AN EXPERIMENTAL STUDY OF "MAD ITCH" WITH ESPECIAL REFERENCE TO ITS RELATIONSHIP TO PSEUDORABIES.

The clinical picture and gross pathology of spontaneous and experimental "mad itch" have been described and the inciting agent has been shown to be a filtrable virus. It has been possible to prepare virucidal serum capable of neutralizing the virus. Fatal infections are regularly produced in rabbits when the virus is administered subcutaneously, intracerebrally, intravenously, intratesticularly, intraperitoneally, intranasally, or when it is dropped on a scarified area of skin. Its infectivity for other species by various routes is reported upon. The rabbit, guinea pig, white rat, white mouse, gray field mouse, cow, cat, duck, chicken, and hog are susceptible to experimental infection. The disease is not contagious under laboratory conditions and the virus is restricted in the animal body largely to the region of inoculation and the lung. The virus can be stored for relatively long periods in 50 per cent glycerol or in the dried state. A comparison of "mad itch" with pseudorabies leads to the tentative conclusion that the inciting agents of both are the same, although the strains of the two viruses that are under study possess readily demonstrable differences.