None of the filaricidal drugs appearing at present are superior to arsenicals as adult-filaricidals. With the aim of decreseing the volume of arsenical without diminishing its effect, experiments were conducted by injecting dichlorophenarsine hydrochloride in amounts of 0.75 mg As/kg. The heretofore accepted dose had been 1.0 mg As/kg. It was found that difference in effectiveness was very little. The findings were as follows: (1) Even when the dose of arsenical was decreased there was no appreciable difference in the filaricidal effect.Injections with 0.75mg As/kgover two consecutive days showed a considerably high filaricidal effect (81%) in mild cases and a marked decrease in filariae in severe cases. (2) Occurrence of ill effects from arsenical injection was nil when injection was given over two consecutive days in doses of 0.75 mg As/kg. (3) At the same total dose of injection (3.0 and 2.0 mg As/kg), the filaricidal effect decreased when administered over a number of times with small doses or when intervals between injections prolonged. (4) In the case of injection of 0.75 mg As/kg over two consecutive days no filaricidal effect could be seen on immature worms. Accordingly, this dosage should be administered after worms have reached maturity.
It is desirable that bacteriological investigation should be made completely before infected udders are treated. It is very difficult practically, however, to perform such investigation in the field, because several instruments and a long time are needed. So, in general, bovine mastitis is treated immediately with drugs without any previous bacteriological investigation. This is one of the reasons why drug-resistant strains have been induced from the causative bacteria of bovine mastitis. Recently, the drug-resistant strains, especially those belonging to Staphylococcus aureus, have been rather frequently detected from milk samples drawn from mastitis udders. The author has been studying these ploblems and invented a rapid means called the resistancetester to detect drug-resistant strains easily in the field. This method needs no apparatus, no isolating media, nor an incubator. In the field the resistance-tester is employed immediately, a test sample being inoculated directly from the teat of an affected udder. The presence of any resistant strain, with its sensitivity to the concentration of the drug, is recognized easily by change of the color of the tester. The resistance-tester is available to detect not only resistant strains in mastitis milk, but also those of many species of bacteria causing infection among human beings and animals so that any effective treatment might be performed correctly and economically.
In 1958, some cases of hog cholera were found at the Animal Quarantine Station at the port of Kobe. A positive diagnosis was made by inoculation of pigs and from histopathological findings. In inoculation tests, two experimental pigs which, had been inoculated with emulsified spleen and mesenteric lymph node of naturally infected pigs took an unusually long chronic course. One pig became moribund on the 72 nd day and the other died on the 54 th day following inoculation. The results of clinical, hematological, and pathological observations on the two cases were described in this paper. As main clinical signs, continuous mild fever of around 40°C, mucous excretion from the eyelids, constipation with nasty smell, and anorexia were observed since the early stage. Furthermore, coughing was seen in a later stage. Paralytic nervous symptoms appeared several days prior to death. In hematological examination, the two cases were lacking of definite signs of hog cholera. The appearance of immature granulocytes (myelocytes and -metamyelocytes) was slight and seen only in a later stage. At autopsy, hemorrhagic lesions in the visceral organs and lymph nodes were main findings. Histologically, the lesions consisted of aplasia and necrosis in the lymphatic tissue, hemorrhage, activation of the reticuloendothelial system, and proliferation of vascular connective tissue. These changes coincided with those of animals experimentally and naturally infected with hog cholera. The histological lesions of the two cases, however, were unexpectedly slight in spite of a very long course of disease. On the other hand, the severity of hog cholera lesions is generally parallel to the length of course in acute and subacute cases. Sasahara and Dunne divided hog cholera into four types peracute, acute, subacute, and chronic, from the length of course. The two cases reported here seem to be the first cases of chronic type which were observed in the laboratory in Japan.