STUDIES ON NEWCASTLE DISEASE VIRUS

Studies on Newcastle Disease Virus

1. It is likely that certain tailed and filamentous particles seen on electron microscope examination of partially purified saline suspensions of Newcastle virus are the individual virus particles because: (a) They have a highly characteristic shape not seen in other virus preparations. (b) They are present whenever the virus is present in high concentration. (c) Their size agrees with the size...

Studies on the immunogenic properties of three lentogenic strains of newcastle disease virus

Studies on Newcastle disease virus by the plaque method.

The establishment of a successful plaque method for counting infectious virus particles by Dulbecco (1952), with subsequent refinements by Dulbecco and Vogt (1953, 1954a), makes it possible to quantitatively assay animal viruses with a high degree of accuracy in a manner comparable to assays of bacterial viruses. Two methods of assay commonly used in characterizing any particular Newcastle dise...

Replication of Newcastle Disease Virus

Infection of L cells with Newcastle disease virus (NDV) results in abortive replication, with the production of very few plaque-forming units (PFU) of virus per cell (W. C. Wilcox, Virology 9:30, 1959; K. Paucker et al., Virology 17:301, 1962). It is known that interferon is synthesized by L cells infected with NDV, and the possibility exists that this endogenously produced inhibitor may be res...

Efficacy of Thermostable Newcastle Disease Virus Strain I-2 in Broiler Chickens Challenged with Highly Virulent Newcastle Virus

Newcastle disease (ND) is a major threat to poultry industry production throughout developing countries. The Newcastle disease viruses (NDVs) infecting industrialized and indigenous poultry in Iran are velogenic strains and responsible for the frequent outbreaks of ND in poultry farms even in vaccinated flocks causing serious economic losses in the commercial and indigenous poultry. However, va...