The newly developed low toxic preparation of organic phosphorus, 0, 0-dimethyl-0-1, 2-dibromo-2, 2-dichloroethyl phosphate, or JSR-381, was examined for anthelmintic effect upon canine filariae. Ten dogs infected with Dirofilaria immits were used. A course of treatment consisted of five doses of 75 mg/10 lbs, or approximately 16.7 mg/kg, each given. for five consecutive days. Medication was done once a day immediately before meal. Each dog was submitted to a total of four courses of treatment conducted at five days' intervals. The dogs were held under clinical observation from two days before the treatment to the day of autopsy. Five of them were sacrificed for autopsy on the first day and the remaining five on the 60th day after the completion of treatment of four courses. Blood samples of 0.01 ml each were collected from the auricular vein to determine the number of larvae in the blood. Adult worms which had been harvested from the dogs at autopsy were placed in physiological saline solution and heated, so that living worms might be distinguished from dead. Female worms were examined for the formation of larvae in the uterus. The following results were obtained. 1. Larvae decreased remarkably in number during the period of four courses of treatment, although they did not disappear from the body completely. They increased gradually in number after the medication came to an end. 2. No destructive effect, either quick or slow, was displayed by this drug upon adult worms. 3: The dogs excreted soft feces or suffered from diarrhea during the period of treatment. Eight of them sometimes revealed vomiting and five manifested anorexia and depression during the period of the first course of medication.
Studies were carried out on various factors which seemed to exert influence upon the antigenicity of crystal violet (CV) hog cholera vaccine during the process of manufacturing this vaccine from viral blood. of swine. Four types of CV vaccine, i.e., CV glycerin, CV phosphate, CV ethylene glycol, and Mario D'Apices vaccine, were prepared and analyzed to determine which of the CV, glycerin, and virus strain contained in each vaccine exercised the most remarkable influence on the inactivation and antigenicity of the virus. As a result, it seemed that glycerin (U.S.P., produced in Taiwan, or Formosa), ethylene glycol, physiological saline solution, distilled water, and the virus strains (Taiwan, Jen-Sal, and ALD strains) hardly gave any influence upon the antigenicity of the vaccine prepared. The most influential factor was presumed to be CV. The brands of CV used for inactivation of virus were derived from four companies, Colemand Bell, Takeda Pharmaceutical Industries, E. Merck, and Du Pont. An effective vaccine with satisfactory antigenicity was obtained when the Du Pont product was used. Preparation of an effective vaccine failed when any of the other products of CV was applied. These results indicate that CV of Du Pont make must be used selectively for the manufacturing of CV hog cholera vaccine.