Intestinal microbiota diversity from broilers with runting and stunting syndrome performed by metagenomics.

Runting and stunting syndrome (RSS) is an enteric viral disease in commercial poultry that directly affects gut health; however, its influence on gut microbiota remains unknown. This study aimed to investigate the compositional changes in the bacterial community of the ileum of 7-day-old broiler chicks naturally affected or not affected by RSS, using next-generation sequencing (NGS) technology. Twenty-one samples were obtained from the ileal contents and mucosa of 11 chicks with RSS and 10 healthy chicks, raised in a dark house system located on a farm in the state of Minas Gerais, Brazil. The results revealed overall changes in the gut microbiota of the chicks with RSS, including a decrease in microbial richness and diversity. In particular, there was a decrease in Lactobacillus and an increase in Candidatus Arthromitus and Clostridium sensu stricto 1. These results indicate a relationship between viral infection and the gut microbial composition, which can cause gut dysbiosis and may influence inflammation in this organ.RESEARCH HIGHLIGHTS RSS causes dysbiosis of the gut microbiota of the ilea of chicks.A difference was found in gut microbiota between chicks with or without RSS.Candidatus Arthromitus was predominant in chicks with RSS.Clostridium sensu stricto 1 was strictly associated with chicks with RSS.

Exploring the association of weather variability on Campylobacter - A systematic review.

BACKGROUND: Previous work has found climate change-induced weather variability is suspected to increase the transmission of enteric pathogens, including Campylobacter, a leading cause of bacterial gastroenteritis. While the relationship between extreme weather events and diarrheal diseases has been documented, the specific impact on Campylobacter infections remains underexplored. OBJECTIVE: To synthesize the peer-reviewed literature exploring the effect of weather variability on Campylobacter infections in humans. METHODS: The review included English language, peer-reviewed articles, published up to September 1, 2022 in PubMed, Embase, GEOBASE, Agriculture and Environmental Science Database, and CABI Global Health exploring the effect of an antecedent weather event on human enteric illness caused by Campylobacter (PROSPERO Protocol # 351884). We extracted study information including data sources, methods, summary measures, and effect sizes. Quality and weight of evidence reported was summarized and bias assessed for each article. RESULTS: After screening 278 articles, 47 articles (34 studies, 13 outbreak reports) were included in the evidence synthesis. Antecedent weather events included precipitation (n = 35), temperature (n = 30), relative humidity (n = 7), sunshine (n = 6), and El Niño and La Niña (n = 3). Reviewed studies demonstrated that increases in precipitation and temperature were correlated with Campylobacter infections under specific conditions, whereas low relative humidity and sunshine were negatively correlated. Articles estimating the effect of animal operations (n = 15) found presence and density of animal operations were significantly associated with infections. However, most of the included articles did not assess confounding by seasonality, presence of animal operations, or describe estimates of risk. DISCUSSION: This review explores what is known about the influence of weather events on Campylobacter and identifies previously underreported negative associations between low relative humidity and sunshine on Campylobacter infections. Future research should explore pathogen-specific estimates of risk, which can be used to influence public health strategies, improve source attribution and causal pathways, and project disease burden due to climate change.

The Costly Vicious Cycle of Infections and Malnutrition.

Malnutrition, which continues to affect hundreds of millions of people worldwide, is both a cause and consequence of a range of infectious diseases. In this perspective piece, we provide an overview of the bidirectional relationship between malnutrition and infectious diseases. In addition to enteric infections, we use tuberculosis as a case study of this relationship between malnutrition and infectious diseases and to demonstrate the potential of nutritional interventions to mitigate mortality and morbidity from infectious diseases. We conclude with suggestions on advancing our understanding of the vicious cycle of microbes and malnutrition and finding ways to break it.

Enteric Infections in Men Who Have Sex With Men.

BACKGROUND: Enteric pathogens are often associated with exposure to food, water, animals, and feces from infected individuals. However, in sexual networks of men who have sex with men (MSM), transmission of enteric pathogens may occur during direct or indirect oral-anal contact. METHODS: We performed a scoping review of the literature for studies prior to July 2019 with key terms for gastrointestinal syndromes ("proctitis," "enteritis," "proctocolitis"), enteric pathogens or sexually transmitted infections (STIs), and outbreaks using multiple electronic databases. RESULTS: We identified 5861 records through database searches, bibliography reviews, and keyword searches, of which 117 references were included in the pathogen-specific reviews. CONCLUSIONS: The strength of observational data describing enteric pathogens in MSM and possible sexual transmission of enteric pathogens varies by pathogen; however, a robust body of literature describes the sexual transmission of Campylobacter, Giardia lamblia, and Shigella (particularly antimicrobial-resistant strains) in sexual networks of MSM. Providers are encouraged to consider enteritis or proctocolitis in MSM as possibly having been sexually transmitted and encourage targeted STI testing. Risk/harm reduction and prevention messages should also be incorporated, though there is an acknowledged paucity of evidence with regards to effective strategies. Further research is needed to understand the transmission and prevention of enteric pathogens in MSM.

AraC-type regulators HilC and RtsA are directly controlled by an intestinal fatty acid to regulate Salmonella invasion.

Invasion of the intestinal epithelium is an essential but energetically expensive survival strategy and is, therefore, tightly regulated by using specific cues from the environment. The enteric pathogen Salmonella controls its invasion machinery through the elegant coordination of three AraC-type transcription activators, HilD, HilC, and RtsA. Most environmental signals target HilD to control invasion, whereas HilC and RtsA are known only to augment these effects on HilD. Here we show that a fatty acid found in the murine colon, cis-2-hexadecenoic acid (c2-HDA), represses Salmonella invasion by directly targeting HilC and RtsA, in addition to HilD. c2-HDA directly binds each of these regulators and inhibits their attachment to DNA targets, repressing invasion even in the absence of HilD. Fatty acid binding, however, does not affect HilC and RtsA protein stability, unlike HilD. Importantly, we show that HilC and RtsA are highly effective in restoring HilD production and invasion gene expression after elimination of the repressive fatty acid c2-HDA. Together, these results illuminate a precise mechanism by which HilC and RtsA may modulate invasion as Salmonella navigates through different regions of the intestine, contributing to our understanding of how this enteric pathogen senses and adapts to a diverse intestinal environment while maintaining its virulence.

A multi-epitope plant-made chimeric protein (LTBentero) targeting common enteric pathogens is immunogenic in mice.

KEY MESSAGE: A plant-based multiepitopic protein (LTBentero) containing epitopes from ETEC, S. typhimurium, and V. parahaemolyticus was produced in plants cells and triggered systemic and intestinal humoral responses in immunized mice. Around 200 million people suffer gastroenteritis daily and more than 2 million people die annually in developing countries due to such pathologies. Vaccination is an alternative to control this global health issue, however new low-cost vaccines are needed to ensure proper vaccine coverage. In this context, plants are attractive hosts for the synthesis and delivery of subunit vaccines. Therefore, in this study a plant-made multiepitopic protein named LTBentero containing epitopes from antigens of enterotoxigenic E. coli, S. typhimurium, and V. parahaemolyticus was produced and found immunogenic in mice. The LTBentero protein was expressed in tobacco plants at up to 5.29 µg g-1 fresh leaf tissue and was deemed immunogenic when administered to BALB/c mice either orally or subcutaneously. The plant-made LTBentero antigen induced specific IgG (systemic) and IgA (mucosal) responses against LTB, ST, and LptD epitopes. In conclusion, multiepitopic LTBentero was functionally produced in plant cells, being capable to trigger systemic and intestinal humoral responses and thus it constitutes a promising oral immunogen candidate in the fight against enteric diseases.

Multiple Introductions of Salmonella enterica Serovar Typhi H58 with Reduced Fluoroquinolone Susceptibility into Chile.

Salmonella enterica serovar Typhi H58, an antimicrobial-resistant lineage, is globally disseminated but has not been reported in Latin America. Genomic analysis revealed 3 independent introductions of Salmonella Typhi H58 with reduced fluoroquinolone susceptibility into Chile. Our findings highlight the utility of enhanced genomic surveillance for typhoid fever in this region.

Molecular Characterization of the Chicken Parvovirus Based on VP1 Gene Circulating in Brazilian Chicken Flocks.

Parvovirus infection affects several animal species, especially young animals. In birds, parvovirus infection has been described in Muscovy ducks, turkeys, and chickens, all of which had enteric diseases characterized by diarrhea. Chicken parvovirus (ChPV) has been detected in poultry around the world in animals affected by enteric problems, showing dwarfism, cloacal pasting, and diarrhea. In Brazil, ChPV was detected in chickens affected by diarrhea fifteen years ago. However, the genetic characteristics of ChPV circulating in chicken flocks were not determined. Therefore, the aim of the present investigation was to determine the genetic characteristics of the VP1 gene from ChPV detected in chickens affected by enteric diseases in Brazil. For this purpose, a molecular approach was used. Specific primers were designed to flank the complete VP1 gene of ChPV and amplify it using PCR. The amplified products from samples of chickens with enteric diseases were sequenced, and 22 complete CDs of the VP1 gene were obtained. These samples, compared to the ABU-P1 sequence, showed 17 sequences with high nucleotide (NT) similarity of 92.7-97.4% and amino acid (AA) similarity of 94.8-99.5% associated with Runting and Stunting syndrome (RSS); there were also five samples associated with hens with diarrhea with unusual jejunal dilatation (JD) that had less similarity than the RSS sequences (NT of 86.5% and AA of 93-93.1%). The phylogenetic analysis determined four groups. Group I had sequences from Korea. The second group included sequences from Korea, China, and Brazil (not included in this work). The third group had studied RSS sequences grouped with the ABU-P1 strain and sequences from China and the United States. Finally, the sequences from JD were clustered in a separate group with a bootstrap of 100%, a group that was denoted as group IV, and included sequences from China. RDP4 and SimPlot analysis showed one point of recombination with the sequences of group III ChPV in the JD sequences. Herein, we show that circulating strains of ChPV exhibit genetic differences in the VP1 gene in Brazilian chicken flocks. Nevertheless, more studies are needed to determine the probability of a new genetic group of ChPV based on the analysis of the complete genome.

The 2022 Vaccines Against Shigella and Enterotoxigenic Escherichia coli (VASE) Conference: Summary of abstract-based presentations.

The global nonprofit organization PATH hosted the third Vaccines Against Shigella and Enterotoxigenic Escherichia coli (VASE) Conference in Washington, DC, on November 29 to December 1, 2022. With a combination of plenary sessions and posters, keynote presentations, and breakout workshops, the 2022 VASE Conference featured key updates on research related to the development of vaccines against neglected diarrheal pathogens including Shigella, enterotoxigenic Escherichia coli (ETEC), Campylobacter, and Salmonella. The presentations and discussions highlighted the significant impact of these diarrheal pathogens, particularly on the health of infants and young children in low- and middle-income countries, reflecting the urgent need for the development and licensure of new enteric vaccines. Oral and poster presentations at the VASE Conference explored a range of topics, including: the global burden and clinical presentation of disease, epidemiology, and the impact of interventions; the assessment of the value of vaccines against enteric pathogens; preclinical evaluations of vaccine candidates and models of enteric diseases; vaccine candidates in clinical trials and human challenge models; host parameters and genomics that predict responses to infection and disease; the application of new omics technologies for characterization of emerging pathogens and host responses; novel adjuvants, vaccine delivery platforms, and immunization strategies; and strategies for combination/co-administered vaccines. The conference agenda also featured ten breakout workshop sessions on topics of importance to the enteric vaccine field, which are summarized separately. This article reviews key points and highlighted research presented in each of the plenary conference sessions and poster presentations at the 2022 VASE Conference.

The 2022 Vaccines Against Shigella and Enterotoxigenic Escherichia coli (VASE) Conference: Summary of breakout workshops.

The global public health nonprofit organization PATH hosted the third Vaccines Against Shigella and Enterotoxigenic Escherichia coli (VASE) Conference in Washington, DC, from November 29 to December 1, 2022. This international gathering focused on cutting-edge research related to the development of vaccines against neglected diarrheal pathogens including Shigella, enterotoxigenic Escherichia coli (ETEC), Campylobacter, and non-typhoidal Salmonella. In addition to the conference's plenary content, the agenda featured ten breakout workshops on topics of importance to the enteric vaccine field. This unique aspect of VASE Conferences allows focused groups of attendees to engage in in-depth discussions on subjects of interest to the enteric vaccine development community. In 2022, the workshops covered a range of topics. Two focused on the public health value of enteric vaccines, with one examining how to translate evidence into policy and the other on the value proposition of potential combination vaccines against bacterial enteric pathogens. Two more workshops explored new tools for the development and evaluation of vaccines, with the first on integrating antigen/antibody technologies for mucosal vaccine and immunoprophylactic development, and the second on adjuvants specifically for Shigella vaccines for children in low- and middle-income countries. Another pair of workshops covered the status of vaccines against two emerging enteric pathogens, Campylobacter and invasive non-typhoidal Salmonella. The remaining four workshops examined the assessment of vaccine impact on acute and long-term morbidity. These included discussions on the nature and severity of intestinal inflammation; cellular immunity and immunological memory in ETEC and Shigella infections; clinical and microbiologic endpoints for Shigella vaccine efficacy studies in children; and intricacies of protective immunity to enteric pathogens. This article provides a brief summary of the presentations and discussions at each workshop in order to share these sessions with the broader enteric vaccine field.

Diagnostic Approach to Enteric Disorders in Pigs.

The diagnosis of enteric disorders in pigs is extremely challenging, at any age. Outbreaks of enteric disease in pigs are frequently multifactorial and multiple microorganisms can co-exist and interact. Furthermore, several pathogens, such as Clostridium perfrigens type A, Rotavirus and Lawsonia intracellularis, may be present in the gut in the absence of clinical signs. Thus, diagnosis must be based on a differential approach in order to develop a tailored control strategy, considering that treatment and control programs for enteric diseases are pathogen-specific. Correct sampling for laboratory analyses is fundamental for the diagnostic work-up of enteric disease in pigs. For example, histology is the diagnostic gold standard for several enteric disorders, and sampling must ensure the collection of representative and optimal intestinal samples. The aim of this paper is to focus on the diagnostic approach, from sampling to the aetiological diagnosis, of enteric disorders in pigs due to different pathogens during the different phases of production.

Challenges and opportunities in developing a Shigella-containing combination vaccine for children in low- and middle-income countries: Report of an expert convening.

The gram-negative bacterium Shigella is an enteric pathogen responsible for significant morbidity and mortality due primarily to severe diarrhea and dysentery, mainly among children younger than five years of age living in low- and middle-income countries (LMICs). Long considered a priority target for vaccine development, recent scientific advances have led to a number of promising Shigella vaccine candidates now entering advanced stages of clinical testing. Yet, there is no guarantee that even a highly efficacious Shigella vaccine will be recommended, prioritized, purchased, and widely adopted-especially if it requires additional doses in the immunization schedule and/or visits within the immunization program. This uncertainty is due to a variety of factors, including continuing declines in Shigella-specific and overall diarrheal disease mortality rates, the increasing complexity and cost of infant immunization programs in LMICs, and the recent availability of other high-priority vaccines. Since combining a Shigella vaccine with an existing infant vaccine would conceivably increase its attractiveness, there is a need to systematically consider the challenges determining the public health value, clinical development, manufacturing, licensure, policy recommendations, and financing for a Shigella-containing combination vaccine. The international non-governmental health organization PATH convened an independent panel of 34 subject matter experts across academic, industry, philanthropic, and global health sectors to discuss hypothetical combinations of a notional parenteral Shigella vaccine with three existing vaccines in order to begin exploring the challenges associated with their development. The resulting insights and recommendations from this meeting contribute to PATH's broader effort to evaluate the public health value of potential Shigella vaccines. They may also help guide future combination vaccine development efforts more broadly.

Controlled human infectious models, a path forward in uncovering immunological correlates of protection: Lessons from enteric fevers studies.

Enteric infectious diseases account for more than a billion disease episodes yearly worldwide resulting in approximately 2 million deaths, with children under 5 years old and the elderly being disproportionally affected. Enteric pathogens comprise viruses, parasites, and bacteria; the latter including pathogens such as Salmonella [typhoidal (TS) and non-typhoidal (nTS)], cholera, Shigella and multiple pathotypes of Escherichia coli (E. coli). In addition, multi-drug resistant and extensively drug-resistant (XDR) strains (e.g., S. Typhi H58 strain) of enteric bacteria are emerging; thus, renewed efforts to tackle enteric diseases are required. Many of these entero-pathogens could be controlled by oral or parenteral vaccines; however, development of new, effective vaccines has been hampered by lack of known immunological correlates of protection (CoP) and limited knowledge of the factors contributing to protective responses. To fully comprehend the human response to enteric infections, an invaluable tool that has recently re-emerged is the use of controlled human infection models (CHIMs) in which participants are challenged with virulent wild-type (wt) organisms. CHIMs have the potential to uncover immune mechanisms and identify CoP to enteric pathogens, as well as to evaluate the efficacy of therapeutics and vaccines in humans. CHIMs have been used to provide invaluable insights in the pathogenesis, host-pathogen interaction and evaluation of vaccines. Recently, several Oxford typhoid CHIM studies have been performed to assess the role of multiple cell types (B cells, CD8+ T, Tregs, MAIT, Monocytes and DC) during S. Typhi infection. One of the key messages that emerged from these studies is that baseline antigen-specific responses are important in that they can correlate with clinical outcomes. Additionally, volunteers who develop typhoid disease (TD) exhibit higher levels and more activated cell types (e.g., DC and monocytes) which are nevertheless defective in discrete signaling pathways. Future critical aspects of this research will involve the study of immune responses to enteric infections at the site of entry, i.e., the intestinal mucosa. This review will describe our current knowledge of immunity to enteric fevers caused by S. Typhi and S. Paratyphi A, with emphasis on the contributions of CHIMs to uncover the complex immunological responses to these organisms and provide insights into the determinants of protective immunity.

The Use of Ascophyllum nodosum and Bacillus subtilis C-3102 in the Management of Canine Chronic Inflammatory Enteropathy: A Pilot Study.

The aim was to assess the effects of Ascophyllum nodosum (AN) with/without Bacillus subtilis C-3102 as alternative treatments for Chronic Inflammatory Enteropathy (CIE) of dogs. Fourteen CIE patients, which had received the same control (CTR) diet, were enrolled to serially receive three diets: (1) hydrolysed protein (HP) diet; (2) 4.0% AN supplemented HP (HPA) food, (3) HPA diet fortified with 125 billion B. subtilis C-3102 spores/10 kg body weight (HPAB diet). Clinical outcome was assessed by Canine Inflammatory Bowel Disease Activity Index (CIBDAI), whereas gut microbiota compositional variations were investigated via 16S rRNA gene analysis, and faecal fermentation end-products by liquid chromatography. Higher abundances of the Ruminococcaceae and Rikenellaceae families were shown in HPA relative to CTR treatment, with Bacillus genus being differentially abundant on HPAB diet. Concentrations of acetate were higher (p < 0.05) in dogs fed HPA compared to CTR diet, and amounts of isovalerate and isobutyrate were greater (p < 0.05) in HPA compared to HP food. A tendency for higher amounts of faecal butyrate was found for the HPAB treatment (p = 0.06). Comprehensively, while displaying potentially positive effects on faecal fermentations, the tested substances failed to improve CIBDAI scores and microbial richness in CIE dogs.

A Significant Decrease in the Incidence of Shigellosis in Israel during COVID-19 Pandemic.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes COVID-19 and is mostly person-to-person transmitted through respiratory droplets. The implications of the strategies implemented to prevent COVID-19 transmission on other infectious diseases are unclear. We aimed to appraise trends in the incidence of salmonellosis, shigellosis and campylobacteriosis in Israel during COVID-19 pandemic. Positive stool samples for Salmonella, Shigella and Campylobacter are reported on a monthly basis to the Israel Center for Disease Control from sentinel laboratories, within the framework of a surveillance network of bacterial culture-proven enteric diseases. Age-adjusted incidence rates per 100,000 of shigellosis, salmonellosis and campylobacteriosis were calculated. Mean rates before and after the local onset of COVID-19 pandemic in Israel were compared and Relative Risk Reduction (RRR) was calculated. Joinpoint was used to evaluate secular trends. The mean age-adjusted incidence rate of shigellosis in March-July 2020 was lower than the rate observed in March-July 2018-2019 (RRR = 86.6%), but also decreased for salmonellosis (RRR = 33.0%) and campylobacteriosis (RRR = 30.0%). Using Joinpoint we have shown that the decrease observed for shigellosis was significantly sharper (Annual Percent Change (APC) = -77.7) between February 2020 and May 2020 than for salmonellosis (APC = -14.0) between July 2019 and April 2020 and for campylobacteriosis (APC = -1.1) between January 2018 and July 2020. The preventive measures applied to reduce transmission of COVID-19, including social distancing and hand washing, were ecologically associated with a decreased risk of bacterial enteric diseases in Israel. The association was strongest for shigellosis, a disease that is mostly person-to-person transmitted, as compared to salmonellosis and campylobacteriosis which are mostly foodborne transmitted.

A Systems Biology Approach Identifies B Cell Maturation Antigen (BCMA) as a Biomarker Reflecting Oral Vaccine Induced IgA Antibody Responses in Humans.

Vaccines against enteric diseases could improve global health. Despite this, only a few oral vaccines are currently available for human use. One way to facilitate such vaccine development could be to identify a practical and relatively low cost biomarker assay to assess oral vaccine induced primary and memory IgA immune responses in humans. Such an IgA biomarker assay could complement antigen-specific immune response measurements, enabling more oral vaccine candidates to be tested, whilst also reducing the work and costs associated with early oral vaccine development. With this in mind, we take a holistic systems biology approach to compare the transcriptional signatures of peripheral blood mononuclear cells isolated from volunteers, who following two oral priming doses with the oral cholera vaccine Dukoral®, had either strong or no vaccine specific IgA responses. Using this bioinformatical method, we identify TNFRSF17, a gene encoding the B cell maturation antigen (BCMA), as a candidate biomarker of oral vaccine induced IgA immune responses. We then assess the ability of BCMA to reflect oral vaccine induced primary and memory IgA responses using an ELISA BCMA assay on a larger number of samples collected in clinical trials with Dukoral® and the oral enterotoxigenic Escherichia coli vaccine candidate ETVAX. We find significant correlations between levels of BCMA and vaccine antigen-specific IgA in antibodies in lymphocyte secretion (ALS) specimens, as well as with proportions of circulating plasmablasts detected by flow cytometry. Importantly, our results suggest that levels of BCMA detected early after primary mucosal vaccination may be a biomarker for induction of long-lived vaccine specific memory B cell responses, which are otherwise difficult to measure in clinical vaccine trials. In addition, we find that ALS-BCMA responses in individuals vaccinated with ETVAX plus the adjuvant double mutant heat-labile toxin (dmLT) are significantly higher than in subjects given ETVAX only. We therefore propose that as ALS-BCMA responses may reflect the total vaccine induced IgA responses to oral vaccination, this BCMA ELISA assay could also be used to estimate the total adjuvant effect on vaccine induced-antibody responses, independently of antigen specificity, further supporting the usefulness of the assay.

Recent Progress in Torovirus Molecular Biology.

Torovirus (ToV) has recently been classified into the new family Tobaniviridae, although it belonged to the Coronavirus (CoV) family historically. ToVs are associated with enteric diseases in animals and humans. In contrast to CoVs, which are recognised as pathogens of veterinary and medical importance, little attention has been paid to ToVs because their infections are usually asymptomatic or not severe; for a long time, only one equine ToV could be propagated in cultured cells. However, bovine ToVs, which predominantly cause diarrhoea in calves, have been detected worldwide, leading to economic losses. Porcine ToVs have also spread globally; although they have not caused serious economic losses, coinfections with other pathogens can exacerbate their symptoms. In addition, frequent inter- or intra-recombination among ToVs can increase pathogenesis or unpredicted host adaptation. These findings have highlighted the importance of ToVs as pathogens and the need for basic ToV research. Here, we review recent progress in the study of ToV molecular biology including reverse genetics, focusing on the similarities and differences between ToVs and CoVs.

Milk Product Safety and Household Food Hygiene Influence Bacterial Contamination of Infant Food in Peri-Urban Kenya.

BACKGROUND: Milk is a common infant food in peri-urban Kenya that can transmit diarrhea-causing enteric pathogens. Little is known about how contamination of milk at point of purchase and household handling of milk-based infant foods contribute to infant exposure to enteric pathogens. OBJECTIVE: To compare the prevalence and concentrations of bacterial indicator organisms and enteric pathogens in unpackaged, fresh pasteurized, and ultra-high temperature (UHT) treated milk at purchase and assess the influence of the type of milk used to prepare infant food on contamination of this food. METHODS: Paired samples of purchased milk and infant food prepared with this milk were obtained from 188 households in low-income neighborhoods in Kisumu, Kenya. Samples were cultured on selective media to isolate Salmonella enterica, Shigella spp., Klebsiella aerogenes, Proteus spp., and Escherichia coli, with pathogens validated by PCR. Probability of detection of these bacteria was compared by milk product treatment and packaging method, and between milk at point of purchase vs. food at point of infant consumption. RESULTS: Unpackaged milk was most contaminated at point of purchase, but bacterial contamination was also present in pasteurized and UHT milk at purchase. Presence of bacteria in UHT and fresh pasteurized milk at purchase predicted presence of the same bacteria type in infant food. Prevalence of bacterial contamination and concentration level for bacterial indicators generally increased between point of purchase and consumption in UHT and fresh pasteurized milk-based food but decreased in unpackaged milk-based food. Prevalence of the four fecal bacteria were similar in infant foods prepared with each type of milk. CONCLUSION: Both pre-market contamination and post-purchase handling influence the likelihood of infants ingesting foods contaminated by diarrheal pathogens.

Meeting Report: WHO Workshop on modelling global mortality and aetiology estimates of enteric pathogens in children under five. Cape Town, 28-29th November 2018.

Investment in vaccine product development should be guided by up-to-date and transparent global burden of disease estimates, which are also fundamental to policy recommendation and vaccine introduction decisions. For low- and middle-income countries (LMICs), vaccine prioritization is primarily driven by the number of deaths caused by different pathogens. Enteric diseases are known to be a major cause of death in LMICs. The two main modelling groups providing mortality estimates for enteric diseases are the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, Seattle and the Maternal Child Epidemiology Estimation (MCEE) group, led by Johns Hopkins Bloomberg School of Public Health. Whilst previous global diarrhoea mortality estimates for under five-year-olds from these two groups were closely aligned, more recent estimates for 2016 have diverged, particularly with respect to numbers of deaths attributable to different enteric pathogens. This has impacted prioritization and investment decisions for vaccines in the development pipeline. The mission of the Product Development for Vaccines Advisory Committee (PDVAC) at the World Health Organisation (WHO) is to accelerate product development of vaccines and technologies that are urgently needed and ensure they are appropriately targeted for use in LMICs. At their 2018 meeting, PDVAC recommended the formation of an independent working group of subject matter experts to explore the reasons for the difference between the IHME and MCEE estimates, and to assess the respective strengths and limitations of the estimation approaches adopted, including a review of the data on which the estimates are based. Here, we report on the proceedings and recommendations from a consultation with the working group of experts, the IHME and MCEE modelling groups, and other key stakeholders. We briefly review the methodological approaches of both groups and provide a series of proposals for investigating the drivers for the differences in enteric disease burden estimates.

Vaccines against gastroenteritis, current progress and challenges.

Enteric viral and bacterial infections continue to be a leading cause of mortality and morbidity in young children in low-income and middle-income countries, the elderly, and immunocompromised individuals. Vaccines are considered an effective and practical preventive approach against the predominantly fecal-to-oral transmitted gastroenteritis particularly in the resource-limited countries or regions where implementation of sanitation systems and supply of safe drinking water are not quickly achievable. While vaccines are available for a few enteric pathogens including rotavirus and cholera, there are no vaccines licensed for many other enteric viral and bacterial pathogens. Challenges in enteric vaccine development include immunological heterogeneity among pathogen strains or isolates, a lack of animal challenge models to evaluate vaccine candidacy, undefined host immune correlates to protection, and a low protective efficacy among young children in endemic regions. In this article, we briefly updated the progress and challenges in vaccines and vaccine development for the leading enteric viral and bacterial pathogens including rotavirus, human calicivirus, Shigella, enterotoxigenic Escherichia coli (ETEC), cholera, nontyphoidal Salmonella, and Campylobacter, and introduced a novel epitope- and structure-based vaccinology platform known as MEFA (multiepitope fusion antigen) and the application of MEFA for developing broadly protective multivalent vaccines against heterogenous pathogens.