Outbreak Of Strangles Research Articles

Serological responses of horses in response to vaccination in a farm associated with a natural outbreak of strangles

Serological responses of horses in response to vaccination in a farm associated with a natural outbreak of strangles

Evaluating Trends in Strangles Outbreaks Using Temperature and Precipitation Data in the United States of America for 2018-2022.

Strangles is a highly contagious upper respiratory infection of equids that is globally distributed. The causative agent of strangles, Streptococcus equi subspecies equi, can be spread through indirect contact with infected fomites, and studies have shown this microbe to live well in varying environmental conditions. The purpose of this study was to analyze strangles case numbers across the United States of America from 2018 to 2022 to investigate potential temporal or weather patterns associated with outbreaks. Diagnosed case records were obtained from the Equine Disease Communication Center, university databases, government agencies, or veterinary diagnostic labs, and geographic information systems (GISs) were used to map cases and to acquire relevant meteorological data from outbreak areas. These data were analyzed using logistic regression to explore trends that occur between outbreaks and changes in temperature and precipitation. Initial review of weather data suggested monthly changes in strangles case numbers corresponded with changing seasons. Logistic regression indicated that changes in monthly average temperature and minimum temperature were significantly associated with increased or decreased odds of strangles outbreaks, respectively. Future analyses should focus on weather data isolated within a smaller region or state to better resolve trends in strangles outbreaks throughout the continental USA.

The hygienic aspects in the management of strangles

SummaryStreptococcus equi subsp. equi (S. equi) is a frequently encountered pathogen in equine practice. S. equi causes infection of the upper airways of horses, a condition known as strangles. Strangles is a highly contagious disease and may be economically devastating as well. Difficulties in the eradication of the disease using vaccines and medical treatments make hygienic measures crucial in order to limit transmission of the pathogen during outbreaks. This review aims to elucidate the challenges in handling an outbreak of strangles as well as develop a basic plan on how such an outbreak is handled in a hygienically optimal fashion. The results of this review suggest a longer environmental survival time of S. equi than previously assumed and support the importance of modification of surfaces for proper disinfection with appropriate disinfectants. Furthermore, the efficiency of using a colour‐coding system in dividing healthy, exposed and clinically affected horses is discussed. Individual temperature monitoring twice daily is recommended for the identification of diseased horses before they pose a contagious risk. Additionally, changing clothes between visiting different stable units is likewise recommended, to minimise transmission of disease. In conclusion, veterinarians, personnel and horse owners at equestrian centres need to be aware of the importance of isolation, monitoring and dividing the site into zones according to the risk of infection. Finally, it can be concluded that regardless of size, practical biosecurity measures can be implemented within all equine facilities.

UnsaddlingStreptococcus equiinfection of horses

Infection with Streptococcus equi, which forms abscesses in the lymph nodes of the head and neck in horses, is endemic in almost all countries around the world. The identification and isolation of horses with fever, an early sign of disease, is critical to minimising the number of horses affected and the severity of an outbreak, while the identification and treatment of persistently infected ‘carrier’ horses can reduce the risk of recurrent outbreaks and transmission between equine populations. Rapid diagnostic testing plays a key role in the identification of infected horses, which can then be isolated before the development of acute disease or treated to clear persistent infection. Vaccination can also be used to reduce the number of horses that become infected and the severity of their ensuing disease. This review describes the tools available to veterinarians and the journey towards the development and launch of a multi-component fusion protein vaccine that does not trigger positive diagnoses with any of the available diagnostic tests for strangles. The use of vaccination, alongside conventional methods of biosecurity and diagnostic testing, has the potential to unsaddle S. equi, reducing the number of strangles outbreaks and enhancing the health of horses.

Repeated nasopharyngeal lavage predicts freedom from silent carriage of Streptococcus equi after a strangles outbreak.

BackgroundThe value of repeated nasopharyngeal lavage (NPL) to detect silent carriers of Streptococcus equi has not been investigated.Hypothesis/ObjectivesDetermine if results of serial testing for S. equi by NPL predicts subsequent true carrier status as determined by both NPL and guttural pouch lavage.AnimalsAn outbreak of strangles with 100% morbidity in 41 mature Icelandic horses was followed prospectively to investigate development of silent carriers. All were initially positive to S. equi on NPL. The farm was closed to horse movement during the entire study.MethodsProspective observational study. Testing for S. equi was performed by NPL at weeks 18, 28, 29, and 30 postindex case and subsequently at week 45 by both NPL and guttural pouch lavage. Carrier status at week 45 was compared to results obtained at weeks 18, 28, 29, and 30. Descriptive statistics were calculated. Comparisons were made using Fisher's exact test or the Freeman‐Halton extension with a P < .05 level of significance.ResultsOf 24 noncarriers at week 45, only 4 horses were negative on all 3 consecutive weekly NPL samples at weeks 28 to 30. However, 10 of the 11 horses with at least 3 negative NPL obtained from weeks 18, 28, 29, and 30 were S. equi‐free at week 45 (P = .03).Conclusions and Clinical ImportanceRepeated NPL on at least 3 separate occasions can assist in predicting S. equi carrier‐free status in horses after recovery from a strangles outbreak.

An Outbreak of Strangles in Arabian Horses in Saudi Arabia: Epidemiology, Clinical Signs and Treatment Outcomes

This study was carried out to investigate an outbreak of strangles in horses at the Qassim Region, Central Saudi Arabia. From 29 horses included in this study, the disease was observed in 13, five of them were died: representing a morbidity rate of 44.8% and a mortality rate of 17.24%. The morbidity and mortality rates significantly (P≤0.05) differed among different age groups. In contrast, the case fatality rate was not significantly different among different ages. Gender has no significant effect on disease occurrence. Clinically, signs observed in infected horses were high fever, anorexia, soft non-productive cough, muco-purulent bilateral nasal discharge, enlargement and abscessation of submandibular lymph nodes. Metastatic infection, including abdominal abscessation, was observed in 5 of the infected cases where signs of acute abdominal pain were recorded. Streptococcus equi subspecies equi was the only organism isolated from the lesions. Significant increases in the total white blood cells and neutrophils were detected in the diseased horses compared to healthy ones. Penicillin therapy, surgical intervention of the ripened sub-mandibular abscesses, isolation of healthy horses away from infected ones and thorough disinfection of the contaminated environment were the control measures that were applied to manage this outbreak. Treatment was very effective in the typical form of the disease whereas it had no value in the bastard form. Finally, it can be concluded that strangles in horses in the Qassim Region represents a great risk due to the high case fatality rate, and therefore using a protective vaccine is essential.

Nursing a horse with strangles

Strangles can be an extremely debilitating and unpleasant experience for an infected horse. Diligent nursing care is important as the disease runs its course, to maximise the chances of a full and straightforward recovery. Veterinary nurses can play a critical role in strangles outbreaks by ensuring horses are in a comfortable environment within quarantine, are encouraged to eat and drink, benefit from careful abscess management and are monitored closely. Nurses also provide essential support for vets during procedures such as guttural pouch endoscopy, as well as helping to maintain strict biosecurity protocols to prevent further spread of disease.

Nasopharyngeal Microbiomes in Donkeys Shedding Streptococcus equi Subspecies equi in Comparison to Healthy Donkeys

Streptococcus equi subsp. equi (S. equi) is the pathogen causing strangles, a highly infectious disease that can affect equids including donkeys of all ages. It can persistently colonize the upper respiratory tract of animals asymptomatically for years, which serves as a source of infection. Several strangles outbreaks have been reported in the donkey industry in China in the last few years and pose a great threat to health, production, and the welfare of donkeys. Nasopharyngeal swab samples for culture and PCR are used widely in strangles diagnosis. Additionally, microbiomes within and on the body are essential to host homoeostasis and health. Therefore, the microbiome of the equid nasopharynx may provide insights into the health of the upper respiratory tract in animals. There has been no study investigating the nasopharyngeal microbiome in healthy donkeys, nor in donkeys shedding S. equi. This study aimed to compare nasopharyngeal microbiomes in healthy and carrier donkeys using 16S rRNA gene sequencing. Nasopharyngeal samples were obtained from 16 donkeys recovered from strangles (group S) and 14 healthy donkeys with no history of strangles exposure (group H). Of those sampled, 7 donkeys were determined to be carriers with positive PCR and culture results in group S. In group H, all 14 donkeys were considered free of strangles based on the history of negative exposure, negative results of PCR and culture. Samples from these 21 donkeys were used for microbial analysis. The nasopharyngeal microbiome composition was compared between the two groups. At the phylum level, relative abundance of Proteobacteria was predominantly higher in the S. equi carrier donkeys than in healthy donkeys (P < 0.01), while Firmicutes and Actinobacteria were significantly less abundant in the S. equi carrier donkeys than in healthy donkeys (P < 0.05). At the genus level, Nicoletella was detected in the upper respiratory tract of donkeys for the first time and dominated in carrier donkeys. It is suspected to suppress other normal flora of URT microbiota including Streptococcus spp., Staphylococcus spp., and Corynebacterium spp. We concluded that the nasopharyngeal microbiome in S. equi carrier donkeys still exhibited microbial dysbiosis, which might predispose them to other airway diseases.

Molecular detection of Streptococcus equi subspecies equi in face flies (Musca autumnalis) collected during a strangles outbreak on a Thoroughbred farm.

The objective of this study was to detect Streptococcus equi subspecies equi (S.equi) (Lactobacillales: Streptococcaceae) using quantitative polymerase chain reaction (qPCR) in flies collected from a farm with a documented outbreak of strangles. A total of 1856 face flies [Musca autumnalis (Diptera: Muscidae)] were collected using conventional fly traps. The flies were processed for nucleic acid purification and tested for the presence of S.equi by qPCR. A total of 10/1856 flies (0.54%) tested qPCR-positive for S.equi. The results may implicate the presence of face flies as a risk factor for the transmission of S.equi and highlight the need to institute proper husbandry measures, biosecurity protocols and fly control in order to reduce the potential for infection in at-risk horses.

An outbreak of strangles associated with a novel genotype of Streptococcus equi subspecies equi in donkeys in China during 2018.

Strangles is a highly contagious respiratory disease of equids caused by the bacterium Streptococcus equi subspecies equi. 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. Cross-sectional. 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. 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 1year exhibiting clinical signs compared with 12.5% (191/1525) of donkeys aged one to 2years and 3.8% (17/442) of donkeys over 2years 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. Healthy donkeys were not sampled in this study. 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.

Long term silent carriers of Streptococcus equi ssp. equi following strangles; carrier detection related to sampling site of collection and culture versus qPCR

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.

Possibilities and limitations of the prevention of strangles outbreaks on horse farms

Possibilities and limitations of the prevention of strangles outbreaks on horse farms

Decreased Clinical Severity of Strangles in Weanlings Associated with Restricted Seroconversion to Optimized Streptococcus equi ssp equi Assays.

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/ObjectivesClinical, serologic, and microbiologic factors related to unexpectedly mild disease severity in a natural outbreak of strangles in immunologically naïve weanlings were investigated.AnimalsOne‐hundred and twelve warmblood weanlings.MethodsProspective 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.ResultsOutbreak 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 ImportanceAbsence of clinical signs alone in naïve 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.

Persistence of Streptococcus equi ssp. equi Antibodies in a Prolonged Strangles Outbreak, Assessed By An Enhanced Indirect Enzyme‐Linked Immunosorbent Assay

Persistence of <i>Streptococcus equi</i> ssp. equi Antibodies in a Prolonged Strangles Outbreak, Assessed By An Enhanced Indirect Enzyme‐Linked Immunosorbent Assay

A case-control study developing a model for predicting risk factors for high SeM-specific antibody titers after natural outbreaks of Streptococcus equi subsp equi infection in horses.

OBJECTIVE To develop a risk prediction model for factors associated with an SeM-specific antibody titer ≥ 3,200 in horses after naturally occurring outbreaks of Streptococcus equi subsp equi infection and to validate this model. DESIGN Case-control study. ANIMALS 245 horses: 57 horses involved in strangles outbreaks (case horses) and 188 healthy horses (control horses). PROCEDURES Serum samples were obtained from the 57 cases over a 27.5-month period after the start of outbreaks; serum samples were obtained once from the 188 controls. A Bayesian mixed-effects logistic regression model was used to assess potential risk factors associated with an antibody titer ≥ 3,200 in the case horses. A cutoff probability for an SeM-specific titer ≥ 3,200 was determined, and the model was externally validated in the control horses. Only variables with a 95% credibility interval that did not overlap with a value of 1 were considered significant. RESULTS 9 of 57 (6%) case horses had at least 1 titer ≥ 3,200, and 7 of 188 (3.7%) of control horses had a titer ≥ 3,200. The following variables were found to be significantly associated with a titer ≥ 3,200 in cases: farm size > 20 horses (OR, 0.11), history of clinically evident disease (OR, 7.92), and male sex (OR, 0.11). The model had 100% sensitivity but only 24% specificity when applied to the 188 control horses (area under the receiver operating characteristic curve = 0.62.) CONCLUSIONS AND CLINICAL RELEVANCE Although the Bayesian mixed-effects logistic regression model developed in this study did not perform well, it may prove useful as an initial screening tool prior to vaccination. We suggest that SeM-specific antibody titer be measured prior to vaccination when our model predicts a titer ≥ 3,200.

The global population diversity of Streptococcus equi highlights transmission across international boundaries

The genomes of 499 strains of S. equi, which were isolated between 1955 and 2015 from horses across the world, were sequenced to study the phylogenetic relationships of strains of different geographical and temporal origins. Phylogenetic trees were reconstructed based on single nucleotide polymorphisms in the core genome and the genetic diversity of isolates was examined relative to the country of origin. The molecular epidemiology of outbreaks, where information was available, was investigated in greater depth to enable the identification of outbreak sources. Sequencing strains from an outbreak at a rehoming centre in Norfolk, UK, in early 2015 identified that a breakdown in biosecurity measures in the isolation yard was responsible for recent cases of disease. This information enabled rapid remedial actions to be implemented, which minimised further cases and facilitated the resolution of the outbreak. The sequences of isolates recovered from an outbreak of strangles at a rehoming centre in Lincolnshire, UK, during 2007/8 provided evidence that this outbreak was triggered by persistently infected carrier animals, most likely from a previous spate of disease on this site. Following the outbreak, the identification and treatment of persistently infected horses enabled the eradication of S. equi from these premises. The transmission of four strains of S. equi linked to the import of horses from Europe led to multiple outbreaks of strangles in Dubai. Our data highlight potential benefits of preexport screening for the effective identification and treatment of carrier animals. Certain groups of S. equi were restricted to particular outbreaks or countries, for example isolates in Australia and New Zealand were related. However, the populations of S. equi recovered from several European countries (Ireland, Sweden, Belgium, France, the Netherlands, Spain, Italy and the UK) and Dubai were virtually indistinguishable. Our data highlight that the international movement of horses facilitates cross-border transmission of S. equi. International transmission is most likely to occur through a failure of pre-import health checks and quarantine procedures to identify outwardly healthy persistently infected animals. Pre-movement screening can identify persistently infected horses and prevent outbreaks of strangles. However,

Characterization of a Streptococcus equi ssp. equi Isolate From a Strangles Outbreak in Thailand

Strangles, which is caused by Streptococcus equi ssp. equi, is one of the major infectious respiratory diseases in horses. Knowledge of isolates from different areas of the world is important for investigating the different strains of the disease. In contrast to many other countries, currently little is known about S. equi ssp. equi isolates in Thailand. In 2014, a farm in Thailand imported 20 horses from Europe. Approximately 1 month after arrival, 50% of the horses had developed pyrexia, mucopurulent nasal discharge, and abscesses of the mandibular lymph nodes. Nasal swabs of mucopurulent discharge were sent to a diagnostic laboratory, and two isolates of S. equi ssp. equi were identified. One of the isolates was further characterized using seM gene polymerase chain reaction and sequence analysis. The seM sequence was then compared to the database of PubMLST-seM. It was found to contain SeM allele 48, an allele isolated from horses in the United Kingdom in 2006 and 2010. This result demonstrates the usefulness of SeM allele identification as a tool for investigating the source of related strains and for the epidemiologic study of strangles. To the best of the authors' knowledge, this is the first report of the identification of an SeM allele of the S. equi ssp. equi isolate in Thailand.

Primary bilateral guttural pouch empyema in a two-month-old foal

The present report describes a 2-month-old foal which signs of respiratory infectious disease, bilateral retropharyngeal swelling and nasal mucopurulent discharge, suggesting guttural pouch empyema. The owners reported that the foal lived in a herd that experienced an outbreak of strangles. Foals younger than 3 months are usually protected against infectious diseases, however in this case, the foal was exposed to an environment heavily populated by Streptococcus equi equi during the outbreak of strangles. Although uncommon in such young animals, the foal was infected and developed a primary bilateral guttural pouch empyema, without signs of lymph nodes alteration

Outbreaks of Strangles due to Capnophilic Streptococcus equi subsp equi in South Korea

We reported an outbreak of clinical strangles in thoroughbred horses due to capnophilic Streptococcus equi subsp equi in South Korea. On three different farms, we isolated 17 S equi subsp equi isolates from 29 horses with or without abscesses in their lymph nodes. Of the 17 isolates, two isolates from clinical cases grew well in aerobic conditions, whereas 7/7 isolates from clinical cases and 8/22 isolates from the nasal discharges of horses did not. The latter 15 isolates were capnophilic, oxygen-sensitive, and CO₂-requiring S equi subsp equi, which could not grow in aerobic conditions, but which grew well in a CO₂ incubator with 5% CO₂, in anaerobic conditions using a GasPak, and with reduced oxygen tension in a candle jar. This study is the first report of a strangles outbreak caused by capnophilic S equi subsp equi in South Korea.

The use of diagnostic tests to help control strangles

Equine HealthVol. 2014, No. 20 VeterinaryThe use of diagnostic tests to help control stranglesAndy E DurhamAndy E DurhamSearch for more papers by this authorAndy E DurhamPublished Online:12 Nov 2014https://doi.org/10.12968/eqhe.2014.1.20.22AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article References Grønbaek LM, Angen O, Vigre H, et al. (2006) Evaluation of a nested PCR test and bacterial culture of swabs from the nasal passages and from abscesses in relation to diagnosis of Streptococcus equi infection (strangles) Equine Vet J 38, 59–63 Crossref, Google ScholarIjaz M, Khan MS, Khan MA, et al. (2010) Prevalence and serum proteinvalues of strangles (Streptococcus equi) affected mules at Remount Depot, Sargodha (Pakistan). Equine Vet Educ 22, 196–8 Crossref, Google ScholarIjaz M, Khan MS, Khan MA, et al. (2012) Comparative study of culture and PCR for detection of carriers of Streptococcus equi in naturally infected mules in Pakistan. J Anim Plant Sci 22, 256–9 Google ScholarLindahl S, Båverud V, Egenvall A, et al. (2013) Comparison of sampling sites and laboratory diagnostic tests for S. equi subsp. equi in horses from confirmed strangles outbreaks. J Vet Intern Med 27, 542–7 Crossref, Google ScholarNewton JR, Verheyen K, Talbot NC, et al. (2000) Control of strangles outbreaks by isolation of guttural pouch carriers identified using PCR and culture of Streptococcus equi. Equine Vet J 32, 515–26 Crossref, Google ScholarNewton JR, Wood JL, Dunn KA, et al. (1997) Naturally occurring persistent and asymptomatic infection of the guttural pouches of horses with Streptococcus equi. Vet Rec 140, 84–90 Crossref, Google ScholarRobinson C, Steward KF, Potts N, et al. (2013) Combining two serological assays optimises sensitivity and specificity for the identification of Streptococcus equi subsp. equi exposure. Vet J 197, 188–91 Crossref, Google ScholarTimoney JF, Artiushin S (1997) Detection of Streptococcus equi in equine nasal swabs and washes by DNA amplification. Vet Rec 141, 446–7 Crossref, Google ScholarWebb K, Barker C, Harrison T, et al., (2013) Detection of Streptococcus equi subspecies equi using a triplex qPCR assay. Vet J 195, 300–304 Crossref, Google ScholarWeese JS, Jarlot C, Morley PS (2009) Survival of Streptococcus equi on surfaces in an outdoor environment. Can Vet J 50, 968–70 Google Scholar FiguresReferencesRelatedDetails 2 November 2014Volume 2014Issue 20ISSN (print): 2047-9867ISSN (online): 2052-2967 Metrics History Published online 12 November 2014 Published in print 2 November 2014 Information© MA Healthcare LimitedPDF download