Interference between Virulent and Avirulent Strains of Sendai Virus

Characteristics of virulent, attenuated, and avirulent Mycoplasma pneumoniae strains.

Homologous pairs of virulent and attenuated or avirulent Mycoplasma pneumoniae strains were derived and compared in an effort to elucidate the mechanisms of virulence. These related strains were found to vary in growth, glycolysis, protein electrophoretic patterns, peroxide formation, morphology, and cytadsorption. Variations in the last two characteristics closely correlated with avirulence. T...

Effect of cyclophosphamide on infections in mice caused by virulent and avirulent strains of influenza virus.

Induced immunosuppression with the drug cyclophosphamide was shown to convert the relatively harmless infection with an avirulent strain of Kunz influenza virus into a fatal pneumonic illness. The drug was also shown to increase the mortality of mice infected with low concentrations of a virulent variant of this strain, but it delayed the time of death of mice that were infected with high conce...

Rescue of Recent Virulent and Avirulent Field Strains of Bluetongue Virus by Reverse Genetics

Since 1998, Bluetongue virus (BTV)-serotypes 1, 2, 4, 9, and 16 have invaded European countries around the Mediterranean Basin. In 2006, a huge BT-outbreak started after incursion of BTV-serotype 8 (BTV8) in North-Western Europe. More recently, BTV6 and BTV11 were reported in North-Western Europe in 2008. These latter strains are closely related to live-attenuated vaccine, whereas BTV8 is virul...

Differences in susceptibilities of virulent strains and avirulent strains of Neisseria gonorrhoeae to antimicrobial agents.

Virulent cells (T1 colony type) and avirulent cells (T4 colony type) of Neisseria gonorrhoeae were grown in a defined liquid medium in the presence of different antimicrobial agents. Bacteria of T1 colony type were found to be more resistant than bacteria of T4 colony type to the inhibitory effects of specific concentrations of ampicillin (0.50 mug/ml) and penicillin (0.01 mug/ml). Bacteria of ...

Role of Interferon in Replication of Virulent and Attenuated Strains of Measles Virus