Enteropathogens associated with childhood diarrhea in Italy. The Italian Study Group on Gastrointestinal Infections

Evaluation of Fecal Inflammatory Biomarkers to Identify Bacterial Diarrhea Episodes: Systematic Review and Protocol for the Enterics for Global Health Shigella Surveillance Study

Background

The measurement of fecal inflammatory biomarkers among individuals presenting to care with diarrhea could improve the identification of bacterial diarrheal episodes that would benefit from antibiotic therapy. We reviewed prior literature in this area and describe our proposed methods to evaluate 4 biomarkers in the Enterics for Global Health (EFGH) Shigella surveillance study.

Methods

We systematically reviewed studies since 1970 from PubMed and Embase that assessed the diagnostic characteristics of inflammatory biomarkers to identify bacterial diarrhea episodes. We extracted sensitivity and specificity and summarized the evidence by biomarker and diarrhea etiology. In EFGH, we propose using commercial enzyme-linked immunosorbent assays to test for myeloperoxidase, calprotectin, lipocalin-2, and hemoglobin in stored whole stool samples collected within 24 hours of enrollment from participants in the Bangladesh, Kenya, Malawi, Pakistan, Peru, and The Gambia sites. We will develop clinical prediction scores that incorporate the inflammatory biomarkers and evaluate their ability to identify Shigella and other bacterial etiologies of diarrhea as determined by quantitative polymerase chain reaction (qPCR).

Results

Forty-nine studies that assessed fecal leukocytes (n = 39), red blood cells (n = 26), lactoferrin (n = 13), calprotectin (n = 8), and myeloperoxidase (n = 1) were included in the systematic review. Sensitivities were high for identifying Shigella, moderate for identifying any bacteria, and comparable across biomarkers. Specificities varied depending on the outcomes assessed. Prior studies were generally small, identified red and white blood cells by microscopy, and used insensitive gold standard diagnostics, such as conventional bacteriological culture for pathogen detection.

Conclusions

Our evaluation of inflammatory biomarkers to distinguish diarrhea etiologies as determined by qPCR will provide an important addition to the prior literature, which was likely biased by the limited sensitivity of the gold standard diagnostics used. We will determine whether point-of-care biomarker tests could be a viable strategy to inform treatment decision making and increase appropriate targeting of antibiotic treatment to bacterial diarrhea episodes.

Human milk glycosaminoglycans inhibit in vitro the adhesion of Escherichia coli and Salmonella fyris to human intestinal cells

BACKGROUND

Breast-fed infants have a lower incidence of acute gastroenteritis due to the presence of several anti-infective factors in human milk. The aim of this work is to study the capacity of human milk glycosaminoglycans (GAGs) to inhibit the adhesion of some common pathogenic bacteria.

METHODS

GAGs were isolated from a pool of milk samples collected from different mothers during the first month of lactation. Experiments were carried out to study the ability of GAGs to inhibit the adhesion of two intestinal micro-organisms (enteropathogenic Escherichia coli serotype 0119 and Salmonella fyris) to Caco-2 and Int-407 cell lines.

RESULTS

The study showed that the GAGs had an anti-adhesive effect on the two pathogenic strains studied with different degrees of inhibition. In particular, in the presence of human milk GAGs, the adhesion of S. fyris to Caco-2 cells and to Int-407 cells of both tested strains was significantly reduced.

CONCLUSION

Our results demonstrated that GAGs in human milk can be one of the important defensive factors against acute diarrheal infections in breast-fed infants.

Enteric Bacteria Isolated from Diarrheal Patients in Korea in 2014

OBJECTIVES

The aim of this study was to characterize the pathogens responsible for causing diarrhea according to season, region of isolation, patient age, and sex as well as to provide useful data for the prevention of diarrheal disease.

METHODS

Stool specimens from 14,886 patients with diarrhea were collected to identify pathogenic bacteria from January 2014 to December 2014 in Korea. A total of 3,526 pathogenic bacteria were isolated and analyzed according to season, region of isolation, and the age and sex of the patient.

RESULTS

The breakdown of the isolated pathogenic bacteria were as follows: Salmonella spp. 476 (13.5%), pathogenic Escherichia coli 777 (22.0%), Vibrio parahaemolyticus 26 (0.74%), Shigella spp. 13 (0.37%), Campylobacter spp. 215 (6.10%), Clostridium perfringens 508 (14.4%), Staphylococcus aureus 1,144 (32.4%), Bacillus cereus 356 (10.1%), Listeria monocytogenes 1 (0.03%), and Yersinia enterocolitica 10 (0.3%). The isolation rate trend showed the highest ratio in the summer season from June to September for most of the pathogenic bacteria except the Gram-positive bacteria. The isolation rate of most of the pathogenic bacteria by patient age showed highest ratio in the 0-19 year age range. For isolation rate by region, 56.2% were isolated from cities and 43.8% were isolated from provinces.

CONCLUSION

Hygiene education should be addressed for diarrheal disease-susceptible groups, such as those younger than 10 years, aged 10-19 years, and older than 70 years, and monitoring for the pathogens is still required. In addition, an efficient laboratory surveillance system for infection control should be continued.

Community based case-control study of rotavirus gastroenteritis among young children during 2008-2010 reveals vast genetic diversity and increased prevalence of G9 strains in Kolkata

BACKGROUND

Group A Rotaviruses are a major etiologic agent of gastroenteritis in infants and young children (<5 years) worldwide. Although rotavirus vaccines have been successfully administered in many countries, in India the introduction of rotavirus vaccine in national immunization program was approved in 2014. Since high disease burden and large number of genetic variants have been reported from low income countries including India, monitoring of rotavirus was initiated prior to implementation of the vaccine in the region.

METHODS

A total number of 3,582 stool samples were collected from an urban slum community in Kolkata, among which 1,568 samples were obtained from children of ≤ 5 years of age, with moderate to severe diarrhoea and 2,014 samples were collected from age-sex matched healthy neighbourhood controls. Rotavirus positive samples were typed by multiplex semi-nested PCR and nucleotide sequencing. Circulating strains were phylogenetically analyzed.

RESULTS

Among 1,568 children with diarrhoea, 395 (25.2%), and among 2,014 asymptomatic children, 42 (2%) were rotavirus positive. G1P[8] was identified as the most common strain (32%) followed by G9P[8] (16.9%), G2P[4] (13.5%) and G9P[4] (10.75%). G12 strains with combinations of P[4], P[6] and P[8] comprised 11.9% of total positive strains. The rest (<10%) were rare and uncommon strains like G1P[4], G1P[6], G2P[8] and animal-like strains G4P[6], G6P[14] and G11P[25]. The 42 rotavirus positive samples from asymptomatic children revealed common genotypes like G1, G2 and G9.

CONCLUSION

This community based case-control study showed increased predominance of genotype G9 in Kolkata. It also confirmed co-circulation of a large number of genetic variants in the community. Asymptomatic rotavirus positive children though low in number can also be a source of dispersal of infection in the community. This study provides background information to the policy makers for implementation of rotavirus vaccines in this region.

Preponderance of toxigenic Escherichia coli in stool pathogens correlates with toxin detection in accessible drinking-water sources

Since early detection of pathogens and their virulence factors contribute to intervention and control strategies, we assessed the enteropathogens in diarrhoea disease and investigated the link between toxigenic strains of Escherichia coli from stool and drinking-water sources; and determined the expression of toxin genes by antibiotic-resistant E. coli in Lagos, Nigeria. This was compared with isolates from diarrhoeal stool and water from Wisconsin, USA. The new Luminex xTAG GPP (Gastroplex) technique and conventional real-time PCR were used to profile enteric pathogens and E. coli toxin gene isolates, respectively. Results showed the pathogen profile of stool and indicated a relationship between E. coli toxin genes in water and stool from Lagos which was absent in Wisconsin isolates. The Gastroplex technique was efficient for multiple enteric pathogens and toxin gene detection. The co-existence of antibiotic resistance with enteroinvasive E. coli toxin genes suggests an additional prognostic burden on patients.

Differential yield of pathogens from stool testing of nosocomial versus community-acquired paediatric diarrhea

OBJECTIVES

To evaluate the role of routine stool examination for all pathogens in paediatric nosocomial diarrhea (NAD) and community-acquired diarrhea (CAD) over a two-year period at Alberta Children's Hospital and current practices in other Canadian hospitals. A secondary objective was to characterize features that may predict NAD or CAD etiology.

STUDY DESIGN

Retrospective cohort study and telephone survey.

SETTING

Alberta Children's Hospital (retrospective review) and Canadian tertiary care paediatric centres (telephone survey).

METHODS

The health and microbiological records of all children with an admission or discharge diagnosis of diarrhea were reviewed using a standardized data collection form. In addition, a telephone survey of laboratories serving all paediatric hospitals in Canada was conducted using a standard questionnaire to obtain information about practices for screening for pathogens related to NAD.

RESULTS

Four hundred and thirty-four CAD episodes and 89 NAD episodes were identified. Overall, rotavirus and Clostridium difficile were the most commonly identified pathogens. Bacterial culture was positive in 10.6% CAD episodes tested, with Escherichia coli O157:H7 identified as the most common non-C difficile organism. In NAD, no bacteria were identified other than C difficile (toxin). Screening for ova and parasites had negligible yield. Viruses were more frequent in the winter months, while bacterial pathogens were more common in the summer and fall months. Over 50% of Canadian paediatric hospitals still routinely process NAD specimens similarly to CAD specimens.

CONCLUSIONS

There is a need for the re-evaluation of routine ova and parasite screening, and bacterial culture in nonoutbreak episodes of NAD in children.

First description of Adenovirus, Enterovirus, Rotavirus and Torque teno virus in water samples collected from the Arroio Dilúvio, Porto Alegre, Brazil

Adenovirus (AdV), enterovirus (EV), genogroup A rotaviruses (GARV) and Torque teno virus (TTV) are non-enveloped viral agents excreted in feces and so may contaminate water bodies. In the present study, the molecular detection of these viruses was performed in samples of surface water collected from the Arroio Dilúvio, a waterstream that crosses the city of Porto Alegre, RS, Brazil, receiving great volumes of non-treated sewage from a large urban area. Sampling was performed during 2009, in three different occasions (January, April and September). The highest detection rate was observed for EV (64.28%), followed by TTV (28.57%) and AdV (21.43%). Rotaviruses were not detected. More than on kind of tested virus was detected in five (35. 71%) of 14 samples. January was the month with the highest viral detection rate, being all samples, collected in this month, positive for at least one group of tested virus. The correlation between the detection of these different viral agents and environmental factors is discussed. To the knowledge of the authors, this is the first description of viral genomes in water samples taken from the Arroio Dilúvio, Porto Alegre (Brazil).

Randomised clinical trial: efficacy of a new synbiotic formulation containing Lactobacillus paracasei B21060 plus arabinogalactan and xilooligosaccharides in children with acute diarrhoea

BACKGROUND

Acute diarrhoea is a frequent problem in children with heavy economic burden for families and society.

AIM

To test the efficacy of a new synbiotic formulation containing Lactobacillus paracasei B21060, arabinogalactan and xilooligosaccharides in children with acute diarrhoea.

METHODS

Double-blind, randomised, placebo-controlled trial, including children (age 3-36 m) with acute diarrhoea who were allocated to placebo or synbiotic group. Major outcome was resolution rate of diarrhoea at 72 h. Total duration of diarrhoea, daily stool outputs, stool consistency, working days lost by parents, adjunctive medications, and hospitalisation were also assessed.

RESULTS

We enrolled 55 children in placebo group and 52 in synbiotic group. The two groups were similar for demographic and clinical characteristics. Resolution rate of diarrhoea at 72 h was significantly higher in synbiotic group (67%) compared to placebo group (40%, P = 0.005). Children in synbiotic group showed a significant reduction in the duration of diarrhoea (90.5 h, 78.1-102.9 vs. 109.8 h, 96.0-123.5, P = 0.040), daily stool outputs (3.3, 2.8-3.8 vs. 2.4, 1.9-2.8, P = 0.005) and stool consistency (1.3, 0.9-1.6 vs. 0.6, 0.4-0.9, P = 0.002) compared to placebo group (data expressed as mean, 95% CI). Rate of parents that missed at least one working day (41.8% vs. 15.4%, P = 0.003), rate of children that needed adjunctive medications (25.5% vs. 5.8%, P = 0.005) or hospitalisation (10.9% vs. 0%, P = 0.014) after the first 72 h of treatment, were reduced in synbiotic group.

CONCLUSION

The synbiotic formulation studied is effective in children with acute diarrhoea. Australian New Zealand Clinical Trials Registry (ACTRN12611000641998).

Global distribution, public health and clinical impact of the protozoan pathogen cryptosporidium

Cryptosporidium spp. are coccidians, oocysts-forming apicomplexan protozoa, which complete their life cycle both in humans and animals, through zoonotic and anthroponotic transmission, causing cryptosporidiosis. The global burden of this disease is still underascertained, due to a conundrum transmission modality, only partially unveiled, and on a plethora of detection systems still inadequate or only partially applied for worldwide surveillance. In children, cryptosporidiosis encumber is even less recorded and often misidentified due to physiological reasons such as early-age unpaired immunological response. Furthermore, malnutrition in underdeveloped countries or clinical underestimation of protozoan etiology in developed countries contribute to the underestimation of the worldwide burden. Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc.) and host determinants of the infection (e.g., age, immunological status, travels, community behaviours). The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems. The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis.

Acute gastroenteritis in Hong Kong: a population-based telephone survey

A population-based telephone survey of acute gastroenteritis (AG) was conducted in Hong Kong from August 2006 to July 2007. Study subjects were recruited through random digit-dialing with recruitments evenly distributed weekly over the 1-year period. In total, 3743 completed questionnaires were obtained. An AG episode is defined as diarrhoea >or=3 times or any vomiting in a 24-h period during the 4 weeks prior to interview, in the absence of known non-infectious causes. The prevalence of AG reporting was 7%. An overall rate of 0.91 (95% CI 0.81-1.01) episodes per person-year was observed with women having a slightly higher rate (0.94, 95% CI 0.79-1.08) than men (0.88, 95% CI 0.73-1.04). The mean duration of illness was 3.6 days (S.D.=5.52). Thirty-nine percent consulted a physician, 1.9% submitted a stool sample for testing, and 2.6% were admitted to hospital. Of the subjects aged >or=15 years, significantly more of those with AG reported eating raw oysters (OR 2.4, 95% CI 1.3-4.4), buffet meals (OR 1.8, 95% CI 1.3-2.5), and partially cooked beef (OR 1.8, 95% CI 1.2-2.7) in the previous 4 weeks compared to the subjects who did not report AG. AG subjects were also more likely to have had hot pot, salad, partially cooked or raw egg or fish, sushi, sashimi, and 'snacks bought at roadside' in the previous 4 weeks. This first population-based study on the disease burden of AG in Asia showed that the prevalence of AG in Hong Kong is comparable to that experienced in the West. The study also revealed some 'risky' eating practices that are more prevalent in those affected with AG.

Estimated mortality and hospital admission due to rotavirus infection in the WHO European region

In 2006 two rotavirus vaccines were licensed for use in young children in Europe. This study aimed to estimate the mortality and hospital admissions due to rotavirus in children aged <5 years in the WHO European region using data from routine sources and published literature. We grouped 49/52 countries in the region by their World Bank Gross National Income (GNI) per capita. We obtained for children aged <5 years: populations, hospital discharges for diarrhoeal disease, estimated mortality rates and the percentage of deaths attributable to diarrhoeal disease, from WHO data sources or published literature, and combined them to estimate country-specific diarrhoeal disease mortality. Rotavirus-attributable percentages of hospital admissions due to diarrhoeal disease were obtained through a literature search, and an income-group median applied to countries in each GNI category. In the countries we studied in the WHO European region, rotavirus infection causes an estimated 6550 deaths (range 5671–8989) and 146 287 (range 38 374–1 039 843) hospital admissions each year in children aged <5 years. Hospital admission rates were similar across income groups (medians 2·0, 2·8, 4·2 and 1·9/1000 per year in low-, lower-middle-, upper-middle- and high-income countries, respectively). Seven countries, mostly in the low- and lower-middle-income groups, accounted for 93% of estimated deaths. Disease burden varied dramatically by income level in the European region. Rotavirus vaccination in Azerbaijan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan and Turkey could potentially prevent 80% of all regional rotavirus deaths. Data from low-income countries is still sparse, and improved disease burden studies are required to better inform regional vaccine policy.

Enteric bacteria isolated from acute diarrheal patients in the Republic of Korea between the year 2004 and 2006

In an epidemiological survey of human enterobacterial infections in the Republic of Korea during three years from 2004 to 2006, we isolated 1,784 (6.2%, isolation rate of enteropathogens from stool samples) in 2004, 2,547 (9.5%) in 2005 and 3,506 bacteria (12.3%) from people who visited clinics. Among the isolated bacteria, pathogenic Escherichia coli, especially, EAEC was the most frequently identified pathogen in both urban and rural regions followed by Staphylococcus aureus, Salmonella species, Bacillus cereus, Vibrio parahaemolyticus, Campylobacter jejuni, Clostridium perfringens, and Shigella species. Distinct seasonality was found in V. parahaemolyticus species, while this pathogen showed no age-specific patterns. However, other bacteria, i.e., pathogenic E. coli, S. aureus, Salmonella spp., and B. cereus showed similar seasonality throughout the year, showing a slight increase in the infection rate during the summer months and high prevalence among children under 10 years of age and elder-age people. The antibiotic susceptibility patterns of pathogenic E. coli, Salmonella spp., and S. aureus showed high resistance to penicillins. However, both pathogenic E. coli and Salmonella spp. were susceptible to several cephems, imipenem, and amikacin. Moreover, S. aureus strains resistant to vancomycin were not found. In conclusion, these surveillances can play an important role for the control and prevention to the diseases originated by enteritis bacteria.

Probiotics for treatment of acute diarrhoea in children: randomised clinical trial of five different preparations

OBJECTIVE

To compare the efficacy of five probiotic preparations recommended to parents in the treatment of acute diarrhoea in children. Design Randomised controlled clinical trial in collaboration with family paediatricians over 12 months.

SETTING

Primary care.

PARTICIPANTS

Children aged 3-36 months visiting a family paediatrician for acute diarrhoea.

INTERVENTION

Children's parents were randomly assigned to receive written instructions to purchase a specific probiotic product: oral rehydration solution (control group); Lactobacillus rhamnosus strain GG; Saccharomyces boulardii; Bacillus clausii; mix of L delbrueckii var bulgaricus, Streptococcus thermophilus, L acidophilus, and Bifidobacterium bifidum; or Enterococcus faecium SF68.

MAIN OUTCOME MEASURES

Primary outcomes were duration of diarrhoea and daily number and consistency of stools. Secondary outcomes were duration of vomiting and fever and rate of admission to hospital. Safety and tolerance were also recorded.

RESULTS

571 children were allocated to intervention. Median duration of diarrhoea was significantly shorter (P<0.001) in children who received L rhamnosus strain GG (78.5 hours) and the mix of four bacterial strains (70.0 hours) than in children who received oral rehydration solution alone (115.0 hours). One day after the first probiotic administration, the daily number of stools was significantly lower (P<0.001) in children who received L rhamnosus strain GG and in those who received the probiotic mix than in the other groups. The remaining preparations did not affect primary outcomes. Secondary outcomes were similar in all groups.

CONCLUSIONS

Not all commercially available probiotic preparations are effective in children with acute diarrhoea. Paediatricians should choose bacterial preparations based on effectiveness data.

TRIAL REGISTRATION NUMBER

Current Controlled Trials ISRCTN56067537 [controlled-trials.com].

G and P rotavirus genotypes in stool samples from children in Teresina, State of Piauí

A total of 123 stool specimens collected in Teresina, Piauí between 1994 and 1996, from 0 to 2-year-old children with diarrhea, were used for this study. Molecular characterization of the G and P rotavirus genotypes was performed using the reverse transcriptase polymerase chain reaction. The following results were obtained for the P genotypes: P[8] (17. 1%), P[1] (4. 9%), P[4] (3. 3%), P[6, M37] (2. 4%) and mixtures (27. 6%). The P[1]+P[8] mixture was found in 19. 5% of the samples. For the G genotypes, the results were: G1 (25. 2%), G5 (13. 8%), G2 (2. 5%), G4 (2. 5%), G9 (0. 8%) and mixtures (41. 5%). G1+G5 was the mixture most frequently found (12. 1%). Our results showed unusual combinations such as P[1]G5 and P[1]+P[8]G5. The high percentage of mixtures and unusual combinations containing mixtures of human and animal rotavirus genotypes strongly suggests the possibility of gene reassortment and interspecies transmission.

Detection by PCR of eight groups of enteric pathogens in 4,627 faecal samples: re-examination of the English case-control Infectious Intestinal Disease Study (1993-1996)

The English case-control Infectious Intestinal Disease Study (1993-1996) failed to detect an enteric pathogen or toxin in 49% of cases of gastroenteritis. In the present study, polymerase chain reaction (PCR) assays were applied to DNA and cDNA generated from 4,627 faecal samples from cases and controls archived during the original study for the detection of norovirus, rotavirus, sapovirus, Campylobacter spp., Salmonella spp., enteroaggregative Escherichia coli, Cryptosporidium spp., and Giardia spp. The percentage of archived samples from cases and from controls in which at least one agent (or toxin) was detected increased from 53% in the original study to 75% and from 19 to 42%, respectively, after the application of PCR assays. Among cases, the following percentages of enteric pathogens were detected: norovirus 36%, rotavirus A 31%, sapovirus 4%, Salmonella spp. 6%, Campylobacter jejuni 13%, Campylobacter coli 2%, other Campylobacter spp. 8%, enteroaggregative E. coli 6%, Giardia spp. 2%, and Cryptosporidium spp. 2%. The present study provides additional insight into the aetiology of infectious intestinal disease in England and highlights the occurrence of viral infections in cases as well as in asymptomatic individuals. Other notable findings include the frequent presence of Campylobacter spp. other than C. jejuni or C. coli, the high frequency of multiple agents in 41% of cases and in 13% of controls, and the variation in the aetiology and rate of infection found for different age groups. The results demonstrate the greater sensitivity of PCR-based methods compared to current conventional methods.

Giardia and Cryptosporidium and public health: the epidemiological scenario from the Italian perspective

Giardia and Cryptosporidium spp. are protozoa that cause human and animal disease worldwide and often exhibit zoonotic transmission. This review gives ample information concerning the epidemiology of these parasites in Italy, i.e. prevalence data in humans, farm and pet animals, shellfish and aquatic environment. Moreover, it reports genotyping results obtained from different isolates, with particular emphasis on the spread of host-specific and zoonotic species/genotypes of various origin, and on molecular data that make the Italian situation different from that of other countries. Finally, possible explanations are given for the infrequent reports of Giardia and Cryptosporidium spp. outbreaks, despite widespread faecal contamination by these parasites.

Polymerase chain reaction in the detection of an 'outbreak' of asymptomatic viral infections in a community birth cohort in south India

Asymptomatic enteric infections are important where sequelae or protection from subsequent illness is an outcome measure. The use of reverse transcription-polymerase chain reaction (RT-PCR) to identify asymptomatic enteric infections in a birth cohort followed for rotaviral infections in a south Indian urban slum is reported. Of 1191 non-diarrhoeal samples from 371 children collected in May-June 2003, 22 (1.9%) were positive by ELISA. A total of 147 (40.6%) of 362 samples tested by VP6 RT-PCR were positive. In those samples that could be typed, a high diversity of G types including G1, G2, G4, G8, G9 and G10, and a high proportion (34.4%) of mixed infections were detected. Noroviruses were identified in 6/28 (21.4%) samples tested. The identification of infections undetectable by conventional techniques indicates the importance of the use of sensitive diagnostic techniques in research studies. Asymptomatically infected children may also act as a source of infection for other susceptible hosts.

Diversity of human rotaviruses detected in Sicily, Italy, over a 5-year period (2001-2005)

Rotavirus infection was detected in 39.9% of 1030 children hospitalized with gastroenteritis in Palermo, Italy, in the period 2001-2005. Rotavirus strains belonging to G1, G4 and G9 types were continually detected, with G1 being the most common type in 2001, 2002 and 2004. A G4 epidemic occurred in 2003, while G9 was predominant in 2005. G2 strains displayed a low prevalence, except in 2003. G3 rotaviruses accounted for 2.7-17% of the gastroenteritis episodes in 2002-2005. The P-type of a subset of 166 strains confirmed the circulation of the usual G/P combinations, but single G1P[6], G9P[9] and G6P[9] strains were also found.

Incidence, impact on the family and cost of gastroenteritis among 4 to 6-year-old children in South Australia

BACKGROUND

Gastroenteritis is an important cause of morbidity in both adults and children worldwide. Although the burden of morbidity and mortality is highest in developing countries, gastroenteritis is still a significant cause of morbidity in Australia, particularly in young children. The aims of the present study were to determine the incidence of gastroenteritis among 4-6-year-old children in South Australia, to describe the impact on daily activities of the child and caregiver and estimate the cost of gastroenteritis in this population.

METHODS

A diary study of drinking water consumption and gastrointestinal and respiratory symptoms was undertaken among 965 rural children in South Australia over a 6-week period during February-May 1999. Data on the response to gastrointestinal episodes were collected by telephone surveys midway and at the end of the 6-week period. Costing was based on the methods of Hellard et al.

RESULTS

The incidence of community gastroenteritis among 4-6-year-old children was 5.53 episodes per child-year (95% confidence interval: 4.87-5.80). The costs associated with childhood gastroenteritis were estimated to be between 16,858,360 AU dollars and 22,477,814 AU dollars per annum.

CONCLUSIONS

The incidence of community gastroenteritis among the 4-6-year-olds in the South Australian population is high and it costs the community a significant amount of money in terms of direct medical costs and time lost by parents and carers looking after their ill children.

Public health implications of a case of haemolytic-uraemic syndrome associated with a concomitant outbreak of mild gastroenteritis in a small rural community

The concomitant occurrence of a case of haemolytic-uraemic syndrome (HUS) and 62 cases of mild gastroenteritis in schools of a small rural community in southern Italy induced the health authorities to suspect a foodborne outbreak of shiga-toxin-producing Escherichia coli (STEC) infection. The schools were closed and the catering service involved was investigated. However, STEC were not isolated from the HUS case or from the 56 cases of gastroenteritis examined, and the HUS case and the outbreak of gastroenteritis were probably just coincidental. A retrospective cohort study failed to show any correlation with consumption of school meals and suggested that the outbreak probably started outside the school setting and then spread within the schools by person-to-person transmission. All the cases examined were negative for common enteric pathogens and the responsible agent for the cases of gastroenteritis was not identified. The concern raised in the small community by the occurrence of a severe case of HUS and the lack of a rapid epidemiological assessment excluding the occurrence of a STEC outbreak, turned an epidemic episode of mild gastroenteritis into a public health emergency with relevant socioeconomic consequences. Prompt intervention in outbreaks following timely and effective risk communication are crucial for taking the most appropriate control measures and avoiding the spread of fear and panic in the community.

Does dog or cat ownership lead to increased gastroenteritis in young children in South Australia?

The aim of this study was to investigate the relationship between dog and cat ownership and gastroenteritis in young children. A diary study of 965 children aged 4-6 years living in rural or semi-rural South Australia was undertaken. Data were collected on pet ownership, drinking water and other risk factors for gastroenteritis. Overall 89% of households had pets and dog ownership was more common than cat ownership. The multivariable models for gastroenteritis and pet ownership indicated that living in a household with a dog or cat was associated with a reduced risk of gastroenteritis (adj. OR 0.71, 95% CI 0.55-0.92; OR 0.70, % CI 0.51-0.97 respectively). This paper adds to the evidence that pets are not a major source of gastroenteritis in the home and lends support to the health benefits of pet ownership. However, this must be weighed against the potential negative consequences, such as dog bites, particularly for this age group.

Human milk oligosaccharides inhibit the adhesion to Caco-2 cells of diarrheal pathogens: Escherichia coli, Vibrio cholerae, and Salmonella fyris

Breast-fed children, compared with the bottle-fed ones, have a lower incidence of acute gastroenteritis due to the presence of several antiinfective factors in human milk. The aim of this work is to study the ability of human milk oligosaccharides to prevent infections related to some common pathogenic bacteria. Oligosaccharides of human milk were fractionated by gel-filtration and characterized by thin-layer chromatography and high-performance anion exchange chromatography. Fractions obtained contained, respectively, 1) acidic oligosaccharides, 2) neutral high-molecular-weight oligosaccharides, and 3) neutral low-molecular-weight oligosaccharides. Experiments were carried out to study the ability of oligosaccharides in inhibiting the adhesion of three intestinal microorganisms (enteropathogenic Escherichia coli serotype O119, Vibrio cholerae, and Salmonella fyris) to differentiated Caco-2 cells. The study showed that the acidic fraction had an antiadhesive effect on the all three pathogenic strains studied (with different degrees of inhibition). The neutral high-molecular-weight fraction significantly inhibited the adhesion of E. coli O119 and V. cholerae, but not that of S. fyris; the neutral low-molecular-weight fraction was effective toward E. coli O119 and S. fyris but not V. cholerae. Our results demonstrate that human milk oligosaccharides inhibit the adhesion to epithelial cells not only of common pathogens like E. coli but also for the first time of other aggressive bacteria as V. cholerae and S. fyris. Consequently, oligosaccharides are one of the important defensive factors contained in human milk against acute diarrheal infections of breast-fed infants.

Intestinal Parasites in Healthy Subjects in Albania

The purpose of this study was to evaluate the prevalence of intestinal parasites in 277 healthy subjects in the city of Mamuras (Albania, South Eastern Europe) and the correlation between parasitic infections and possible risk factors. Faecal samples collected with sodium-acetate-formalin fixative were concentrated by formalin ethylacetate sedimentation and examined as wet mounts, permanent stains and by anti-Giardia/Cryptosporidium fluorescent antibodies. Data concerning age, sex, level of education, availability of piped water, number of people living in the same house, and residence in rural or urban area were collected for each subject. Statistical analysis was performed by chi-square test and regression logistic analysis. The overall prevalence of intestinal parasites was 183/277 (66.06%). In particular, pathogenic protozoa or helminths were found in 67 subjects (24.18%), including Trichuris trichiura in 34 (12.27%), Giardia duodenalis in 31 (11.19%), Hymenolepis nana in 5 (1.8%), Ascaris lumbricoides in 3 (1.08%). A significant correlation was observed only between parasite colonization and older age and between Trichuris trichiura infection and residence in rural areas.

Nontyphoidal Salmonella from Human Clinical Cases, Asymptomatic Children, and Raw Retail Meats in Yucatan, Mexico

BACKGROUND

We report the results of a 3-year Salmonella surveillance study of persons with diarrhea; asymptomatic children; and retail pork, poultry, and beef in Yucatan, Mexico.

METHODS

Isolates were characterized according to serotype, antimicrobial susceptibility, and genetic relatedness with pulsed-field gel electrophoresis.

RESULTS

Salmonella Typhimurium was the most common serotype found in ill humans (21.8% of isolates), followed by Salmonella Agona (21% of isolates). Salmonella Enteritidis was a minor serotype (4.2% of isolates). Asymptomatic children carried S. Agona (12.1% of isolates), Salmonella Meleagridis (11.6% of isolates), Salmonella Anatum (8% of isolates) and S. Enteritidis (5.8% of isolates). A high percentage of retail meat samples contained Salmonella; it was most commonly found in pork (58.1% of samples), followed by beef (54% of samples) and poultry (39.7% of samples). Resistance to oral drugs used for the treatment of salmonellosis was observed for ampicillin (14.6% of isolates were resistant), chloramphenicol (14.0% of isolates), and trimethoprim-sulfamethoxazole (19.7% of isolates). Resistance to ceftriaxone emerged in 2002 and was limited to the serotype S. Typhimurium. Twenty-seven percent of the isolates were resistant to nalidixic acid, and none were resistant to ciprofloxacin. Multidrug resistance was most common among isolates of serotypes S. Typhimurium and S. Anatum. Pulsed-field gel electrophoresis showed that strains found in retail meats were genetically identical to strains found in both asymptomatic children and ill patients.

CONCLUSIONS

Our study found a high prevalence of Salmonella in retail meats and persons with enteric infection; many of these isolates were resistant to clinically important antimicrobials. A random selection of isolates from people and retail meat showed genetic relatedness, which suggests that, in Yucatan, considerable transfer of Salmonella occurs through the food chain.

Detection of the norovirus variants GGII.4 hunter and GGIIb/hilversum in Italian children with gastroenteritis

Noroviruses (NoVs) are important enteric pathogens of humans. Although they exhibit an impressive genetic diversity, few NoV strains appear to predominate worldwide. Limited epidemiological data are available on NoV gastroenteritis in Italy. In this study, we assessed the prevalence of human NoV in Italian children with gastroenteritis by using a reverse-transcription nested polymerase chain reaction (RT-PCR) assay specific for the RNA-dependent RNA polymerase (RdRp) on faecal samples collected throughout the 2004 surveillance activity in Palermo, Italy. NoVs were detected in 47% of the stool samples obtained from children <5 years age, admitted to hospital with acute non-bacterial gastroenteritis. A selection of strains was further analyzed by partial sequence analysis of the RdRp gene. The strains were characterized as genogroup (GG) II and clustered into two distinct virus populations that resembled the emerging European GGIIb/Hilversum strains and the Australian Hunter GGII.4 strains. A temporal pattern of distribution of the two NoV strains was observed which was consistent with an independent circulation of two separate strains in the local population. Based on this 1-year study we concluded that NoVs were a diffuse cause of sporadic cases of acute childhood gastroenteritis and that strains of global epidemiological relevance were circulating in Palermo, Italy in 2004.

Atypical haemolytic uraemic syndrome and mutations in complement regulator genes

Haemolytic uraemic syndrome (HUS) is a thrombotic microangiopathy (TMA) disorder characterised by the association of haemolytic anaemia, thrombocytopenia and acute renal failure. Atypical forms (non-related to shigatoxin) may be familial or sporadic, with frequent recurrences and most of them lead to end stage renal failure. During the last years, different groups have demonstrated genetic predisposition of atypical HUS involving complement components factor H (FH), CD46 [or membrane co-factor protein (MCP)] and factor I. These three proteins are involved in the regulation of the alternative pathway of the complement system. Several series have reported mutations in the FH gene (called HF1) in between 10 and 22% of atypical HUS patients. At this time, four pedigrees corresponding to 13 cases have been reported with an MCP mutation and four cases with a sporadic disease presented factor I mutation. Whereas FH mutations were reported in both familial and sporadic forms of HUS, CD46 mutations were restricted to familial HUS, and factor I mutations were only observed in cases of sporadic HUS. We speculate that the penetrance of the disease may be variable regarding the identified susceptibility factors. Recently, the analysis of single nucleotide polymorphisms in both HF1 and MCP in three large cohorts of HUS patients identified significant association between atypical HUS and HF1 and MCP particular alleles. All these results, together with the finding of anti-FH antibodies in some atypical HUS patients, strongly suggest that an abnormality in the regulation of the alternative pathway participates in the patho-physiological mechanisms of atypical HUS. The recent progress made in the determination of susceptibility factors for atypical HUS has permitted the development of new diagnostic tests and may eventually lead to new specific treatments to block the pathological process.

Etiology of diarrhea in young children in Denmark: a case-control study

Infectious gastroenteritis is one of the most common diseases in young children. To clarify the infectious etiology of diarrhea in Danish children less than 5 years of age, we conducted a 2-year prospective case-control study. Stools from 424 children with diarrhea and 870 asymptomatic age-matched controls were examined, and their parents were interviewed concerning symptoms. Rotavirus, adenovirus, and astrovirus were detected by enzyme-linked immunosorbent assay, and norovirus and sapovirus were detected by PCR. Salmonella, thermotolerant Campylobacter, Yersinia, Shigella, and Vibrio spp. were detected by standard methods. Shiga toxin-producing (STEC), attaching-and-effacing (A/EEC), enteropathogenic (EPEC), enterotoxigenic, enteroinvasive, and enteroaggregative Escherichia coli were detected by using colony hybridization with virulence gene probes and serotyping. Parasites were detected by microscopy. Overall, a potential pathogen was found in 54% of cases. More cases than controls were infected with rotavirus, Salmonella, norovirus, adenovirus, Campylobacter, sapovirus, STEC, classical EPEC, Yersinia, and Cryptosporidium strains, whereas A/EEC, although common, was not associated with illness. The single most important cause of diarrhea was rotavirus, which points toward the need for a childhood vaccine for this pathogen, but norovirus, adenovirus, and sapovirus were also major etiologies. Salmonella sp. was the most common bacterial pathogen, followed by Campylobacter, STEC, Yersinia, and classical EPEC strains. A/EEC not belonging to the classical EPEC serotypes was not associated with diarrhea, underscoring the importance of serotyping for the definition of EPEC.

Prevalence of Salmonella enterica and Listeria monocytogenes contamination in foods of animal origin in Italy

The present survey collected and analyzed the results of routine testing for Salmonella enterica and Listeria monocytogenes on foods of animal origin submitted for official controls in Italy during 2001 to 2002. Salmonella was detected in 2.2% of 71,643 food samples examined, and the isolation rates ranged from 9.9% for raw poultry meat to less than 0.1% for dairy products. Isolation rates were also high in raw pork (4.9%) and processed meats (5.3%), which often involved pork. Low rates were observed in seafood (0.5%) and in ready-to-eat foods, such as grocery products (0.7%) and ice creams (0.1%). Serotyping showed that approximately 50% of the isolates belonged to the serotypes most commonly isolated from humans in Italy, thus confirming that most cases of human salmonellosis have a foodborne origin. Levels of L. monocytogenes were higher than what is accepted by the current regulation in 2.4% of 42,300 food samples. The positivity rates ranged from 10.3% in raw pork to none in eggs and egg products. Contamination rates were higher in other meat products (between 2 and 5%) and fish (6.5%) than in cheeses (1.1%) and other dairy products (0.6%). Routine control activities on the microbial contamination of foods can generate data with statistical and epidemiological value. Such data can be used as a basis for estimating the exposure of consumers to foodborne pathogens, following the trends of contamination over time, and evaluating the effects of control measures on the contamination of food.

Cryptosporidiumparvum oocysts in seawater clams (Chameleagallina) in Italy

Bivalves filter large volumes of water and can concentrate organisms which are pathogenic for humans and animals. Our aim was to evaluate the presence of Cryptosporidium spp. in clams from the Adriatic coast (Abruzzo region) and genetically characterize the oocysts isolated from the clams. From March to July 2003, 960 specimens of clams (Chamelea gallina) present in nature were collected at 500 m from the Tordino, Tronto, Vibrata and Vomano river mouths on the Adriatic sea. The haemolymph and tissues were extracted from the specimens (240 per river mouth) after the specimens had been identified, measured and weighed (live weight). Immunofluorescence tests (IFA) were performed on pools (n = 32) of samples and oocysts of Cryptosporidium spp. were detected in 23 pools of C. gallina. To identify the Cryptosporidium species, all the pools IFA-positive were tested by a PCR assay specific for the Cryptosporidium outer wall protein (COWP) gene. Positive amplicons then were sequenced and analysed. Two pools of clams were positive for Cryptosporidium parvum Genotype 2 (the "bovine" i.e. zoonotic genotype). This is the first time that C. parvum was found in clams from the Adriatic sea in Italy and the case might be of public health importance.

G2 rotavirus infections in an infantile population of the South of Italy: Variability of viral strains over time

Rotavirus positive samples collected in Palermo, Italy, during 2002-2004 did not react with the G2 type-specific RV5:3 monoclonal antibodies (MAbs) and could be identified as G2 only by RT-PCR genotyping. The genetic variation of VP7 and VP4 antigenic proteins was studied in 14 G2 samples including a selection of both those successfully characterized by serotyping and those failing to be serotyped. The phylogenetic analysis performed on partial VP7 sequences showed a temporal clustering of these strains, with those isolated in Palermo in 2003 belonging to the same lineage of G2 MAbs-unreactive strains identified in UK in 1996-1997 and in Bari, Italy, in 2003-2004. A single amino acid substitution in VP7 antigenic region A, at position 96 (Asp-->Asn), was consistently associated with the loss of antigenic reactivity. Five of the G2 strains were further characterized by sequencing of VP4-encoding genes as belonging to the P[4] type, and separate lineages clustering the strains according to a temporal distribution could be described. VP7 and VP4 antigenic proteins analysis provided evidence that over the last 11 years, at least two different populations of G2P[4] rotavirus strains have been infecting the infant population in Palermo. Considering the role of anti-VP7 and anti-VP4 neutralizing antibodies in rotavirus immunity, the emergence of new VP7-VP4 gene combinations might influence rotavirus circulation in the infant population and should be taken into consideration when devising vaccination strategies.

Anti-Factor H autoantibodies associated with atypical hemolytic uremic syndrome

Several studies have demonstrated genetic predisposition in non-shigatoxin-associated hemolytic uremic syndrome (HUS), involving regulatory proteins of the complement alternative pathway: Factor H (FH) and membrane co-factor protein (CD46). Regarding the observations of thrombotic thrombocytopenic purpura patients, in whom a von Willebrand factor protease (ADAMST-13) deficiency may be inherited or acquired secondary to IgG antibodies, it was speculated that HUS might occur in a context of an autoimmune disease with the development of anti-FH antibodies leading to an acquired FH deficiency. The presence of FH autoantibodies was investigated by an ELISA method using coated purified human FH in a series of 48 children who presented with atypical HUS and were recruited from French university hospitals. Anti-FH IgG antibodies were detected in the plasma of three children who presented with recurrent HUS. The anti-FH specificity was conserved by the Fab'2 fraction. The plasma FH activity was found to be decreased, whereas plasma FH antigenic levels and FH gene analysis were normal, indicating that the presence of anti-FH antibodies led to an acquired functional FH deficiency. This report supports for the first time that HUS may occur in a context of an autoimmune disease with the development of anti-FH-specific antibody leading to an acquired FH deficiency. This new mechanism of functional FH deficiency may lead to the design of new approaches of diagnosis and treatment with a particular interest in plasma exchanges or immunosuppressive therapies.

Genotyping of Cryptosporidium isolates from Chamelea gallina clams in Italy

Chamelea gallina clams collected from the mouths of rivers along the Adriatic Sea (central Italy) were found to harbor Cryptosporidium parvum (genotype 2), which is the lineage involved in zoonotic transmission. The clams were collected from the mouths of rivers near whose banks ruminants are brought to graze. This paper reports the environmental spread of C. parvum in Italy and highlights the fact that genotyping of seaborne Cryptosporidium isolates is a powerful tool with which to investigate the transmission patterns and epidemiology of this microorganism.

Costs associated with outpatient diarrhoea in infants and toddlers: a nationwide study of the Italian Society of Paediatric Gastroenterology and Hepatology (SIGEP)

BACKGROUND

As diarrhoea mortality is negligible in Italy, other costs should be considered when planning health strategies. Little is known about the costs associated with diarrhoea in Italian children.

AIMS

To assess the costs associated with outpatient infantile diarrhoea in Italy.

METHODS

Primary care paediatricians from five regions filled in a questionnaire for the first 10 children (1-47 months) they visited for acute diarrhoea during a 3-month period.

RESULTS

We analysed 473 questionnaires. Mean age (standard deviation) of children was 21 (11) months; mean duration of diarrhoea (standard deviation) was 4.3 (2.6) days. An overall cost of 110 (137) euro per episode was estimated, with significant difference between children younger and older than 36 months (116 euro versus 72 euro). Missed work by relatives accounts for 75% of the cost. The parents of children attending a day-care centre had an increased risk to miss work (relative risk = 2.15). A weak relationship was found between days of diarrhoea and missed work (r = 0.30); it could be estimated that the diarrhoea should be shortened by about 4 days in order to save I day of missed work.

CONCLUSIONS

Acute outpatient diarrhoea is associated with a significant financial burden in Italy. Simply shortening the diarrhoea does not seem to be the most expeditious way to reduce the cost of diarrhoea itself.

Etiology of sporadic cases of pediatric acute gastroenteritis in asturias, Spain, and genotyping and characterization of norovirus strains involved

From November 2000 to October 2001, a reverse transcription-PCR using primers directed to the norovirus RNA polymerase coding region was included in a viral and bacterial routine screening to diagnose sporadic cases of acute gastroenteritis among children in Asturias, Spain. The role of noroviruses (8.6% of the positively diagnosed cases) as the cause of sporadic pediatric gastroenteritis was evaluated with respect to the detection rates of other gastroenteritis-associated viruses and bacteria. The results indicated that noroviruses were less common than rotaviruses (36.9%), Campylobacter spp. (28.8%), and Salmonella spp. (18.4%) but more frequent than astroviruses (4.3%), adenoviruses (3.8%), and Yersinia spp. (2.2%). Mixed infections involving noroviruses were rarely observed (0.5%). The presence of a norovirus-associated pediatric gastroenteritis peak in summer, as well as the complete absence of norovirus-associated cases in colder months, challenges the view that norovirus infections exclusively have wintertime seasonality. On the other hand, phylogenetic analysis of the amplified fragments showed that the norovirus strains responsible were closely related. A further study using the full-length capsid region showed that these strains could be included into genogroup II, Bristol/Lorsdale cluster, and were closely related to the 1995 and 1996 U.S. subset of strains associated with outbreaks recorded worldwide between 1995 and 1996.

Burden of hospitalizations attributable to rotavirus infection in children in Spain, period 1999–2000

The aim of this study is to provide estimates on the incidence of rotavirus infection requiring hospitalization in children <or=5 years of age during the 1999-2000 period in Spain and the associated direct cost of these hospitalizations. Hospital admissions attributable to rotavirus were estimated by using data on confirmed laboratory reports of rotavirus and hospital admissions due to acute gastroenteritis. During the study period a total of 32541 cases of pathogens responsible for acute gastroenteritis were reported to the microbiological information national system (SIM) and 14.0% were rotavirus. The proportion of laboratory-confirmed rotavirus cases was extrapolated to the total number of hospitalizations for acute gastroenteritis in children <or=5 years of age. An annual incidence of 1.0 hospital admissions attributable to rotavirus per 1000 persons <or=5 years of age was found, although during the winter season it reached 2.5 hospitalizations per 1000. Overall, the estimated annual number of days of hospitalization attributable to rotavirus was 8742 days that results in a cost of 3.6 million per year.

A 5-year study of the bacterial pathogens associated with acute diarrhoea on the island of Crete, Greece, and their resistance to antibiotics

During a 5-year period (1995-1999) a total of 7090 stool samples obtained from patients with acute diarrhoea, mostly community-acquired, were examined for bacterial pathogens, in the Greek island of Crete. One or more enteric pathogens were isolated from 987 patients (14%). Salmonella enterica were the most commonly isolated bacteria (6%), followed by Campylobacter spp. (4.2%), and enteropathogenic Escherichia coli (EPEC) (1.8%). Yersinia enterocolitica (0.6%), Shigella spp. (0.3%), and Aeromonas hydrophila (0.04%), were less frequently isolated. Clostridium difficile was isolated from 65 out of 451 diarrhoeal specimens examined (14.4%). Toxin B was detected in all cases. No verotoxigenic E. coli strains were identified. Resistance to ampicillin was observed in 31.5% of the Salmonella, 58.3% of the Shigella and 31.5% of the EPEC isolates. Resistance to trimethoprim-sulfamethoxazole was observed in 4.4% of the Salmonella, 30.5% of the Shigella, and 18.5% of the EPEC isolates. High percentages of resistance to quinolones (44.5% to norfloxacin, and 40.5% to ciprofloxacin), were found among Campylobacter isolates, while resistance to erythromycin was observed in 14.9% of them. With the present study we continue the surveillance of bacterial pathogens associated with diarrhoeal disease on the island of Crete.

Acute viral gastroenteritis: proportion and clinical relevance of multiple infections in Spanish children

Dual infections associated with acute infectious diarrhoea and its microbiological, epidemiological and clinical findings have been evaluated in patients selected from a comprehensive survey of children under 4 years old, admitted to hospital emergency rooms from October 1996 to November 1997. A total of 820 children (433 males and 387 females) were enrolled. Stools were tested for rotavirus, adenovirus, astrovirus and bacterial enteropathogens. Patients were grouped according to age, and the seasonality of mixed infections was evaluated. Clinical trends and severity of gastrointestinal disease by Ruuska's score were also analysed. Mixed infections were identified in 39 cases (5 %), of which 23 were males and 16 were females. The majority of cases were in the 7-18-month age group (26 cases) and occurred in autumn (67 %). Virus-virus co-infections were more frequent (26/39) than virus-bacteria co-infections (13/39). More than two infectious agents were detected in only four cases. The most common viral co-infections were rotavirus-astrovirus (13/26) and rotavirus-adenovirus (10/26). The present report is the first prospective analysis of clinical-epidemiological trends of dual infections in young Spanish children with acute viral gastroenteritis. Our results emphasize the clinical importance of mixed infections as a cause of severe diarrhoea in children.

Domestic poultry-raising practices in a Peruvian shantytown: implications for control of Campylobacter jejuni-associated diarrhea

Raising poultry at home is common in many periurban communities in low-income countries. Studies demonstrate that free-range domestic poultry increase children's risk of infection with diarrhea-causing organisms such as Campylobacter jejuni. Corralling might reduce risk, but research on the socioeconomic acceptability of corralling is lacking. To explore this issue, we studied local knowledge and practices related to poultry-raising in a Peruvian shantytown. Our objectives were to understand: (1). motives for raising domestic poultry; (2). economic and cultural factors that affect the feasibility of corralling; and (3). local perceptions about the relationship between domestic poultry and disease. During 1999-2000, we met with community health volunteers and conducted ethnographic and structured interviews with residents about poultry-raising practices. We then enrolled 12 families in a 2-month trial of corral use during which field workers made biweekly surveillance visits to each family. Most participants reported that they raise birds because home-grown poultry and eggs taste better and are more nutritious and because they enjoy living around animals. Some want to teach their children about raising animals. To prevent theft, many residents shut their birds in provisional enclosures at night, but most stated that birds are healthier, happier, and produce better meat and eggs when let loose by day. Many view bird feces in the house and yard as dirty, but few see a connection to illness. Residents consider chicks and ducklings more innocuous than adult birds and are more likely to allow them inside the house and permit children to play with them. After extensive orientation and technical assistance, participants were willing to corral birds more often. But due to perceived disadvantages, many kept birds penned only intermittently. Additional food and water costs were a significant obstacle for some. Adequate space, bird care and corral hygiene would also need to be addressed to make this intervention viable. Developing a secure, acceptable and affordable corral remains a challenge in this population.

Viruses causing gastroenteritis

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viruses are recognized as important causes of this disease, particularly in children. Since the Norwalk virus was identified as a cause of gastroenteritis, the number of viral agents associated with diarrheal disease in humans has steadily increased. Rotavirus is the most common cause of severe diarrhea in children under 5 years of age. Astrovirus, calicivirus and enteric adenovirus are also important etiologic agents of acute gastroenteritis. Other viruses, such as toroviruses, coronaviruses, picobirnaviruses and pestiviruses, are increasingly being identified as causative agents of diarrhea. In recent years, the availability of diagnostic tests, mainly immunoassays or molecular biology techniques, has increased our understanding of this group of viruses. The future development of a safe and highly effective vaccine against rotavirus could prevent, at least, cases of severe diarrhea and reduce mortality from this disease.