Biomaterial Database

Thermostability of Newcastle disease virus strains of different virulence. 1975

B Lomniczi

The thermal inactivation rate constant for infectivity of a total of 24 Newcastle disease virus (NDV) strains was determined at 50 degrees and 56 degrees C. The greater part of the examined NDV strains were found, irrespective of virulence properties, to be thermostable, since the loss of infectivity titre did not exceed 2 logarithmic orders after exposure at 50 degrees C for 60 minutes. Thermostable (I+) and thermolabile (I minus) strains with respect to infectivity were uniformly encountered among the 12 avirulent (lentogenic) and 10 fully virulent (velogenic) strains studied. Strains with both heat stable (Ha+) and heat labile (Ha minus) haemagglutinin were found in the lentogenic group, whereas haemagglutinins of all examined velogenic strains were heat stable. On the basis of I/Ha character, i.e. combination of thermosensitivity of infectivity and haemagglutinin, all examined strains could be classified into one of three categories: I minus Ha minus (8 lentogenic strains), I+Ha+ (4 lentogenic and 7 velogenic strains) and I minus Ha+ (2 mesogenic and 3 velogenic strains). The possible fourth combination, I+Ha+ minus, was not encountered among the strains studied. Determination of the I/Ha character may be helpful in clarifying the origin of a lentogenic NDV strain.

UI	MeSH Term	Description	Entries
D009522	Newcastle disease virus	The most well known avian paramyxovirus in the genus AVULAVIRUS and the cause of a highly infectious pneumoencephalitis in fowl. It is also reported to cause CONJUNCTIVITIS in humans. Transmission is by droplet inhalation or ingestion of contaminated water or food.	Avian Paramyxovirus 1,Paramyxovirus 1, Avian
D010948	Viral Plaque Assay	Method for measuring viral infectivity and multiplication in CULTURED CELLS. Clear lysed areas or plaques develop as the VIRAL PARTICLES are released from the infected cells during incubation. With some VIRUSES, the cells are killed by a cytopathic effect; with others, the infected cells are not killed but can be detected by their hemadsorptive ability. Sometimes the plaque cells contain VIRAL ANTIGENS which can be measured by IMMUNOFLUORESCENCE.	Bacteriophage Plaque Assay,Assay, Bacteriophage Plaque,Assay, Viral Plaque,Assays, Bacteriophage Plaque,Assays, Viral Plaque,Bacteriophage Plaque Assays,Plaque Assay, Bacteriophage,Plaque Assay, Viral,Plaque Assays, Bacteriophage,Plaque Assays, Viral,Viral Plaque Assays
D002642	Chick Embryo	The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.	Embryo, Chick,Chick Embryos,Embryos, Chick
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D006389	Hemagglutinins, Viral	Specific hemagglutinin subtypes encoded by VIRUSES.	Viral Hemagglutinin,Viral Hemagglutinins,Hemagglutinin, Viral
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014774	Virulence	The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.	Pathogenicity