The use of Baypamun N in crowding-associated infectious respiratory disease: efficacy of Baypamun N (freeze dried product) in 2-week-old veal calves.

The efficacy of an immunomodulator, Baypamun N, was tested in 10-20-day-old veal calves from different farms, which were exposed to stress by transport and commingling (crowding). Verum and placebo animals (n = 50, each group) received three intramuscular injections of the investigational products (days 0, 2, 4) starting the day of arrival on the farm. Data from 49 calves in each group could be used for statistical evaluation. The incidence of acute bovine respiratory disease was anticipated to be high during the first 2 weeks after arrival on farm based on experience from other years. The clinical scores in the Baypamun N group were significantly reduced by 52.7% (P < 0.001) compared to the placebo group. The number of antibiotic treatments was significantly reduced by 53.8% (P < 0.001) in the Baypamun N group. Of the calves treated with Baypamun N, 51.02% remained untreated with antibiotics during the first 2 weeks after arrival on the farm compared with only 16.3% of the placebo treated control calves (P < 0.001).

The use of Baypamun N in crowding associated infectious respiratory disease: efficacy of Baypamun N (freeze dried product) in 4-10 month old horses.

The efficacy of an immunomodulator, Baypamun N, was tested in 4-10-month-old horses which were exposed to stress by weaning, transport and commingling with yearlings from different breeders (crowding). Verum (n = 26) and placebo animals (n = 27) received three intramuscular injections of the investigational preparations (days 0, 2, 9) starting at the day of commingling in one stable. The incidence of acute respiratory disease was high during the first 4 weeks after commingling. Approximately 50% of all horses showed seroconversion due to field infection by EHV1 and EHV4 during the observation period. The clinical scores in the Baypamun N group were significantly reduced by 40.3% (P < 0.05) compared to the placebo group. The proportion of horses with purulent nasal discharge during the observation period (4 weeks) was also significantly reduced by 58.7% (P < 0.01) in the Baypamun N group. Fifty per cent of the horses injected with Baypamun N showed no purulent nasal discharge and therefore no signs of complicated disease of the upper respiratory airways in contrast to only 14.8% in the non-protected placebo group. The challenge conditions studied in this investigation were rather severe because of the permanent exposure of Baypamun N treated individuals to the non-separated and untreated horses (n = 51). This indicates that treatment with Baypamun N is a successful tool to avoid severe clinical consequences of stress in young horses.

A gE deleted infectious bovine rhinotracheitis marker vaccine for use in improved bovine herpesvirus 1 control programs.

Based on a glycoprotein E (gE) deleted bovine herpesvirus 1 (BHV1) strain (Kaashoek et al., 1994) a killed virus as well as a modified live virus marker vaccine have been developed that allow differentiation between immunized and BHV1 infected cattle. Safety and efficacy of both vaccines were tested extensively following the current European Union (EU) requirements for the development of bovine vaccines. The minimum vaccine dose, vaccination regimen, route of administration and duration of immunity were evaluated for both vaccines in comprehensive vaccination/challenge trials in cattle. The most potent adjuvant formulation for the killed virus vaccine was also selected by experimental challenge infections. For the modified live virus marker vaccine it could be demonstrated that maternally derived BHV1 specific antibodies did not interfere with vaccination. Safety could be demonstrated for both the killed virus and the modified live virus vaccine in all target animal categories including veal calves, beef cattle, bulls, heifers and dairy cattle, including pregnant animals.

Safety aspects in the development of an infectious bovine rhinotracheitis marker vaccine.

Clinical trials in cattle demonstrated that the IBR marker modified live vaccine based on the gE-deleted IBR strain Difivac is immunogenic and safe for bovines of all ages. Potential effects of the vaccine virus have also been tested in swine and sheep and proved safe for these species as well. For evaluation of other environmental aspects, the spread of the vaccine virus after immunisation was investigated. The data indicated that the vaccine virus may be shed by immunised animals but that it has a limited ability to pass from animal to animal. It was also demonstrated that the attenuated Difivac strain does not revert to virulence during calf passage. Preliminary results indicated that the gE-deleted vaccine virus of the IBR marker vaccine cannot be reactivated after dexamethasone treatment, an important advantage for a vaccine strain. Furthermore, immunisation with the Difivac strain reduced the ability of a superinfecting challenge virus to become latent or to be reactivated.

[The effectiveness of the paramunity inducer Baypamun (PIND-ORF) for the prevention and metaphylaxis of an experimental infection with the infectious bovine rhinotracheitis virus in cattle]. / Wirksamkeit des Paramunitätsinducers Baypamun (PIND-ORF) zur Prophylaxe und Metaphylaxe einer experimentellen Infektion mit Virus der Infektiösen Bovinen Rhinotracheitis beim Rind.

Efficacy of the paramunity inducer Baypamun (PIND-ORF) was evaluated by an IBR challenge trial in cattle, as one model for infectious diseases in bovine. Prophylactic treatment with Baypamun protected cattle against manifestation of clinical symptoms after experimental IBR infection. The degree of protection depended on the time between paramunization and challenge infection. Even in metaphylactically paramunized cattle Baypamun reduced the IBR symptoms. In correlation to the reduction of clinical symptoms paramunization also reduced virus excretion by more than 99% in treated cattle compared to non paramunized animals. The induction of interferon following IBR infection was investigated in paramunized cattle. Application of Baypamun enabled treated animals to react faster with interferon synthesis following IBR infection than control animals did. The demonstration of the status of paramunity following Baypamun application in cattle provides a concept in the prevention of infectious disease in the practice.

[Spongiform encephalopathy in mice inoculated with scrapie material of sheep origin].

The authors report spongy degeneration in experimental scrapie (second passage) in mice. The scrapie agent was originally isolated from Suffolk sheep imported from Canada and diagnosed histopathologically to be infected with scrapie by intracerebral inoculation into JCL/ICR mice. Ten female SIc/ICR mice, 4 weeks of age, were injected intracerebrally in the right frontal lobus with 20 microliter of 10(-1) or 10(-4) dilution of JCR/ICR mice brain homogenate involving scrapie agent. All animals showed signs of the advanced stages of the disease, clinically manifested by lassitude, arched backs, lethargy and paresis of hind quarters. They were sacrificed five to six months post inoculation, and sections of the brain and spinal cord were examined by light and electron microscopy. Focal symmetrical spongiform lesions were seen light microscopically in the cerebral mantle, thalamus, hypothalamus, midbrain, medulla oblongata, cerebellum and cervical mark. There was evidence that these lesions tended to be more intense in the mice inoculated a higher concentration of scrapie agent. Astrocytic proliferation was present in the deep layer of cerebral gray matter, white matter, corpus callosum, dorsal part of hippocampus and thalamus. No leukocytic infiltration was observed. Electron microscopically, the spongiform lesions were shown to be caused by vacuolation or swelling within the neuropil, and vacuolation and focal swelling in the neuronal perikaryon. The changes in the neuronal perikaryon were caused by enlargement of endoplasmic reticulum and cisterns of the Golgi apparatus, accompanied by spherical swelling of a part of the cytoplasm. The vacuolation near or within the neuron produced deformation of the cell contours and displacement of the nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)