Naturally occurring lethal parvovirus infection of juvenile and young-adult rats

A lethal disease characterized by hemorrhage and necrosis of the brain, testes, and epididymides developed in young adult rats housed in specific pathogen free quarters. Morphological, virological, and serological investigations of the outbreak indicated that the probable causative agent was rat virus (Kilham), a common parvovirus of rats that usually induces persistent, asymptomatic infection in adult rats.     

Haemolytic activity of sheep complement for two assay systems

Sheep complement (C) is haemolytic for sheep erythrocytes sensitized with rabbit antibody (sheep E-rabbit A) provided serum is used as soon as possible after collection. If left at 4 °C to separate from the clot, serum C activity for sheep E-rabbit A is markedly reduced. Heparinized plasma retains its haemolytic titre for at least 24 h at 4 °C. Plasma from Mg²⁺-ethyleneglycoltetraacetic acid (EGTA) blood is non-haemolytic, but addition of Ca²⁺ partially restores the titre. A high concentration of rabbit A is necessary to sensitize sheep E.Sheep C is haemolytic for human erythrocytes sensitized with sheep antibody (human E-sheep A) in the presence of Mg²⁺-EGTA. This C activity is stable at 4 °C for 24 h in serum, Mg²⁺-EGTA plasma and heparinized plasma. Haemolytic activity of serum heated at 50 °C for 30 min was restored by a factor B containing CM-cellulose fraction of foetal lamb serum in the presence of Mg²⁺-EGTA for human E-sheep A but not sheep E-rabbit A.These findings show that sheep C haemolysis of sheep E-rabbit A requires a Ca²⁺-Mg²⁺-dependent pathway that is labile in vitro for 24 h at 4 °C.     

Effects of diets with cereal grains contaminated by graded levels of two Fusarium toxins on selected immunological and histological measurements in the spleen of gilts

Feeding experiments with diets containing Fusarium toxin-contaminated wheat were conducted to clarify the pathogenesis of immunological effects of Fusarium toxins to porcine spleen cells. Contaminated diets were fed to 36 Landrace prepubertal gilts for 35 d. Concentrations (as-fed basis) of the indicator toxins deoxynivalenol (DON) and zearalenone (ZON), respectively, were 210 and 4 (control--group I), 3,070 and 88 (group II), 6,100 and 235 (group III), and 9,570 and 358 microg/kg (group IV). No signs of hyperestrogenism or uterotrophic effects were observed because of dietary treatments. The feeding of mycotoxin-contaminated diets did not cause gross pathological findings in the spleens of animals. In vivo, no inhibitory effects were detected on concanavalin A-stimulation of blood lymphocytes; however, the proliferation rate of splenocytes was inhibited (P < 0.05) in pigs fed the diet with the highest DON/ZON concentration. With in vitro studies, lower proliferation rates of blood lymphocytes and splenocytes preexposed to DON were detected. Serum IgA concentrations of pigs in group II were increased (P < 0.05) compared with the baseline value before feeding the DON/ZON diet. The histopathological data indicated elevated (P < 0.05) iron staining in the red pulp of spleens in gilts from groups I to IV after 35 d of feeding. The presence of hemosiderin particles in the spleen sections was confirmed by transmission electron microscopic investigation. Together, the results provide evidence of spleen dysfunction (hemosiderosis) in the absence of clinical signs, especially in pigs fed higher concentrations (groups III and IV) of Fusarium toxin-contaminated wheat.     

Markers of Borna disease virus infection in cats with staggering disease

Borna disease virus (BDV) is a RNA-virus causing neurological disorders in a wide range of mammals. In cats, BDV infection may cause staggering disease. Presently, staggering disease is a tentative clinical diagnosis, only confirmed at necropsy. In this study, cats with staggering disease were investigated to study markers of BDV infection aiming for improvement of current diagnostics. Nineteen cats fulfilled the inclusion criteria based on neurological signs and pathological findings. In 17/19 cats, BDV infection markers (BDV-specific antibodies and/or BDV-RNA) were found, and antibodies in serum (13/16, 81%) were the most common marker. BDV-RNA was found in 11/19 cats (58%). In a reference population without neurological signs, 4/25 cats were seropositive (16%). The clinical history and neurological signs in combination with presence of BDV infection markers, where serology and rRT-PCR on blood can be helpful tools, improve the diagnostic accuracy in the living cat.     

Salmonellosis of sheep: Use of serum from a vaccinated ewe in a mouse passive protection test

Extract

Because of the large range of neoplasms included in this report, a summary of all reports on the subject has not been attempted. References will be made only to those ovine neoplasms which have been reported from New Zealand.     

Failure of immunisation against sporidesmin or a structurally related compound to protect ewes against facial eczema

Sixty ewes, divided randomly into four groups of 15, were immunised subcutaneously against sporidesmin (sdm) — bovine thyroglobulin (BTG) or 2-amino-5-chIoro-3,4-dimethoxy benzyl alcohol (ACDMBA) coupled to heat killed staphylococci or to bovine gamma globulin. Fifteen ewes served as untreated controls. Approximately 10 weeks after inoculation ewes were dosed orally with sdm at a rate of 0.1 mg/kg body weight/day for three consecutive days. Sdm antibody binding values, in plasma collected before dosing were higher in ewes immunised with sdm-BTG than ewes given the ACDMB A-complexes. Levels in the 15 untreated ewes were all very low. However, despite the presence of antibodies, the immunised ewes were not protected against sdm challenge; and cholesterol and bilirubin levels in serum and liver and urinary bladder damage scores, at slaughter, were all significantly higher (P<0.05) in the immunised compared to the control ewes six weeks after dosing. It is concluded from these results that subcutaneous immunisation against sdm or the structurally related substance used did not protect sheep against sdm dosing.     

Physiological mechanisms for antagonistic interaction of manganese and aluminum in barley

In a previous study, we found that the combined addition of Al and Mn in the culture solution could alleviate the inhibition of barley growth by addition of Al or Mn alone. The current experiment was conducted in a greenhouse to investigate the physiological mechanisms of the antagonistic interaction using two barley genotypes, XZ16 (both Al and Mn tolerant) and ZU9 (both Al and Mn sensitive). The treatments consisted of three Al levels (0, 0.1, and 0.5?mM) and three Mn levels (0, 0.2, and 1.0?mM) and their combinations, and a completely randomized block design was used with three replications. The combined treatments had larger plant biomass, lower Al and Mn concentrations and accumulation in plant tissues, lower malondialdehyde content, and higher root ATPases activities, compared with Al or Mn alone treatment. The two genotypes had the similar trend in the antagonistic interaction, with ZU9 being more predominant than XZ16.