Abstract. Porcine necrotic ear syndrome is a disease of swine characterized by large erosive lesions at the margin of the pinna(e). The gross and microscopic characteristics of the lesions were studied in 38 pigs selected from eight affected swine herds. The progression of the lesions was examined in a herd of 174 weaned pigs in a total confinement nursery. The lesions began as a superficial vesicular dermatitis associated with superficial auricular trauma and progressed to become exudative and encrusted. Localized lesions slowly healed or sporadically progressed to deep necrotic ulcers. The early lesions resembled the epidermal changes produced by Staphylococcus hyicus. Deep ulceration and necrosis was attributed to the invasion of streptococci into the dermis resulting in cellulitis, vasculitis, thrombosis, ischemia, and necrosis.Porcine necrotic ear syndrome is a disease of swine characterized by large erosive lesions on the ears. The disease has been called ear-biting,I6 streptococcal auricular dermatitis, I2 porcine ulcerative ~pirochetosis,~ or colloquially, ear necrosis. The name porcine necrotic ear syndrome is suggested as an alternative taxon until the pathogenesis and etiology of the disease is defined completely.Porcine necrotic ear syndrome has two distinct clinical patterns. In the milder form, the lesion remains as a localized, narrow, encrusted sore along the ventral auricular margin or tip, causing little discomfort to the pig or concern to the producer. These localized encrusted lesions usually evolve slowly to produce either slight scalloping of the auricular margin or resolve with no auricular necrosis. Sporadically, the lesions become much more severe. An acute inflammatory response develops, the epidermis ulcerates, and a large, irregular necrotic lesion develops along the auricular margin.The pathogenesis of the lesion remains undefined. Biting and cannibalism are thought by some to be the cause of the syndrome2*6.15,16 while others suggest bacteria such as spirochetes,' Staphylococcus hyicus,'* or B-hemolytic streptococci" as possible etiologic agents.Limited gross and histologic descriptions of the lesions of porcine necrotic ear syndrome are found scattered in several report^,^*'^*^^ but there is no detailed study of the gross and histologic character of the lesions. This paper describes spontaneous lesions in pigs affected with endemic necrotic ear syndrome. Materials and MethodsThe lesions of porcine necrotic ear syndrome were examined in two studies. Study A was designed to examine the progression of the lesions. The pigs in this study were the litters from 20 sows in a farrow-to-finish production unit with endemic necrotic ear syndrome. The piglets were the product of a modified three breed cross-breeding system. Their tails were docked at four days and at 34 to 52 days of age, the pigs were placed into seven 10.5 X 8 foot pens in a total-confinement slatted nursery. The mean population of the pens was 26. After weaning, the pigs were evaluated regularly from 12 days when the lesion...
Several structurally and functionally distinct classes of antibodies have been described for numerous species of animals. The present investigation was designed to elucidate the spectrum and interrelationships of ovine immunoglobulins (1s) and to establish the basic temporal features of the antibody response of the sheep. Materials and Methods.Purified ovine Ig were prepared by several methods from whole normal ovine serum (NOS) or immune ovine serum and from serum fractions obtained by ammonium sulfate or low ionic strength precipitation. Two stepwise elution schemes were used for the chromatographic purification of serum proteins on DEAE-cellulose. In the first, proteins were eluted by t-ris-phosphate buffer, pH 8.6, at molarities of 0.01, 0.04, 0.05, 0.08, and 0.09. In the second, proteins were eluted with 0.02, 0.035, 0.05, 0.1 and 0.15 M phosphate buffers and with 1 M NaCl, at pH 6.3. Serum was also separated by gel filtration on Sephadex G-200 using tris-HC1 buffer at pH 8 with 1 M NaCl and by preparative zone electrophoresis ( 1). Antisera to whole ovine serum and purified Ig were prepared in rabbits by the multiple injection of antigen with complete or incomplete Freund's adjuvant. Sera were rendered specific for one or more classes of Ig by stepwise absorption with appropriate ovine Ig.Microimmunoelectrophoresis (IEP) ( 2) and immunodiffusion (3) were used to characterize the antigenic relationships of Ig. Radioimmunoelectrophoresis (RIEP) (4), and passive hemagglutination (HA) (5) were used to characterize the ovine antibody response to a protein antigen, human y-globulin. Microscopic agglutination (MA) ( 6 ) ,
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