59,742 research outputs found

    Cattle develop neutralizing antibodies to rotavirus serotypes which could not be isolated from faeces of symptomatic calves

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    Neutralizing antibodies against 10 serotypes of rotavirus were measured in sera from different age groups of German cattle. Only five of 143 sera did not neutralize heterologous serotypes. Sera from 64 of 76 calves younger than 1 year neutralized bovine rotavirus NCDV (serotype 6). From these calves, sera 54, 26, 51, 24, 12, 10 and 37, in neutralized addition, the heterologous serotypes 1, 2, 3, 4, 5, 7 and 9, respectively. Thirty-eight of 46 rotavirus isolates from Bavarian calves with diarrhoea were serotyped by neutralization: 22, 2 and 14 isolates were typed as serotype 6, serotype 10 (B223) and a newly defined subtype of serotype 10 (V1005), respectively. All serotype 6 isolates and none of the serotype 10 or V1005-like viruses tested hybridized to a NCDV-specific cDNA probe. Eight isolates gave equivocal results by neutralization. We failed however to identify serotype 1, 2, 3, 4 or 8 bovine rotavirus isolates by neutralization with hyperimmune sera and dot blot hybridization with serotype-specific cDNA probes. Thus cross-reacting antibodies in cattle might not represent an anamnestic response, but the recognition of a cross-reacting neutralization epitope shared by many rotavirus serotype

    Genome analysis of a highly virulent serotype 1 strain of streptococcus pneumoniae from West Africa

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    Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, and bacteremia, estimated to cause 2 million deaths annually. The majority of pneumococcal mortality occurs in developing countries, with serotype 1 a leading cause in these areas. To begin to better understand the larger impact that serotype 1 strains have in developing countries, we characterized virulence and genetic content of PNI0373, a serotype 1 strain from a diseased patient in The Gambia. PNI0373 and another African serotype 1 strain showed high virulence in a mouse intraperitoneal challenge model, with 20% survival at a dose of 1 cfu. The PNI0373 genome sequence was similar in structure to other pneumococci, with the exception of a 100 kb inversion. PNI0373 showed only15 lineage specific CDS when compared to the pan-genome of pneumococcus. However analysis of non-core orthologs of pneumococcal genomes, showed serotype 1 strains to be closely related. Three regions were found to be serotype 1 associated and likely products of horizontal gene transfer. A detailed inventory of known virulence factors showed that some functions associated with colonization were absent, consistent with the observation that carriage of this highly virulent serotype is unusual. The African serotype 1 strains thus appear to be closely related to each other and different from other pneumococci despite similar genetic content

    Yersinia ruckeri isolates recovered from diseased Atlantic Salmon (Salmo salar) in Scotland are more diverse than those from Rainbow Trout (Oncorhynchus mykiss) and represent distinct subpopulations

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    Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease of farmed salmonids. Enteric redmouth disease is traditionally associated with rainbow trout (Oncorhynchus mykiss, Walbaum), but its incidence in Atlantic salmon (Salmo salar) is increasing. Yersinia ruckeri isolates recovered from diseased Atlantic salmon have been poorly characterized, and very little is known about the relationship of the isolates associated with these two species. Phenotypic approaches were used to characterize 109 Y. ruckeri isolates recovered over a 14-year period from infected Atlantic salmon in Scotland; 26 isolates from infected rainbow trout were also characterized. Biotyping, serotyping, and comparison of outer membrane protein profiles identified 19 Y. ruckeri clones associated with Atlantic salmon but only five associated with rainbow trout; none of the Atlantic salmon clones occurred in rainbow trout and vice versa. These findings suggest that distinct subpopulations of Y. ruckeri are associated with each species. A new O serotype (designated O8) was identified in 56 biotype 1 Atlantic salmon isolates and was the most common serotype identified from 2006 to 2011 and in 2014, suggesting an increased prevalence during the time period sampled. Rainbow trout isolates were represented almost exclusively by the same biotype 2, serotype O1 clone that has been responsible for the majority of ERM outbreaks in this species within the United Kingdom since the 1980s. However, the identification of two biotype 2, serotype O8 isolates in rainbow trout suggests that vaccines containing serotypes O1 and O8 should be evaluated in both rainbow trout and Atlantic salmon for application in Scotland

    Characterization of virulence factors in the newly described <i>Salmonella enterica</i> serotype Keurmassar emerging in Senegal (sub-Saharan Africa)

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    From 2000 to 2001, nine strains of Salmonella enterica belonging to the new serotype Keurmassar have been isolated from human and poultry samples at the Senegalese National Salmonella and Shigella Reference Laboratory at the Pasteur Institute, in Dakar. All strains carried virulence factors including Salmonella Pathogenicity Islands (SPI)-1, -2, -3 and -5 encoded genes. Strains did not harbour virulence plasmid. Ribotyping analysis revealed a single clone identical to Salmonella Decatur isolated in Zimbabwe. These data suggest that strains are closely related, and may have been spread clonally. In this new serotype, insertion sequence IS200 is not present

    Protection of pigs against challenge with virulent <i>Streptococcus suis</i> serotype 2 strains by a muramidase-released protein and extracellular factor vaccine

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    The efficacy of a muramidase-released protein (MRP) and extracellular factor (EF) vaccine in preventing infection and disease in pigs challenged either with a homologous or a heterologous Streptococcus suis serotype 2 strain (MRP EF ) was compared with the efficacy of a vaccine containing formalin-killed bacterin of S suis serotype 2 (MRP EF ). The enhancement of the immune response by different adjuvants (a water-in-oil emulsion [wo] and an aluminium hydroxide-based adjuvant [AH]) and their side effects were also studied. The MRP and EF were purified by affinity chromatography. Pigs were vaccinated twice at three weeks and six weeks of age and challenged intravenously with virulent S suis serotype 2 strains (MRP EF ) at eight weeks of age. At challenge, the pigs vaccinated with MRP EF/WO had high anti-MRP and anti-EF titres and were protected as effectively as pigs vaccinated with wo-formulated vaccines with bacterin. Eight of the nine pigs survived the challenge and almost no clinical signs of disease were observed. The titres obtained with the MRP EF/AH vaccine were low and only two of the five pigs were protected. Pigs vaccinated with either MRP or EF were less well protected; three of the four pigs died after challenge but the clinical signs of disease were significantly less severe than those observed in the placebo-vaccinated pigs. The protective capacity of the bacterin/AH vaccine was very low, and the mortality among these pigs was as high as in the placebo-vaccinated pigs (80 per cent). Postmortem histological examination revealed meningitis, polyserositis and arthritis in the clinically affected pigs. The results demonstrate that a subunit vaccine containing both MRP and EF, formulated with the wo adjuvant, protected pigs against challenge with virulent S suis type 2 strains

    Emerg. Infect. Dis

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    The multidrug-resistant (MDR) Salmonella enterica serotype Newport strain that produces CMY-2 β-lactamase(Newport MDR-AmpC) was the source of sporadic cases and outbreaks in humans in France during 2000–2005. Because this strain was not detected in food animals, it was most likely introduced into France through imported food products

    Antigenic and biochemical characterization of bovine rotavirus V1005, a new member of rotavirus serotype 10

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    Bovine rotavirus (BRV) V1005 is serologically distinct from rotavirus serotypes 1, 2, 3, 4, 5, 6, 8 and 9. BRV V1005 showed cross-reactions with BRV B223, the American prototype of serotype 10 rotavirus, and with BRV E4049, a British serotype 10 isolate. BRV V1005 was, however, not neutralized by four monoclonal antibodies directed against VP7 of BRV B223. Two-way cross-reactions were observed between BRV V1005 and a reassortant rotavirus containing the VP4 from BRV UK. In addition the major tryptic cleavage product of VP4, VP5*, from BRV V1005 is indistinguishable by peptide mapping and its isoelectric point from the homologous protein of BRV UK, but is clearly different from VP5* of BRV NCDV. The peptide map of VP7 from BRV V1005 differed from that obtained for VP7 of BRV U

    Temporal changes in nasopharyngeal carriage of Streptococcus pneumoniaeserotype 1 genotypes in healthy Gambians before and after the 7-valent pneumococcal conjugate vaccine

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    Streptococcus pneumoniae serotype 1 is one of the leading causes of invasive pneumococcal disease. However, this invasive serotype is hardly found in nasopharyngeal asymptomatic carriage and therefore large epidemiological studies are needed to assess the dynamics of serotype 1 infection. Within the context of a large cluster randomized trial conducted in rural Gambia to assess the impact of PCV-7 vaccination on nasopharyngeal carriage, we present an ancillary analysis describing the prevalence of nasopharyngeal carriage of pneumococcal serotype 1 and temporal changes of its more frequent genotypes. Nasopharyngeal swabs (NPS) were collected before PCV-7 vaccination (December 2003–May 2004) and up to 30 months after PCV-7 vaccination. The post-vaccination time was divided in three periods to ensure an equal distribution of the number of samples: (1) July 2006–March 2007, (2) April 2007–March 2008 and (3) April 2008–Feb 2009. S. pneumoniae serotype 1 were genotyped by MLST. Serotype 1 was recovered from 87 (0.71%) of 12,319 NPS samples collected. In the pre-vaccination period, prevalence of serotype 1 was 0.47% in both study arms. In the post-vaccination periods, prevalence in the fully vaccinated villages ranged between 0.08% in period 1 and 0.165% in period 2, while prevalence in partly vaccinated villages was between 0.17% in period 3 and 1.34% in period 2. Overall, four different genotypes were obtained, with ST3081 the most prevalent (60.71%), followed by ST618 (29.76%). ST3081 was found only in post-vaccination period 2 and 3, while ST618 had disappeared in post-vaccination period 3. Distribution of these major genotypes was similar in both study arms. Emergence of ST3081 and concomitant disappearance of ST618 may suggest a change in the molecular epidemiology of pneumococcal serotype 1 in this region. This change is not likely to be associated with the introduction of PCV-7 which lacks serotype 1, as it was observed simultaneously in both study arms. Future population-based epidemiological studies will provide further evidence of substantive changes in the pneumococcal serotype 1 epidemiology and the likely mechanisms

    Streptococcus pneumoniae Serotype-2 Childhood Meningitis in Bangladesh: A Newly Recognized Pneumococcal Infection Threat

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    BACKGROUND: Streptococcus pneumoniae is a leading cause of meningitis in countries where pneumococcal conjugate vaccines (PCV) targeting commonly occurring serotypes are not routinely used. However, effectiveness of PCV would be jeopardized by emergence of invasive pneumococcal diseases (IPD) caused by serotypes which are not included in PCV. Systematic hospital based surveillance in Bangladesh was established and progressively improved to determine the pathogens causing childhood sepsis and meningitis. This also provided the foundation for determining the spectrum of serotypes causing IPD. This article reports an unprecedented upsurge of serotype 2, an uncommon pneumococcal serotype, without any known intervention. METHODS AND FINDINGS: Cases with suspected IPD had blood or cerebrospinal fluid (CSF) collected from the beginning of 2001 till 2009. Pneumococcal serotypes were determined by capsular swelling of isolates or PCR of culture-negative CSF specimens. Multicenter national surveillance, expanded from 2004, identified 45,437 patients with suspected bacteremia who were blood cultured and 10,618 suspected meningitis cases who had a lumber puncture. Pneumococcus accounted for 230 culture positive cases of meningitis in children <5 years. Serotype-2 was the leading cause of pneumococcal meningitis, accounting for 20.4% (45/221; 95% CI 15%-26%) of cases. Ninety eight percent (45/46) of these serotype-2 strains were isolated from meningitis cases, yielding the highest serotype-specific odds ratio for meningitis (29.6; 95% CI 3.4-256.3). The serotype-2 strains had three closely related pulsed field gel electrophoresis types. CONCLUSIONS: S. pneumoniae serotype-2 was found to possess an unusually high potential for causing meningitis and was the leading serotype-specific cause of childhood meningitis in Bangladesh over the past decade. Persisting disease occurrence or progressive spread would represent a major potential infection threat since serotype-2 is not included in PCVs currently licensed or under development

    Perbandingan Tingkat Keparahan Infeksi Sekunder Virus Dengue pada Keempat Serotipe di Indonesia: Systematic Review

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    Secondary infection with the dengue virus causes mild to severe manifestations. The distribution of dengue virus serotypes varies in various areas and can change over time. There are four dengue serotypes, namely DENV-1, DENV-2, DENV-3 and DENV-4. Objectives: To knew the distribution of virus serotypes in an area and determined the pathogenesis of the disease, which can cause severe manifestations in patients with secondary infections. Methods: The data taken is the severity of secondary infections and dengue serotypes. The literature search was performed on PMC and Cochrane. Search criteria were performed using keywords (secondary infection * OR secondary dengue infection *) AND (Dengue Virus * OR Dengue Infection * OR Dengue * OR DENV) AND (Serotype * OR Serogroup) AND (severe dengue * OR severity * OR severity of illness indexs * OR dengue fever * OR dengue haemorrhage fever * OR dengue shock syndrome * OR DF * OR DHF * OR DSS *) AND (Indonesia *). Results: Literature study search found 387 literature with five studies conducted the analysis. From the results of the analysis, it was found that secondary infections were more common in patients with recurrent dengue infection with serotype 2 (DENV-2), serotype 3 (DENV-3) and serotype 4 (DENV-4). Conclusion: Secondary infection of dengue virus serotype 2 (DENV-2) and serotype 3 (DENV-3) can cause severe dengue infection.Keywords:  Dengue Virus, Indonesia, Secondary Infection, Serotype, Severit
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