Pathogenic characterization of Erysipelothrix rhusiopathiae Met-203 type SpaA strains from chronic and subacute swine erysipelas in Japan.

To characterize the Erysipelothrix rhusiopathiae Met-203 type surface protective antigen (Spa) A strains causing swine erysipelas in Japan, the nucleotide sequence of the hypervariable region of the spaA gene was determined in 80 E. rhusiopathiae (serotype 1a) isolates collected from pigs with chronic and subacute swine erysipelas in 14 prefectures in 2008-2014. In this study, 14 (17.5%) isolates were Met-203 type SpaA strains. We confirmed the pathogenicity of a Met-203 type SpaA strain in specific-pathogen-free pigs. In this experiment, the two challenged pigs displayed arthritis, urticaria and other clinical signs, but recovered within 10 days. Our results reveal the existence of the E. rhusiopathiae Met-203 type strains that have been causing chronic erysipelas in Japan.

Outbreak of swine erysipelas in a semi-intensive wild boar farm in Spain.

Swine erysipelas (SE) is a disease caused by the bacterium Erysipelothrix rhusiopathiae and is one of the best-known and most serious diseases affecting domestic pigs. However, few studies exist concerning the susceptibility of wild boars to this disease and the role of this species as a reservoir. This study investigates and describes an outbreak of SE that occurred on a semi-intensive wild boar breeding farm housing 40 boars in Extremadura (SW Spain) on 11-18 February 2010. Seven animals died, of which four were examined post-mortem. Of these, three (two females and one male) were approximately 3 months old, and one was 1 year old (male). Lesions were consistent with acute septicaemia, consisting of cutaneous erythema/cyanosis and petechial haemorrhages in kidneys, urinary bladder, lungs and meninges. The 1-year-old male also had proliferative polyarthritis. Histopathology confirmed the presence of disseminated intravascular coagulation and vasculitis. Additionally, a bilateral acute panuveitis with concurrent necrotizing vasculitis and diffuse corneal oedema, neither of which have been described before in this disease, were found in the 3-month-old male boar. E. rhusiopathiae was isolated from all four animals in pure cultures from several tissues. Of these four animals, antibodies against E. rhusiopathiae, using an indirect ELISA test, were only detected in the 1-year-old male boar with polyarthritis. Posteriorly, of nine live adults tested for antibodies, four (including an adult male with polyarthritis) were positive.

Endocarditis-associated brain lesions in slaughter pigs.

Left-sided valvular endocarditis (LSVE) is a common finding in slaughter pigs. The lesion is often associated with renal thromboembolism, but information on embolization to other organs is sparse. This study focuses on the presence and type of endocarditis-associated brain lesions (EABLs). The brains of 20 slaughter pigs with spontaneously arising LSVE and 11 controls were examined by sectioning half of a formalin-fixed brain into 4mm slices for histological examination. The aetiology of the endocarditis was determined by bacteriological and, in some cases, by fluorescence in-situ hybridization examinations. These examinations identified 11 cases of Streptococcus suis, six cases of Erysipelothrix rhusiopathiae, one Streptococcus spp. and two cases that remained aetiologically undetermined. One of the S. suis cases had a dual infection with S. suis in the aortic valve lesions and Streptococcus dysgalactiae subsp. equisimilis in the atrioventricular valve lesions. Renal infarcts were present in eight cases. Focal encephalitis was found in 12 cases, with the number of lesions ranging from one to 11. Most pigs had less than four microscopical lesions. Acute lesions were characterized by focal microabscesses without observable bacteria. Chronic lesions were characterized by astrocytosis and focal accumulation of mononuclear leucocytes. An infarct was observed in one animal. Perivascular inflammation was seen in 14 cases, mostly as two or three lesions, while focal leptomeningitis was found in eight cases. EABLs are therefore common in slaughter pigs with LSVE. The number of lesions per animal is small, which may explain the limited attention paid to this sequela of LSVE. EABLs have rarely been reported in domestic animals and mostly in patients with neurological signs. The frequent occurrence of EABLs in slaughter pigs suggests that this pathology should be investigated in other animal species with LSVE.

Vaccination of porcine circovirus type 2 (PCV2)-infected sows against porcine Parvovirus (PPV) and Erysipelas: effect on post-weaning multisystemic wasting syndrome (PMWS) and on PCV2 genome load in the offspring.

The effect of different Parvovirus+Erysipelas vaccination schemes in PCV2-infected sows on PMWS outcome in the offspring was investigated under experimental conditions. Six PCV2-free sows were first infected oro-nasally with PCV2 two months before insemination (D0; "Day 0") and then by the intra-uterine route at insemination (D62). On D21 and D42, vaccinated sows received either the two commercial monovalent vaccines, A1(PPV) and A2(Erysipelas), or the bivalent vaccine B (PPV+Erysipelas). In addition, three SPF sows (foster-sows) were synchronized for farrowing dates to enable them to foster piglets born to infected sows and removed at birth before colostrum intake. A significantly higher proportion of mummified fetuses was obtained from PCV2-infected non-vaccinated sows than from vaccinated sows. Acute myocarditis lesions were found in their piglets, together with a high PCV2 genome load. The latter was significantly higher than in those born to PCV2-infected vaccinated sows. Sentinel PCV2-negative piglets, born to SPF foster-sows, seroconverted at almost the same time as piglets without PCV2 passive immunity and born to infected sows. Sixteen of the 84 liveborn piglets born to infected sows and foster-sows were affected by a syndrome possibly related to PMWS, as judged by clinical signs and histological lesions. Most were born to PCV2-infected non-vaccinated sows and 12/16 did not receive PCV2 passive immunity. The probability of PCV2 infection and the number of PCV2 genome copies per gram of tissue were significantly increased in piglets that did not receive PCV2 passive immunity.

Comparison of inoculation regimes for the experimental production of swine erysipelas arthritis. I. Clinical, pathological and bacteriological findings.

The arthritic form of swine erysipelas was induced in pigs by multiple intravenous inoculation of 2 strains of Erysipelothrix rhusiopathiae. The strains differed significantly in their arthritogenicity but not in the number of cases of lameness induced. The use of 3 intravenous inoculations instead of 5 did not significantly affect the outcome. In a second trial, the more arthritogenic strain was injected in ten-fold dilutions from 5 x 10(9) to 5 x 10(4) organisms. Pigs receiving the lower doses showed high variability in their arthritic responses that precluded sensitive analysis of the dose effects on the number of arthritic and infected joints. However, slaughter weights showed a significant negative correlation with dose. Mean slaughter weights in treatment groups varied by 14.6 kg per pig, an average weight loss of 3 kg per pig for each ten-fold rise in dose of the highly virulent strain, and significantly correlated with the number of arthritic and infected joints. Culture of homogenised synovial membrane through selective horse meat-serum broth containing kanamycin, neomycin and vancomycin identified 66% and 59% more infected joints than primary blood agar culture of synovial fluid or synovial membrane homogenate, respectively.

Pathogenicity of field isolates of Erysipelothrix rhusiopathiae in mice, rats and pigs.

Eight field isolates of Erysipelothrix rhusiopathiae serotypes 1 and 2, from different sources, were examined for their pathogenicities for mice and pigs. Arthritogenicity for pigs correlated with virulence for mice at the highest and lowest levels, but not with strains of intermediate virulence. The most virulent strain was also arthritogenic in rats. In pigs, after repeated intravenous challenge the number of affected joints ranged from 0 to 11 of 12 examined. For the 8 strains, the mean number of affected joints ranged from 1 to 7.7 per pig. Clinical course and pathological findings were correlated, but the onset, severity and duration of lameness was variable both within and between groups. Clinical lameness, joint swelling and urticariae were of limited use as indicators of joint changes. The more virulent strains caused lameness as early as 2 days, whereas strains of low virulence took up to 8 weeks.

[The pathogenesis of erysipelas arthritis]. / Die Pathogenese der Rotlaufarthritis.

Experimental chronic erysipelas polyarthritis in rat, induced by living erysipelas bacteria, histologically can be divided into four different phases. In the phase of population bacteria are distributed diffusely within the whole joint but accumulate in the transitional zones and entheses by multiplication within the ground substance of cartilage. In the phase of acute destruction a severe inflammation of all joint tissues predominates. Bacterial antigen is eliminated by a pannus tissue destroying the cartilaginous structures. In the following phase a diffuse dystrophy of articular cartilage dominates. The reason for this process is not clear; within the cartilage bacterial antigen can seldom be demonstrated, but it accumulates intracellularly in the periphery of the joints (e.g. dense connective tissue, muscles). In the chronic phase we find a lymphoplasmacytic infiltration of the subsynovium, a lining cell hyperplasia, and pannus formation arising from the epiphyseal bone marrow cavity. The relation between chronic inflammation and destruction in the central and antigen persistence in the outer parts of the joints is a matter of current investigation.

[Morphologic studies of reactive changes in the joint cartilage in experimental erysipelas arthritis]. / Morphologische Utersuchungen zu reaktiven Veränderungen des Gelenkknorpels bei experimenteller Rotlauf-Arthritis.

In experimentally Erysipelothrix rhusiopathiae-induced polyarthritis of pigs, important pathomechanisms of bacterial invasion of the articular cartilage matrix were studied. Furthermore, observations were made concerning inflammatory cartilage changes in the transitional zone of the distal femur condyle. The morphological changes were a loss of proteoglycans, proliferation and transformation of cartilage cells, compensatory formation of collagenous fibers progressing to cartilage fibrosis and pannus formation. As histology only represents a static picture, different methods are necessary to finally verify the dynamics of this process. It appears likely, that cartilage and pannus combined, and synergistically after fibroblastic transformation, produce a reparative scar in the area of cartilage alteration.

A report of swine erysipelas in a litter of piglets.

Out of a litter of 7 two-week old Landrace piglets, 6 developed cutaneous haemorrhages especially on the limbs and ears. Two of these piglets died within 24 hours of the haemorrhages appearing whilst the other 4 recovered following penicillin therapy. The histopathological lesions were centred around the smaller vessels of the dermis and hypodermis. These included hyperaemia, leukostasis and intravascular fibrin coagulation or thrombosis. Bacterial emboli were present within the vessels of the skin, spleen, liver and kidney and loose in the areolar tissue of the dermis and hypodermis. Other lesions included scattered but extensive dermal and hypodermal haemorrhages and a mild cellular infiltration of the dermis and hypodermis.

Discospondylitis in swine.

Gross and microscopic lesions of discospondylitis in swine are described. Gross lesions were characterized by areas of destruction and cavitation involving intervertebral discs and adjacent structures. Microscopically, acute lesions had hemorrhage and necrosis with infiltration of granulocytes and mononuclear cells. In chronic cases intradiscal structures were replaced by vascular connective tissue which contained plasma cells and lymphocytes. These lesions were most frequently associated with chronic erysipelas polyarthritis.

[Immune reactivity of piglets vaccinated at an early age with a live vaccine against erysipelas]. / Prouchvane vurkhu imunnata reaktivnost pri praseta, vaksinirani v ranna vuzrast s zhiva vaksina protiv chervenka.

Studies were carried out on the immune response in pigs that had been treated at various intervals following birth with a live vaccine against erysipelothrix rhusiopathiae. The pigs originated from sows that had been vaccinated against the disease on the 80th day of pregnancy. Both biologic and morphologic investigation were performed. It was found that passive immunity protected the small pigs against an experimental infection up to the age of 45 days, inhibiting during this period being the action of the vaccine applied. The young pigs built up an active immunity against swine erysipelas after their vaccination at the age of 2 months, which protected them against control challenging, while the nonvaccinated animals reacted with a rise in temperature and reddening at the site of scarification. The morphologic studies confirmed the results of the biologic experiments.

[Immunopathology and pathogenesis of chronic erysipelas polyarthritis of swine]. / Immunpathologie und Pathogenese der chronischen Rotlauf-Polyarthritis des Schweines

Several immuno-pathological aspects of polyarthritis following experimental infection with erysipelas in pigs were studied for two years. Aseptic and specifically pathogenfree animals were infected subcutaneously and intravenously-intraarticularly with living erysipeals bacteria (erysipelothrix rhusiopathiae) of serotype B. After an initial febrile phase a progressive polyarthritis and disco-spondylitis developed. Some animals also developed thrombo-endocarditis. Hypergammaglobulinemia and high titers of specific antibodies were observed during the whole experimental period. Antiglobulin factors, however, were not detected in the serum or the synovium. In some animals collagen antibodies were demonstrated in synovial tissue. Bacterial examination of the synovium showed that erysipelas bacteria were present in arthritic joints for months. Living erysipelas bacteria were isolated 24 months after the experimental infection from synovial tissue of two pigs. The polyarthritis was characterised by exudates rich in fibrin, villous proliferation, pannus formation, cartilage erosions, and peri-articular fibrosis. IgG and specific erysipelas antibodies were demonstrated in plasma cells from synovial tissue by immuno-histological methods. The findings emphasize the morphological resemblance of the erysipelas induced chronic polyarthritis in pigs to human rheumatoid arthritis.

Erysipelas arthritis in swine: concentrations of complement and third component of complement in synovia.

Concentrations of hemolytic complement and of 3rd component of complement were determined in serums and in synovia of normal and arthritic joints in swine affected with arthritis experimentally produced by the inoculation of Erysipelothrix rhusiopathiae. Mean concentrations of complement in arthritic joints were increased from 24.7 to 37.5 50% hemolytic units of complement per milliliter. Third component of complement, expressed as a percentage of the serum concentration, was increased from a mean of 16.9 (normal joint synovia) to a mean of 27.1 (arthritic joint synovia). Also, fast-migrating conversion products of 3rd component of complement were not detected in synovia from arthritic joints. These results are interpreted as indicating a relatively less important role for immune complexes in the pathogenesis of erysipelothrix arthritis than is described for rheumatoid arthritis in persons.