Acute and persistent diarrhea

The incidence and factors associated with dysnatremia in children with acute gastritis/gastroenteritis

BACKGROUND

The incidence of dysnatremia in children with acute gastritis/gastroenteritis varies, and factors associated with either dysnatremia or hyponatremia at presentation have not been identified clearly.

METHODS

This retrospective study included patients aged 1 month to 18 years hospitalized for community-acquired acute gastritis/gastroenteritis from January to October 2016. Factors associated with dysnatremia at presentation were identified using multivariable analysis.

RESULTS

Among the 304 children included, the median age was 2.2 (1.0, 4.2) years. The incidence of dysnatremia at presentation was 17.1% (hyponatremia 15.8%; hypernatremia 1.3%). Patients who had moderate (p = 0.03) and severe dehydration (p = 0.04) and presented with vomiting and diarrhea simultaneously (p = 0.03) were associated with dysnatremia at presentation. Patients presented with vomiting and diarrhea simultaneously was associated with hyponatremia at presentation (p = 0.02).

CONCLUSIONS

Dysnatremia was common in children with acute gastritis/gastroenteritis. Moderate to severe dehydration and the presence of vomiting and diarrhea simultanously were significantly associated with dysnatremia at presentation. Furthermore, presenting with vomiting and diarrhea silmutaneously was associated with hyponatremia at presentation. Serum electrolytes should be monitored in patients with those conditions.

Overcrowding and Hazardous Dwelling Condition Characteristics: A Systematic Search and Scoping Review of Relevance for Health

Crowding in dwellings is an important public health issue. We hypothesize that overcrowding may cause indirect health effects by adversely affecting the dwelling itself, for example, by increasing dampness leading to mold. We therefore performed a systematic search and a scoping review on overcrowding leading to dwelling condition characteristics of relevance for health. A literature search was performed using the PubMed and Scopus databases up to 5 March 2021. The search yielded 100 records with relevant information. We found that overcrowding is defined in numerous ways and often address "socially deprived" populations. Six studies report associations of overcrowding with at least one dwelling condition characteristic, namely lead, cadmium, microorganism distribution, dust mite and cockroach allergens in dust, cockroach infestation, peeling paint, and mold. One of the studies reports associations between several characteristics, e.g., association of mold with cleanliness and rodent infestation, and points out the common use of pesticides. Additional characteristics were extracted from the remaining 94 records, without data on statistical associations with overcrowding. Our review suggests that multiple potentially hazardous dwelling condition characteristics often coincide in overcrowded dwellings. The epidemiological attribution of health effects to any characteristic is therefore difficult. Causal relationships are even more difficult to establish, as overcrowding is also associated with a range of social and other circumstances that may affect health. The complexity should be considered by scientists and practitioners dealing with overcrowding in dwellings.

Meteorological and social conditions contribute to infectious diarrhea in China

Infectious diarrhea in China showed a significant pattern. Many researchers have tried to reveal the drivers, yet usually only meteorological factors were taken into consideration. Furthermore, the diarrheal data they analyzed were incomplete and the algorithms they exploited were inefficient of adapting realistic relationships. Here, we investigate the impacts of meteorological and social factors on the number of infectious diarrhea cases in China. A machine learning algorithm called the Random Forest is utilized. Our results demonstrate that nearly half of infectious diarrhea occurred among children under 5 years old. Generally speaking, increasing temperature or relative humidity leads to increased cases of infectious diarrhea in China. Nevertheless, people from different age groups or different regions own different sensitivities to meteorological factors. The weight of feces that are harmfully treated could be a possible reason for infectious diarrhea of the elderly as well as children under 5 years old. These findings indicate that infectious diarrhea prevention for children under 5 years old remains a primary task in China. Personalized prevention countermeasures ought to be provided to different age groups and different regions. It is essential to bring the weight of feces that are harmfully treated to the forefront when considering infectious diarrhea prevention.

Identifying threshold sizes for enlarged abdominal lymph nodes in different age ranges from about 200,000 individual's data

The threshold size for enlarged abdominal lymph nodes (E-ALNs), a common pediatric disorder, has yet to be standardized. According to the maximum short-axis diameter, this study divided ALNs into Grade A (≥ 10 mm), Grade B (8–10 mm), Grade C (5–8 mm), and Grade D (< 5 mm, normal). To identify the threshold size for E-ALNs, the prevalence of each grade was compared between asymptomatic individuals and symptomatic (e.g., abdominal pain) individuals without other diseases (e.g., appendicitis) that could explain the symptoms for different ages using data from > 200,000 individuals. The results showed the following: (1) For ages 1–3 years, the recommended threshold size is 8 mm, as the differences in the prevalence between the two groups were nonsignificant for Grade C but significant (p < 0.05) for both Grades A and B. (2) For ages 3–14 years, the recommended threshold size is 5 mm, as the differences between the two groups were significant (p < 0.05) for Grades A, B, and C. (3) The prevalence of Grades A, B, and C was very low for ages 0–1 years and high for ages 1–6 years. (4) The prevalence for males was generally higher than that for females for Grades A and B.

Reference intervals of mesenteric lymph node size according to lymphocyte counts in asymptomatic children

There is no acknowledged reference interval of mesenteric lymph node size in healthy children, and the size criterion for mesenteric lymph node enlargement (MLNE) has long been controversial. This study aimed to explore the reference intervals of mesenteric lymph node size according to lymphocyte counts in asymptomatic children and to develop a more appropriate definition of MLNE. The asymptomatic children included were divided into five age strata: 2 to 3 yr; 3 to 4 yr; 4 to 5 yr; 5 to 6 yr; and 6 to 7 yr. Correlation analyses between lymphocyte counts and the long-axis diameter, short-axis diameter, and average diameter of the largest mesenteric lymph node (LMLN) were performed. A reference interval of the short-axis diameter of LMLN was established according to this correlation analysis in each age group. We also report a reference interval of lymphocyte count in each age group. This study revealed significant correlations between the short-axis diameter of LMLN and lymphocyte count in all age groups, as well as in subdivided boy groups and girl groups. The overall reference interval of the short-axis diameter of LMLN in children was 0.54 cm—1.03 cm, with mean value of 0.75 cm. This study supports the use of the short-axis diameter greater than 8–10 mm as the diagnostic criterion for primary mesenteric lymphadenitis based on the presence of a cluster of three or more mesenteric lymph nodes and in the absence of other abnormalities.

Caregivers' knowledge and attitudes about childhood diarrhea among refugee and host communities in Gambella Region, Ethiopia

BACKGROUND

Maternal knowledge, attitudes, and practices related to hygiene, breastfeeding, sanitary food preparation, and appropriate weaning practices are potentially important determinants in the occurrence of diarrhea in children. However, few studies have been carried out about the knowledge and attitudes about childhood diarrhea among parents in refugee camps and host communities.

OBJECTIVE

This study aims at assessing the caregivers' knowledge and attitudes regarding acute diarrhea in under-five children among refugee and host communities in Gambella Region, Ethiopia.

METHODOLOGY

This cross-sectional study, employing multistage sampling, was carried out from September to December 2016. Data was collected by a questionnaire-based interview, and 1667 caregivers were included in this study. A composite knowledge score was calculated, and a five-point Likert type of attitude scale was developed to assess the attitudes of the caregivers towards childhood diarrhea. Appropriate descriptive statistics and logistic regression models were used. Odds ratios (ORs) are presented with their 95% confidence intervals (CIs), and all analyses were performed at the 5% significance level (p < 0.05).

RESULT

The study indicates that 633 (28.0%) of the caregivers had poor knowledge, while 393 (23.6%) of them had unfavorable attitudes towards childhood diarrhea. Knowledge of the caregivers was significantly associated with formal education (AOR, 1.3; 95% CI, 1.03-1.5) and health information obtained from a health care institution (AOR, 1.8; 95% CI, 1.28-2.3). Caregivers' knowledge is a single predictor of their attitude (p < 0.001), and Pearson's correlation coefficient revealed that there was a significant positive correlation (r = 0.2, p < 0.001) between knowledge and attitude scores.

CONCLUSION

The study indicates that significant numbers of caregivers had inadequate knowledge and unfavorable attitudes about diarrhea in under-five children. Designing and implementing an inclusive health education intervention focusing on uneducated child caregivers may be beneficial for improving knowledge and attitudes towards reducing the incidence of acute childhood diarrhea in the region.

The geo-spatial distribution of childhood diarrheal disease in West Africa, 2008-2013: A covariate-adjusted cluster analysis

Diarrhea is a major cause of morbidity and mortality among children in West Africa. To determine whether there are areas of heightened risk and if so, how they may be influenced by household and climatic variables, we describe the geo-spatial distribution of childhood diarrhea in ten countries of West Africa for the period 2008-2013 using data from Demographic and Health Surveys. The purely spatial scan statistic was applied, where the observed diarrhea cases were modeled as a Poisson variable and were compared to expected cases predicted from non-spatial logistic regression. Covariate-adjusted cluster analysis detected statistically significant clusters (p < 0.05) in ten cities and thirteen largely rural areas. Areas with particularly high relative risk included Cotonou, Benin (7.16), and Kaduna, Nigeria (7.21). The study demonstrates the importance of development and adaptation measures to protect child health, and that these interventions should be tailored to meet the needs of specific populations.

Using the Healthy Community Assessment Tool: Applicability and Adaptation in the Midwest of Western Australia

Population-based studies have associated poor living conditions with the persistent disparity in the health of Aboriginal and non-Aboriginal Australians. This project assesses the applicability of the Health Community Assessment Tool and its role in improving the environment of a small community in the Midwest of Western Australia (WA). The action research cycles started with the initial reflection on the suitability of the HCAT version 2 for the local community context and whether it was fit-for-purpose. The researcher provided ‘critical companionship’, while the participants of the study were invited to be co-researchers (the Assessors) who critically examined the HCAT and assess the community. The relevant domains to the serviced town (an outer regional community) were pest control and animal management; healthy housing; food supply; community vibrancy, pride and safety; reducing environmental tobacco smoke; and promoting physical activity. The Assessors found the HCAT descriptors mostly aligned with their community context but found some of the items difficult to apply. Based on participant’s suggestions, some of the original scoring scales were reformatted. School attendance and illicit drug use were identified as a key outcome indicator for youth but were missing from the HCAT. The HCAT domains applied helped streamlining core business of agencies in the local community. The face validity of HCAT items were confirmed in this research with minor adjustments to reflect local context. Youth engagement to education is of high community concern and the development of an item would create similar interagency collaborative dialogues.

Course of acute nonspecific mesenteric lymphadenitis: single-center experience

Available reports dealing with acute nonspecific mesenteric lymphadenitis do not address the total duration of symptoms. However, it is commonly assumed a time for recovery ≤ 4 weeks. The purpose of this report was to investigate the course of acute nonspecific mesenteric lymphadenitis in childhood. A review was made of the patients aged ≤ 16 years in whom the diagnosis of acute nonspecific mesenteric lymphadenitis was established between 2011 and 2015 at the Pediatric Emergency Unit. The records of the Pediatric Emergency Unit, those of the referring family doctors, and the results of a structured telephone interview with each family were used. Forty-four patients (25 girls and 19 boys) aged 2.5 to 16, median 8.2, years were included. A bimodal distribution in duration of symptoms was observed: symptoms persisted for ≤ 2 weeks in 22 patients and 3 to 10 weeks in 22. Clinical and laboratory characteristics were similar in children with symptoms persisting for 2 weeks or less 28 and in those with symptoms persisting for 3-10 weeks.

CONCLUSION

In patients affected with acute nonspecific mesenteric lymphadenitis, it is advantageous to think of the time span for recovery in terms of ≥ 4 weeks. What is Known: • Mesenteric adenitis is a self-limiting inflammatory condition with well-characterized clinical presentation and imaging features. • A total duration of symptoms of ≤ 4 weeks is usually hypothesized. What is New: • Symptoms persist for 3 to 10 weeks in half of the patients. • At presentation, clinical and laboratory characteristics are similar in children with symptoms persisting for 2 weeks or less and in those with 45 symptoms persisting for 3-10 weeks.

A cross-sectional survey of environmental health in remote Aboriginal communities in Western Australia

INTRODUCTION

The Australian Aboriginal population experiences significantly poorer health than the non-Aboriginal population. The contribution of environmental risk factors in remote communities to this health disparity is poorly understood.

OBJECTIVE

To describe and quantify major environmental risk factors and associated health outcomes in remote Aboriginal communities in Western Australia.

METHODS

The association between environmental health indicators, community infrastructure and reported health outcomes was analysed using linear and logistic regression of survey data.

RESULTS

Housing/overcrowding was significantly associated with increased reports of hearing/eyesight (OR 3.01 95 % CI 1.58-5.73), skin (OR 2.71 95 % CI 1.31-5.60), gastrointestinal (OR 3.51 95 % CI 1.49-8.26) and flu/colds (OR 2.47 95 % CI 1.27-4.78) as health concerns. Dust was significantly associated with hearing/eyesight (OR 3.16 95 % CI 1.82-5.48), asthma/respiratory (OR 2.48 95 % CI 1.43-4.29) and flu/colds (OR 3.31 95 % CI 1.88-5.86) as health concerns.

CONCLUSION

Poor environmental health is prevalent in remote Aboriginal communities and requires further delineation to inform environmental health policy.

Coverage and Determinants of Uptake for Privately Funded Rotavirus Vaccine in a Canadian Birth Cohort, 2008-2013

BACKGROUND

Rotavirus can lead to serious illness or death, even in developed countries. While vaccination can provide protection, many jurisdictions are still grappling with the issue of whether to introduce a universal publicly funded rotavirus vaccination program. This retrospective population-based study assessed rotavirus vaccine coverage, determinants of uptake, and compliance with the recommended schedule in a Canadian jurisdiction with a privately-funded rotavirus vaccination program.

METHODS

Analysis of pharmaceutical dispensing, vital statistics, and administrative health data determined vaccine coverage and schedule compliance from 2008 to 2013. Multivariable logistic regression was used to assess characteristics of families purchasing vaccine.

RESULTS

Vaccine coverage ranged from 1% to 4% between 2008-2013, with 52% of vaccinated children completing the full vaccine series; 7.9% and 3.8% of children received doses before and after the recommended ages, respectively. Children who received ≥1 doses of the vaccine were more likely to have mothers who were married (adjusted odds ratio [aOR] 1.76, 95% CI1.64-1.88), fewer siblings (aOR 3.44, 95%CI 3.01-3.94), be non-First Nations (aOR 2.29, 95%CI 1.78-2.94), and be born prematurely (aOR 1.32, 95%CI 1.23-1.42). Income was a strong influence in urban areas, but not in rural regions, where coverage was lower overall.

CONCLUSIONS

Vaccine coverage in a privately-funded model was very low and left high risk populations unprotected. Vaccine series completion and compliance with recommended scheduling was also suboptimal.

Clostridial Infections in Children: Spectrum and Management

Clostridia can cause unique histotoxic syndromes produced by specific toxins (e.g., gas gangrene and food poisoning) as well as non-syndromic infections (e.g., abscess, local infections, and blood born infection). Clostridia can also be recovered from various body sites as part of polymicrobial aerobic-anaerobic infection. These include intra-abdominal (peritonitis and abscess), biliary tract, female genital tract, abscess (rectal area and oropharyngeal), pleuropulmonary, central nervous system, and skin and soft-tissue infections. Clostridia were recovered from children with bacteremia of gastrointestinal origin, necrotizing enterocolitis, and sickle cell disease. They have also been isolated in acute and chronic otitis media, chronic sinusitis and mastoiditis, peritonsillar abscesses, and neonatal conjunctivitis. Early and aggressive surgical debridement, decompression, and drainage of affected tissues are critical to successful outcome of histotoxic infections. Effective antimicrobials include penicillin, clindamycin, chloramphenicol, third-generation cephalosporins, carbapenems, and vancomycin.

[Acute diarrheal disease caused by enteropathogenic Escherichia coli in Colombia]

Intestinal Escherichia coli pathogens are leading causes of acute diarrheal disease in children less than 5 years in Latin America, Africa and Asia and a leading cause of death in children living in poorest communities in Africa and South East Asia. Studies on the role of E. coli pathogens in childhood diarrhea in Colombia and other countries in Latin America are limited due to the lack of detection assays in clinical laboratories at the main urban medical centers. Recent studies report that enterotoxigenic E. coli is the most common E. coli pathogens associated with diarrhea in children less than 5 years of age. Other E. coli pathotypes have been detected in children with diarrhea including enteropathogenic, enteroaggregative, shiga-toxin producing and diffusely adherent E. coli. It was also found that meat and vegetables at retail stores are contaminated with Shiga-toxin producing E. coli and enteroaggregative E. coli, suggesting that food products are involved in transmission and infection of the susceptible host. More studies are necessary to evaluate the mechanisms of transmission, the impact on the epidemiology of diarrheal disease, and management strategies and prevention of these pathogens affecting the pediatric population in Colombia.

Indigenous health and environmental risk factors: an Australian problem with global analogues?

Indigenous people experience poorer health than non-Indigenous people, and this well-described inequality has been observed in many countries. The contribution of different risk factors to the health ‘gap’ has understandably focussed on those factors for which there are sufficient data. However, this has precluded environmental risk factors – those present in air, water, food, and soil – due to a lack of data describing exposures and outcomes. These risk factors are demonstrably important at the global scale, as highlighted by the 2010 Global Burden of Disease study. Here, we describe how a greater focus on environmental risk factors is required in order to define their role in the Indigenous health gap. We use the Australian context as a case study of an issue we feel has global analogues and relevance. Suggestions for how and why this situation should be remedied are presented and discussed.

The significance of serum and fecal levels of interleukin-6 and interleukin-8 in hospitalized children with acute rotavirus and norovirus gastroenteritis

BACKGROUND

Rotavirus and norovirus are the most common known causes of viral gastroenteritis in children. This study examined the association between serum interleukin 6 (IL-6) and interleukin 8 (IL-8) levels and disease severity in the acute phase of rotavirus and norovirus gastroenteritis in children, and it also explored the role of fecal cytokine levels in children with viral and bacterial gastroenteritis.

METHODS

This prospective study enrolled patients aged 4 months to 14 years admitted with acute gastroenteritis in a tertiary care center. Peripheral blood samples were collected for IL-6 and IL-8 assays within the first 3 days of diarrhea. Stool samples were obtained from the patients in the first 24 hours after admission.

RESULTS

Serum IL-6 and IL-8 were measured in children with viral (n = 66) and bacterial (n = 23) infections, and in healthy controls (n = 10). In the acute phase of gastroenteritis, a moderately positive correlation was found between serum IL-6 levels and disease severity (rs = 0.41, p < 0.01). Serum IL-8 levels correlated with the duration of fever (rs = 0.28, p = 0.03). Fecal IL-6 levels correlated with the maximum number of daily bowel movements (rs = 0.35, p < 0.05). Rotavirus infection induced significantly higher serum IL-8 levels than norovirus infection (p < 0.05). Receiver operating characteristic (ROC) curve analysis showed that absolute neutrophil count (ANC), maximum body temperature (BT), and Vesikari score were significant predictors in discriminating rotavirus from norovirus gastroenteritis.

CONCLUSION

IL-6 and IL-8 are involved in the pathogenesis of acute gastroenteritis in both rotavirus and norovirus. An ANC of less than 9000/mm(3), maximum BT of less than 38.2°C, and Vesikari score of less than 14 at the end of the course are potential predictors of norovirus infection in children compared with rotavirus gastroenteritis.

Diarrhea after laparoscopic cholecystectomy: associated factors and predictors

BACKGROUND

Diarrhea is part of the postlaparoscopic cholecystectomy syndrome, but is not well defined. Published reports have ignored possible associated factors such as the preoperative excretion pattern, gastrointestinal disorders, personality disorders, the effect of drugs, unsanitary food, and high-fat diets.

PURPOSE

The aim of this study was to define the associated factors and predictors of postlaparoscopic cholecystectomy diarrhea (PLCD) at different time intervals after the operation and to identify the possible associated factors and predictors of PLCD. We also aimed to determine the effectiveness of a low-fat diet in these patients and to educate the patients about their diet after the operation.

METHODS

Data were obtained from clinical records and preoperative interviews with patients, who were also interviewed or contacted by telephone 1 week after the operation, and then surveyed by telephone 3 months later using standardized questionnaires. A total of 125 consecutive patients who were adequately informed and who had assented to accepting a prescription of a low-fat diet after undergoing laparoscopic cholecystectomy participated in this prospective study.

RESULTS

Thirty-eight patients (25.2%) had diarrhea 1 week after laparoscopic cholecystectomy and seven patients (5.7%) had diarrhea 3 months after laparoscopic cholecystectomy. The important predictors of PLCD at 1 week were a low-fat diet (B = -0.177, p = 0.000) and a high score on a preoperative diarrhea scale (B = 0.311, p = 0.031). There was no predictor for PLCD 3 months after laparoscopic cholecystectomy.

CONCLUSION

We advise patients who have undergone laparoscopic cholecystectomy to follow a low-fat diet for at least 1 week to reduce the possibility of diarrhea, especially when they are ≤45 years of age, of male sex, and had a high preoperative tendency for diarrhea.

Diverging trends in gastroenteritis hospitalizations during 2 decades in western Australian Aboriginal and non-Aboriginal children

BACKGROUND

Gastroenteritis is a major cause of pediatric morbidity. We describe temporal, spatial and seasonal trends in age-specific gastroenteritis hospitalizations among Aboriginal and non-Aboriginal Australian children during 2 decades, providing a baseline to evaluate the impact of a rotavirus vaccine program begun in 2007.

METHODS

We conducted a population-based, data linkage study of Aboriginal and non-Aboriginal births in Western Australia, 1983 to 2006, and analyzed gastroenteritis-coded hospitalizations before age 15 years in the cohort of 596,465 births. Hospitalization rates in Aboriginal and non-Aboriginal children and between geographical regions were compared between 1983 to 1994 and 1995 to 2006.

RESULTS

Gastroenteritis rates were highest in children 6-11 months of age (Aboriginal: 259.3/1000/annum; non-Aboriginal: 22.7/1000/annum). Rates declined in Aboriginal children between 1983 to 1994 and 1995 to 2006, particularly in those 12-17 months of age (309/1000 to 179/1000). Rates in non-Aboriginal children<5 years increased 10-40%. The disparity for gastroenteritis rates between Aboriginal and non-Aboriginal children<5 years declined from being 15.4 times higher to 7.6 times higher in those aged 12-17 months and from 8.4 to 4.4 in those aged 2-4 years. Rates were highest in rural and remote regions, and diverging temporal trends were seen in different geographical regions. Seasonality varied between Aboriginal and non-Aboriginal children and climatic zones.

CONCLUSIONS

This is the largest study of gastroenteritis hospitalization trends in children. We found diverging trends of gastroenteritis hospitalization rates in Aboriginal and non-Aboriginal children. Although rates have declined in Aboriginal children, disparity between Aboriginal and non-Aboriginal children continues. Our findings highlight the need to consider age, ethnicity, seasonality and climate when evaluating rotavirus vaccine programs.

Antidiarrheal properties of different extracts of Chinese herbal medicine formula Bao-Xie-Ning

OBJECTIVE

Bao-Xie-Ning (BXN), a traditional Chinese herbal medicine (CHM) formula composed of Fructus Evodiae, Flos Caryophylli and Cortex Cinnamomi, and used for the treatment of infant diarrheal illness, was subject to systematic assessment for its putative multiple pharmacodynamic effects and pharmacological antidiarrheal mechanisms.

METHODS

High-performance liquid chromatography-diode array detector-electrospray ionization-mass spectrometric/mass spectrometry was developed and validated for identification and quantification of the main constituents in different extracts of BXN. Male Kunming mice weighing 20 to 25 g were used for detecting the antidiarrheal activity of the extracts. Ethanolic extract (EE), volatile oil extract (VOE), and aqueous extract (AE) of BXN were respectively subjected to pharmacodynamic and pharmacological comparison in assessing antidiarrheal effects with senna-induced diarrhea, castor oil-induced diarrhea, acetic acid-induced writhing assay, and isolated duodenum test.

RESULTS

The highest yields of three detected components of BXN, rutaecarpine, eugenol and cinnamaldehyde were observed in EE. EE showed the most remarkable antidiarrheal activity in dose-dependent and time-dependent manners in both senna- and castor oil-induced diarrhea models, and presented dose-dependent analgesic activity in acetic acid-induced algesthesia model. In addition, EE extract of BXN also exhibited strong antimobility action on the intestine and strongest depression on spontaneous contraction of isolated duodenum.

CONCLUSION

Ethanol extraction is an efficient method to extract the active constituents of BXN. BXN extract demonstrated multiple pharmacological activities affecting the main mechanisms of diarrhea, which validated BXN's usage in the comprehensive clinical treatment of diarrhea.

Persistent diarrhea: still a serious public health problem in developing countries

Diarrhea is still responsible for high rates of morbidity and mortality in children under 5 years of age. The prolongation of the acute episode may cause digestive and absorptive malfunction and, consequently, malnutrition, raising the risk of death. The objective of this review is to supply the most recent knowledge in the field of persistent diarrhea and to contribute to the decrease of its incidence. Some possible etiologic agents may be involved, including viruses, bacteria, and parasites. Treatment must be addressed to avoid malabsorption of the nutrients of the diet, associated with replacement of the hydroelectrolytic losses, to prevent its prolongation. In the great majority of the episodes, antibiotics are not indicated. Breastfeeding, introduction of safe dietary strategies to prevent protein-energy malnutrition, and improvement of sanitary conditions and hygiene are measures to be promoted with the objective of decreasing the morbidity/mortality of the diarrheic disease in children less than 5 years of age.

Acute infectious diarrhea

Infectious diarrhea is both a local and a global concern. Illnesses can range from mild inconveniences to life-threatening epidemics. Although diarrhea can be caused by a vast array of pathogens, the cornerstone of prevention is provision of a safe food and water supply, application of basic hygiene principles, and the development and administration of vaccines. The cornerstone of treatment is rehydration. Selection of specific antimicrobial therapy should be based on disease presentation and epidemiologic factors.

Inhibition of development of Shiga toxin-converting bacteriophages by either treatment with citrate or amino acid starvation

OBJECTIVES

Shiga toxin-producing Escherichia coli (STEC) are pathogenic strains, whose virulence depends on induction of Shiga toxin-converting prophages and their subsequent lytic development. We explored which factors or conditions could inhibit development of these phages, potentially decreasing virulence of STEC.

MATERIALS AND METHODS

Lytic development of Shiga toxin-converting bacteriophages was monitored after mitomycin C-provoked prophage induction under various conditions. Phage DNA replication efficiency was assessed by measurement of DNA amount in cells using quantitative polymerase chain reaction.

RESULTS

We demonstrated that the use of citrate delayed Shiga toxin-converting phage development after prophage induction. This effect was independent on efficiency of prophage induction and phage DNA replication. However, an excess of glucose reversed the effect of citrate. Amino acid starvation prevented the phage development in bacteria both able and unable to induce the stringent response.

CONCLUSIONS

Lytic development of Shiga toxin-converting bacteriophages can be inhibited by either the presence of citrate or amino acid starvation. We suggest that the inhibition caused by the latter condition may be due to a block in prophage induction or phage DNA replication or both.

APPLICATIONS

Our findings may facilitate development of procedures for treatment of STEC-infected patients.

Replication of plasmids derived from Shiga toxin-converting bacteriophages in starved Escherichia coli

The pathogenicity of Shiga toxin-producing Escherichia coli (STEC) depends on the expression of stx genes that are located on lambdoid prophages. Effective toxin production occurs only after prophage induction, and one may presume that replication of the phage genome is important for an increase in the dosage of stx genes, positively influencing their expression. We investigated the replication of plasmids derived from Shiga toxin (Stx)-converting bacteriophages in starved E. coli cells, as starvation conditions may be common in the intestine of infected humans. We found that, unlike plasmids derived from bacteriophage λ, the Shiga toxin phage-derived replicons did not replicate in amino acid-starved relA(+) and relA(-) cells (showing the stringent and relaxed responses to starvation, respectively). The presence of the stable fraction of the replication initiator O protein was detected in all tested replicons. However, while ppGpp, the stringent response effector, inhibited the activities of the λ P(R) promoter and its homologues from Shiga toxin-converting bacteriophages, these promoters, except for λ P(R), were only weakly stimulated by the DksA protein. We suggest that this less efficient (relative to λ) positive regulation of transcription responsible for transcriptional activation of the origin contributes to the inhibition of DNA replication initiation of Shiga toxin-converting bacteriophages in starved host cells, even in the absence of ppGpp (as in starved relA(-) hosts). Possible clinical implications of these results are discussed.

Rotavirus infections and vaccines: burden of illness and potential impact of vaccination

Rotaviruses are the most common cause of severe gastroenteritis in children. By 5 years of age virtually every child worldwide will have experienced at least one rotavirus infection. This leads to an enormous disease burden, where every minute a child dies because of rotavirus infection and another four are hospitalized, at an annual societal cost in 2007 of $US2 billion. Most of the annual 527 000 deaths are in malnourished infants living in rural regions of low and middle income countries. In contrast, most measurable costs arise from medical expenses and lost parental wages in high income countries. Vaccines are the only public health prevention strategy likely to control rotavirus disease. They were developed to mimic the immunity following natural rotavirus infection that confers protection against severe gastroenteritis and consequently reduces the risk of primary healthcare utilization, hospitalization and death. The two currently licensed vaccines--one a single human strain rotavirus vaccine, the other a multiple strain human-bovine pentavalent reassortant rotavirus vaccine--are administered to infants in a two- or three-dose course, respectively, with the first dose given at 6-14 weeks of age. In various settings they are safe, immunogenic and efficacious against many different rotavirus genotypes. In high and middle income countries, rotavirus vaccines confer 85-100% protection against severe disease, while in low income regions of Africa and Asia, protection is less, at 46-77%. Despite this reduced efficacy in low income countries, the high burden of diarrheal disease in these regions means that proportionately more severe cases are prevented by vaccination than elsewhere. Post-licensure effectiveness studies show that rotavirus vaccines not only reduce rotavirus activity in infancy but they also decrease rates of rotavirus diarrhea in older and unimmunized children. A successful rotavirus vaccination program will rely upon sustained vaccine efficacy against diverse and evolving rotavirus strains and efficient vaccine delivery systems. The potential introduction of rotavirus vaccines into the world's poorest countries with the greatest rates of rotavirus-related mortality is expected to be very cost effective, while rotavirus vaccines should also be cost effective by international standards when incorporated into developed countries immunization schedules. Nonetheless, cost effectiveness in each country still depends largely on the local rotavirus mortality rate and the price of the vaccine in relation to the per capita gross domestic product.

Clostridial infection in children

A survey of the isolation of Clostridium spp. from 1543 specimens sent to anaerobic microbiology laboratories revealed 113 isolates from 107 specimens (7.0% of all specimens) from 96 children. The isolates comprised 43 (38%) unidentified Clostridium spp., 37 (33%) C. perfringens, 13 (12%) C. ramosum, five (4%) C. innocuum, six (5%) C. botulinum, three (3%) C. difficile, two (2%) C. butyricum, and one isolate each of C. bifermentans, C. clostridiiforme, C. limosum and C. paraputrificum. Most clostridial isolates were from abscesses (38), peritonitis (26), bacteraemia (10), and chronic otitis media (7). Predisposing or underlying conditions were present in 31 (32%) cases. These were immunodeficiency (12), malignancy (9), diabetes (7), trauma (7), presence of a foreign body (6) and previous surgery (6). The clostridia were the only bacterial isolates in 14 (15%) cases; 82 (85%) cases had mixed infection. The species most commonly isolated with clostridia were anaerobic cocci (57); Bacteroides spp. (B. fragilis group) (50), Escherichia coli (22), pigmented Prevotella or Porphyromonas spp. (18) and Fusobacterium spp. (10). Most Bacteroides and Escherichia coli isolates with clostridia were from abdominal infections and skin and soft tissue infections adjacent to the rectal area; most pigmented Prevotella and Porphyromonas isolates were from oropharyngeal, pulmonary, and head and neck sites. Antimicrobial therapy was given to all patients, in conjunction with surgical drainage in 34 (35%). Only two patients died. These data illustrate the importance of Clostridium spp. in paediatric infections.