Sporadic Human Diseases Research Articles

Sensitive detection and propagation of brain-derived tau assemblies in HEK293 based wild-type tau seeding assays.

The assembly of tau into filaments defines tauopathies, a group of neurodegenerative diseases including Alzheimer's disease (AD), Pick's disease (PiD), corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). The seeded aggregation of tau has been modelled in cell culture using pro-aggregant modifications such as truncation of N- and C-termini and point-mutations within the microtubule-binding repeat domain. This limits the applicability of research findings to sporadic disease, where aggregates contain wild-type, full-length tau. We aimed to develop sensitive and specific biosensor assays for brain-derived tau species utilizing 0N3R and 0N4R tau expressed in HEK293 cells. We further generate a cell line that propagates insoluble tau which is hyperphosphorylated at disease relevant sites and retains a seeding profile similar to AD. We propose these systems as an advance over existing cell-based seeding assays, as they display specificity to the conformation and isoform composition of sporadic human disease.

Occurrence of Campylobacter in Faeces, Livers and Carcasses of Wild Boars Hunted in Tuscany (Italy) and Evaluation of MALDI-TOF MS for the Identification of Campylobacter Species

A total of 193 wild boars hunted in Tuscany, an Italian region with a high presence of wild ungulates, were examined to assess the occurrence of Campylobacter species in faeces, bile, liver and carcasses, with the aim of clarifying their contribution to human infection through the food chain. Campylobacter spp. were found in 44.56% of the animals, 42.62% of the faecal samples, 18.18% of the carcass samples, 4.81% of the liver tissues and 1.97% of the bile samples. The Campylobacter species genotypically identified were C. coli, C. lanienae, C. jejuni and C. hyointestinalis. The prevalent species transpired to be C. coli and C. lanienae, which were isolated from all the matrices; C. jejuni was present in faeces and liver, while C. hyointestinalis only in faeces. Identification was carried out by matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) on 66 out of 100 isolates identified genotypically, and the technique yielded unsatisfactory results in the case of C. lanienae, which is responsible for sporadic human disease cases. The level of Campylobacter spp. contamination of meat and liver underlines the need to provide appropriate food safety information to hunters and consumers.

Hepatitis E as a Zoonosis.

Hepatitis E viruses in the family of Hepeviridae have been classified into 2 genus, 5 species, and 13 genotypes, involving different animal hosts of different habitats. Among all these genotypes, four (genotypes 3, 4, 7, and C1) of them are confirmed zoonotic causing sporadic human diseases, two (genotypes 5 and 8) were likely zoonotic showing experimental animal infections, and the other seven were not zoonotic or unconfirmed. These zoonotic HEV carrying hosts include pig, boar, deer, rabbit, camel, and rat. Taxonomically, all the zoonotic HEVs belong to the genus Orthohepevirus, which include genotypes 3, 4, 5, 7, 8 HEV in the species A and genotype C1 HEV in the species C. In the chapter, information of zoonotic HEV such as swine HEV (genotype 3 and 4), wild boar HEV (genotypes 3-6), rabbit HEV (genotype 3), camel HEV (genotype 7 and 8), and rat HEV (HEV-C1) was provided in detail. At the same time, their prevalence characteristics, transmission route, phylogenetic relationship, and detection technology were discussed. Other animal hosts of HEVs were introduced briefly in the chapter. All these information help peer researchers have basic understanding of zoonotic HEV and adopt reasonable strategy of surveillance and prevention.

First clinical trial of a MERS coronavirus DNA vaccine

Middle East respiratory syndrome (MERS) coronavirus is an emerging pathogen with pandemic potential that continues to cause sporadic human disease 7 years after the first case in a human was detected in 2012.1 Zoonotic transmission with consequent risk of human epidemics will probably continue into the future, given that MERS coronavirus appears to be highly endemic among dromedary camels from geographically widespread areas of the Middle East and Africa.2 In light of this potential threat to global public health, WHO along with the Coalition for Epidemic Preparedness Innovations have prioritised research and development of countermeasures against MERS coronavirus,3,4 and WHO has developed a target product profile for both preventive and reactive use of MERS coronavirus vaccines.

Monitoring of the Epidemic Situation with Q Fever in the Regions of Ukraine

ObjectiveTo investigate Q fever pathogen distribution among ixodic ticks, myomorphic rodents, febrile patients, residents of enzootic areas with Q fever and persons in contact with Q fever, specifically infected persons in the Southern and Western regions of Ukraine.IntroductionImprovement of the Q fever epizootic and epidemiological surveillance system remains an urgent veterinary service and healthcare problem in Ukraine. The grounds for this should be laid by the results of monitoring studies of persons with a professional infection risk (livestock farms, animal processing enterprises, veterinary specialists, etc.) and living in enzootic territories , as well as research of Q fever pathogen possible sources reservoirs.MethodsReal-time PCR - detection of specific DNA segments of Coxiella burnetii with application of commercial reagent kits. Immunofluorescence microscopy - detection of antigens/antibodies of studied rickettsia in biological substrates using luminescent immune sera labeled with fluorescein-5-isothiocyanate. Epidemiological methods - analysis of infectious diseases foci epidemiological maps. Statistical methods - data analysis using such software as Excel and Quantum GIS (1.6.0).ResultsPrimarily, Q fever endemic areas are formed because of the circulation of Coxiella burnetii in warm-blooded animal populations and their blood-sucking ectoparasites, which are the main source of the infection in humans. Based on the aggregated data received from multi-year research projects in Ukraine, Q fever enzootic territories were found in 18 administrative regions, Crimea and the city of Sevastopol. Currently we know of 257 areas where the pathogen was detected. The epidemic process in these territories is manifested by sporadic human diseases and the detection of the pathogen in natural carriers. The possibility of the natural foci epidemic potential increase in these territories is confirmed by the higher titers of Q fever pathogen specific antibodies detected in the local population.The results of the research of the infected material that was collected in Southern Ukraine during 2014-2016, showed the preservation of the Q fever causative agent in natural foci both in Danube-Dniester interfluve area of Odesa region and in Trans-Dnistrer areas, and its significantly less prevalent in the area adjacent to Odessa. In addition, the signs of natural foci formation have been revealed in other areas, which is indicative of current epidemic activity of natural foci of the infection. The results of serological studies and clinical and epidemiological surveys indicate that in the immunological structure of the population of the Danube-Dniester interfluve areas of Odessa region, Q fever is most common in rural population of working age, especially those constantly contact with farm animals. In the Ivano-Frankivsk region, serological studies in 2014 -2016, detected no Q fever seropositive people, indicating the pathogen being in the reserve stage, which corresponds to the inter-epidemic period. At the same time, the detection of C. burnetii in ticks in the enzootic territories indicates the possibility of the pre-epidemic process being formed.Since by pathogen range and transmission mechanisms Q fever in Ukraine is associated with many natural-focal zoonotic infections, it is advisable to monitor endemic areas using a modern observation algorithm using the introduction of geoinformation systems and the molecular genetic characteristics of circulating strains. This will increase the effectiveness of the detection of current natural and anthropurgic foci of such infections, will contribute to their detailed characterization and systematization, improve epidemiological surveillance and prevent the emergence of epidemic outbreaks among the population. The results of the research will contribute to the improvement of differential diagnosis of febrile states with an unclear etiologic agent.ConclusionsThe results of the Q fever pathogen detection in the material collected in Southern and Western regions of Ukraine showed that the area of prevalence of this agent has been expanded to the areas and settlements that are not included in the list of enzootic territories. Involvement in the ecological cycles of ixodic ticks and mouse-like rodents was observed. The presence of polyvectoral and polyhostal natural foci of this infection was found. The circulation of the causative agent of Q fever in the territories of Odesa and Ivano-Frankivsk regions where epidemic outbreaks and sporadic disease in people were also observed.

ERp57 is protective against mutant SOD1-induced cellular pathology in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder and mutations in superoxide dismutase 1 (SOD1) account for 20% of familial ALS cases. The aetiology of ALS remains unclear, but protein misfolding, endoplasmic reticulum (ER) stress and neuronal apoptosis are implicated. We previously established that protein disulphide isomerase (PDIA1) is protective against ER stress and apoptosis in neuronal cells expressing mutant SOD1, and recently mutations in PDIA1 and related PDI family member endoplasmic reticulum protein 57 (ERp57/PDIA3), were associated with ALS. Here, we examined whether ERp57 is also protective against mutant SOD1 or whether distinct specificity exists amongst individual PDI family members. Neuronal cells co-expressing SOD1 and ERp57 were examined for inclusion formation, ER stress, ubiquitin proteasome system (UPS) dysfunction and apoptosis. Over-expression of ERp57 inhibited inclusion formation, ER stress, UPS dysfunction and apoptosis, whereas silencing of ERp57 expression enhanced mutant SOD1 inclusion formation, ER stress and toxicity, indicating a protective role for ERp57 against SOD1 misfolding. ERp57 also inhibited the formation of mutant SOD1 inclusions and apoptosis in primary cortical neurons, thus confirming results obtained from cell lines. ERp57 partially co-localized with TAR DNA-binding protein-43 (TDP-43)-positive inclusions in spinal cords from sporadic ALS patients, thus linking ERp57 to protein misfolding in human sporadic disease. Our results therefore imply that ERp57 has a protective role against pathological events induced by mutant SOD1 and they link ERp57 to the misfolding of TDP-43. This study therefore has implications for the design of novel therapeutics based on the activities of the PDI family of proteins.

Secretome profiling of highly virulent Mycobacterium bovis 04-303 strain reveals higher abundance of virulence-associated proteins

Mycobacterium bovis is the causative agent of tuberculosis in farms, wildlife and causes sporadic disease in humans. Despite the high similitude in genome sequence between M. bovis strains, some strains like the wild boar 04-303 isolate show a highly virulent phenotype in animal models. Comparative studies will contribute to link protein expression with the virulence phenotype. In vitro, the 04-303 strain was more phagocytized by J774A.1 macrophages in comparison with 444 strain (a cow isolate with the same genotype) and BCG. The secretome of these strains showed a significant proportion of shared proteins (368 spots). Among the proteins only visualized in the secretome of the 04-303 strain, we identify the nine most abundant proteins by LC-MS/MS. The most relevant were EsxA and EsxB proteins, which are encoded in the RD1 region, deleted in BCG strains. These proteins are the major virulence factor of M. tuberculosis. The other proteins identified belong to functional categories of virulence, detoxification, and adaptation; lipid metabolism; and cell wall and cell processes. The relatively high proportion of proteins involved in the cell wall and cell process is consistent with the previously described variation among M. bovis genomes.

Fibroblast-like cells as an effective feeder for the cultivation and derivation of new lines of human induced pluripotent stem cells.

Induced pluripotent stem cells (iPSCs) can be a highly informative model of hereditary and sporadic human diseases. In the future, such cells can be used in substitution and regenerative therapy of a wide range of diseases and for the treatment of injuries and burns. The ability of iPSCs derived from patients with Parkinson's disease to differentiate into fibroblast-like cells (derivatives) was studied. It was found that these cells can serve as an effective feeder layer not only to maintain the pluripotency of allogenic and autologous iPSCs but also to derive new iPSC lines.

The quest for canine leishmaniasis in Romania: the presence of an autochthonous focus with subclinical infections in an area where disease occurred.

BackgroundCanine leishmaniasis is a severe, potentially life-threatening, systemic vector-borne disease of dogs caused by protozoan parasites of the genus Leishmania. Romania has been traditionally regarded as a non-endemic country for leishmaniasis with sporadic human disease cases. However, the recent report of an autochthonous canine leishmaniasis case (the first in the last 80 years) suggested the presence of an infection focus in the area of Râmnicu Vâlcea. The present study describes a survey of canine leishmaniasis in this geographical area with comparison to a georeferenced dataset of sand fly distribution based on historical literature records.MethodsThe study was carried out in Râmnicu Vâlcea and included samples (serum, blood and conjunctival swabs) collected from 80 dogs including client-owned dogs from two local practices and dogs from two public shelters. Serum anti-leishmanial antibodies were assessed by ELISA. All blood and conjunctival samples were assessed by real-time quantitative PCR, targeting the leishmanial kinetoplast minicircle DNA.ResultsThree dogs (3.7 %) were seropositive and another four (5.0 %) showed borderline results indicative of exposure or infection. TaqMan PCR was performed for all dogs, on both blood and conjunctival swabs. Seven dogs (8.7 %) were positive by conjunctival swab PCR and one dog (1.2 %) by blood PCR. None of the positive dogs presented clinical signs compatible with canine leishmaniasis.ConclusionsThis is the first study evaluating canine leishmaniasis in a dog population in Romania by both highly sensitive PCR and serology. Although the prevalence was relatively low compared to other endemic regions, our results clearly demonstrate the presence of a canine leishmaniasis focus in Romania.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1583-5) contains supplementary material, which is available to authorized users.

Zika Virus Spreads to New Areas - Region of the Americas, May 2015-January 2016.

Zika virus is a mosquito-borne flavivirus that was first identified in Uganda in 1947 (1). Before 2007, only sporadic human disease cases were reported from countries in Africa and Asia. In 2007, the first documented outbreak of Zika virus disease was reported in Yap State, Federated States of Micronesia; 73% of the population aged ≥3 years is estimated to have been infected (2). Subsequent outbreaks occurred in Southeast Asia and the Western Pacific (3). In May 2015, the World Health Organization reported the first local transmission of Zika virus in the Region of the Americas (Americas), with autochthonous cases identified in Brazil (4). In December, the Ministry of Health estimated that 440,000-1,300,000 suspected cases of Zika virus disease had occurred in Brazil in 2015 (5). By January 20, 2016, locally-transmitted cases had been reported to the Pan American Health Organization from Puerto Rico and 19 other countries or territories in the Americas* (Figure) (6). Further spread to other countries in the region is being monitored closely.

Post-zygotic Point Mutations Are an Underrecognized Source of De Novo Genomic Variation

De novo mutations are recognized both as an important source of genetic variation and as a prominent cause of sporadic disease in humans. Mutations identified as de novo are generally assumed to have occurred during gametogenesis and, consequently, to be present as germline events in an individual. Because Sanger sequencing does not provide the sensitivity to reliably distinguish somatic from germline mutations, the proportion of de novo mutations that occur somatically rather than in the germline remains largely unknown. To determine the contribution of post-zygotic events to de novo mutations, we analyzed a set of 107 de novo mutations in 50 parent-offspring trios. Using four different sequencing techniques, we found that 7 (6.5%) of these presumed germline de novo mutations were in fact present as mosaic mutations in the blood of the offspring and were therefore likely to have occurred post-zygotically. Furthermore, genome-wide analysis of "de novo" variants in the proband led to the identification of 4/4,081 variants that were also detectable in the blood of one of the parents, implying parental mosaicism as the origin of these variants. Thus, our results show that an important fraction of de novo mutations presumed to be germline in fact occurred either post-zygotically in the offspring or were inherited as a consequence of low-level mosaicism in one of the parents.

Emerging types of Shiga toxin-producing E. coli (STEC) O178 present in cattle, deer, and humans from Argentina and Germany.

More than 400 serotypes of Shiga toxin-producing Escherichia coli (STEC) have been implicated in outbreaks and sporadic human diseases. In recent years STEC strains belonging to serogroup O178 have been commonly isolated from cattle and food of bovine origin in South America and Europe. In order to explore the significance of these STEC strains as potential human pathogens, 74 German and Argentinean E. coli O178 strains from animals, food and humans were characterized phenotypically and investigated for their serotypes, stx-genotypes and 43 virulence-associated markers by a real-time PCR-microarray. The majority (n = 66) of the O178 strains belonged to serotype O178:H19. The remaining strains divided into O178:H7 (n = 6), O178:H10 (n = 1), and O178:H16 (n = 1). STEC O178:H19 strains were mainly isolated from cattle and food of bovine origin, but one strain was from a patient with hemolytic uremic syndrome (HUS). Genotyping of the STEC O178:H19 strains by pulsed-field gel electrophoresis revealed two major clusters of genetically highly related strains which differ in their stx-genotypes and non-Stx putative virulence traits, including adhesins, toxins, and serine-proteases. Cluster A-strains including the HUS-strain (n = 35) carried genes associated with severe disease in humans (stx2a, stx2d, ehxA, saa, subAB1, lpfAO113, terE combined with stx1a, espP, iha). Cluster B-strains (n = 26) showed a limited repertoire of virulence genes (stx2c, pagC, lpfAO113, espP, iha). Among O178:H7 strains isolated from deer meat and patients with uncomplicated disease a new STEC variant was detected that is associated with the genotype stx1c/stx2b/ehxA/subAB2/espI/[terE]/espP/iha. None of the STEC O178 strains was positive for locus of enterocyte effacement (LEE)- and nle-genes. Results indicate that STEC O178:H19 strains belong to the growing group of LEE-negative STEC that should be considered with respect to their potential to cause diseases in humans.

Genetic inducible fate mapping in adult mice using tamoxifen-dependent Cre recombinases.

The Cre/lox site-specific recombination system allows the control of gene activity in space and time in almost any tissue of the mouse. A major technical advance was the development of tamoxifen-dependent Cre recombinases, such as CreER(T2), that can be activated by administration of tamoxifen to the animal. This powerful tool greatly facilitates the study of gene functions and the generation of more realistic animal models of sporadic human diseases. Another important application of tamoxifen-dependent Cre recombinases is genetic inducible fate mapping (GIFM). In GIFM studies, the inducible Cre/lox system is used to genetically label a defined cell population at a selected time by irreversible activation of the expression of a Cre-responsive reporter transgene. Then, marked cells are detected at later time points to determine how the originally labeled progenitors contribute to specific structures and cell types during pre- and postnatal development. GIFM was initially applied during mouse embryogenesis, but is now increasingly used for cell lineage tracing in adult mice under physiological and pathophysiological conditions. Here we describe the design of GIFM experiments in adult mice as exemplified by CreER(T2)-assisted tracing of vascular smooth muscle cells during the development of atherosclerotic lesions. First, we give an overview of reporter transgenes available for genetic cell marking that are expressed from the Rosa26 locus, such as β-galactosidase and fluorescent proteins. Then we present detailed protocols for the generation of experimental mice for GIFM studies, the induction of cell labeling by tamoxifen treatment, and the detection of marked cells in fixed and live tissues. Each section also provides a discussion of limitations and common pitfalls of GIFM experiments. Most of the protocols can be easily adapted to other developmental stages, cell types, Cre recombinases, and reporter transgenes and, thus, can be used as general guidelines for GIFM studies in mice.

Chronic suppurative joint effusion due to burkholderia pseudomallei: A case report

Burkholderia pseudomallei, a Gram-negative bacillus is the causative agent of Melioidosis, a glanders-like disease, primarily a disease of animals. Melioidosis has been only a rare and sporadic disease in humans outside its endemic region. Currently, diagnosis of B. pseudomallei in the clinical laboratory is very difficult, owing to low awareness of physicians to the nonspecific clinical manifestations, lack of responsiveness among microbiologists outside endemic areas, identification systems in the average sentinel laboratory, and the biosafety conditions necessary to process these organisms. We report a case of chronic left hip joint effusion in a known case of diabetes mellitus. Gram stain of computed tomography (CT)-guided aspirate from the joint revealed Gram-negative bacilli along with pus cells. Culture was confirmed as Burkholderia pseudomallei on Vitek2C, which was sensitive to ceftazidime and trimethoprim/sulfmethoxazole. Unfortunately, patient could not be started on appropriate antibiotics due to delay in detection and patient succumbed to severe septicemia. This case is reported to highlight importance of automated identification and sensitivity especially in nonendemic areas and unusual antibiogram of this organism for which disc diffusion method is not standardized.

MASTR: A Technique for Mosaic Mutant Analysis with Spatial and Temporal Control of Recombination Using Conditional Floxed Alleles in Mice

Mosaic mutant analysis, the study of cellular defects in scattered mutant cells in a wild-type environment, is a powerful approach for identifying critical functions of genes and has been applied extensively to invertebrate model organisms. A highly versatile technique has been developed in mouse: MASTR (mosaic mutant analysis with spatial and temporal control of recombination), which utilizes the increasing number of floxed alleles and simultaneously combines conditional gene mutagenesis and cell marking for fate analysis. A targeted allele (R26(MASTR)) was engineered; the allele expresses a GFPcre fusion protein following FLP-mediated recombination, which serves the dual function of deleting floxed alleles and marking mutant cells with GFP. Within 24 hr of tamoxifen administration to R26(MASTR) mice carrying an inducible FlpoER transgene and a floxed allele, nearly all GFP-expressing cells have a mutant allele. The fate of single cells lacking FGF8 or SHH signaling in the developing hindbrain was analyzed using MASTR, and it was revealed that there is only a short time window when neural progenitors require FGFR1 for viability and that granule cell precursors differentiate rapidly when SMO is lost. MASTR is a powerful tool that provides cell-type-specific (spatial) and temporal marking of mosaic mutant cells and is broadly applicable to developmental, cancer, and adult stem cell studies.

Genotypic characterization of non-O157 Shiga toxin-producing Escherichia coli in beef abattoirs of Argentina.

The non-O157 Shiga toxin-producing Escherichia coli (STEC) contamination in carcasses and feces of 811 bovines in nine beef abattoirs from Argentina was analyzed during a period of 17 months. The feces of 181 (22.3%) bovines were positive for non-O157 STEC, while 73 (9.0%) of the carcasses showed non-O157 STEC contamination. Non-O157 STEC strains isolated from feces (227) and carcasses (80) were characterized. The main serotypes identified were O178:H19, O8:H19, O130:H11, and O113:H21, all of which have produced sporadic cases of hemolytic-uremic syndrome in Argentina and worldwide. Twenty-two (7.2%) strains carried a fully virulent stx/eae/ehxA genotype. Among them, strains of serotypes O103:[H2], O145:NM, and O111:NM represented 4.8% of the isolates. Xba I pulsed-field gel electrophoresis pattern analysis showed 234 different patterns, with 76 strains grouped in 30 clusters. Nine of the clusters grouped strains isolated from feces and from carcasses of the same or different bovines in a lot, while three clusters were comprised of strains distributed in more than one abattoir. Patterns AREXSX01.0157, AREXBX01.0015, and AREXPX01.0013 were identified as 100% compatible with the patterns of one strain isolated from a hemolytic-uremic syndrome case and two strains previously isolated from beef medallions, included in the Argentine PulseNet Database. In this survey, 4.8% (39 of 811) of the bovine carcasses appeared to be contaminated with nonO157 STEC strains potentially capable of producing sporadic human disease, and a lower proportion (0.25%) with strains able to produce outbreaks of severe disease.

Molecular Risk Assessment and Epidemiological Typing of Shiga Toxin-Producing Escherichia coli by Using a Novel PCR Binary Typing System

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen that causes diarrheal disease in humans and is of public health concern because of its ability to cause outbreaks and severe disease such as hemorrhagic colitis or hemolytic-uremic syndrome. More than 400 serotypes of STEC have been implicated in outbreaks and sporadic human disease. The aim of this study was to develop a PCR binary typing (P-BIT) system that could be used to aid in risk assessment and epidemiological studies of STEC by using gene targets that would represent a broad range of STEC virulence genes. We investigated the distribution of 41 gene targets in 75 O157 and non-O157 STEC isolates and found that P-BIT provided 100% typeability for isolates, gave a diversity index of 97.33% (compared with 99.28% for XbaI pulsed-field gel electrophoresis [PFGE] typing), and produced 100% discrimination for non-O157 STEC isolates. We identified 24 gene targets that conferred the same level of discrimination and produced the same cluster dendrogram as the 41 gene targets initially examined. P-BIT clustering identified O157 from non-O157 isolates and identified seropathotypes associated with outbreaks and severe disease. Numerical analysis of the P-BIT data identified several genes associated with human or nonhuman sources as well as high-risk seropathotypes. We conclude that P-BIT is a useful approach for subtyping, offering the advantage of speed, low cost, and potential for strain risk assessment that can be used in tandem with current molecular typing schema for STEC.

Quorum sensing and a global regulator TsrA control expression of type VI secretion and virulence in Vibrio cholerae

Vibrio cholerae is a human pathogen that causes the life-threatening diarrheal disease cholera. A type VI secretion system (T6SS) was recently shown to be required for full virulence in the O37 serogroup strain V52, which causes only sporadic human disease, but T6SS is not expressed in seventh pandemic O1 El Tor strains under standard laboratory conditions. In this study, we show that in the O1 El Tor strain C6706, T6SS is repressed by both quorum sensing and the uncharacterized protein VC0070 (TsrA). Disruption of TsrA and the quorum sensing regulator LuxO induces expression and secretion of the T6SS substrate Hcp, and this is dependent on the downstream regulator HapR, which directly binds to the promoter region of the T6SS genes hcp1 and hcp2 to induce expression. The activated T6SS in C6706 is functional and can translocate the effector protein VgrG-1 into macrophage cells, and T6SS activation leads to fecal diarrhea and intestinal inflammation in infant rabbits. Using an infant mouse infection model, we show that deletion of tsrA results in a 9.3-fold increase in intestinal colonization compared with wild type. TsrA functions as a global regulator to activate expression of hemagglutinin protease and repress cholera toxin and toxin coregulated pilus. Our findings provide significant insight into the molecular mechanism of T6SS and ToxT regulon gene regulation by quorum sensing and TsrA.

Case report: Eastern equine encephalitis virus imported to the UK

Eastern equine encephalitis (EEE) is rare, but the most severe of the mosquito-borne encephalitides in the United States with a high case fatality rate of 30%. Here, we present a patient with EEE. EEE virus causes sporadic human disease in the Eastern parts of the United States, but the case we describe was a Scottish tourist who acquired the disease from mosquito bites while in holiday in the United States. This is a first report of an imported case to Europe.

Protein tyrosine phosphatases: dual‐specificity phosphatases in health and disease

Dual-specificity phosphatases (DSPs) constitute a subfamily of protein tyrosine phosphatases (PTPs) that dephosphorylates phospho-Tyr, phospho-Ser and nonproteinaceous substrates. DSPs are involved in the regulation of both developmental and postnatal essential processes, such as early embryogenesis, placental development and immune responses. Several DSP genes are implicated in familial and sporadic human diseases, including tumor-related, neurological and muscle disorders, and cardiovascular and inflammatory diseases. This association ranges from disease-causative mutations to disease-risk-prone single-nucleotide polymorphisms, promoter methylation or gene duplication (most often in cancer). Deconvolution of the role of DSPs in disease is challenging. The enzymes' activities are regulated at many levels and they form part of extensive, intricate networks with other signaling components. Here, we review current knowledge of the role of cysteine-based PTP-domain DSPs in health and disease, and their suitability as putative therapeutic targets for drugs is discussed.