The Reaction of Vesicular Stomatitis Virus to Ultra Violet Light.

Abstract

Since bacteriological methods have so far failed to yield direct evidence of the nature of the active agent of vesicular stomatitis of horses, which is classed as a filterable virus disease, we have sought indirect evidence of its character in a comparison of the behavior of this virus with that of a common bacterium, S. aureus, under exposure to ultra violet light. The reactions of S. aureus to measured amounts of monochromatic energy at various frequencies may be considered typical of the behavior of bacterial protoplasms, and we have used the loss of transmissibility of a fixed vesicular stomatitis virus, active for guinea pigs, and the failure of subsequent colony formation by S. aureus, as indices of a similar reaction under ultra violet irradiation.

Active vesicle contents from lesions in the posterior foot pads of guinea pigs was aspirated and diluted 1:10 in buffered peptone broth at pH 7.4. This fluid, or a suspension of an 18-hour culture of S. aureus in the same medium, was spread on the surface of nutrient agar in small Petri plates, and corresponding areas of the respective plates were exposed to measured monochromatic radiations of the quartz mercury arc. After exposure the bacterial plates were incubated and the resulting colonies in the exposed areas were counted, in comparison with those in like areas from the unexposed portions of the plates. Exposed areas and unexposed control areas were cut from the agar of the virus plates, ground up in phosphate buffer solution at pH 7.5, and 0.4 cc. specimens of the virus-agar suspensions were injected intradermally into the posterior pads of guinea pigs, These animals were subsequently examined for the characteristic lesions of vesicular stomatitis, and the diagnoses were later confirmed by inimimity tests.