Seroprevalence of turkey rhinotracheitis in Germany

The seroprevalence of turkey rhinotracheitis virus (TRTV) in North Germany from 1980 to 1983 was estimated by testing a non-random sample of 499 turkey sera from 234 turkey flocks in the virus neutralization assay. The turkeys had been submitted to a diagnostic laboratory. Source of all data were the necropsy reports of the diagnostic investigations and the corresponding results of serological testing for TRTV antibodies. The clinical sign respiratory disease as well as the pathological findings conjunctivitis, rhinitis, sinusitis, air sacculitis and pneumonia were used in the analysis. The data analysis revealed highly significant associations between TRTV seropositivity and respiratory disease as well as rhinitis and sinusitis. The results of this sample with unknown selection bias show that TRTV was present in turkey flocks in North Germany at least since 1980 and that TRTV could have played an important role in the occurrence of respiratory disease.     

Immuno-gold labelling of turkey rhinotracheitis virus.

The morphology and morphogenesis of five viruses isolated in Great Britain, France and South Africa from turkeys with rhinotracheitis were examined. The five isolates were antigenically related by immunofluorescence and were indistinguishable by negative contrast and thin section electron microscopy. Negative contrast electron microscopy of infected Vero cell cultures revealed ortho- or paramyxovirus-like particles and helical nucleocapsids 14 nm in diameter with a pitch of 6 nm. The viral nature of these structures was confirmed by immuno-gold labelling, using a hyperimmune rabbit antiserum to TRT virus and 15 nm gold-labelled goat anti-rabbit IgG. Ultrastructural changes characteristics of paramyxovirus infection were observed in Vero cell cultures infected with each of the five TRT virus isolates. These alterations, which included areas of localised thickening of plasma membrane, associated cytoplasmic inclusions of nucleocapsids and budding virus particles also labelled specifically following immunogold staining. These observations are in accord with the suggestion that TRT virus is an avian pneumovirus.     

Effect of cyclophosphamide on selected hematologic parameters of the turkey

The effect of three daily cyclophosphamide (CY) injections (doses of 0-100 mg/kg.day) on selected hematologic parameters in 7-to-8-week-old female Nicholas turkeys was examined. CY induced significant leukopenia, lymphopenia, thrombocytopenia, and heteropenia 24 to 72 hours after the initial injection; time depended on cell type and dose of CY. Significant linear correlation between increasing CY dose and increasing severity of circulating cell depression occurred. CY had no significant effect on circulating numbers of monocytes, packed cell volume, or plasma protein. Changes in basophils and eosinophils could not be identified because of their low numbers.     

The clinical course of the Infectious Laryngotracheitis (ILT) field case in hens and estimation of immunoprophylaxis efficiency

The ILT case was observed in laying hen farm where birds of different age (from 40 to 107 weeks) were kept in 10 flocks. A rapid spread of the disease, the decrease in egg production (in flock No. 1 it reached 58%) and higher mortality (the highest in 76 and 77 week-old birds, accounting for 0.11% and 0.36%, respectively ) was recorded during first 2 weeks of disease. Antibodies against ILT virus were detected in serum of the examined birds during the whole observation period (50 weeks after the disease outbreak). The laying hens were vaccinated at 8 weeks of age and boosted after 5 weeks. The vaccine was applied in drinking water, in a dose twice as high as usually recommended per one bird. Immunopropylaxis efficiency was estimated on the basis of immunological response in birds (serum samples, ILT ELISA kit, Guildhay Ltd.) and general health status of hens in flocks. Postvaccinal immunity, the presence of specific antibodies against ILT, was observed in all birds during the observation period (51 weeks). During that time GMT value ranged from 8261,3 (week 10) to 5196 (week 51) after the second vaccination, and CV amounted in this period to 41.1% and 51%, respectively. Subsequently, clinical symptoms of the disease disappeared and the egg production, as well as mortality, returned to the level of technological norms for laying hens.     

The immunoprophylaxis of of rotavirus infections in lambs.

The effect of colostrum or serum feeding on subsequent rotavirus infections was investigated in neonatal gnotobiotic lambs. Immunity after feeding colostrum did not depend on absorption of passively acquired antibody into the circulation. Protection against clinical disease depended on the volume of colostrum ingested. The protection afforded by feeding serum was specific, since serum free of rotavirus antibody failed to confer protection. Immune serum fed at a rate of 2.5 ml per kg twice daily protected against rotavirus infection. Also, it was shown by intraperitoneal inoculation of immune serum that protection could occur in the absence of ingested antibody, presumably by transfer of antibody into the gut. The implications of these findings for immunoprophylaxis of rotavirus diarrhoea in lambs and calves are discussed.