What ails the pet rat? A retrospective study of more than 300 biopsy samples of externally palpable masses submitted from pet rats for histopathology (2013-2021).

Biopsy data on externally palpable masses in pet rats (Rattus norvegicus) were retrieved from the archives of a large commercial pathology laboratory between November 2013 and July 2021. A total of 330 samples were submitted from 292 individual animals. Of the 330 samples submitted, 182 (55.2%) were of mammary gland origin and the majority were benign neoplasms, with fibroadenoma most frequent. Of the remaining 148 samples, 101 were neoplastic in nature, with 76 tumours classified as mesenchymal, 23 as epithelial and two classified only as malignant neoplasia not otherwise specified. Malignant neoplasms accounted for 88 of these non-mammary masses, with the most diagnosed tumours including soft tissue sarcoma (including fibrosarcoma) and sarcomas not otherwise specified.

The equine umbilical cord in clinically healthy pregnancies.

BACKGROUND: Excessive umbilical cord length (UCL) is associated with equine pregnancy loss. However, a lack of UCL reference values makes it difficult to define excessive UCL. Further, factors associated with differences in UCL are poorly understood. OBJECTIVES: To (i) report the total, allantoic and amniotic UCL in healthy term pregnancies in Thoroughbreds, (ii) describe the relationship between gestational age and UCL, fetal weight and crown rump length (CRL) using clinically normal pregnancies (CNPs) from mares dying during gestation, and (iii) identify associations between UCL and maternal age and parity, paternal age, and fetal sex. STUDY DESIGN: Cross-sectional. METHODS: Data including UCLs, fetal weight, CRL and maternal age, parity, paternal age and fetal sex were taken from CNPs from Thoroughbred mares dying during gestation (n = 32), and placentas from HTPs (n = 34) in England. Correlations were assessed using Spearman's rank with significant correlations estimated by locally weighted scatter plot smoothing (LOWESS). Regression plots were fitted to highly correlated variables to further assess and quantify relationships. Differences in UCL between categorical variables were assessed using Kruskall Wallis and Mann-Whitney U tests. RESULTS: The median total, amniotic and allantoic HTP UCLs were 53.5 cm (interquartile range [IQR] 16), 29.5 cm (IQR 7) and 25.0 cm (IQR 8) respectively. Gestational age and amniotic UCL were moderately correlated (rho = 0.53, p = 0.04), with LOWESS estimating an exponential increase followed by plateauing at around Day 200. Nonlinear associations were observed between fetal weight and gestational age and CRL (adjusted r2 = 0.98 and 0.95 respectively). A linear association was observed between gestational age and CRL: predicted CRL = -17.60 + 0.38 × gestational age, p < 0.001. MAIN LIMITATIONS: Limited availability of CNPs from mares dying during gestation. Estimated relationships can only approximate growth. CONCLUSIONS: This study provides important UCL and fetal size reference values, which may aid in assessing abnormalities. For the first time, associations between UCL and gestational age have been described.

Lumpy, bumpy guinea pigs: a retrospective study of 619 biopsy samples of externally palpable masses submitted from pet guinea pigs for histopathology.

Biopsy data on externally palpable masses in pet guinea pigs were retrieved from the archives of a large commercial pathology laboratory between November 2013 and July 2021. Of the 619 samples submitted from 493 animals, 54 (8.7%) had arisen from the mammary glands and 15 (2.4%) from the thyroid glands, with the remaining 550 (88.9%) involving the skin and subcutis, muscle (n = 1), salivary glands (n = 4), lips (n = 2), ears (n = 4) and peripheral lymph nodes (n = 23). Most of the samples were neoplastic, with 99 masses classified as epithelial in origin, 347 as mesenchymal, 23 as round cell, five as melanocytic and eight as unclassified malignant neoplasms. Lipomas were the most common neoplasm diagnosed, accounting for 286 of all samples submitted.

Fetal morphological features and abnormalities associated with equine early pregnancy loss.

BACKGROUND: Early pregnancy loss (EPL) occurs in approximately 8% of equine pregnancies, although the aetiology is mostly unknown and embryonic/fetal morphological abnormalities associated with EPL are not defined. OBJECTIVES: To compare the morphology of EPL to clinically normal embryos/fetuses and previously described embryonic/fetal developmental milestones. To identify morphological abnormalities associated with equine EPL. STUDY DESIGN: Observational case-control study. METHODS: Embryos/fetuses were obtained from clinically normal Thoroughbred and pony pregnancies (n = 11) and following EPL from Thoroughbred mares (n = 27). The crown-rump length (CRL) of embryos/fetuses was measured and macroscopic morphology and developmental age were determined independently by three blinded examiners. Sagittal sections of EPL (n = 13) and control (n = 6) embryos/fetuses were assessed microscopically. Fisher's exact test was used to determine significance (P < .05) and correlations were expressed by Pearson coefficient. RESULTS: Age and CRL were strongly positively correlated in clinically normal Thoroughbred and reference (n = 15, R = .9 (95% CI: 0.8-1.0), R2  = .9, P < .0001) but not EPL embryos/fetuses (n = 19, R = .1 (95% CI: -0.4 to 0.5), R2  = .01, P = .75). Relative to controls, the CRL of EPL embryos/fetuses was smaller, with evidence of intrauterine growth retardation (IUGR) in 3/8 fetuses assessed. In 9/13 EPL embryos/fetuses, nonspecific neural tissue alterations were identified including disruption of developing pros-, mes- and rhombencephalon and the presence of haemosiderin, indicating premortem haemorrhage. Failed neural tube closure was identified in 1/13 EPL embryos/fetuses. Subcutaneous haemorrhage was present in 14/27 EPL embryos/fetuses. MAIN LIMITATIONS: Autolysis significantly affected 15/27 EPL embryos/fetuses, excluding them from complete assessment. The IUGR reference cut-off values were based on a small number of controls. CONCLUSIONS: Morphological features associated with equine EPL were a mismatch between embryonic/fetal size and age, and alterations of the developing neural tissue and localised subcutaneous haemorrhage. Failed neural tube closure was confirmed as a rare specific abnormality.

Incidence and causes of pregnancy loss after Day 70 of gestation in Thoroughbreds.

BACKGROUND: Pregnancy loss after Day 70 of gestation manifests as abortion, stillbirth or perinatal death. While previous studies have reported the diagnoses of laboratory submissions, none have quantified the incidence and causes of abortions, stillbirths and perinatal mortality at a population level. OBJECTIVES: To report the incidence and causes of pregnancy loss after Day 70 of gestation in a cohort of Thoroughbreds. STUDY DESIGN: Retrospective cohort study. METHODS: Outcomes of Day 70 pregnancies were collected from eight Thoroughbred farms over the 2013-2017 breeding seasons. Stud, veterinary and laboratory records were supplemented with publicly available data. Cause of loss was categorised using custom criteria. RESULTS: Data were collected on 3,586 pregnancies from 1,802 mares. The incidence risk of a pregnancy failing to produce a live foal at 24 hours post parturition was 7.3% (95% confidence interval (CI) 6.5-8.2, equating to 7.3 cases per 100 Day-70 pregnancies). The incidence of pregnancy loss between Day 70 and 300 of gestation, Day 301-315 and stillbirth/perinatal death was 4.0% (95% CI 3.4-4.7), 0.3% (95% CI 0.2-0.6) and 1.4% (95% CI 1.1-1.9) respectively. Of the pregnancy losses where tissue was available, 61.1% were submitted for post-mortem examination. The incidence risk of loss due to umbilical cord-related pathologies was 1.5% (95% CI 1.1-1.9), 0.4% (95% CI 0.2-0.6) for noninfectious placental disease and 0.3% (95% CI 0.2-0.6) for both infectious placentitis and Equine Herpesvirus infection. No primary diagnosis was made in 11.2% of the cases which underwent full post-mortem examination. MAIN LIMITATIONS: It was not possible to differentiate between intra-partum stillbirth and early post-partum death. CONCLUSION: Pregnancy loss after Day 70 of gestation is a significant source of loss in the Thoroughbred with umbilical cord-related pathologies being the most commonly diagnosed cause. Reporting the incidence of pregnancy loss at a population level with clear case definitions will allow for accurate global comparisons.

Prognostic factors and proposed grading system for cutaneous and subcutaneous soft tissue sarcomas in cats, based on a retrospective study.

OBJECTIVES: The objectives of this study included utilising a large database from a diagnostic laboratory to identify any breed, sex or age predilections for cutaneous and subcutaneous soft tissue sarcomas (STSs), and the most common anatomical locations. The second aim was to obtain clinical outcomes and to assess histological features of those tumours to identify any potentially useful prognostic indicators and propose a grading system. METHODS: Records from the laboratory were searched for feline submissions received from January 2012 to December 2013 diagnosed with STSs; the breed, age, sex and neuter status of the cat and anatomical location of the tumour were recorded. Clinical outcomes were acquired using a questionnaire to submitting practices, and histological features of tumours from patients with known outcomes were assessed. RESULTS: No sex, neuter status or breed predispositions were found. Most STSs arise in middle-aged and older cats, and the most common anatomical location was the trunk. Forty-seven cases had a known clinical outcome and archived tissues allowing for histological assessment of the tumour. Significant differences in median survival time (MST), mitotic index and histological score were detected between those cats that died of tumour-related disease and those that did not. A novel grading system applied to these tumours produced significant differences in MST between cats with low (MST = 900.5 days), intermediate (MST = 514 days) and high grade tumours (MST = 283 days). CONCLUSIONS AND RELEVANCE: This is the first study applying a histological grading system to these common tumours. Local recurrence is often the cause of a poor outcome, with metastatic disease apparently rare. The proposed grading system incorporates features that can be assessed on routine haematoxylin and eosin-stained sections; in this small study, the histological grade of the tumour appears to be associated with survival time.

A retrospective study of more than 400 feline nasal biopsy samples in the UK (2006-2013).

OBJECTIVES: The main objective of this study was to utilise a large database from a UK-based, commercial veterinary diagnostic laboratory to ascertain the prevalence of different forms of nasal disease within the feline population. Further objectives included using this database to detect any breed, sex or age predilections, or associations between the degree of brachycephalism, and the different conditions diagnosed. METHODS: Records from the laboratory were searched for feline submissions received between 31 May 2006 and 31 October 2013. For all samples taken from the nasal cavity, the diagnosis was recorded together with the breed, age, sex and neuter status of the cat, whether the clinical presentation was uni- or bilateral and whether a nasal discharge was present. Pedigree breeds were further subclassified according to skull conformation into brachycephalic, mesocephalic and dolichocephalic. Logistic regression models were constructed to assess the adjusted magnitude of association of significant risk factors with each disease, and each disease was also used as a potential independent risk factor for each other disease. RESULTS: The most prevalent nasal disease was rhinitis, followed by neoplasia and polyps. The most commonly diagnosed neoplasm was lymphoma, followed by adenocarcinoma and undifferentiated carcinoma, with benign tumours being very uncommon. No significant association was found between skull conformation and nasal diseases. The only statistically significant association was polyps being more likely to arise in younger male cats, with a mesocephalic skull conformation and no nasal discharge. CONCLUSIONS AND RELEVANCE: No significant association was found between skull conformation and nasal diseases, contrary to what might be expected. The only significant association found between any of the potential risk factors and various forms of nasal disease was polyps being more likely to arise in younger cats; other identified associations are only likely to be weak.

Retrospective study of more than 9000 feline cutaneous tumours in the UK: 2006-2013.

Objectives The aim of the study was to utilise a large database available from a UK-based, commercial veterinary diagnostic laboratory to ascertain the prevalence of different forms of cutaneous neoplasia within the feline population, and to detect any breed, sex or age predilections for the more common tumours. Methods Records from the laboratory were searched for feline submissions received between 31 May 2006 and 31 October 2013. For masses arising within the skin for which histopathology had been performed, the diagnosis was recorded together with the breed, age, sex and neuter status of the cat. Odds ratios for breed predisposition to skin tumours overall, to histologically malignant tumours and to the more commonly occurring tumours were calculated, with the non-pedigree cat population as the control. Results Of the 219,083 feline samples submitted, masses arising within the skin comprised 4.4% and there were 89 different diagnoses recorded for these masses. Just 6.6% of these cases were non-neoplastic in nature, and, of neoplastic masses, 52.7% were considered histologically malignant. The 10 most common skin tumour types accounted for 80.7% of cases, with the four most common being basal cell tumours, fibrosarcomas, squamous cell carcinomas and mast cell tumours. Conclusions and relevance Despite the large number of different diagnoses in this study, a relatively small number of tumour types accounts for the majority of skin masses occurring in cats, most of which are neoplastic in nature. There are a number of breed predispositions for the more common tumour types, although no pedigree breed had increased odds of developing a malignant tumour compared with the non-pedigree cat population; several breeds had significantly decreased odds. Just over half of the neoplastic masses in this study were considered histologically malignant.

The effects of intrauterine infusion of peanut oil on endometrial health, salivary cortisol and interovulatory period in mares.

Intrauterine infusion of peanut oil at Day 10 post-ovulation has been reported to prolong dioestrus in mares. However, the effects of peanut oil treatment on the endometrium and whether the technique is painful have not been assessed. The objectives of this study were, (i) to determine the effect of intrauterine infusion of peanut oil on endometrial health, (ii) to determine whether use of intrauterine peanut oil is painful and (iii) to confirm that peanut oil causes prolonged dioestrus. Six mares aged 3-12 years old were used in a cross-over design with each mare administered both 1 ml of intrauterine peanut oil and a sham treatment on different oestrous cycles. The effect of intrauterine infusion of 1 ml peanut oil or sham treatment were measured using interovulatory period, uterine fluid accumulation as determined by transrectal ultrasonography, serum progesterone levels, endometrial Kenney biopsy scores and histological features, endometrial eosinophil numbers and salivary cortisol measurements. The individual mare response to intrauterine infusion of peanut oil was variable. Peanut oil infusion did not statistically prolong the luteal phase, nor elevate salivary cortisol levels but did cause superficial erosion of the endometrial surface epithelium in all mares and significantly increased eosinophil numbers in the endometrium (P = 0.0068). The Kenney grade for biopsies from 2/6 mares worsened transiently following infusion. In conclusion, intra-uterine peanut oil does not statistically increase the duration of the luteal phase but results in an inflammatory response and increase in endometrial eosinophil numbers suggesting treatment may be associated with a hypersensitivity-type reaction. Those contemplating using peanut oil to suppress oestrus should also be aware of the legislative and regulatory implications.

Enhanced nasopharyngeal infection and shedding associated with an epidemic lineage of emm3 group A Streptococcus.

BACKGROUND: A group A Streptococcus (GAS) lineage of genotype emm3, sequence type 15 (ST15) was associated with a 6 month upsurge in invasive GAS disease in the UK. The epidemic lineage (Lineage C) had lost 2 typical emm3 prophages, Φ315.1 and Φ315.2 associated with the superantigen ssa, but gained a different prophage (ΦUK-M3.1) associated with a different superantigen, speC and a DNAse spd1. METHODS AND RESULTS: The presence of speC and spd1 in Lineage C ST15 strains enhanced both in vitro mitogenic and DNase activities over non-Lineage C ST15 strains. Invasive disease models in Galleria mellonella and SPEC-sensitive transgenic mice, revealed no difference in overall invasiveness of Lineage C ST15 strains compared with non-Lineage C ST15 strains, consistent with clinical and epidemiological analysis. Lineage C strains did however markedly prolong murine nasal infection with enhanced nasal and airborne shedding compared with non-Lineage C strains. Deletion of speC or spd1 in 2 Lineage C strains identified a possible role for spd1 in airborne shedding from the murine nasopharynx. CONCLUSIONS: Nasopharyngeal infection and shedding of Lineage C strains was enhanced compared with non-Lineage C strains and this was, in part, mediated by the gain of the DNase spd1 through prophage acquisition.

Clinical, histological and prognostic features of a novel nail-bed lesion of cats: 41 cases.

Objectives There is a distinct subset of lesions arising on the digits of cats, located at or close to the nail-bed epithelium, which are typically composed of proliferative fibroblast-like cells, multinucleate giant cells and areas of osseous metaplasia, but currently there is no published literature detailing the clinical or histological features of these lesions. Methods This study identified 41 such cases from two large commercial diagnostic laboratories and assessed various histological and clinical features; 22 cases had additional follow-up data available. Results All masses in this study were exophytic, variably inflamed, contained large numbers of spindle cells and had areas of capillary formation. The majority also had areas of ulceration, multinucleate giant cells and osseous metaplasia. The mitotic count was variable, but mitoses were confined to the fibroblast-like cells. Male cats appeared predisposed and the second digit was the most commonly affected. Conclusions and relevance These distinctive lesions arising on the digits of cats had potential for local recurrence but metastasis was not reported. Based on these clinical and histological features, the masses in this study appear most similar to giant cell reparative granulomas, and trauma, injury to the nail or nail-bed and nail-bed infections may potentially contribute to their development.

OSTEOCHONDROSIS IN THE DISTAL FEMURS OF AN ADULT RETICULATED GIRAFFE (GIRAFFA CAMELOPARDALIS RETICULATA): MACROSCOPIC, RADIOLOGIC, AND HISTOLOGIC FINDINGS.

An adult male reticulated giraffe (Giraffa camelopardalis reticulata) was presented for postmortem examination. During radiologic examination of the hindlimbs, osseous cyst-like lesions were detected in both medial femoral condyles. These lesions were subsequently examined macroscopically and histologically. The gross appearance suggested a diagnosis of bilateral osteochondrosis that was confirmed with histopathologic examination. This finding has not previously been reported in giraffes. Macroscopic visualization of the major limb joints, including the femorotibial joints, is therefore encouraged in future postmortem examinations of giraffes (Giraffa camelopardalis), and further assessment of clinical significance is required.

Feline cutaneous mast cell tumours: a UK-based study comparing signalment and histological features with long-term outcomes.

Feline cutaneous mast cell tumours (MCTs) are the second most common skin tumour in cats; but, unlike in dogs, there is currently no histological grading system for this type of tumour. This study recorded the signalment and anatomical location from a total of 287 records from MCTs submitted to a UK commercial diagnostic laboratory. Questionnaires to submitting practices were used to obtain follow-up data, and the histological features of 86 tumours were evaluated from 69 cats with a known outcome. Twelve of the 69 cats (17.4%) died of MCTs, with significantly lower survival times. The median age of cats presenting with MCTs was 11 years (range 5 months-19 years), with no sex or neutered status predilection. Some pedigree breeds were more susceptible to MCTs, particularly the Siamese, Burmese, Russian Blue and Ragdoll. The head was the most common site in younger cats, compared with the trunk in older cats. The number of tumours had no effect on survival. A new subcategory of well-differentiated MCTs with prominent multinucleated cells is described, and three of the five cats with this novel form died from MCT-related disease. There was an association between mitotic index and survival time. However, there was no significant association between histological type and survival.

Unique topographic distribution of greyhound nonsuppurative meningoencephalitis.

Greyhound nonsuppurative meningoencephalitis is an idiopathic breed-associated fatal meningoencephalitis with lesions usually occurring within the rostral cerebrum. This disorder can only be confirmed by postmortem examination, with a diagnosis based upon the unique topography of inflammatory lesions. Our purpose was to describe the magnetic resonance (MR) imaging features of this disease. Four Greyhounds with confirmed Greyhound nonsuppurative meningoencephalitis were evaluated by MR imaging. Lesions predominantly affected the olfactory lobes and bulbs, frontal, and frontotemporal cortical gray matter, and caudate nuclei bilaterally. Fluid attenuation inversion recovery (FLAIR) and T2 weighted spin-echo (T2W) sequences were most useful to assess the nature, severity, extension, and topographic pattern of lesions. Lesions were predominantly T2-hyperintense and T1-isointense with minimal or absent contrast enhancement.

Congenital keratoconjunctivitis sicca and ichthyosiform dermatosis in 25 Cavalier King Charles spaniel dogs. Part I: clinical signs, histopathology, and inheritance.

The clinical presentation and progression (over 9 months to 13 years) of congenital keratoconjunctivitis sicca and ichthyosiform dermatosis (CKCSID) in the Cavalier King Charles spaniel dog are described for six new cases and six previously described cases. Cases presented with a congenitally abnormal (rough/curly) coat and signs of KCS from eyelid opening. Persistent scale along the dorsal spine and flanks with a harsh frizzy and alopecic coat was evident in the first few months of life. Ventral abdominal skin was hyperpigmented and hyperkeratinized in adulthood. Footpads were hyperkeratinized from young adulthood with nail growth abnormalities and intermittent sloughing. Long-term follow-up of cases (13/25) is described. Immunomodulatory/lacrimostimulant treatment had no statistically significant effect on Schirmer tear test results, although subjectively, this treatment reduced progression of the keratitis. Histopathological analysis of samples (skin/footpads/lacrimal glands/salivary glands) for three new cases was consistent with an ichthyosiform dermatosis, with no pathology of the salivary or lacrimal glands identified histologically. Pedigree analysis suggests the syndrome is inherited by an autosomal recessive mode.

Serological detection of Epstein-Barr virus infection in dogs and cats.

Epstein-Barr virus (EBV) is widespread in humans world-wide. The virus, which is linked to Burkitt's and Hodgkin lymphoma in humans, has recently been detected in pet dogs in Taiwan. The aim of this study was to determine if EBV is present in other canine populations, whether infection is associated with lymphoma in dogs, and whether infection is present in cats. Canine and feline serum samples were analysed by immunofluorescence assay. Antibodies to EBV or an EBV-like virus were detected in 38.4% of UK dog sera, 64% of US dog sera and 38% of cat sera. Canine blood samples, tissue samples from the palatine tonsil and formalin-fixed, paraffin-embedded biopsy samples from canine lymphoma cases were analysed by PCR. Using EBV-specific primers, EBV was detected in one tonsil sample, whereas all other samples tested were negative. PCR using consensus herpesvirus primers identified canine herpesvirus in twelve tonsil samples and one biopsy but no gammaherpesviruses were detected. Canine blood samples from EBV antibody-positive dogs were analysed by RT-PCR to determine if transcripts associated with lytic EBV infection (BcLF1) or latency (LMP2) were present, however all samples tested were negative. In conclusion, there is serological evidence of exposure to EBV or an EBV-like virus in dogs and cats but persistent infection in the canine palatine tonsil is rare and no evidence was found of EBV in canine peripheral blood mononuclear cells. The effect of EBV on canine and feline cells and the possible outcome of the infection for the host require further investigation.

Osteomyelitis and osteonecrosis after intraosseous perfusion with gentamicin.

OBJECTIVE: To describe and discuss previously unreported complications associated with intraosseous perfusion with gentamicin in horses. STUDY DESIGN: Case report. ANIMALS: Ten-year-old Warmblood gelding. METHODS: Intraosseous perfusion with gentamicin into the proximal phalanx (P1) was used as part of the treatment regimen for distal interphalangeal joint and navicular bursa synovial sepsis. Although the sepsis responded favorably complications developed at the perfusion site, including persistent osteomyelitis, progressive osteonecrosis, and ultimately pathologic fracture of P1. RESULTS: The progression of the clinical signs and findings at necropsy are suggestive of a toxic osteonecrosis secondary to intraosseous perfusion. CONCLUSIONS: Further work is needed to investigate the effects of high dose gentamicin on equine mesenchymal cells that may be achieved during intraosseous perfusion. CLINICAL RELEVANCE: Lower doses of perfusate within the medullary canal of P1 or alternative perfusion sites should be considered.

Getting to grips with strangles: an effective multi-component recombinant vaccine for the protection of horses from Streptococcus equi infection.

Streptococcus equi subspecies equi (S. equi) is a clonal, equine host-adapted pathogen of global importance that causes a suppurative lymphodendopathy of the head and neck, more commonly known as Strangles. The disease is highly prevalent, can be severe and is highly contagious. Antibiotic treatment is usually ineffective. Live attenuated vaccine strains of S. equi have shown adverse reactions and they suffer from a short duration of immunity. Thus, a safe and effective vaccine against S. equi is highly desirable. The bacterium shows only limited genetic diversity and an effective vaccine could confer broad protection to horses throughout the world. Welsh mountain ponies (n = 7) vaccinated with a combination of seven recombinant S. equi proteins were significantly protected from experimental infection by S. equi, resembling the spontaneous disease. Vaccinated horses had significantly reduced incidence of lymph node swelling (p = 0.0013) lymph node abscessation (p = 0.00001), fewer days of pyrexia (p = 0.0001), reduced pathology scoring (p = 0.005) and lower bacterial recovery from lymph nodes (p = 0.004) when compared with non-vaccinated horses (n = 7). Six of 7 vaccinated horses were protected whereas all 7 non-vaccinated became infected. The protective antigens consisted of five surface localized proteins and two IgG endopeptidases. A second vaccination trial (n = 7+7), in which the IgG endopeptidases were omitted, demonstrated only partial protection against S. equi, highlighting an important role for these vaccine components in establishing a protective immune response. S. equi shares >80% sequence identity with Streptococcus pyogenes. Several of the components utilized here have counterparts in S. pyogenes, suggesting that our findings have broader implications for the prevention of infection with this important human pathogen. This is one of only a few demonstrations of protection from streptococcal infection conferred by a recombinant multi-component subunit vaccine in a natural host.

Imaging diagnosis--necrotizing meningomyelitis and polyarthritis.

A vaccinated 2-year-old female neutered Weimaraner had bilateral pelvic limb ataxia that progressed over 12 h. The dog became nonambulatory, with signs of pain on palpation of the lumbar spine. The dog also developed multiple joint effusions. On magnetic resonance (MR) imaging, there was a diffuse, asymmetric T2-hyperintensity in the thoracolumbar spinal cord which was characterized by contrast enhancement. Lumbar cerebrospinal fluid (CSF) analysis had an elevated white blood cell count and protein. On the basis of MR images and CSF analysis, a presumptive diagnosis of diffuse myelitis was made. The dog became paraplegic and was euthanized. Postmortem examination confirmed the presence of myelitis with vasculitis and nonerosive polyarthritis.