Myasthénie grave chez un jeune chien

Myasthenia gravis in a young dog     

A Serological Survey of Leptospira interrogans serotype pomona in Alberta and Saskatchewan Striped Skunks and Possible Transmission Between Cattle and Skunks

The range of known occurrence of Leptospira interrogans serotype pomona is extended to Alberta in striped skunks (Mephitis mephitis); no evidence of L. sejroe was found. Reacting sera from skunks were confined to the southern portion of Alberta and adjacent Saskatchewan, although a number of reactors were found sufficiently further north in Saskatchewan suggesting that a different mode of infection may be functioning there. Of 95 skunk sera from near a dairy farm infected with serotype pomona 40% were reactors. Of 438 skunk sera from other areas only 5.7% were reactors; that difference was suggestive of transmission from cattle to skunks on the dairy farm. Of 22 skunk sera collected near the dairy farm in summer none were reactors, whereas 52% of skunk sera taken the previous and following winters were. That seasonal difference was not evident among sera from other locations.     

Osteolytic Osteosarcoma in a German Shepherd Bitch

Necropsy of a six year old female German Shepherd revealed the presence of a large oval mass in the thoracic cavity originating from the thickened proximal portion of the right fourth rib. Osteolytic osteosarcoma was diagnosed on the basis of gross appearance, presence of many pleomorphic spindle cells, containing pink stained intracytoplasmic granules in cytological preparations of impression smears of the tumor and histopathology. The tumor was considered highly malignant and was characterized by an abundant osteoblastic and connective tissue stroma with extreme cellular pleomorphism including giant cells, atypical mitoses and occasional trabeculae of tumor bone and osteoid. Metastases were found in the lung and spleen. Electron microscopy was carried out to support the diagnosis.     

A Study of the Oral Toxicity of Calcium Chloride in Dairy Cows

The effects of oral administration of calcium chloride solutions to dairy cows were studied. When a 0.3 per cent solution was given ad libitum, and as the sole source of water for a period of 75 days, we observed no significant changes in feed consumption, body weight or milk production. The average daily water intake was increased by approximately 20 per cent, and signs of slight gastro-intestinal irritation were seen. No major changes in blood hemoglobin levels, hematocrits, total and differential white cell counts or thrombocyte numbers could be attributed to the treatment. We observed no significant effect on the serum calcium, chloride, magnesium, potassium, or sodium content. The level of inorganic phosphate in the serum rose to higher, but still normal values. During the entire experiment the urine pH was abnormally acid for dairy cows. Electrocardiograms were taken after 45 days of calcium chloride administration, and they appeared normal. When 0.1 and 0.2 per cent solutions were given as the sole source of water for a period of 81 days, the cows remained in good condition, and we observed no changes in appetite, body weight or milk production. In general, dairy cows will refuse to drink calcium chloride solutions when the concentration exceeds 0.5 per cent, even when they have been deprived of water for 18-24 hours. On the other hand, since the administration of lower concentrations for periods of 75 and 81 days did not cause any clinical sign of disease, it seems that on farms where more than one source of water are usually available, poisoning of dairy cattle by calcium chloride in solution is quite unlikely.     

Some Observations on the Diagnosis and Epidemiology of Leptospirosis in Swine

The results of combined epidemiological, clinical, serological, bacteriological and histopathological studies following an outbreak of disease caused by L. pomona on a farm stocked with cattle, sheep, pigs, goats and horses maintained for experimental purposes, are reported.

The incidence of infection was high in horses, cattle and pigs. A few low titres were seen in sheep. The goats were not infected. Apart from a single bovine abortion all the clinical symptoms observed occurred in pregnant sows. Seven of these aborted or gave birth to stillborn pigs within a six week period.

Fifteen species of wildlife were trapped or shot on the farm during the year following the outbreak. L. pomona was isolated from four skunks and a porcupine. Epidemiological studies indicated that wildlife reservoir hosts were the primary source of infection for the domestic livestock.

Leptospiruria and the serological response were studied in a group of eight infected sows. Microscopic agglutination titres of 10² or less could not be associated with leptospiruria and the duration of leptospiruria was found to range from a few weeks to over two years in individual sows. Direct dark-field examination of urine proved superior to guinea-pig inoculation as a method of detecting leptospiruria and it is suggested that the former technique could be adopted with advantage as a routine aid to diagnosis.

     

Salmonella Contamination of the Product and Environment of Selected Canadian Chicken Processing Plants

Of 345 market chicken carcasses received directly from selected processing plants across Canada, six yielded salmonellae. One of the plants submitted 122 carcasses none of which yielded these organisms. A second plant had one Salmonella-contaminated carcass among 20 which were examined. Each of these two plants was subected to detailed bacteriological examinations on four occasions.

In these detailed examinations a total of 175 samples or specimens for culture were taken from a variety of surfaces including vent areas of carcasses, operators' hands, equipment surfaces and from water in tanks of iced birds. Twenty-five (14 per cent) of the cultures yielded salmonellae and all but one of these were either S. oranienburg or S. infantis. Isolations were made during five of the eight series of examinations. The evidence indicated that Salmonella-infected flocks were frequently slaughtered and that Salmonella contamination could become widespread in the plant during processing. The organisms are apparently eliminated from all but a small percentage of the carcasses during processing but opportunities exist for recontamination during subsequent handling.

     

一种水产养殖用微生物制剂的研究

利用枯草芽孢杆菌、干酪乳杆菌、沼泽红假单胞菌和啤酒酵母4种菌株配制了一种复合微生物制剂,试验结果表明,该制剂除含有丰富的营养成分外,在水产养殖中还能起到净水剂的作用,它能增加水中的溶解氧,显著降低氨氮、亚硝态氮、硫化物等不利于水产养殖的污染成分。此微生物制剂在水产养殖中将能发挥营养、保健及净化水质的功效。