Israel Green Hopkins

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Two infectious bursal disease vaccines were administered to separate groups of maternally immune and susceptible chickens at various ages. Vaccine B caused no damage to the bursae of chickens examined histologically at nine and 20 days after vaccination. The bursae of chickens given vaccine A were shown to be severely damaged when similarly examined. Both(More)
Methods for the detection of two strains of avian encephalomyelitis virus (AEV) in chick embryo brain cell cultures and chickens were compared. It was found that the agar gel precipitin test (AGPT) and the enzyme-linked immunosorbent assay (ELISA) carried out on the serum of inoculated chickens were more sensitive than either the indirect fluorescent(More)
A comparison was made of the potency of live lentogenic Newcastle disease vaccines using a multipoint challenge assay. In general, La Sota vaccines gave better protection than B1 vaccines and both were superior to products made from the Ulster 2C strain. However, variation was found within products prepared from the same strains, depending on their source.(More)
The protective properties of two commercial Leptospira hardjo vaccines in calves were compared with the serological responses induced in guinea-pigs with a view to establishing a potency test based on serology. Groups of calves were given graded doses of the two vaccines and after eight weeks were challenged with virulent L. hardjo. Infection was monitored(More)
M~)flkey kidney stable ceIIs developed characterist:c changes when infected with ail known types of African horse-sickness virus. First, there was an increase in the size of ceII nuclei. Then, basophilic Feulgen-positive granules were seen in the v:cin;ty of nucleoli. The granules increased in number and were scattered throughout the nucleus. As infection(More)
The serological response of chicks to Brucella abortus strain 19 was monitored over a period of seven weeks to assess the degree of immunosuppression caused by vaccination at one day of age with two infectious bursal disease vaccines. One of the vacy. This vaccine caused severe immunosuppression judged by the minimal serological response following B abortus(More)
Factors associated with the indirect fluorescent antibody test used for the titration of avian encephalomyelitis virus (AEV) in chick embryo brain cell cultures were examined for their influence on virus replication. It was found that virus should be inoculated onto semi-confluent cell cultures and adsorbed for two hours at room temperature. The cells(More)