Evaluation of a Low Toxic Preparation of Organic Phosphorus (JSR-381), for Removal of Canine Filariae

Abstract

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.