Biochemical changes in fowl serum during infection with strains of Newcastle disease virus of differing virulence. Changes in serum proteins, uric acid, lipids and electrolytes.

Chickens aged five to six weeks were inoculated with three strains of Newcastle disease virus of differing pathogenicity. The serum level of the metabolites: total protein, albumin, globulin, uric acid, total lipids, cholesterol and electrolytes: calcium, magnesium, sodium and potassium were determined. The changes in serum levels of metabolites were as follows: velogenic infection was accompanied by decrease in total protein and albumin, reduction of lipids and cholesterol and increase in uric acid. No significant changes were found in the values of these metabolites in the serum of chickens infected with mesogenic strain. Lentogenic strain caused elevation of uric acid and cholesterol. All three strains caused decrease of the level of potassium in serum.

Development of a new vaccine against turkey meningo-encephalitis using a virus passaged through the Japanese quail (Coturnix coturnix japonica).

Turkey meningo-encephalitis virus could be adapted to the Japanese quail by intra-cerebral inoculation. After 4 passages the virus was found to be less pathogenic for the turkey. Further attenuation could be achieved by growing the virus in Japanese quail kidney cell cultures for 11 passages. This attenuated virus was used for the preparation of a live vaccine against turkey meningo-encephalitis. The safety and efficacy of the vaccine was shown in laboratory and field experiments.

Biochemical changes in chicken serum during infection with strains of Newcastle disease virus of differing virulence. I. Enzyme study.

Chickens aged 5-6 weeks were inoculated with 3 strains of Newcastle disease virus of differing pathogenicity. The levels of the enzymes lactate dehydrogenase (LDH), isocitrate dehydrogenase (ICDH), cholinesterase (ChE), alkaline and acid phosphatase (ALP and AcP), glutamate-oxaloacetate and glutamate-pyruvate transaminases (GOT and GPT) in serum were measured. Significant decreases in the levels of ChE and ALP were found in chickens infected with high doses of a velogenic strain of virus. The levels of LDH, ICDH and GOT were elevated in these chickens, but the levels of AcP and GPT were unchanged. ALP levels were slightly decreased and LDH levels were slightly elevated in chickens that were inoculated with a mesogenic strain. No significant changes in enzyme levels were found in chickens infected with lentogenic virus. Changes in enzyme levels were found to be correlated with the clinical findings in the infected chicks.

Turkey meningo-encephalitis: pathogenic and immunological aspects of the infection.

The distribution of turkey meningo-encephalitis virus in infected birds and the development of immunity were studied. The turkey meningo-encephalitis virus was present in the blood as early as 24 h after experimental inoculation, and persisted for 5-8 d. Antibodies could be detected about the 5th d. A good correlation was found between haemagglutinin-inhibiting and virus-neutralizing antibodies. The virus could not be reisolated from any blood or organ sample collected after the 14th d and no sign of latent infection or carrier state could be found. The infection did not spread from the inoculated turkeys to control un inoculated birds in close contact. The possible existence of a natural reservoir and an arthropod vector of this virus is discussed.