factors influencing the risk of salmonellosis or due to the quality of the available data.

Epidemiology of Infant Salmonellosis in the United States, 1996-2008: A Foodborne Diseases Active Surveillance Network Study.

Infants have increased risk for salmonellosis; but epidemiologic information is limited. We reviewed Foodborne Diseases Active Surveillance Network reports of laboratory-confirmed non-Typhi Salmonella infections in infants from 1996-2008. We calculated incidence, estimated relative risks, and assessed trends over the duration of the study period, using the first 3 years as reference. Average annual incidence of salmonellosis per 100 000 infants was 177.8 (95% confidence interval [CI], 152.7-202.8) in blacks, 129.7 (95% CI, 94.8-164.7) in Asians, and 81.1 (95% CI, 70.2-92.0) in whites. Our analysis of ethnicity independent of race showed salmonellosis incidence of 86.7 (95% CI, 74.6-98.9) in Hispanics and 69.4 (95% CI, 54.8-84.1) in non-Hispanics. Salmonellosis was invasive more often in blacks (9.4%) and Asians (6.4%) than whites (3.6%, P <.001 and P = .01, respectively). Asian infants with salmonellosis were older (median, 31 weeks [range, 0-52]) than black (24 weeks [range, 0-52], P < .001) or white infants (23 weeks [range, 0-52], P < .001). Incidence of all salmonellosis remained stable for whites from 1996-1998 through 2008, but blacks had a sustained decrease, with relative risk of 0.48 (95% CI, .37-.63) in 2008 compared with 1996-1998. However, 2008 incidence remained highest among blacks (141.0 of 100 000 vs 113.5 of 100 000 among whites and 109.9 of 100 000 among Asians). Black infants had a greater risk of salmonellosis and invasive disease than other racial groups, and despite the greatest decrease in incidence over the study period, they continued to have the highest incidence of salmonellosis. The decrease in salmonellosis in black infants suggests that future improvements may be possible for other population subgroups.

Salmonella colonization activates the plant immune system and benefits from association with plant pathogenic bacteria

Despite increasing incidences of human salmonellosis caused by consumption of contaminated vegetables, relatively little is known about how the plant immune system responds to and may inhibit Salmonella colonization. Here we show that Salmonella Typhimurium activates the plant immune system primarily due to its recognition of the flg22 region in Salmonella flagellin. Several previously identified plant genes that play a role in immunity were found to affect the host response to Salmonella. The Salmonella flg22 (Seflg22) peptide induced the immune response in leaves which effectively restricted the growth of Salmonella as well as the plant pathogenic bacterium, Pseudomonas syringae pv. tomato. Induction of immune responses by Seflg22 was dependent on the plant FLS2 receptor. Salmonella multiplied poorly on plant tissues similar to other bacteria which are non-pathogenic to plants. However, Salmonella populations increased significantly when co-inoculated with P. syringae pv. tomato but not when co-inoculated with a type III secretion system mutant of this pathogen. Our results suggest that Salmonella benefits from the immune-suppressing effects of plant pathogenic bacteria, and this growth enhancement may increase the risk of salmonellosis.

Review of Canadian Literature to Estimate Risks Associated with Salmonella in Broilers from Retail to Consumption in Canadian Homes

The objective was to review the literature related to the risk of salmonellosis from chicken consumed in private homes in Canada. The pathway of concern was retail-to-consumption at private homes due to the direct link between this pathway and public health. A qualitative review was conducted by searching Canadian governmental agencies' webpages, published peer-reviewed journals, and by contacting experts in the field. Overall, with the data available, estimating risk from Salmonella in chicken breasts using only Canadian information was limited. Enumeration data for Salmonella in retail raw chicken at different regions across Canada are needed to be able to generalize the risk of salmonellosis in the Canadian population. Few Canadian surveys were found to describe consumers' food safety behaviors at Canadians' private homes. Observational designs to study food safety practices and Canadian consumers' behavior in private kitchens are needed to ensure that consumer behavior is consistent with consumer perceptions of their behavior. The results of such studies will give valuable input for designing educational programs needed to increase awareness of safe food handling practices by Canadian consumers when preparing food at their homes.

English

Susceptibility of 45&nbsp;Salmonella&nbsp;spp. strains isolated from beef and beef and chicken hamburgers was evaluated. Twelve antimicrobial drugs were used in the disc diffusion method. A cladogram was constructed and similarity across strains was assessed. Strains were susceptible to co-trimoxazole, chloramphenicol, amikacin, tetracycline and gentamicin (91.11, 91.11, 84.44, 80.0, 77.78%), though resistance was detected against cefotaxime, ampicilin, cephalothin, ceftriaxone, cefotixin, ceftazidime, and aztreonam (88.89, 71.11, 68.89, 53.33, 48.89, 42.22, 35.56%). The least effective antimicrobial drug was cefotaxime (88.89%). A high percentage of multiresistant&nbsp;Salmonella&nbsp;spp. strains was observed. This raises concerns as to the high risk for salmonellosis in humans, when these food items are consumed underdone, or by cross-contamination during preparation. Another important aspect in terms of public health is that these infections may become even more severe due to&nbsp;the&nbsp;lower efficacy of antimicrobials in treatments, both in humans and animals. &nbsp; Key words:&nbsp;Resistance,&nbsp;susceptibility,&nbsp;antimicrobial,&nbsp;Salmonella,&nbsp;hamburger,&nbsp;cladogram.

Risk Factors for Salmonella Gastroenteritis in Children Less Than Five Years of Age in Taiwan

Nontyphoid Salmonella spp. have been among the most common pathogens of acute gastroenteritis in children in Taiwan. However, the principal sources of transmission remain poorly defined. A matched case-control study was conducted from January 2009 to October 2010. Cases were children aged 2-60 months who were hospitalized at 3 medical centers in Taiwan because of diarrhea and found to have culture-proven nontyphoidal Salmonella infection. Controls were healthy children or children with acute diseases other than gastroenteritis and matched to cases by age, gender, study site and enrollment date. A total of 396 cases and 930 matched controls were included for analysis. Multivariate analysis using conditional logistic regression identified contact with household members having diarrhea (matched odds ratio [mOR], 17.9; 95% confidence interval [CI]: 8.82-36.34; P < 0.0001), consumption of instant powdered milk (mOR, 2.04; 95% CI: 1.05-3.94; P = 0.0344), visits to health-care facilities (mOR, 1.66; 95% CI: 1.12-2.48; P = 0.0126) and consumption of purchased groundwater (mOR, 1.50; 95% CI: 1.06-2.11; P = 0.0214) within 1 week preceding enrollment as independent factors associated with increased risk of salmonellosis. Hand washing before meals (P = 0.0311), breastfeeding (P = 0.0370), consumption of chicken (P = 0.0019) and consumption of food prepared by caregivers (P = 0.0011) were protective against Salmonella infection. The principal transmission routes of Salmonella infection in Taiwanese children are person-to-person, waterborne and environmental contacts. The possibility of powdered milk and groundwater contamination of Salmonella cannot be excluded and requires further investigation.

Immunogenicity of Salmonella enterica serovar Enteritidis virulence protein, InvH, and cross-reactivity of its antisera with Salmonella strains

Acellular vaccines containing bacterial immunodominant components such as surface proteins may be potent alternatives to live attenuated vaccines in order to reduce salmonellosis risk to human health. invH gene, an important part of needle complex in type three secretion system (TTSS) plays important role in efficient bacterial adherence and entry into epithelial cells. In this work we hypothesize that use of a 15kDa recombinant InvH as Salmonella enterica serovar Enteritidis surface protein could provoke antibody production in mouse and would help us study feasibility of its potential for diagnosis and/or a recombinant vaccine. The purified InvH provoked significant rise of IgG in mice. Active protection induced by immunization with InvH against variable doses of S. enterica serovar Enteritidis, indicated that the immunized mice were completely protected against challenge with 104 LD50. The immunoreaction of sera from immunized mice with other Salmonella strains or cross reaction with sera of Salmonella strains inoculated mice is indicative of possessing by Salmonella strains of the surface protein, InvH, that can be employed in both prophylactic and diagnostic measures against S. enterica. Bacteria free spleen and ileum of the immunized mice in this study indicate that the invH gene affects bacterial invasion. Efficacy of the virulence protein, InvH, in shuttling into host cells in injectisome of S. enterica serovar Enteritidis and inhibition of this phenomenon by active immunization was shown in this study. In conclusion immunization with InvH protein can develop protection against S. enterica serovar Enteritidis infections. InvH in Salmonella strains can be exploited in protective measures as well as a diagnostic tool in Salmonella infections.

Quantitative Risk Assessment of Human Salmonellosis in Canadian Broiler Chicken Breast from Retail to Consumption

The current quantitative risk assessment model followed the framework proposed by the Codex Alimentarius to provide an estimate of the risk of human salmonellosis due to consumption of chicken breasts which were bought from Canadian retail stores and prepared in Canadian domestic kitchens. The model simulated the level of Salmonella contamination on chicken breasts throughout the retail-to-table pathway. The model used Canadian input parameter values, where available, to represent risk of salmonellosis. From retail until consumption, changes in the concentration of Salmonella on each chicken breast were modeled using equations for growth and inactivation. The model predicted an average of 318 cases of salmonellosis per 100,000 consumers per year. Potential reasons for this overestimation were discussed. A sensitivity analysis showed that concentration of Salmonella on chicken breasts at retail and food hygienic practices in private kitchens such as cross-contamination due to not washing cutting boards (or utensils) and hands after handling raw meat along with inadequate cooking contributed most significantly to the risk of human salmonellosis. The outcome from this model emphasizes that responsibility for protection from Salmonella hazard on chicken breasts is a shared responsibility. Data needed for a comprehensive Canadian Salmonella risk assessment were identified for future research.

Effect of Farm Type on Within-Herd Salmonella Prevalence, Serovar Distribution, and Antimicrobial Resistance

Salmonella represents a major challenge to the pig industry, as pork presents a risk for human salmonellosis. In this study, we have examined the effect of farm type on the prevalence of fattening pigs shedding Salmonella on 12 farms at risk for harboring Salmonella. On six open (grow-to-finish) and six closed (farrow-to-finish) farms, the prevalence of pigs shedding Salmonella was determined on two occasions approximately 2 months apart. The serovar, phage type, and antimicrobial resistance of the obtained Salmonella isolates were determined. On all farms, pigs shedding Salmonella were detected on at least one of the two sampling days. The mean within-herd prevalence was 7.8%. Closed farms were two times less likely to have pigs shedding Salmonella than open farms. On open farms, the odds of finding Salmonella shedding in pigs were 1.9 times higher when sampling was performed at slaughter age than when samples were taken halfway through the fattening period. Salmonella enterica serovar Typhimurium was the most predominant serotype, with a prevalence of 62 to 63% on both farm types. Of all the Salmonella Typhimurium isolates, 65% had the tetraresistant profile ASSuT (ampicillin, streptomycin, sulfonamide, and tetracycline) with or without additional resistance to trimethoprim-sulfonamide. Phage type DT120 seemed to be especially associated with this antimicrobial-resistant profile. The prevalence of Salmonella Typhimurium isolates showing resistance to ampicillin, streptomycin, tetracycline, sulfonamide, trimethoprim-sulfonamide, and lincomycin hydrochloride and spectinomycin sulfate tetrahydrate was significantly higher on open farms than on closed farms.

A Risk Assessment of Campylobacteriosis and Salmonellosis Linked to Chicken Meals Prepared in Households in Dakar, Senegal

We used a quantitative microbiological risk assessment model to describe the risk of Campylobacter and Salmonella infection linked to chicken meals prepared in households in Dakar, Senegal. The model uses data collected specifically for this study, such as the prevalence and level of bacteria on the neck skin of chickens bought in Dakar markets, time-temperature profiles recorded from purchase to consumption, an observational survey of meal preparation in private kitchens, and detection and enumeration of pathogens on kitchenware and cooks' hands. Thorough heating kills all bacteria present on chicken during cooking, but cross-contamination of cooked chicken or ready-to-eat food prepared for the meal via kitchenware and cooks' hands leads to a high expected frequency of pathogen ingestion. Additionally, significant growth of Salmonella is predicted during food storage at ambient temperature before and after meal preparation. These high exposures lead to a high estimated risk of campylobacteriosis and/or salmonellosis in Dakar households. The public health consequences could be amplified by the high level of antimicrobial resistance of Salmonella and Campylobacter observed in this setting. A significant decrease in the number of ingested bacteria and in the risk could be achieved through a reduction of the prevalence of chicken contamination at slaughter, and by the use of simple hygienic measures in the kitchen. There is an urgent need to reinforce the hygiene education of food handlers in Senegal.

Distribution of Salmonella serovars and antimicrobial susceptibility of Salmonella Enteritidis from poultry in Zimbabwe

A study was carried out to determine the distribution and antimicrobial susceptibility profiles of Salmonella serovars from chickens from large-scale commercial (LSC), small-scale commercial (SSC), and rural free-range (RFR) farms of Zimbabwe. Pooled cloacal swabs were collected for culture and isolation of Salmonella spp. A chi-square test was used to assess distribution differences of salmonellas among the farming sectors. Approximately 10% (283/2833) of the swabs were positive for Salmonella enterica, with only subspecies enterica (98.6%) and arizonae (1.4%) being detected. The prevalence of S. enterica varied significantly (P<0.05) among areas, with Harare (27.8%) and Buhera (1.3%) recording the highest and the least prevalence, respectively. S. enterica was only isolated from LSC and SSC farms, with the former having a significantly (P<0.001; χ2=155.3) higher prevalence than the latter. S. arizonae was only isolated from the SSC farms while none were obtained from the RFR farms. The serovars isolated were Salmonella Enteritidis (72.8%), Group C (20.1%), Group B (4.2%), Salmonella Typhimurium (1.1%) and Salmonella Gallinarum (0.4%). S. Enteritidis predominated in the urban/periurban areas. Approximately 26% (53/206) of S. Enteritidis isolates were resistant to one or more antimicrobial agents. Resistance to tetracycline was the most common, while no resistance was detected for furazolidone, neomycin and trimethoprim-sulfamethoxazole. There were 12.1% multi-drug-resistant S. Enteritidis isolates, and the resistance to ampicillin/kanamycin was predominant. The identification of multi-drug-resistant S. Enteritidis is of public health concern. Thus, stringent control of S. Enteritidis will reduce the public health risk of human salmonellosis.

Salmonellosis and charter tourism: epidemiology and trends of imported human cases to Norway from the Canary Islands and Thailand, 1994–2008

More than 70% of reported human Salmonella infections in Norway are infected abroad. The Canary Islands and Thailand are two of the most popular charter tourist destinations for Norwegians. Using surveillance data for the years 1994-2008, and denominator data on travel to the Canary Islands 2000-2008 and to Thailand 1997-2008, we present the epidemiology and trends of Salmonella infections in Norwegian tourists to these destinations. We found a declining trend in risk of salmonellosis in tourists returning from the Canary Islands, and a change in serovar distribution in travellers to Thailand with more S. Enteritidis infections, similar to that observed in Western European countries. The use of denominator data is important when studying risk of travel-related disease, as surveillance data tend to reflect travel activity more than the risk. Infections among tourists do not always affect the local residents and therefore may not be detected by local public health authorities. Sharing knowledge on the epidemiology of infections in tourists could be useful for observation of changes in trends in the countries visited, and in future outbreak investigations.