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E B Davies

Publications and source records attributed to E B Davies.

11 recordsLinked to original sources

Influence of environmental factors upon the survival of Aujeszky's disease virus.

The survival of Aujeszky's disease (pseudorabies) virus outside the living host was found to be dependent on pH level and temperature. Virus inactivation occurred at a rate varying from 0.04 log10 per day at 4 degrees C to 0.6 log10 per day at 37 degrees C at the optimum pH levels of 6 to 8. Fluctuation of the temperature between 4 degrees C and 37 degrees C had no apparent effect upon the titre of the virus. At a steady temperature of -13 degrees C, the virus was rapidly inactivated at all tested pH levels. For long-term storage it is recommended that the pH should be adjusted to between 6 and 7, that suspensions should be kept at -90 degrees C and that freezing and thawing should be rapid so as to pass through the just subzero temperature zone as quickly as possible. Drying, both on glass and on gelatin, caused inactivation of the virus at all pH levels, as did exposure to ultraviolet light.

Culture Media

Persistence of pseudorabies virus in infected swine.

The persistence of pseudorabies virus (PRV) in pigs clinically recovered from the disease was detected by culture of tissue fragments. Weanling pigs were infected by intranasal instillation of 200,000 plaque-forming units of a strain of PRV isolated from sick pigs in Iowa, and virus was recovered from them 6 weeks to 13 months later. Tonsil, trigeminal ganglia, or pooled trigeminal ganglia and olfactory and optic nerve tissue were most consistently the source of virus. The tissue-fragment culture technique was compared with a co-culture technique for detection of virus in tissue specimens from the recovered pigs. Use of these procedures provided the means to detect PRV in pigs for periods longer than previously recognized.

Animals