Comparative antigenic analysis of extracellular proteins of Bacteroides nodosus isolated from virulent and benign ovine footrot

Antigens in the extracellular protein (ECP) complexes of Bacteroides nodosus, isolated from sheep with either benign or virulent footrot, were studied by immunoelectrophoresis (IEP). Rabbit antisera against ECP from virulent and benign strains, were used in homologous and heterologous crossed IEP. Four precipitin peaks unique to the virulent strain, and five peaks unique to the benign strain were identified. In an attempt to characterize the different antigens in ECP, rabbit antisera were raised against an outer membrane protein (OMP, mol. wt. 35 000 daltons), pili and various proteases of virulent and benign strains of B. nodosus. No precipitin band was observed when ECP from both B. nodosus strains were reacted against anti-OMP and anti-pilus antisera. However, single precipitin bands unique to one protease from the benign strain and one protease from the virulent strain were identified. The results suggest that specific antigens other than proteases or pili are important in determining whether a B. nodosus isolate is virulent or benign.     

Effect of diet on results obtained by use of two commercial test kits for detection of occult blood in feces of dogs.

To evaluate the effect of diet on results obtained by use of 2 commercial test kits for detection of occult blood in feces, 5 dogs were fed 7 diets in randomized sequence. Dry and canned diets with various principal ingredients were evaluated. Each diet was offered twice over a 24-hour period, followed by a 36-hour nonfeeding period. Fecal specimens were collected twice daily, and tests for occult blood were performed within 12 hours. The dietary origin of fecal specimens was confirmed by use of colored markers fed with each diet, and was correlated with estimates of gastrointestinal tract transit time. A modified guaiac paper test and an o-tolidine tablet test were performed on each specimen. Of 59 specimens, 4 were positive for occult blood, using the o-tolidine tablet test. Three positive results were associated with a mutton-based canned diet, and 1 positive result was associated with a canned beef-based diet. Of 59 specimens, 11 were positive for occult blood, using the modified guaiac paper test. Four positive results were associated with the mutton diet, and 3 positive results were associated with the beef diet. Of the remaining 5 diets, 4 caused 1 positive reaction. Results were inconsistent with the null hypothesis that the distribution of positive occult blood test results is not affected by diet (P < 0.025), and indicate that diet can affect the specificity of peroxidase-based tests for detection of occult blood in canine feces. Diet modification prior to testing is recommended.     

猪轮状病毒2型(PCV2)是潜在的“定时炸弹”吗?

对猪轮状病毒2型(PCV2)的研究,为全球探讨断奶后多系统消瘦综合征(PMWS)的特殊问题,提供了许多答案。但是本文提出了一些还需要特别注意的地方 ,用以避免其可能导致的“恶果”出现。过去几年里 ,在关于断奶后多系统消瘦综合征(PMWS)、猪轮状病毒病(PCVD )全球性的探讨中 ,已经对许多关于疾病流行特点的来源和特征进行了广泛的研究。猪血清中猪轮状病毒2型 (PCV2)抗体以及猪的组织样本的检测表明 ,至少从1969年起 ,猪轮状病毒2型 (PCV2)的抗体就已经存在于猪的群体中了。现在已经确定 ,从1986年起在西班牙和英国就发现了传统的PMWS…     

Responses of ponies to equid herpesvirus-1 Iscom vaccination and challenge with virus of the homologous strain

An experimental (Iscom) vaccine previously shown to protect hamsters from lethal challenge with equid herpesvirus-1 (Ehv-1), was tested in horses. Vaccination with Ehv-1 Iscoms induced serum antibodies to the major virus glycoproteins gp10, 13, 14, 17, 18 and 21/22a, whereas antibody responses to gp2 were weak or absent. High levels of virus neutralising antibody of long duration were induced, but did not prevent challenge infection with virus of the homologous strain. However, in the vaccinated ponies there was a significant reduction in clinical signs, nasal virus excretion and cell associated viraemia compared with age-matched unvaccinated controls. There was a strong correlation between pre-challenge levels of serum virus neutralising antibody and the duration and total amount of virus excreted from the nasopharynx.