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Andrew S. Waller - One of the best experts on this subject based on the ideXlab platform.
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intramuscular vaccination with strangvac is safe and induces protection against equine Strangles caused by streptococcus equi
Vaccine, 2020Co-Authors: Carl Robinson, Andrew S. Waller, Margareta Flock, Bengt Guss, Lars Frykberg, Olof Zachrisson, Janingmar FlockAbstract:Abstract The equine disease Strangles, caused by Streptococcus equi, remains a major cause of welfare and economic cost to the global horse industry. Here we report the safety, immunogenicity and efficacy of a novel multi-component chimeric fusion protein vaccine, called Strangvac, when administered to ponies via the intramuscular route. Across the four studies, Strangvac was safe and induced robust antibody responses towards the vaccine components in blood serum and the nasopharynx, which were boosted by revaccination up to 12 months after a primary course of 2 vaccinations 4 weeks apart. The vaccine response did not cross-react with a commercial Strangles iELISA, which identifies horses that have been exposed to S. equi, demonstrating that it was possible to differentiate infected from vaccinated animals (DIVA). Following challenge with S. equi strain 4047 (Se4047), all 36 control ponies that had received an adjuvant-only placebo vaccine developed clinical signs of Strangles. In contrast, intramuscular vaccination with Strangvac protected ponies significantly from challenge with Se4047 at two weeks (5 of 16 ponies protected (31%), P = 0.04) and two months (7 of 12 ponies protected (58%), P = 0.0046 (including pooled control data) after second vaccination. Optimal protection (15 of 16 ponies protected (94%), P
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influence of penicillin treatment of horses with Strangles on seropositivity to streptococcus equi ssp equi specific antibodies
Journal of Veterinary Internal Medicine, 2020Co-Authors: John Pringle, Andrew S. Waller, Emma Storm, Miia RiihimakiAbstract:BACKGROUND Antibiotic treatment of horses with Strangles is reported to impair the development of immunity to subsequent exposure to Streptococcus equi ssp equi (S. equi). However, apart from a single clinical report, evidence-based studies for this hypothesis are lacking. HYPOTHESIS/OBJECTIVE To determine whether penicillin treatment during clinical Strangles influences the development or persistence of seropositivity to S. equi-specific antibodies. ANIMALS A natural outbreak of Strangles with 100% morbidity in 41 unvaccinated mature Icelandic horses. METHODS A prospective longitudinal study of acute clinical Strangles from onset through full recovery approximately 10 months after the index case. Horses were monitored clinically 6 times for S. equi, as well as serologically for antibodies to antigens A and C of S. equi using an enhanced indirect ELISA. Seven horses received penicillin within 11 days of onset of fever (Group 1), 5 between 16 and 22 days after onset of fever (Group 2), and the remainder (Group 3, n = 29) received no antibiotics during clinical disease. The proportions of seropositive horses in each group were compared using an extension of Fisher's exact test with P < .05 as the level of significance. RESULTS Although all horses were seropositive to S. equi within 2 months of the index case, significantly fewer horses treated early (Group 1) remained seropositive by 4 to 6 months (P = .04 and .02, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE Findings support earlier suggestions that penicillin administered during acute Strangles can interfere with persistence of humoral immunity to S. equi.
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an outbreak of Strangles associated with a novel genotype of streptococcus equi subspecies equi in donkeys in china during 2018
Equine Veterinary Journal, 2019Co-Authors: Andrew S. Waller, Jianbao Dong, Nannan Gao, Frank R Cook, S Fan, Dongfang Yuan, J Norimine, W ZhuAbstract:Background Strangles is a highly contagious respiratory disease of equids caused by the bacterium Streptococcus equi subspecies equi. Objectives To identify the cause of an outbreak of Strangles that occurred on donkey farms within the Shandong Province of China and determine the prevalence of the disease. Study design Cross-sectional. Methods Samples were taken from clinically affected animals to measure the prevalence of Strangles within the population of donkeys at six intensive farms in China and identify the SeM type of isolate recovered from affected animals. Diagnosis was confirmed by bacterial isolation, biochemical tests and PCR. Epidemiological data were analysed using Chi-square test and a Fisher's exact two-sided test. The SeM gene of S. equi isolates recovered from affected animals was determined and compared with the SeM database PubMLST-seM. Results In July and August 2018, an outbreak of Strangles occurred on six donkey farms within the Shandong Province of China. The overall prevalence of disease within the different donkey herds was 13.4%. Younger animals were worst affected with 40.3% (83/206) of donkey foals aged under 1 year exhibiting clinical signs compared with 12.5% (191/1525) of donkeys aged one to 2 years and 3.8% (17/442) of donkeys over 2 years of age. Analysis of SeM sequencing data identified that the farms were affected by the same strain of S. equi, SD201807, which contains the novel 136 allele of SeM. Main limitations Healthy donkeys were not sampled in this study. Conclusions The number of intensive donkey breeding farms in China has risen recently. The higher numbers of animals that are in closer proximity to one another raise the potential for the transmission of infectious diseases such as Strangles. This is the first description of a Strangles outbreak among donkey herds in China. The Summary is available in Chinese - see Supporting information.
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serological responses of australian horses using a commercial duplex indirect elisa following vaccination against Strangles
Australian Veterinary Journal, 2019Co-Authors: C M Elhage, Andrew S. Waller, Hiroshi Bannai, Anke K Wiethoelter, Simon M Firestone, C M Heislers, Joanne L Allen, J R GilkersonAbstract:OBJECTIVE: To determine the nature of serological responses in Australian horses using a commercial duplex indirect ELISA (iELISA) following vaccination against Strangles. DESIGN: A group (n = 19) of client-owned horses from five properties were recruited to receive a primary course of a Streptococcus equi subsp. equi (S. equi) extract vaccine. Serological responses were determined by duplex iELISA incorporating S. equi-specific fragments of two cell wall proteins, SEQ2190 and SeM (antigens (Ag) A and C, respectively). METHODS: The horses were administered a primary Strangles vaccination course. Blood was collected immediately prior to each of the three vaccinations at 2-week intervals and additionally at 28 and 56 days following the 3rd vaccination (V3). RESULTS: Significant increases in mean antibody levels of horses following vaccination were limited only to AgC, which was significantly increased at T2/V3, 14 days following V2 (ratio of geometric means = 3.7; 95% confidence interval (CI): 1.6, 8.4; P = 0.003). There was no increase in mean antibody to Ag A (ratio of geometric means = 1.4; 95% CI: 0.6, 3.2; P = 0.39). Four horses (22%) exceeded the test cut-off for AgC following vaccination. CONCLUSION: Vaccination of Australian horses is unlikely to interfere greatly with detection of Strangles using the duplex iELISA. No responses would be anticipated to AgA following vaccination with Equivac© S/Equivac© 2in1 and only a minority are likely to respond to AgC. We conclude that the results of this study validate the usefulness of the duplex iELISA to assist control measures for Strangles outbreaks in Australian horse populations.
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Streptococcus equi: breaking its Strangles-hold.
The Veterinary record, 2018Co-Authors: Andrew S. WallerAbstract:Andrew Waller, head of bacteriology at the AHT, describes Streptococcus equi, the causative agent of Strangles in horses, and discusses progress with the latest research aimed at improving vaccines against this global disease.
John Pringle - One of the best experts on this subject based on the ideXlab platform.
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influence of penicillin treatment of horses with Strangles on seropositivity to streptococcus equi ssp equi specific antibodies
Journal of Veterinary Internal Medicine, 2020Co-Authors: John Pringle, Andrew S. Waller, Emma Storm, Miia RiihimakiAbstract:BACKGROUND Antibiotic treatment of horses with Strangles is reported to impair the development of immunity to subsequent exposure to Streptococcus equi ssp equi (S. equi). However, apart from a single clinical report, evidence-based studies for this hypothesis are lacking. HYPOTHESIS/OBJECTIVE To determine whether penicillin treatment during clinical Strangles influences the development or persistence of seropositivity to S. equi-specific antibodies. ANIMALS A natural outbreak of Strangles with 100% morbidity in 41 unvaccinated mature Icelandic horses. METHODS A prospective longitudinal study of acute clinical Strangles from onset through full recovery approximately 10 months after the index case. Horses were monitored clinically 6 times for S. equi, as well as serologically for antibodies to antigens A and C of S. equi using an enhanced indirect ELISA. Seven horses received penicillin within 11 days of onset of fever (Group 1), 5 between 16 and 22 days after onset of fever (Group 2), and the remainder (Group 3, n = 29) received no antibiotics during clinical disease. The proportions of seropositive horses in each group were compared using an extension of Fisher's exact test with P < .05 as the level of significance. RESULTS Although all horses were seropositive to S. equi within 2 months of the index case, significantly fewer horses treated early (Group 1) remained seropositive by 4 to 6 months (P = .04 and .02, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE Findings support earlier suggestions that penicillin administered during acute Strangles can interfere with persistence of humoral immunity to S. equi.
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long term silent carriers of streptococcus equi ssp equi following Strangles carrier detection related to sampling site of collection and culture versus qpcr
Veterinary Journal, 2019Co-Authors: John Pringle, M Venner, L Tscheschlok, L Bachi, Miia RiihimakiAbstract:After Strangles outbreaks, Streptococcus equi ssp. equi (S. equi) can persist in clinically normal silent carriers for months to years. Two naturally occurring outbreaks of Strangles with 53 and 100% morbidity, respectively, were followed longitudinally to assess occurrence of carrier state and optimal detection methods Outbreak A involved 98 yearling warmbloods, and outbreak B 38 mature Icelandic horses. Fully recovered horses were sampled at least 6 months after index cases using nasal swabs (one sampling occasion only) nasopharyngeal lavage and guttural pouch visualisation and lavages for culture and qPCR to S. equi. Any horse with at least a single sample positive was deemed a carrier. Descriptive statistics and sensitivity and negative predictive values were calculated. Comparisons were made with McNemars and Fishers exact tests. Carrier rates in outbreak A were 3% based on culture and 15% based on qPCR and for outbreak B 13% based on culture and 37% based on qPCR. All culture positives were also qPCR positive. One carrier culture negative sampled after an additional 8 months was culture positive to S. equi, indicating that qPCR positives should be suspected to carry live bacteria. Findings indicate that reliance on guttural pouch sampling and appearance does not capture all silent carriers. All culture positives were identified by qPCR and even horses positive by qPCR but culture negative should be suspected carriers of live bacteria.
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long term dynamics of a streptococcus equi ssp equi outbreak assessed by qpcr and culture and sem sequencing in silent carriers of Strangles
Veterinary Microbiology, 2018Co-Authors: Miia Riihimaki, Anna Aspan, Helena Ljung, John PringleAbstract:The aim of the study was to use culture, qPCR and seM sequencing to map Streptococcus equi subspec. equi (S.equi) isolates in long term carrier animals. A Strangles outbreak affecting 41 Icelandic horses was followed to determine Strangles free status using nasal and/or guttural pouch lavages collected serially on eleven separate occasions over 13 months. Ten persistent carriers, of which eight had repeated culture positive samples for S. equi, were selected for the study. Of 115 samples collected, 61 were S. equi positive on qPCR; from which 32 were also culture positive. Amplification of parts of the gene encoding the M-protein seM was performed on isolated colony material (n = 32) or, where only PCR product was obtained, directly on the DNA sample (n = 29) with a nested amplification approach. The seM sequence could be determined for six of the 29 samples that were solely qPCR positive. The outbreak was due to a S. equi strain of seM type 72. Three months after initial sampling isolates from two horses had seM gene sequences with one amino acid change. After six months S. equi with truncated seM genes were found in two horses; one variant in a single horse once, and in the other horse a variant that persisted and that was later identified in two additional horses. Non- mucoid S. equi colonies were found in two horses. Importantly, after acute Strangles outbreaks many horses not only remain persistently qPCR positive for S. equi but are also intermittently culture positive.
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decreased clinical severity of Strangles in weanlings associated with restricted seroconversion to optimized streptococcus equi ssp equi assays
Journal of Veterinary Internal Medicine, 2018Co-Authors: Lisa Tscheschlok, Miia Riihimaki, Karen F Steward, Monica Venner, R Bose, John PringleAbstract:Background Streptococcus equi ssp. equi causes characteristic clinical signs that are most severe in young horses, including fever, purulent nasal discharge, and lymph node abscessation in the head region. Hypothesis/objectives Clinical, serologic, and microbiologic factors related to unexpectedly mild disease severity in a natural outbreak of Strangles in immunologically naive weanlings were investigated. Animals One-hundred and twelve warmblood weanlings. Methods Prospective longitudinal observational study of a natural outbreak of Strangles. The entire cohort was examined at the peak of the outbreak by deep nasal swabs for culture and quantitative PCR (qPCR) for the presence of S. equi and clinically and serologically in a sequential manner by an optimized ELISA from the index case throughout the outbreak until resolution. Descriptive statistics were calculated and comparisons made using a nondirectional Wilcoxon signed-rank test. Results Outbreak morbidity was 53%, with 9 of 14 horses culture positive and 26 of 53 horses qPCR positive for S. equi lacking clinical signs characteristic of Strangles. By resolution, 91 of 112 had seroconverted to Antigen A by ELISA but seroconversion to antigen C (part of the SeM protein) was minimal. Sequencing of the isolates detected no alterations in the SeM protein, but identified a 61 bp deletion in the gene SEQ_0402. Conclusions and clinical importance Absence of clinical signs alone in naive horses may be an insufficient criterion to release horses from Strangles quarantine measures. Restricted seroconversion to antigen C may have been associated with decreased clinical severity. The role of a minor gene deletion in SEQ_0402 in the virulence of S. equi warrants further investigation.
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comparison of sampling sites and laboratory diagnostic tests for s equi subsp equi in horses from confirmed Strangles outbreaks
Journal of Veterinary Internal Medicine, 2013Co-Authors: S Lindahl, Viveca Baverud, Agneta Egenvall, Anna Aspan, John PringleAbstract:Background Strangles is a contagious equine-specific disease caused by Streptococcus equi subsp. equi. Unfortunately, detection of S. equi can fail in up to 40% of horses with Strangles. Whereas recent molecular biologic methods and sampling techniques have improved recovery of S. equi optimal sampling methods and laboratory analyses remain ill-defined. Objectives To determine the yield of S. equi from horses with acute Strangles in confirmed outbreaks by field-sampling methods subjected to culture and biochemical identification, and real-time PCR directly and after culture. Animals Fifty-seven horses of varying breeds and ages from 8 Strangles outbreaks. Methods Prospective study. Culture with biochemical identification and real-time PCR directly, and from culture, were performed on nasal swabs, nasopharyngeal swabs, and nasopharyngeal lavages. Results Real-time PCR directly from samples identified the highest number of infected horses, with 45/57 nasal swabs, 41/57 nasopharyngeal swabs, and 48/57 nasopharyngeal lavages S. equi positive. Biochemical identification (highest positives 22/57) was inferior to real-time PCR for S. equi recovery regardless of sampling method. Real-time PCR of nasopharyngeal lavage directly and after culture yielded 52/57 positives whereas direct real-time PCR of nasopharyngeal lavage combined with either nasopharyngeal swabs or nasal swabs yielded 53/57 positives. Three horses were negative on all samples. Conclusions and Clinical Importance Nasopharyngeal lavage analyzed by a combination of real-time PCR directly and after culture or, alternatively, real-time PCR directly on a nasopharyngeal lavage and a nasal/nasopharyngeal swab can identify S. equi in over 90% of acute Strangles cases.
Carl Robinson - One of the best experts on this subject based on the ideXlab platform.
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intramuscular vaccination with strangvac is safe and induces protection against equine Strangles caused by streptococcus equi
Vaccine, 2020Co-Authors: Carl Robinson, Andrew S. Waller, Margareta Flock, Bengt Guss, Lars Frykberg, Olof Zachrisson, Janingmar FlockAbstract:Abstract The equine disease Strangles, caused by Streptococcus equi, remains a major cause of welfare and economic cost to the global horse industry. Here we report the safety, immunogenicity and efficacy of a novel multi-component chimeric fusion protein vaccine, called Strangvac, when administered to ponies via the intramuscular route. Across the four studies, Strangvac was safe and induced robust antibody responses towards the vaccine components in blood serum and the nasopharynx, which were boosted by revaccination up to 12 months after a primary course of 2 vaccinations 4 weeks apart. The vaccine response did not cross-react with a commercial Strangles iELISA, which identifies horses that have been exposed to S. equi, demonstrating that it was possible to differentiate infected from vaccinated animals (DIVA). Following challenge with S. equi strain 4047 (Se4047), all 36 control ponies that had received an adjuvant-only placebo vaccine developed clinical signs of Strangles. In contrast, intramuscular vaccination with Strangvac protected ponies significantly from challenge with Se4047 at two weeks (5 of 16 ponies protected (31%), P = 0.04) and two months (7 of 12 ponies protected (58%), P = 0.0046 (including pooled control data) after second vaccination. Optimal protection (15 of 16 ponies protected (94%), P
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identification of genes required for the fitness of streptococcus equi subsp equi in whole equine blood and hydrogen peroxide
Microbial genomics, 2020Co-Authors: Carl Robinson, Duncan J Maskell, Amelia R L Charbonneau, Emma Taylor, Catriona Mitchell, Amy K Cain, J A LeighAbstract:The availability of next-generation sequencing techniques provides an unprecedented opportunity for the assignment of gene function. Streptococcus equi subspecies equi is the causative agent of Strangles in horses, one of the most prevalent and important diseases of equids worldwide. However, the live attenuated vaccines that are utilized to control this disease cause adverse reactions in some animals. Here, we employ transposon-directed insertion-site sequencing (TraDIS) to identify genes that are required for the fitness of S. equi in whole equine blood or in the presence of H2O2 to model selective pressures exerted by the equine immune response during infection. We report the fitness values of 1503 and 1471 genes, representing 94.5 and 92.5 % of non-essential genes in S. equi , following incubation in whole blood and in the presence of H2O2, respectively. Of these genes, 36 and 15 were identified as being important to the fitness of S. equi in whole blood or H2O2, respectively, with 14 genes being important in both conditions. Allelic replacement mutants were generated to validate the fitness results. Our data identify genes that are important for S. equi to resist aspects of the immune response in vitro, which can be exploited for the development of safer live attenuated vaccines to prevent Strangles.
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AS: Contribution of each of four superantigens to Streptococcus equi-induced mitogenicity, IFN gamma synthesis and immunity. Infect Immun 2010
2016Co-Authors: Romain Paillot, Carl Robinson, Karen Steward, Nicola Wright, Thibaud Jourdan, Nicola Butcher, Zoe Heather, Andrew S. WallerAbstract:Streptococcus equi is the causative agent of Strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation and swelling of the lymph nodes of the head and neck, which can literally strangle the horse to death. S. equi produces four recently acquired phage-associated bacterial superantigens (sAgs; SeeH, SeeI, SeeL, and SeeM) that share homology with the mitogenic toxins of Streptococcus pyogenes. The aim of this study was to characterize the contribution of each of these S. equi sAgs to mitogenic activity in vitro and quantify the sAg-neutralizing capacity of sera from naturally infected horses in order to better understand their role in pathogenicity. Each of the sAgs was successfully cloned, and soluble proteins were produced in Escherichia coli. SeeI, SeeL, and SeeM induced a dose-dependent proliferative response in equine CD4 T lymphocytes and synthesis of gamma interferon (IFN-). SeeH did not stimulate equine peripheral blood mononuclear cells (PBMC) but induced proliferation of asinine PBMC. Allelic replacement mutants of S. equi strain 4047 with sequential deletion of the superantigen genes were generated. Deletion of seeI, seeL, and seeM completely abrogated the mitogenic activity and synthesis of IFN-, in equine PBMC, of the strain 4047 culture supernatant. Sera from naturally infected convalescent horses had only limited sAg-neutralizing activities. We propose that S. equi sAgs play an important role in S. equi pathogenicity by stimulating an overzealous and inappropriate Th1 response that may interfere with the development of a
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vaccination with a live multi gene deletion strain protects horses against virulent challenge with streptococcus equi
Vaccine, 2015Co-Authors: Carl Robinson, K C Smith, Josh Slater, Zoe Heather, Karen F Steward, Nicola Potts, Duncan J Maskell, Michael C Fontaine, Jeongjin Lee, Andrew S. WallerAbstract:Strangles, caused by Streptococcus equi subspecies equi (S. equi) is one of the most frequently diagnosed infectious diseases of horses and there remains a significant need to develop new preventative vaccines. We generated a live vaccine strain of S. equi containing deletions in six genes: sagA, hasA, aroB, pyrC, seM and recA, which was administered to nine Welsh mountain ponies via the intramuscular route. Four vaccinated ponies developed adverse reactions following the first vaccination from which the live vaccine strain was isolated. Two of these ponies were withdrawn from the study and seven ponies received a second vaccination, one of which then developed an adverse reaction. Nine control ponies injected with culture media alone developed no adverse reactions. Following challenge with a virulent strain of S. equi, none of the seven vaccinated ponies had developed clinical signs of Strangles eleven days post-challenge, compared to six of nine control ponies over the same period (P = 0.0114). A lymph node abscess was identified in one of the seven vaccinated ponies at post-mortem examination, whilst all nine control ponies had at least one lymph node abscess (P = 0.0009). Three of the six vaccinated ponies that were protected from Strangles had not developed an adverse reaction following vaccination, suggesting that a better understanding of the pro-inflammatory responses to S. equi could lead to the development of a live attenuated vaccine against Strangles that is safe for administration via intramuscular injection.
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contribution of each of four superantigens to streptococcus equi induced mitogenicity gamma interferon synthesis and immunity
Infection and Immunity, 2010Co-Authors: Romain Paillot, Carl Robinson, Nicola Wright, Thibaud Jourdan, Nicola Butcher, Zoe Heather, Karen F Steward, Andrew S. WallerAbstract:Streptococcus equi is the causative agent of Strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation and swelling of the lymph nodes of the head and neck, which can literally strangle the horse to death. S. equi produces four recently acquired phage-associated bacterial superantigens (sAgs; SeeH, SeeI, SeeL, and SeeM) that share homology with the mitogenic toxins of Streptococcus pyogenes. The aim of this study was to characterize the contribution of each of these S. equi sAgs to mitogenic activity in vitro and quantify the sAg-neutralizing capacity of sera from naturally infected horses in order to better understand their role in pathogenicity. Each of the sAgs was successfully cloned, and soluble proteins were produced in Escherichia coli. SeeI, SeeL, and SeeM induced a dose-dependent proliferative response in equine CD4 T lymphocytes and synthesis of gamma interferon (IFN-γ). SeeH did not stimulate equine peripheral blood mononuclear cells (PBMC) but induced proliferation of asinine PBMC. Allelic replacement mutants of S. equi strain 4047 with sequential deletion of the superantigen genes were generated. Deletion of seeI, seeL, and seeM completely abrogated the mitogenic activity and synthesis of IFN-γ, in equine PBMC, of the strain 4047 culture supernatant. Sera from naturally infected convalescent horses had only limited sAg-neutralizing activities. We propose that S. equi sAgs play an important role in S. equi pathogenicity by stimulating an overzealous and inappropriate Th1 response that may interfere with the development of an effective immune response.
John F Timoney - One of the best experts on this subject based on the ideXlab platform.
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globetrotting Strangles the unbridled national and international transmission of streptococcus equi between horses
Microbial genomics, 2021Co-Authors: Catriona Mitchell, John F Timoney, Karen F Steward, Amelia R L Charbonneau, Saoirse Walsh, Hayley Wilson, Ulli Wernery, Marina JosephAbstract:The equine disease Strangles, which is characterized by the formation of abscesses in the lymph nodes of the head and neck, is one of the most frequently diagnosed infectious diseases of horses around the world. The causal agent, Streptococcus equi subspecies equi, establishes a persistent infection in approximately 10 % of animals that recover from the acute disease. Such 'carrier' animals appear healthy and are rarely identified during routine veterinary examinations pre-purchase or transit, but can transmit S. equi to naive animals initiating new episodes of disease. Here, we report the analysis and visualization of phylogenomic and epidemiological data for 670 isolates of S. equi recovered from 19 different countries using a new core-genome multilocus sequence typing (cgMLST) web bioresource. Genetic relationships among all 670 S. equi isolates were determined at high resolution, revealing national and international transmission events that drive this endemic disease in horse populations throughout the world. Our data argue for the recognition of the international importance of Strangles by the Office International des Epizooties to highlight the health, welfare and economic cost of this disease. The Pathogenwatch cgMLST web bioresource described herein is available for tailored genomic analysis of populations of S. equi and its close relative S. equi subspecies zooepidemicus that are recovered from horses and other animals, including humans, throughout the world. This article contains data hosted by Microreact.
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Strangles, convalescent Streptococcus equi subspecies equi M antibody titers, and presence of complications
Wiley, 2019Co-Authors: Katherine M. Delph, John F Timoney, Laurie A. Beard, Amanda C. Trimble, Maureen E. Sutter, Jennifer K. MorrowAbstract:Background Streptococcus equi subspecies equi infection elicits M protein antibody titers in equids. Interpretation of titers is not generally accepted. Hypothesis The magnitude of S. equi M protein (SeM) antibody titer after infection (titer ≥1:12 800) will be useful to monitor for the presence of complications or the risk of development of complications. Animals Forty‐eight horses on 1 farm involved in Strangles outbreak. Methods Clinical and observational study. S. equi M protein antibody titers were measured on all horses 8 weeks after infection and select horses 12 and 28 weeks after infection. Horses were categorized: no disease, uncomplicated case, persistent guttural pouch (GP) infection, or complicated cases (metastatic abscesses, purpura hemorrhagica, secondary infections, and dysphagia). Category was compared to titer. Results Twenty‐eight of 48 (58%) developed clinical signs of S. equi infection. Of those, 11 (39%) had uncomplicated Strangles, 9 (21%) had persistent GP infection, 5 (18%) were complicated cases, and 3 (11%) had both persistent GP infection and complications. Thirty‐three percent of horses (16 of 48) had SeM antibody titers ≥1:12 800 eight weeks after infection. Of horses with titers ≥1:12 800, 6 of 16 had evidence of complications. Of complicated cases, 6 of 8 had titers ≥1:12 800. In this outbreak, the sensitivity (75%; 95% CI [confidence interval] 45‐105) for a SeM antibody titer ≥1:12 800 detecting complications was higher than the specificity (43%; 95% CI 23‐64). Conclusions and Clinical Importance This outbreak demonstrates that SeM antibody titers can be increased after infection (≥1:12 800) in the absence of complications of Strangles
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streptococcus equi infections in horses guidelines for treatment control and prevention of Strangles revised consensus statement
Journal of Veterinary Internal Medicine, 2018Co-Authors: Ashley G. Boyle, John F Timoney, Andrew S. Waller, J R Newton, M T Hines, B R BuchananAbstract:This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of Strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of Strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the importance of judicious use of antibiotics in horses with Strangles. This updated consensus statement reviews current vaccine technology and the importance of linking vaccination with currently advocated disease control and prevention programs to facilitate the eradication of endemic infections while safely maintaining herd immunity. Differentiation between immune responses to primary and repeated exposure of subclinically infected animals and responses induced by vaccination is also addressed.
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control of Strangles outbreaks by isolation of guttural pouch carriers identified using pcr and culture of streptococcus equi
Equine Veterinary Journal, 2010Co-Authors: J R Newton, John F Timoney, K L P Verheyen, Nicola C Talbot, James L N Wood, K H Lakhani, N ChanterAbstract:Previous use of repeated nasopharyngeal swabbing and culture of Streptococcus equi showed that healthy carriers developed in more than 50% of 'Strangles' outbreaks. The guttural pouches were the only detectable site of S. equi colonisation on endoscopic examination of horses during one of these outbreaks and S. equi was sometimes not detected by culture of nasopharyngeal swabs from carriers for up to 2 or 3 months before nasal shedding resumed sporadically. A more sensitive way of detecting S. equi on swabs from established guttural pouch carriers was therefore required. Conveniently selected 'Strangles' outbreaks were investigated in detail using endoscopy, in order to develop and assess a suitable polymerase chain reaction (PCR) test. We report here 3 protracted 'Strangles' outbreaks on different kinds of establishments in which between 29 and 52% of sampled horses were infected as detected by culture and/or PCR. Of the infected horses, between 9 and 44% were identified as carrying S. equi after clinical signs had disappeared and the predominant site of carriage was the guttural pouch. Prolonged carriage of S. equi, which lasted up to 8 months, did not cease spontaneously before treatment was initiated to eliminate the infections. The detection and isolation of the carriers, in conjunction with strict hygiene measures, apparently resulted in the control of the outbreaks and allowed the premises to return to normal activity. Comparing PCR and culture, many more swabs were found to be positive using PCR (56 vs. 30% of 61 swabs). Similar results were obtained for guttural pouch samples from 12 established carriers (PCR 76% and culture 59%). These results from repeated samples from relatively few animals need confirming using more long-term carriers. PCR can also detect dead organisms and is, therefore, liable to yield false positive results. Despite this drawback, it is argued that PCR provides a potentially useful adjunct to culture of nasopharyngeal swabs in the detection of asymptomatic carriers of S. equi following outbreaks of 'Strangles'.
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could we eradicate Strangles in equids
Javma-journal of The American Veterinary Medical Association, 2007Co-Authors: John F Prescott, John F TimoneyAbstract:Views: Commentary 377 S (Streptococcus equi subsp equi infection) is a globally distributed and highly contagious equine scourge first described by veterinarians of ancient Rome. Outbreaks are associated with loss of condition, disruption of training and riding activities, cost of veterinary care, and lethal sequelae including disseminated (bastard) Strangles and purpura hemorrhagica. The overall complication rate can be as high as 20% of affected animals, with a case fatality rate of up to 8%. Control of Strangles is based on various approaches, including screening, quarantine, and immunization. Fully effective and safe vaccines providing long duration of immunity are not available, and the task of developing such vaccines, even with complete genome sequence data for S equi and Streptococcus zooepidemicus, is recognized to be considerable. A recent American College of Veterinary Internal Medicine consensus statement from the United States and United Kingdom on guidelines for treatment, control, and prevention was 12 pages, a length that emphasizes the complexity of control measures. In the United Kingdom, the Codes of Practice Guidelines on Strangles published by the Horserace Betting Levy Board is shorter and, like the consensus statement, focused on dealing with outbreaks. It notes the advisability of informing the relevant breeders’ associations of infection, but acknowledges that there is no legal requirement for this, even for purposes of export. There are no guidelines in Canada agreed to by the horse industry. Strangles has all the hallmarks of an infection that should and could be eradicated (Appendix 1). The causative agent replicates only in equids and survives only briefly in the environment. It causes serious loss through morbidity and death, as well as through cost and implementation of control measures in outbreaks. Because it is not reportable, its presence may fail to be disclosed for economic or other reasons, and therefore, the disease may be introduced unknowingly causing demoralization and conflict. Recent work has shown that the organism is a unique biovar or genovar of an ancestral S zooepidemicus. It appears to be genetically frozen, and unlike most pyogenic streptococcal species, antigenic variation of surface virulence-associated proteins including SeM is slight or absent. In many ways, S equi is an archaeologic relic that could be consigned to history. Could we eradicate Strangles in equids?
Miia Riihimaki - One of the best experts on this subject based on the ideXlab platform.
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influence of penicillin treatment of horses with Strangles on seropositivity to streptococcus equi ssp equi specific antibodies
Journal of Veterinary Internal Medicine, 2020Co-Authors: John Pringle, Andrew S. Waller, Emma Storm, Miia RiihimakiAbstract:BACKGROUND Antibiotic treatment of horses with Strangles is reported to impair the development of immunity to subsequent exposure to Streptococcus equi ssp equi (S. equi). However, apart from a single clinical report, evidence-based studies for this hypothesis are lacking. HYPOTHESIS/OBJECTIVE To determine whether penicillin treatment during clinical Strangles influences the development or persistence of seropositivity to S. equi-specific antibodies. ANIMALS A natural outbreak of Strangles with 100% morbidity in 41 unvaccinated mature Icelandic horses. METHODS A prospective longitudinal study of acute clinical Strangles from onset through full recovery approximately 10 months after the index case. Horses were monitored clinically 6 times for S. equi, as well as serologically for antibodies to antigens A and C of S. equi using an enhanced indirect ELISA. Seven horses received penicillin within 11 days of onset of fever (Group 1), 5 between 16 and 22 days after onset of fever (Group 2), and the remainder (Group 3, n = 29) received no antibiotics during clinical disease. The proportions of seropositive horses in each group were compared using an extension of Fisher's exact test with P < .05 as the level of significance. RESULTS Although all horses were seropositive to S. equi within 2 months of the index case, significantly fewer horses treated early (Group 1) remained seropositive by 4 to 6 months (P = .04 and .02, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE Findings support earlier suggestions that penicillin administered during acute Strangles can interfere with persistence of humoral immunity to S. equi.
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long term silent carriers of streptococcus equi ssp equi following Strangles carrier detection related to sampling site of collection and culture versus qpcr
Veterinary Journal, 2019Co-Authors: John Pringle, M Venner, L Tscheschlok, L Bachi, Miia RiihimakiAbstract:After Strangles outbreaks, Streptococcus equi ssp. equi (S. equi) can persist in clinically normal silent carriers for months to years. Two naturally occurring outbreaks of Strangles with 53 and 100% morbidity, respectively, were followed longitudinally to assess occurrence of carrier state and optimal detection methods Outbreak A involved 98 yearling warmbloods, and outbreak B 38 mature Icelandic horses. Fully recovered horses were sampled at least 6 months after index cases using nasal swabs (one sampling occasion only) nasopharyngeal lavage and guttural pouch visualisation and lavages for culture and qPCR to S. equi. Any horse with at least a single sample positive was deemed a carrier. Descriptive statistics and sensitivity and negative predictive values were calculated. Comparisons were made with McNemars and Fishers exact tests. Carrier rates in outbreak A were 3% based on culture and 15% based on qPCR and for outbreak B 13% based on culture and 37% based on qPCR. All culture positives were also qPCR positive. One carrier culture negative sampled after an additional 8 months was culture positive to S. equi, indicating that qPCR positives should be suspected to carry live bacteria. Findings indicate that reliance on guttural pouch sampling and appearance does not capture all silent carriers. All culture positives were identified by qPCR and even horses positive by qPCR but culture negative should be suspected carriers of live bacteria.
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long term dynamics of a streptococcus equi ssp equi outbreak assessed by qpcr and culture and sem sequencing in silent carriers of Strangles
Veterinary Microbiology, 2018Co-Authors: Miia Riihimaki, Anna Aspan, Helena Ljung, John PringleAbstract:The aim of the study was to use culture, qPCR and seM sequencing to map Streptococcus equi subspec. equi (S.equi) isolates in long term carrier animals. A Strangles outbreak affecting 41 Icelandic horses was followed to determine Strangles free status using nasal and/or guttural pouch lavages collected serially on eleven separate occasions over 13 months. Ten persistent carriers, of which eight had repeated culture positive samples for S. equi, were selected for the study. Of 115 samples collected, 61 were S. equi positive on qPCR; from which 32 were also culture positive. Amplification of parts of the gene encoding the M-protein seM was performed on isolated colony material (n = 32) or, where only PCR product was obtained, directly on the DNA sample (n = 29) with a nested amplification approach. The seM sequence could be determined for six of the 29 samples that were solely qPCR positive. The outbreak was due to a S. equi strain of seM type 72. Three months after initial sampling isolates from two horses had seM gene sequences with one amino acid change. After six months S. equi with truncated seM genes were found in two horses; one variant in a single horse once, and in the other horse a variant that persisted and that was later identified in two additional horses. Non- mucoid S. equi colonies were found in two horses. Importantly, after acute Strangles outbreaks many horses not only remain persistently qPCR positive for S. equi but are also intermittently culture positive.
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decreased clinical severity of Strangles in weanlings associated with restricted seroconversion to optimized streptococcus equi ssp equi assays
Journal of Veterinary Internal Medicine, 2018Co-Authors: Lisa Tscheschlok, Miia Riihimaki, Karen F Steward, Monica Venner, R Bose, John PringleAbstract:Background Streptococcus equi ssp. equi causes characteristic clinical signs that are most severe in young horses, including fever, purulent nasal discharge, and lymph node abscessation in the head region. Hypothesis/objectives Clinical, serologic, and microbiologic factors related to unexpectedly mild disease severity in a natural outbreak of Strangles in immunologically naive weanlings were investigated. Animals One-hundred and twelve warmblood weanlings. Methods Prospective longitudinal observational study of a natural outbreak of Strangles. The entire cohort was examined at the peak of the outbreak by deep nasal swabs for culture and quantitative PCR (qPCR) for the presence of S. equi and clinically and serologically in a sequential manner by an optimized ELISA from the index case throughout the outbreak until resolution. Descriptive statistics were calculated and comparisons made using a nondirectional Wilcoxon signed-rank test. Results Outbreak morbidity was 53%, with 9 of 14 horses culture positive and 26 of 53 horses qPCR positive for S. equi lacking clinical signs characteristic of Strangles. By resolution, 91 of 112 had seroconverted to Antigen A by ELISA but seroconversion to antigen C (part of the SeM protein) was minimal. Sequencing of the isolates detected no alterations in the SeM protein, but identified a 61 bp deletion in the gene SEQ_0402. Conclusions and clinical importance Absence of clinical signs alone in naive horses may be an insufficient criterion to release horses from Strangles quarantine measures. Restricted seroconversion to antigen C may have been associated with decreased clinical severity. The role of a minor gene deletion in SEQ_0402 in the virulence of S. equi warrants further investigation.