A survey was carried out on the secretion of abnormal milk among dairy cows in the eastern part of Hokkaido. At the same time, those quarters of the udders secreting abnormal milk were treated with several drugs, including antibiotics. Secretion of abnormal milk was found in 21.8 percent of the cows surveyed. The majority of the affected cows secreted milk of a little high abnormality showing reaction more than ++ of CMT and containing more than one million cells per milliliter. Etiologic organisms were a little different from area to area. In general, staphylococci alone were detected from about 43 per cent of the affected cows, streptococci alone from about 20 per cent, and both of them combined from about 22 per cent. Of the staphylococci detected, 54.5 per cent was coagulase-positive, and 74.2 per cent of the streptococci detected belonged to group B of Lancefield. Secretion of abnormal milk was found mostly among cows milked by hand and frequently among those kept under no good management. Cows secreting abnormal milk from three or four quarters showed an average daily yield of milk 2.2 kg less than that given by cows secreting normal milk from the four quarters. Treatment was made with an agent prepared by dissolving 100, 000 to 200, 000 units of penicillin Gsodium and 100 to 200 mg of combined streptomycin in 50 to 100 ml of 5 per cent glucose solution. This agent was injected into the cistern of an affected quarter only once after the evening milking. As a result, about one half of the affected quarters was cured to secrete normal milk.
An H5 strain of infectious canine hepatitis virus was isolated from an infected stray dog. This virus was isolated in dog kidney cell culture and subjected to passage through swine kidney cell cultures, so that it might be attenuated in virulence. As a result, the virus which had undergone 22 passages through swine kidney cell cultures was no more pathogenic for dogs. Further more, dogs inoculated with this virus exhibited an increase in neutralizing antibody titer to 125 or more three weeks after inoculation. They withstood challenge made by a strongly virulent virus strain after the establishment of immunity, without manifesting any clinical signs. An antibody survey was conducted on stray dogs in and around Kumamoto, by using this virus. It resulted in giving a positive rate of 37.3 per cent.
A horse was kept in an isolated stable in Akita Prefecture for about eleven years since it was diagnosed as equine infectious anemia (EIA) on January 22, 1954. It was sent to this institute on October 8, 1964. No changes characteristic of EIA were recognized on it from the results of hematological examination and histopathological investigation by liver puncture made after its arrival. Blood was collected from this horse upon its arrival and injected into a healthy horse. The former was slaughtered on the eighth day after its arrival, and emulsions of its visceral organs and blood were injected into two other healthy horses. The three inoculated horses showed typical symtoms of EIA after the lapse of nearly the same period of incubation. Consequently, the horse examined was distinctly confirmed to be an EIA virus carrier, in spite of the lapse of a long time.
From November, 1963, to January, 1965, serum samples were collected from fowls and young chickens showing respiratory symptoms. They were tested for neutralizing antibody against the Shiga strain of infectious bronchitis virus. Sixty-eight serum samples out of 119 (57.1 per cent) revealed a neutralization index of more than 2.0, and 89 samples (74.8 per cent) more than 1.0. Neutralizing antibodies of infectious bronchitis virus are widespread among poultry in Osaka, Nara, Kyoto, and Hyogo Prefectures. In the traditional and intensive poultry farming zones, young chickens have been infected with infectious bronchitis virus.