Cholera, diarrhea, and oral rehydration therapy: triumph and indictment

Multistrain Probiotics Alleviate Diarrhea by Modulating Microbiome-Derived Metabolites and Serotonin Pathway

Diarrhea, a common gastrointestinal symptom in health problems, is highly associated with gut dysbiosis. The purpose of this study is to demonstrate the effect of multistrain probiotics (Sensi-Biome) on diarrhea from the perspective of the microbiome-neuron axis. Sensi-Biome (Lactiplantibacillus plantarum, Bifidobacterium animalis subsp. lactis, Lactobacillus acidophilus, Streptococcus thermophilus, Bifidobacterium bifidum, and Lactococcus lactis) was administered in a 4% acetic acid-induced diarrhea rat model at concentrations of 1 × 108 (G1), 1 × 109 (G2), and 1 × 1010 CFU/0.5 mL (G3). Diarrhea-related parameters, inflammation-related cytokines, and stool microbiota analysis by 16S rRNA were evaluated. A targeted and untargeted metabolomics approach was used to analyze the cecum samples using liquid chromatography and orbitrap mass spectrometry. The stool moisture content (p < 0.001), intestinal movement rate (p < 0.05), and pH (p < 0.05) were significantly recovered in G3. Serotonin levels were decreased in the multistrain probiotics groups. The inflammatory cytokines, serotonin, and tryptophan hydroxylase expression were improved in the Sensi-Biome groups. At the phylum level, Sensi-Biome showed the highest relative abundance of Firmicutes. Short-chain fatty acids including butyrate, iso-butyrate, propionate, and iso-valeric acid were significantly modified in the Sensi-Biome groups. Equol and oleamide were significantly improved in the multistrain probiotics groups. In conclusion, Sensi-Biome effectively controls diarrhea by modulating metabolites and the serotonin pathway.

Spectrum of ctxB genotypes, antibiogram profiles and virulence genes of Vibrio cholerae serogroups isolated from environmental water sources from Odisha, India

BACKGROUND

The present study reports on the comprehensive analysis of Vibrio cholerae O1 and non-O1/non-O139 serogroups isolated from environmental water sources during cholera outbreaks, epidemics and surveillance studies between years 2007 to 2019 from different districts of Odisha, India.

METHODS

A total of 85 stocked cultures of V. cholerae O1 and non-O1/non-O139 strains were analyzed for different ctxB genotypes, toxic genes, antibiogram profiles through PCR assays and pulsotyped by pulsed-field gel electrophoresis (PFGE).

RESULTS

From all V. cholerae strains tested, 51 isolates were O1 Ogawa and the rest 34 strains were non-O1/non-O139. All the V. cholerae O1 strains were altered El Tor variants carrying ctxB1, ctxB3 and ctxB7 genotypes. However, only ctxB1 genotypes were present in V. cholerae non-O1/non-O139. Though non-O1/non-O139 strains were negative by O1 antisera, 20% strains were positive for rfbO1 gene by PCR assay. All the V. cholerae isolates possessed a variety of virulence genes including ace, ctxAB, toxR, zot, hlyA which were in higher percentage in the case of V. cholerae O1. The Vibrio cholerae O1 and non-O1-/non-O139 strains showed multiple antibiotic resistances in 2007 and 2012. The PCR detection of four resistance associated genes (strB, dfrA1, sulll, SXT) confirmed higher prevalence in V. cholerae non-O1/non-O139 strains. The PFGE analysis revealed 3 pulsotypes having 93% similarity among V. cholerae O1 strains.

CONCLUSION

This study indicates the changing epidemiology, antibiogram patterns and continuous genetic variation in environmental V. cholerae strains of Odisha over the years. So continuous surveillance is necessary to understand the changing patterns of V. cholerae different serogroups isolated from stool and water samples from Odisha.

Cooperative defenses during enteropathogenic infection

During their co-evolution with pathogens, hosts acquired defensive health strategies that allow them to maintain their health or promote recovery when challenged with infections. The cooperative defense system is a largely unexplored branch of these evolved defense strategies. Cooperative defenses limit physiological damage and promote health without having a negative impact on a pathogen's ability to survive and replicate within the host. Here, we review recent discoveries in the new field of cooperative defenses using the model pathogens Citrobacter rodentium and Salmonella enterica. We discuss not only host-encoded but also pathogen-encoded mechanisms of cooperative defenses. Cooperative defenses remain an untapped resource in clinical medicine. With a global pandemic exacerbated by a lack of vaccine access and a worldwide rise in antibiotic resistance, the study of cooperative defenses offers an opportunity to safeguard health in the face of pathogenic infection.

Association between cholera treatment outcome and nutritional status in children aged 2-4 years in Nigeria

SETTING

Cholera can aggravate or precipitate malnutrition, and children with severe acute malnutrition (SAM) have a higher incidence and longer duration of diarrhoea.

OBJECTIVE

To describe 1) characteristics of and treatment outcomes in children aged 2-4 years with cholera, 2) the case fatality rate (CFR) in all children treated, and 3) the associations between nutritional status, hydration status, treatment administered and hospital outcomes.

DESIGN

An observational cohort study of children admitted to one cholera treatment centre in Maiduguri, Nigeria, with a focus on children aged 2-4 years. CFRs were examined by cross tabulation and mean length of stay (LOS) using analysis of variance.

RESULTS

SAM was identified in 24% of children aged 2-4 years. The CFR for children aged 2-4 years was 1.4%. As the sample size was small, we did not find any association between nutritional status and death due to cholera. The proportion of children discharged within 2 days was 79%, and the longest stay was 8 days. In general, health facility LOS increased with severity of malnutrition.

CONCLUSION

Our study found that nutritional status affected the LOS, but was unable to find an association between malnutrition and fatality among children aged 2-4 years.

Threats of antibiotic resistance: an obliged reappraisal

We are living in a society of fear, where the objectivity in estimating risks is distorted by the media and the interested parties. During more than half of a century, the feeling of antibiotic resistance as an apocalyptic phenomenon able to push our society to the high mortality rates caused by infectious diseases in the dark pre-antibiotic ages has been steadily rising. However, at the current status of modern medicine, at least in the high-medium income countries, mortality by lack of efficacy of the antibiotic armamentarium in the therapy of infections is a problem, but not a catastrophe. The threat of antibiotic resistance has many other aspects than failures of therapy in the individual patient. Among them, the increase in the frequency of severe and potentially lethal infections, as bacteremia, the population biology alterations of the healthy microbiota, the global acceleration of bacterial evolution by selecting natural genetic tools mediating microbial interactions, and, most importantly, by modifying the equilibrium and composition of environmental microbial communities. All these threats have huge implications for human health as members of a Biosphere entirely rooted in a menaced microbiosphere.

Pandemics: past, present, future: That is like choosing between cholera and plague

The major epidemic and pandemic diseases that have bothered humans since the Neolithic Age and Bronze Age are surveyed. Many of these pandemics are zoonotic infections, and the mathematical modeling of such infections is illustrated. Plague, cholera, syphilis, influenza, SARS, MERS, COVID‐19, and new potential epidemic and pandemic infections and their consequences are described and the background for the spread of acute and chronic infections and the transition to endemic infections is discussed. The way we can prevent and fight pandemics is illustrated from the old and new well‐known pandemics. Surprisingly, the political reactions through different periods have not changed much during the centuries.

A thermo-responsive supramolecular hydrogel that senses cholera toxin via color-changing response

A Pyrene-based hydrogel with terminal lactose residue has been developed for the detection of cholera toxin via color changing response, accompanied by gel to sol transition.

Mapping cholera outbreaks and antibiotic resistant Vibrio cholerae in India: An assessment of existing data and a scoping review of the literature

Although fluid and electrolyte replenishment remains the mainstay of clinical management of cholera, antibiotics are an important component of the strategy for clinical management of moderate to severe cases of cholera. The emergence of antibiotic resistance (ABR) in Vibrio cholerae has led to difficulties in case management. The past decade has also seen the development of cheap and effective oral cholera vaccines (OCVs). In addition to the two-dose strategy for widespread immunization, OCVs have also been shown to be effective in containing outbreaks using a single-dose schedule. In this scoping review we map the states and union territories (SUTs) of India which are prone to cholera outbreaks followed by a scoping review of peer-reviewed publications about ABR outbreaks of cholera employing the Arksey and O'Malley framework. Using the data reported by the Integrated Disease Surveillance Program (IDSP), we identified 559 outbreaks of cholera between 2009 and 2017, affecting 27 SUTs. We defined SUTs which had reported outbreaks in at least three out of the last five years (2012-2016) or had experienced two or more outbreaks in the same year in at least two of the last five years to be outbreak-prone. The scoping review identified 62 ABR outbreaks, with four SUTs accounting for two-thirds of them: West Bengal (14), Maharashtra (10), Odisha (10) and Delhi (7). Overall, this scoping review suggests that there is an increasing trend of ABR in Vibrio cholerae isolated from outbreaks in India. This opens up avenues for exploring the role of antibiotic stewardship in the clinical management of diarrhea, the institution of vaccination as an infection prevention intervention to reduce selection pressure, and the deployment of high quality surveillance systems which report accurate, real-time data allowing appropriate and timely public health responses. It is crucial to counter the issue of ABR in cholera before it assumes a menacing magnitude.

Principles and Practice of Oral Rehydration

PURPOSE OF REVIEW

An understanding of fluid and electrolyte losses from diarrhea and mechanisms of solute cotransport led to development of oral rehydration solution (ORS), representing a watershed in efforts to reduce diarrheal disease morbidity and mortality. This report reviews the scientific rationale and modifications of ORS and barriers to universal application.

RECENT FINDINGS

Solutions with osmolality and electrolyte composition different from original ORS for routine and unique pathophysiology such as in malnutrition have met with varying success. Following the conceptual rationale of sodium-glucose cotransportation to facilitate water absorption, other cotransporters and formulations have been explored with the aim to improve ORS efficacy and acceptance. ORS remains the anchor of acute watery diarrhea and dehydration management worldwide. Despite development of different formulations, the current standard solution is the mainstay of treatment for nearly all situations. Efforts to improve oral hydration solution and to increase acceptance and usage are ongoing.

Antibiotic therapy in acute gastroenteritis: a single-center retrospective cohort study

Background:

Acute gastroenteritis (AGE) is a common reason for emergency department visits and hospitalizations. The role of antibiotics in AGE is unclear, as the current literature shows only a minor impact on the duration of symptoms and the overall clinical course. Our goal was to assess whether antibiotic therapy in patients with AGE affects the length of hospital stay (LOS).

Methods:

In a retrospective study, we evaluated 479 patients admitted to the hospital with a diagnosis of AGE. The study compared the 219 patients (46%) treated with antibiotics to the remainder treated with supportive therapy. The diagnosis of AGE was made either clinically or based on imaging findings. The primary outcome of this study was to compare the LOS in days between both groups.

Results:

Patients treated with antibiotics had a similar LOS to those treated with supportive therapy (2.62 vs. 2.66 days, P=0.77). Patients with presumed sepsis had a higher likelihood of receiving antibiotics compared to those without presumed sepsis (risk ratio 1.49, 62.5% vs. 41.95%; P<0.001). In this subgroup, patients who received antibiotics had a slightly shorter LOS than those who received only supportive therapy, but the difference was not statistically significant (2.09 vs. 2.54 days, P=0.69).

Conclusion:

We found no difference in the LOS for hospitalized patients with AGE treated with antibiotics when compared to supportive therapy. This calls into question the role of antibiotics in the management of AGE.

Virulence gene profiles, biofilm formation, and antimicrobial resistance of Vibrio cholerae non-O1/non-O139 bacteria isolated from West Bengal, India

Vibrio cholerae is the causative agent of acute dehydrating diarrhoeal disease cholera. Among 71 V. cholerae non-O1/non-O139 isolates, all yielded negative results for ctxA, ctxB and tcpA genes in PCR assay. Few strains were positive for stn (28.38%), and ompU (31.08%) genes. While all isolates were negative for ace gene, only two were positive for zot gene. All strains expressed toxR and toxT genes. It was also found that all isolates were slime-producer and these were capable of forming moderate to high biofilm. Biofilm formation was controlled positively by the transcriptional regulators VpsR and VpsT and was regulated negatively by HapR, as well as CRP regulatory complex. These isolates were resistant to ampicillin, furazolidone, doxycycline, vancomycin, erythromycin, while these were susceptible to ciprofloxacin, gentamycin, kanamycin, polymixin B, norfloxacin, chloramphenicol, sulphamethoxazole-trimethoprim, tetracycline, nalidixic acid, and streptomycin. Indeed, 69.01% isolates were resistant to multiple antibiotics (MAR: resistance to 3 or more antibiotics). Treatment protocols for cholera patients should be based on local antibiogram data.

Patterns of triclosan resistance in Vibrionaceae

The antimicrobial additive triclosan has been used in personal care products widely across the globe for decades. Triclosan resistance has been noted among Vibrio spp., but reports have been anecdotal and the extent of phenotypic triclosan resistance across the Vibrionaceae family has not been established. Here, triclosan resistance was determined for Vibrionaceae strains across nine distinct clades. Minimum inhibitory concentrations (MIC) were determined for 70 isolates from clinical (n = 6) and environmental sources (n = 64); only two were susceptible to triclosan. The mean MIC for all resistant Vibrionaceae was 53 µg mL-1 (range 3.1-550 µg mL-1), but was significantly different between clades (p < 0.001). The highest mean triclosan MIC was observed in the Splendidus clade (200 µg mL-1; n = 3). Triclosan mean MICs were 68.8 µg mL-1 in the Damselae clade and 45.3 µg mL-1 in the Harveyi clade. The lowest mean MIC was observed in the Cholerae clade with 14.4 µg mL-1, which was primarily represented by clinical strains. There were no significant differences in triclosan MIC among individual species or among environmental strains isolated from different locations. Overall, phenotypic triclosan resistance appears to be widespread across multiple clades of Vibrionaceae.

Inability to reduce morbidity of diarrhea by ORS: can we design a better therapy?

Diarrheal disease is a worldwide problem that still causes significant morbidity and mortality among children. Currently, oral rehydration solution (ORS) is the standard of care for acute diarrhea in pediatric patients. Although effective in reducing mortality, ORS does not alleviate diarrheal symptoms, thus reducing caregiver compliance and therapeutic efficacy. This article will briefly review the current problem of pediatric diarrhea and the shortcomings of current therapies; however, the focus of this review is to examine the intestinal calcium-sensing receptor (CaSR). The author summarizes the evidence suggesting that targeting the CaSR will enable clinicians to address all four major pathophysiological mechanisms of diarrheal disease, and substantiates the need for future research regarding this therapy.

Vibrio Pathogens: A Public Health Concern in Rural Water Resources in Sub-Saharan Africa

Members of the Vibrio genus are autochthonous inhabitants of aquatic environments and play vital roles in sustaining the aquatic milieu. The genus comprises about 100 species, which are mostly of marine or freshwater origin, and their classification is frequently updated due to the continuous discovery of novel species. The main route of transmission of Vibrio pathogens to man is through drinking of contaminated water and consumption inadequately cooked aquatic food products. In sub-Saharan Africa and much of the developing world, some rural dwellers use freshwater resources such as rivers for domestic activities, bathing, and cultural and religious purposes. This review describes the impact of inadequately treated sewage effluents on the receiving freshwater resources and the associated risk to the rural dwellers that depends on the water. Vibrio infections remain a threat to public health. In the last decade, Vibrio disease outbreaks have created alertness on the personal, economic, and public health uncertainties associated with the impact of contaminated water in the aquatic environment of sub-Saharan Africa. In this review, we carried out an overview of Vibrio pathogens in rural water resources in Sub-Saharan Africa and the implication of Vibrio pathogens on public health. Continuous monitoring of Vibrio pathogens among environmental freshwater and treated effluents is expected to help reduce the risk associated with the early detection of sources of infection, and also aid our understanding of the natural ecology and evolution of Vibrio pathogens.

Anti-Vibriocholerae IgY Antibody Inhibits Mortality in Suckling Mice Model

BACKGROUND

Regarding to the importance of cholera in Iran and the potential advantages of egg yolk antibody (IgY) for immunotherapy, the aim of this study was to produce IgY antibody against V. cholerae Lipopolysaccharide (LPS) and determine its potential for V. cholerae treatment.

METHODS

LPS was prepared, and the Anti-V. cholerae LPS IgY was purified from egg yolk and serially diluted in phosphate-buffered saline (PBS), mixed with V. cholerae and then gavaged into several groups of suckling mice.

RESULTS

The yield of Anti-LPS IgY extraction was 40 mg/Egg yolk. The results demonstrated that up to approximately 75 ng of IgY can detect specifically V. cholerae. The lowest protective dose of anti-V. cholerae LPS IgY was 2.5 μg.

CONCLUSIONS

The produced anti-Vibrio LPS specific IgY showed a good reactivity with its specific antigen and it may use as a complimentary oral immunotherapy for cholera disease.

Effect of Dietary Minerals on Virulence Attributes of Vibrio cholerae

Vibrio cholerae is a water-borne pathogen responsible for causing a toxin-mediated profuse diarrhea in humans, leading to severe dehydration and death in unattended patients. With increasing reports of antibiotic resistance in V. cholerae, there is a need for alternate interventional strategies for controlling cholera. A potential new strategy for treating infectious diseases involves targeting bacterial virulence rather than growth, where a pathogen’s specific mechanisms critical for causing infection in hosts are inhibited. Since bacterial motility, intestinal colonization and cholera toxin are critical components in V. cholerae pathogenesis, attenuating these virulence factors could potentially control cholera in humans. In this study, the efficacy of sub-inhibitory concentration (SIC, highest concentration not inhibiting bacterial growth) of essential minerals, zinc (Zn), selenium (Se), and manganese (Mn) in reducing V. cholerae motility and adhesion to intestinal epithelial cells (Caco-2), cholera toxin production, and toxin binding to the ganglioside receptor (GM1) was investigated. Additionally, V. cholerae attachment and toxin production in an ex vivo mouse intestine model was determined. Further, the effect of Zn, Se and Mn on V. cholerae virulence genes, ctxAB (toxin production), fliA (motility), tcpA (intestinal colonization), and toxR (master regulon) was determined using real-time quantitative PCR. All three minerals significantly reduced V. cholerae motility, adhesion to Caco-2 cells, and cholera toxin production in vitro, and decreased adhesion and toxin production in mouse intestine ex vivo (P < 0.05). In addition, Zn, Se, and Mn down-regulated the transcription of virulence genes, ctxAB, fliA, and toxR. Results suggest that Zn, Se, and Mn could be potentially used to reduce V. cholerae virulence. However, in vivo studies in an animal model are necessary to validate these results.

Efficacy of three feeding regimens for home-based management of children with uncomplicated severe acute malnutrition: a randomised trial in India

OBJECTIVE

To assess the efficacy of ready-to-use therapeutic food (RUTF), centrally produced RUTF (RUTF-C) or locally prepared RUTF (RUTF-L) for home-based management of uncomplicated severe acute malnutrition (SAM) compared with micronutrient-enriched (augmented) energy-dense home-prepared foods (A-HPF, the comparison group).

METHODS

In an individually randomised multicentre trial, we enrolled 906 children aged 6-59 months with uncomplicated SAM. The children enrolled were randomised to receive RUTF-C, RUTF-L or A-HPF. We provided foods, counselling and feeding support until recovery or 16 weeks, whichever was earlier and measured outcomes weekly (treatment phase). We subsequently facilitated access to government nutrition services and measured outcomes once 16 weeks later (sustenance phase). The primary outcome was recovery during treatment phase (weight-for-height ≥-2 SD and absence of oedema of feet).

RESULTS

Recovery rates with RUTF-L, RUTF-C and A-HPF were 56.9%, 47.5% and 42.8%, respectively. The adjusted OR was 1.71 (95% CI 1.20 to 2.43; p=0.003) for RUTF-L and 1.28 (95% CI 0.90 to 1.82; p=0.164) for RUTF-C compared with A-HPF. Weight gain in the RUTF-L group was higher than in the A-HPF group (adjusted difference 0.90 g/kg/day, 95% CI 0.30 to 1.50; p=0.003). Time to recovery was shorter in both RUTF groups. Morbidity was high and similar across groups. At the end of the study, the proportion of children with weight-for-height Z-score (WHZ) >-2 was similar (adjusted OR 1.12, 95% CI 0.74 to 1.95; p=0.464), higher for moderate malnutrition (WHZ<-2 and ≥-3; adjusted OR 1.46, 95% CI 1.02 to 2.08; p=0.039), and lower for those with SAM (adjusted OR 0.58, 95% CI 0.40 to 0.85; p=0.005) in the RUTF-L when compared with the A-HPF group.

CONCLUSIONS

This first randomised trial comparing options for home management of uncomplicated SAM confirms that RUTF-L is more efficacious than A-HPF at home. Recovery rates were lower than in African studies, despite longer treatment and greater support for feeding.

TRIAL REGISTRATION NUMBER

NCT01705769; Pre-results.

Transmission of Infectious Vibrio cholerae through Drinking Water among the Household Contacts of Cholera Patients (CHoBI7 Trial)

Recurrent cholera causes significant morbidity and mortality among the growing population of Dhaka, the capital city of Bangladesh. Previous studies have demonstrated that household contacts of cholera patients are at >100 times higher risk of cholera during the week after the presentation of the index patient. Our prospective study investigated the mode of transmission of Vibrio cholerae, the cause of cholera, in the households of cholera patients in Dhaka city. Out of the total 420 rectal swab samples analyzed from 84 household contacts and 330 water samples collected from 33 households, V. cholerae was isolated from 20%(17/84) of household contacts, 18%(6/33) of stored drinking water, and 27%(9/33) of source water samples. Phenotypic and molecular analyses results confirmed the V. cholerae isolates to be toxigenic and belonging to serogroup O1 biotype El Tor (ET) possessing cholera toxin of classical biotype (altered ET). Phylogenetic analysis by pulsed-field gel electrophoresis (PFGE) showed the V. cholerae isolates to be clonally linked, as >95% similarity was confirmed by sub-clustering patterns in the PFGE (NotI)-based dendrogram. Mapping results showed cholera patients to be widely distributed across 25 police stations. The data suggesting the transmission of infectious V. cholerae within the household contacts of cholera patients through drinking water underscores the need for safe water to prevent spread of cholera and related deaths in Dhaka city.

Expression of serotonin receptors in the colonic tissue of chronic diarrhea rats

BACKGROUND/AIMS

This study aimed to investigate the difference among the expression of serotonin receptors (5-HT3, 5-HT4, and 5-HT7receptors) in colonic tissue of chronic diarrhea rats.

MATERIALS AND METHODS

A rat model of chronic diarrhea was established by lactose diet. The expression of 5-HT3, 5-HT4, and 5-HT7receptors in the colonic tissue was detected using immunohistochemistry, real-time PCR and Western blotting techniques.

RESULTS

There is no significant difference on the protein expression of 5-HT3receptor between the normal group and the chronic diarrhea model group. The mRNA expression of 5-HT3receptor in the chronic diarrhea model group was significantly lower than that in the normal group (n = 10; P< 0.01). The protein and mRNA expression of 5-HT4receptor in the chronic diarrhea model group were significantly higher than those in the normal group (n = 10; P< 0.05, P< 0.01). On the contrary, the protein and mRNA expressions of 5-HT7receptor in the chronic diarrhea model group were significantly decreased compared with the normal group (n = 10; P< 0.01, P< 0.01).

CONCLUSIONS

The results suggested the receptors of 5-HT4and 5-HT7may be involved in inducing diarrhea by lactose diet.

Mass vaccination with a two-dose oral cholera vaccine in a long-standing refugee camp, Thailand

BACKGROUND

During 2005-2012, surveillance in Maela refugee camp, Thailand, identified four cholera outbreaks, with rates up to 10.7 cases per 1000 refugees. In 2013, the Thailand Ministry of Public Health sponsored a two-dose oral cholera vaccine (OCV) campaign for the approximately 46,000 refugees living in Maela.

METHODS

We enumerated the target population (refugees living in Maela who are ≥1 year old and not pregnant) in a census three months before the campaign and issued barcoded OCV cards to each individual. We conducted the campaign using a fixed-post strategy during two eight-day rounds plus one two-day round for persons who had missed their second dose and recorded vaccine status for each individual. To identify factors associated with no vaccination (versus at least one dose) and those associated with adverse events following immunization (AEFI), we used separate marginal log-binomial regression models with robust variance estimates to account for household clustering.

RESULTS

A total of 63,057 OCV doses were administered to a target population of 43,485 refugees. An estimated 35,399 (81%) refugees received at least one dose and 27,658 (64%) received two doses. A total of 993 additional doses (1.5%) were wasted including 297 that were spat out. Only 0.05% of refugees, mostly children, could not be vaccinated due to repeated spitting. Characteristics associated with no vaccination (versus at least one dose) included age ≥15 years (versus 1-14 years), Karen ethnicity (versus any other ethnicity) and, only among adults 15-64 years old, male sex. Passive surveillance identified 84 refugees who experienced 108 AEFI including three serious but coincidental events. The most frequent AEFI were nausea (49%), dizziness (38%), and fever (30%). Overall, AEFI were more prevalent among young children and older adults.

CONCLUSIONS

Our results suggest that mass vaccination in refugee camps with a two-dose OCV is readily achievable and AEFI are few.

(p)ppGpp, a Small Nucleotide Regulator, Directs the Metabolic Fate of Glucose in Vibrio cholerae

When V. cholerae encounters nutritional stress, it activates (p)ppGpp-mediated stringent response. The genes relA and relV are involved in the production of (p)ppGpp, whereas the spoT gene encodes an enzyme that hydrolyzes it. Herein, we show that the bacterial capability to produce (p)ppGpp plays an essential role in glucose metabolism. The V. cholerae mutants defective in (p)ppGpp production (i.e. ΔrelAΔrelV and ΔrelAΔrelVΔspoT mutants) lost their viability because of uncontrolled production of organic acids, when grown with extra glucose. In contrast, the ΔrelAΔspoT mutant, a (p)ppGpp overproducer strain, exhibited better growth in the presence of the same glucose concentration. An RNA sequencing analysis demonstrated that transcriptions of genes consisting of an operon for acetoin biosynthesis were markedly elevated in N16961, a seventh pandemic O1 strain, but not in its (p)ppGpp(0) mutant during glucose-stimulated growth. Transposon insertion in acetoin biosynthesis gene cluster resulted in glucose-induced loss of viability of the ΔrelAΔspoT mutant, further suggesting the crucial role of acetoin production in balanced growth under glucose-rich environments. Additional deletion of the aphA gene, encoding a negative regulator for acetoin production, failed to rescue the (p)ppGpp(0) mutant from the defective glucose-mediated growth, suggesting that (p)ppGpp-mediated acetoin production occurs independent of the presence of AphA. Overall, our results reveal that (p)ppGpp, in addition to its well known role as a stringent response mediator, positively regulates acetoin production that contributes to the successful glucose metabolism and consequently the proliferation of V. cholerae cells under a glucose-rich environment, a condition that may mimic the human intestine.

The molecular basis for control of ETEC enterotoxin expression in response to environment and host

Enterotoxigenic Escherichia coli (ETEC) cause severe diarrhoea in humans and neonatal farm animals. Annually, 380,000 human deaths, and multi-million dollar losses in the farming industry, can be attributed to ETEC infections. Illness results from the action of enterotoxins, which disrupt signalling pathways that manage water and electrolyte homeostasis in the mammalian gut. The resulting fluid loss is treated by oral rehydration. Hence, aqueous solutions of glucose and salt are ingested by the patient. Given the central role of enterotoxins in disease, we have characterised the regulatory trigger that controls toxin production. We show that, at the molecular level, the trigger is comprised of two gene regulatory proteins, CRP and H-NS. Strikingly, this renders toxin expression sensitive to both conditions encountered on host cell attachment and the components of oral rehydration therapy. For example, enterotoxin expression is induced by salt in an H-NS dependent manner. Furthermore, depending on the toxin gene, expression is activated or repressed by glucose. The precise sensitivity of the regulatory trigger to glucose differs because of variations in the regulatory setup for each toxin encoding gene.

Cholera transmission dynamic models for public health practitioners

Great progress has been made in mathematical models of cholera transmission dynamics in recent years. However, little impact, if any, has been made by models upon public health decision-making and day-to-day routine of epidemiologists. This paper provides a brief introduction to the basics of ordinary differential equation models of cholera transmission dynamics. We discuss a basic model adapted from Codeço (2001), and how it can be modified to incorporate different hypotheses, including the importance of asymptomatic or inapparent infections, and hyperinfectious V. cholerae and human-to-human transmission. We highlight three important challenges of cholera models: (1) model misspecification and parameter uncertainty, (2) modeling the impact of water, sanitation and hygiene interventions and (3) model structure. We use published models, especially those related to the 2010 Haitian outbreak as examples. We emphasize that the choice of models should be dictated by the research questions in mind. More collaboration is needed between policy-makers, epidemiologists and modelers in public health.

Postgenomic approaches to cholera vaccine development

Cholera remains an important public health threat. A cholera vaccine that provides durable protection at the mucosal surface, especially among children in endemic settings, is urgently needed. The availability of the complete genome sequence of a clinical isolate of Vibrio cholerae O1 El Tor has allowed for comparative and functional genomic approaches in the study of cholera. This work holds promise for the identification of bacterial targets of protective human immune responses and may contribute to the development of a new generation of cholera vaccines.

Comparative genome analysis of non-toxigenic non-O1 versus toxigenic O1 Vibrio cholerae

Pathogenic strains of Vibrio cholerae are responsible for endemic and pandemic outbreaks of the disease cholera. The complete toxigenic mechanisms underlying virulence in Vibrio strains are poorly understood. The hypothesis of this work was that virulent versus non-virulent strains of V. cholerae harbor distinctive genomic elements that encode virulence. The purpose of this study was to elucidate genomic differences between the O1 serotypes and non-O1 V. cholerae PS15, a non-toxigenic strain, in order to identify novel genes potentially responsible for virulence. In this study, we compared the whole genome of the non-O1 PS15 strain to the whole genomes of toxigenic serotypes at the phylogenetic level, and found that the PS15 genome was distantly related to those of toxigenic V. cholerae. Thus we focused on a detailed gene comparison between PS15 and the distantly related O1 V. cholerae N16961. Based on sequence alignment we tentatively assigned chromosome numbers 1 and 2 to elements within the genome of non-O1 V. cholerae PS15. Further, we found that PS15 and O1 V. cholerae N16961 shared 98% identity and 766 genes, but of the genes present in N16961 that were missing in the non-O1 V. cholerae PS15 genome, 56 were predicted to encode not only for virulence-related genes (colonization, antimicrobial resistance, and regulation of persister cells) but also genes involved in the metabolic biosynthesis of lipids, nucleosides and sulfur compounds. Additionally, we found 113 genes unique to PS15 that were predicted to encode other properties related to virulence, disease, defense, membrane transport, and DNA metabolism. Here, we identified distinctive and novel genomic elements between O1 and non-O1 V. cholerae genomes as potential virulence factors and, thus, targets for future therapeutics. Modulation of such novel targets may eventually enhance eradication efforts of endemic and pandemic disease cholera in afflicted nations.

Small-molecule inhibitors of toxT expression in Vibrio cholerae

Vibrio cholerae, a Gram-negative bacterium, infects humans and causes cholera, a severe disease characterized by vomiting and diarrhea. These symptoms are primarily caused by cholera toxin (CT), whose production by V. cholerae is tightly regulated by the virulence cascade. In this study, we designed and carried out a high-throughput chemical genetic screen to identify inhibitors of the virulence cascade. We identified three compounds, which we named toxtazin A and toxtazin B and B', representing two novel classes of toxT transcription inhibitors. All three compounds reduce production of both CT and the toxin-coregulated pilus (TCP), an important colonization factor. We present evidence that toxtazin A works at the level of the toxT promoter and that toxtazins B and B' work at the level of the tcpP promoter. Treatment with toxtazin B results in a 100-fold reduction in colonization in an infant mouse model of infection, though toxtazin A did not reduce colonization at the concentrations tested. These results add to the growing body of literature indicating that small-molecule inhibitors of virulence genes could be developed to treat infections, as alternatives to antibiotics become increasingly needed.

IMPORTANCE

V. cholerae caused more than 580,000 infections worldwide in 2011 alone (WHO, Wkly. Epidemiol. Rec. 87:289-304, 2012). Cholera is treated with an oral rehydration therapy consisting of water, glucose, and electrolytes. However, as V. cholerae is transmitted via contaminated water, treatment can be difficult for communities whose water source is contaminated. In this study, we address the need for new therapeutic approaches by targeting the production of the main virulence factor, cholera toxin (CT). The high-throughput screen presented here led to the identification of two novel classes of inhibitors of the virulence cascade in V. cholerae, toxtazin A and toxtazins B and B'. We demonstrate that (i) small-molecule inhibitors of virulence gene production can be identified in a high-throughput screen, (ii) targeting virulence gene production is an effective therapeutic strategy, and (iii) small-molecule inhibitors can uncover unknown layers of gene regulation, even in well-studied regulatory cascades.

Comparison between normal saline and a polyelectrolyte solution for fluid resuscitation in severely dehydrated infants with acute diarrhoea

The optimal intravenous solution for rehydration of infants and children with severe dehydration is debated.

AIM

The aim was to compare the efficacy of a polyelectrolyte solution (group PS) with sodium chloride 0.9% solution (group NS) in rapid parenteral rehydration of severely dehydrated infants with acute diarrhoea.

METHODS

Primary outcomes were volume and time to hydration. Secondary outcomes were urea, creatinine, electrolytes, glucose, arterial pH and bicarbonate levels. Patients were assigned randomly and openly to one of the two treatment groups. Severe dehydration was defined as one or more of the following associated with any other sign of dehydration: depressed consciousness, a weak or absent pulse or capillary refill time > 10 sec. Peripheral blood samples for chemical pathology were collected before and after rapid fluid therapy. The mean age of the 36 enrolled infants was 9.1 mths. All had depressed consciousness or severe hypotension/shock. The fluid infusion rate was 50 ml/kg/hr until haemodynamic stability was restored (absence of severe hypotension and two urine emissions). Fluid volume, time to rehydration and weight before and after rehydration were recorded.

RESULTS

All infants recovered full pulse within 1 hr; most had a better level of consciousness or capillary refill <3 sec. Group NS (15 infants) showed (before and after treatment, respectively) a decrease of plasma potassium (3.4 to 3.1 mmol/L, p=0.07), bicarbonate (13.3 to 12.2 mmol/L, p=0.01) and glucose (8.2 to 5.8 mmol/L, p<0.01). Group PS (21 infants) showed a decrease of potassium (4.4 to 3.2 mmol/L, p<0.01) but an increase in bicarbonate (11.6 to 13.3 mmol/L, p<0.01) and glucose (11.4 to 14.8 mmol/L, p=0.08).

CONCLUSION

Polyelectrolyte solution was as effective as normal saline on volume expansion and better for correcting acidosis.

Robert K. Crane-Na(+)-glucose cotransporter to cure?

Dr. Robert K. Crane made major contributions to our understanding of carbohydrate metabolism and transport of the intestine over a very long and productive career. This Perspective examines, briefly, his early life and academic positions, but more importantly, this Perspective highlights his contributions to the understanding of coupled Na(+)-glucose absorption by the small intestine. I discuss how his early hypothesis of a "cotransport" of sodium and glucose ushered in and provided the physiological explanation for the clinical treatment of acute diarrhea and cholera when using oral rehydration therapy (ORT). ORT saves millions of lives each year. Certainly, humankind is better off because of Crane's hypothesis of the Na(+)-glucose cotransporter that he put forth over 50 years ago?

Development of a Spatial and Temporal Agent-Based Model for Studying Water and Health Relationships: The Case Study of Two Villages in Limpopo, South Africa

Diarrhea, the second leading cause of child morbidity and mortality, can have detrimental effects in the physical and cognitive development of children in developing countries. Health interventions (e.g., increased access to health services and safe water) designed to address this problem are difficult to implement in resource-limited settings. In this paper, we present a tool for understanding the complex relationship between water and public health in rural areas of a developing country. A spatial and temporal agent-based model (ABM) was developed to simulate the current water, sanitation, and health status in two villages in Limpopo Province, South Africa. The model was calibrated using empirical data and published sources. It was used to simulate the effects of poor water quality on the frequency of diarrheal episodes in children, and consequently on child development. Preliminary simulation results show that at the current total coliform levels in the water sources of the studied villages, children are expected to experience stunting by as much as -1.0 standard deviations from the World Health Organization height norms. With minor modifications, the calibrated ABM can be used to design and evaluate intervention strategies for improving child health in these villages. The model can also be applied to other regions worldwide that face the same environmental challenges and conditions as the studied villages.

Ecology of Vibrio parahaemolyticus and Vibrio vulnificus in the coastal and estuarine waters of Louisiana, Maryland, Mississippi, and Washington (United States)

Vibrio parahaemolyticus and Vibrio vulnificus, which are native to estuaries globally, are agents of seafood-borne or wound infections, both potentially fatal. Like all vibrios autochthonous to coastal regions, their abundance varies with changes in environmental parameters. Sea surface temperature (SST), sea surface height (SSH), and chlorophyll have been shown to be predictors of zooplankton and thus factors linked to vibrio populations. The contribution of salinity, conductivity, turbidity, and dissolved organic carbon to the incidence and distribution of Vibrio spp. has also been reported. Here, a multicoastal, 21-month study was conducted to determine relationships between environmental parameters and V. parahaemolyticus and V. vulnificus populations in water, oysters, and sediment in three coastal areas of the United States. Because ecologically unique sites were included in the study, it was possible to analyze individual parameters over wide ranges. Molecular methods were used to detect genes for thermolabile hemolysin (tlh), thermostable direct hemolysin (tdh), and tdh-related hemolysin (trh) as indicators of V. parahaemolyticus and the hemolysin gene vvhA for V. vulnificus. SST and suspended particulate matter were found to be strong predictors of total and potentially pathogenic V. parahaemolyticus and V. vulnificus. Other predictors included chlorophyll a, salinity, and dissolved organic carbon. For the ecologically unique sites included in the study, SST was confirmed as an effective predictor of annual variation in vibrio abundance, with other parameters explaining a portion of the variation not attributable to SST.

Garcinia buchananii bark extract is an effective anti-diarrheal remedy for lactose-induced diarrhea

ETHNOPHARMACOLOGICAL RELEVANCE

The extract from the stem bark of Garcinia buchananii trees is used as an anti-diarrhea remedy in sub-Saharan Africa. We tested the hypothesis that G. buchananii bark extract and its anti-motility fractions are effective treatments against lactose-induced diarrhea.

MATERIALS AND METHODS

A high-lactose (35%) diet was used to induce diarrhea in Wistar rats, which were then treated with either G. buchananii bark extract (0.1, 0.5, 1.0 and 5.0 g bark powder), and its anti-motility fractions isolated using preparative thin layer chromatography; termed PTLC1 (15 mg) and PTLC5 (3.8 mg) or loperamide (8.4 mg). Drug preparations were dissolved in 1L except PTCL1 and PTLC5 that were dissolved in 100mL tap water. Numerous parameters were measured in each condition including consistency, fluid and mucus content of feces, body weight, water and food consumption, urine production and bloating.

RESULTS

Diarrheic rats produced watery or loose, mucuoid, sticky, feces. Fluids constituted 86% of stool mass compared with only 42% for control rats fed standard chow. Compared with controls, diarrheic rats produced more urine, lost weight and had bloated ceca and colons. All doses of the extract, its anti-motility fractions and loperamide individually stopped diarrhea within 6-24 h of administration, whilst significantly reducing mucus and fecal fluid content, urine production and intestinal bloating. Rats treated with 0.1g extract, PTLC1 and PTLC5 gained weight, whilst PTLC5 also increased water intake.

CONCLUSIONS

Garcinia buchananii extract and its anti-motility fractions are effective remedies against lactose-induced diarrhea. The extract contains compounds that reverse weight loss, promote food and water intake, supporting the notion that characterization of the compounds could lead to new therapies against diarrheal diseases.

Cholera

Cholera is an acute, secretory diarrhoea caused by infection with Vibrio cholerae of the O1 or O139 serogroup. It is endemic in more than 50 countries and also causes large epidemics. Since 1817, seven cholera pandemics have spread from Asia to much of the world. The seventh pandemic began in 1961 and affects 3-5 million people each year, killing 120,000. Although mild cholera can be indistinguishable from other diarrhoeal illnesses, the presentation of severe cholera is distinct, with pronounced diarrhoeal purging. Management of patients with cholera involves aggressive fluid replacement; effective therapy can decrease mortality from more than 50% to less than 0·2%. Antibiotic treatment decreases volume and duration of diarrhoea by 50% and is recommended for patients with moderate to severe dehydration. Prevention of cholera depends on access to safe water and sanitation. Two oral cholera vaccines are available and the most effective use of these in integrated prevention programmes is being actively assessed.

Deciphering the mechanisms of the Na+/H+ exchanger-3 regulation in organ dysfunction

The Na+/H+ exchanger-3 (NHE3) belongs to the mammalian NHE protein family and catalyzes the electro-neutral exchange of extracellular sodium for intracellular proton across cellular membranes. Its transport function is of essential importance for the maintenance of the body's salt and water homeostasis as well as acid-base balance. Indeed, NHE3 activity is finely regulated by a variety of stimuli, both acutely and chronically, and its transport function is fundamental for a multiplicity of severe and world-wide infection-pathological conditions. This review aims to provide a concise overview of NHE3 physiology and discusses the role of NHE3 in clinical conditions of prominent importance, specifically in hypertension, diabetic nephropathy, heart failure, acute kidney injury, and diarrhea. Study of NHE3 function in models of these diseases has contributed to the deciphering of mechanisms that control the delicate ion balance disrupted in these disorders. The majority of the findings indicate that NHE3 transport function is activated before the onset of hypertension and inhibited thereafter; NHE3 transport function is also upregulated in diabetic nephropathy and heart failure, while it is reported to be downregulated in acute kidney injury and in diarrhea. The molecular mechanisms activated during these pathological conditions to regulate NHE3 transport function are examined with the aim of linking NHE3 dysfunction to the analyzed clinical disorders.

Suppressed induction of proinflammatory cytokines by a unique metabolite produced by Vibrio cholerae O1 El Tor biotype in cultured host cells

Vibrio cholerae O1 has two biotypes, El Tor and Classical, and the latter is now presumed to be extinct in nature. Under carbohydrate-rich growth conditions, El Tor biotype strains produce the neutral fermentation end product 2,3-butanediol (2,3-BD), which prevents accumulation of organic acids from mixed acid fermentation and thus avoids a lethal decrease in the medium pH, while the Classical biotype strains fail to do the same. In this study, we investigated the inhibitory effect of 2,3-BD on the production of two proinflammatory biomarkers, intreleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α), in human intestinal epithelial HT29 and alveolar epithelial A549 cells. Cell-free culture supernatants of El Tor strain N16961 grown in LB supplemented with 1% glucose induced a negligible amount of IL-8 or TNF-α, while the Classical O395 strain induced much higher levels of these proinflammatory cytokines. On the other hand, three mutant strains constructed from the N16961 strain with defects in the constitutive 2,3-BD pathway were also able to induce high levels of cytokines. When HT29 and A549 cells were treated with bacterial flagella, known proinflammatory cytokine inducers, and chemically synthesized 2,3-BD at various concentrations, a dose-dependent decrease in IL-8 and TNF-α production was observed, demonstrating the suppressive effect of 2,3-BD on the production of proinflammatory cytokines in epithelial cells. Upon cotreatment with extraneous 2,3-BD, elevated levels of IκBα, the inhibitor of the NF-κB pathway, were detected in both HT29 and A549 cells. Furthermore, treatments containing 2,3-BD elicited lower levels of NF-κB-responsive luciferase activity, demonstrating that the reduced cytokine production is likely through the inhibition of the NF-κB pathway. These results reveal a novel and potential role of 2,3-BD as an immune modulator that might have conferred a superior pathogenic potential of the El Tor over the Classical biotype.

Health trends in Sub-Saharan Africa: conflicting evidence from infant mortality rates and adult heights

We investigate trends in cohort infant mortality rates and adult heights in 39 developing countries since 1961. In most regions of the world improved nutrition, and reduced childhood exposure to disease, have lead to improvements in both infant mortality and adult stature. In Sub-Saharan Africa, however, despite declining infant mortality rates, adult heights have not increased. We argue that in Sub-Saharan Africa the decline in infant mortality may have been due to interventions that prevent infant deaths rather than improved nutrition and childhood morbidity. Despite declining infant mortality, Sub-Saharan Africa may not be experiencing increases in health human capital.

Relatedness of Vibrio cholerae O1/O139 isolates from patients and their household contacts, determined by multilocus variable-number tandem-repeat analysis

The genetic relatedness of Vibrio cholerae O1/O139 isolates obtained from 100 patients and 146 of their household contacts in Dhaka, Bangladesh, between 2002 and 2005 was assessed by multilocus variable-number tandem-repeat analysis. Isolate genotypes were analyzed at five loci containing tandem repeats. Across the population, as well as within households, isolates with identical genotypes were clustered in time. Isolates from individuals within the same household were more likely to have similar or identical genotypes than were isolates from different households, but even within a household, isolates from different individuals often had different genotypes. When household contacts were sampled regularly for 3 weeks after the illness of the household index patient, isolates with genotypes related to the index patient appeared in contacts, on average, approximately 3 days after the index patient, while isolates with unrelated genotypes appeared in contacts approximately 6 days after. Limited data revealed that multiple isolates from the same individual collected within days of each other or even from a single stool sample may have identical, similar, or unrelated genotypes as well. Our results demonstrate that genetically related V. cholerae strains cluster in local outbreaks but also suggest that multiple distinct strains of V. cholerae O1 may circulate simultaneously within a household.

Engineered bacterial communication prevents Vibrio cholerae virulence in an infant mouse model

To investigate the possibility of using commensal bacteria as signal mediators for inhibiting the disease cholera, we stably transformed Escherichia coli Nissle 1917 (Nissle) to express the autoinducer molecule cholera autoinducer 1 (CAI-1) (shown previously to prevent virulence when present with another signaling molecule, autoinducer 2, at high concentrations) and determined the effect on Vibrio cholerae virulence gene expression and colonization in an infant mouse model. We found that pretreatment of mice for 8 h with Nissle engineered to express CAI-1 (Nissle-cqsA) greatly increased the mice's survival (92%) from ingestion of V. cholerae. Pretreatment with Nissle-cqsA for only 4 h increased survival by 77%, whereas ingesting Nissle-cqsA at the same time as V. cholerae increased survival rates by 27%. Immunostaining revealed an 80% reduction in cholera toxin binding to the intestines of mice pretreated for 8 h with Nissle-cqsA. Further, the numbers of V. cholerae in treated mouse intestines was reduced by 69% after 40 h. This finding points to an easily administered and inexpensive approach where commensal bacteria are engineered to communicate with invasive species and potentially prevent human disease.

Changes in Diarrheal Disease and Treatment Among Brazilian Children from 1986 to 1996

We examined changes in diarrhea prevalence and treatment in Brazil between 1986 and 1996. Over this 10-year period there was a small decline in diarrhea prevalence but treatment with oral rehydration therapy (ORT) increased greatly. Deaths due to dehydration were thus averted, although the costly burden of morbidity remained high. The decline in diarrhea prevalence was largely due to changes in the effects of several key covariates, such as breastfeeding, with only a modest role played by socioeconomic change, infrastructure improvements, and other behavioral factors. ORT treatment of diarrhea was essentially unrelated to child and family characteristics, suggesting that the large increase was due to the success of public health efforts to promote its use widely. Our results suggest that the most effective policies for reducing diarrhea prevalence are likely to be further increases in education and the promotion of breastfeeding. Persistent disparities in diarrhea prevalence mean that policies to prevent the disease should be targeted at disadvantaged socioeconomic groups.

Mechanisms involved in governing adherence of Vibrio cholerae to granular starch

Vibrio cholerae has been shown to adhere to cornstarch granules. The present work explored the mechanisms involved in this adhesion and the possibility of its occurrence in vivo. The findings suggest that both specific and nonspecific interactions are involved in the adhesion. Nonspecific hydrophobic interactions may play a role, since both V. cholerae and cornstarch granules exhibited hydrophobic properties when they were tested using a xylene-water system. In addition, the presence of bile acids reduced the adhesion. The adhesion also involves some specific carbohydrate-binding moieties on the cell surface, as reflected by reduced adhesion following pretreatment of the bacteria with proteinase K and sodium m-periodate. Further investigations supported these observations and showed that media containing low-molecular-weight carbohydrates had a significant inhibitory effect. Binding cell lysate to starch granules and removing the adhered proteins using either glucose or bile acids led to identification (by liquid chromatography-tandem mass spectrometry analysis) of several candidate V. cholerae outer membrane-associated starch-binding proteins. Different sets of proteins were isolated by removal in a glucose solution or bile acids. When the upper gastrointestinal tract conditions were simulated in vitro, both bile salts and the amylolytic activity of the pancreatic juices were found to have an inhibitory effect on the adherence of V. cholerae to starch. However, during acute diarrhea, this inhibitory effect may be significantly reduced due to dilution, suggesting that adhesion does occur in vivo. Such adhesion may contribute to the beneficial effects observed following administration of granular starch-based oral rehydration solutions to cholera patients.

The epidemiology of hospitalization with diarrhea in rural Kenya: the utility of existing health facility data in developing countries

OBJECTIVES

In developing countries where prospective surveillance is resource-intensive, existing hospital data can define incidence, mortality, and risk factors that can help target interventions and track trends in disease burden.

METHODS

We reviewed hospitalizations from 2001 to 2003 at all inpatient facilities in Bondo District, Kenya.

RESULTS

Diarrhea was responsible for 11.2% (n=2158) of hospitalizations. The annual incidence was 550 and 216 per 100,000 persons aged <5 and > or =5 years, respectively. The incidence was highest in infants (1138 per 100,000 persons), decreased in older children, peaked again among 20-29-year-olds (341 per 100,000), and declined among those > or =65 years (157 per 100,000). Female adults had higher incidence than males (rate ratio=1.84, 95% CI 1.61-2.10). Incidence decreased with distance from the district referral hospital (4.5% per kilometer, p<0.0001) and from the nearest inpatient facility (6.6% per kilometer, p=0.012). Case-fatality was high (8.0%), and was higher among adults than young children. Co-diagnosis with malaria, pneumonia, HIV, and tuberculosis was common. Peak diarrhea incidence fell one to two months after heavy rains.

CONCLUSIONS

The trends revealed here provide useful data for public health priority setting and planning, including preventative interventions. The utility of such data justifies renewed efforts to establish and strengthen health management information systems in developing countries.

"Cholera forcing". The myth of the good epidemic and the coming of good water

It has been frequently claimed that cholera epidemics, both in the 19th century and today, were and can be the key stimulus for procurement of safe water and sanitation, an idea that I call "cholera forcing." "Technology forcing" refers to imposition of exogenous factors that suddenly make possible achievements that had not seemed so; cholera has been seen in this light. I argue that this view oversimplifies and underrepresents the importance of industrialization in securing water supplies. Careful study of the financial, political, and administrative foundations of such changes will be more fruitful.

Massive fluid requirements and an unusual BUN/creatinine ratio for pre-renal failure in patients with cholera

Background

Cholera is an important infectious cause of secretory diarrhea. The primary symptom of infection is the sudden onset of watery diarrhea with subsequent volume depletion causing renal insufficiency. The objective of this research is to study the level of dehydration at presentation and subsequent fluid management in patients with cholera.

Methods

This study was conducted on 191 patients of Cholera admitted at a tertiary care hospital in Karachi, Pakistan during the period of 5 years. Medical charts were evaluated retrospectively for initial hydration status, baseline lab investigations on admission and discharge and fluid therapy given to all the patients while their stay in the hospital and the data was analyzed on SPSS 15.0.

Results

Out of the 191 patients, 83(43%) were males and 108 (57%) were females with mean age of 42.3 years (SD±18.34). The average duration of symptoms was 3.75 days (SD±2.04). Of 191 patients, 175 (92.1%) presented with dehydration, 80 (42.3%) were given Ringer's Lactate (R/L) + Normal Saline (N/S), 45 (24%) patients were given R/L + N/S + Oral Rehydration Therapy (ORS), 27 (14.3%) of the patients were kept on R/L only and remaining were given various combinations of R/L, N/S, ORS and Dextrose Saline (D/S). On admission mean Blood Urea Nitrogen (BUN) was 24.54 (SD±16.6), mean creatinine was 2.47 (SD±2.35) and mean BUN/Creatinine ratio was 11.63 (SD±5.7).

Conclusion

Aggressive fluid rehydration remains the cornerstone of management of cholera. Instead of presenting with a classical BUN/Creatinine ratio of >20∶1, patients with pre-renal failure in cholera may present with a BUN/Creatinine ratio of <15∶1.

Gastroenterology in developing countries: issues and advances

Developing countries shoulder a considerable burden of gastroenterological disease. Infectious diseases in particular cause enormous morbidity and mortality. Diseases which afflict both western and developing countries are often seen in more florid forms in poorer countries. Innovative techniques continuously improve and update gastroenterological practice. However, advances in diagnosis and treatment which are commonplace in the West, have yet to reach many developing countries. Clinical guidelines, based on these advances and collated in resource-rich environments, lose their relevance outside these settings. In this two-part review, we first highlight the global burden of gastroenterological disease in three major areas: diarrhoeal diseases, hepatitis B, and Helicobacter pylori. Recent progress in their management is explored, with consideration of future solutions. The second part of the review focuses on the delivery of clinical services in developing countries. Inadequate numbers of healthcare workers hamper efforts to combat gastroenterological disease. Reasons for this shortage are examined, along with possibilities for increased specialist training. Endoscopy services, the mainstay of gastroenterology in the West, are in their infancy in many developing countries. The challenges faced by those setting up a service are illustrated by the example of a Nigerian endoscopy unit. Finally, we highlight the limited scope of many clinical guidelines produced in western countries. Guidelines which take account of resource limitations in the form of "cascades" are advocated in order to make these guidelines truly global. Recognition of the different working conditions facing practitioners worldwide is an important step towards narrowing the gap between gastroenterology in rich and poor countries.