Caryospora-associated dermatitis in dogs

Numerous developmental stages of Caryospora sp. were seen in skin and lymph node of a 2-mo-old-dog with severe pyogranulomatous dermatitis. Schizonts were up to 20 microns long and contained up to 25 merozoites. Gamonts, unsporulated oocytes, sporulated oocysts, and caryocysts were seen in macrophages, connective tissue cells, and in unidentifiable host cells. Caryocysts were up to 18 microns long, and had thin walls, and contained a host cell nucleus and 1-3 sporozoites. All developmental stages of the coccidium reacted positively with anti-Caryospora bigenetica serum when examined in an immunoperoxidase test.     

Automatic imitation in dogs

After preliminary training to open a sliding door using their head and their paw, dogs were given a discrimination task in which they were rewarded with food for opening the door using the same method (head or paw) as demonstrated by their owner (compatible group), or for opening the door using the alternative method (incompatible group). The incompatible group, which had to counterimitate to receive food reward, required more trials to reach a fixed criterion of discrimination performance (85% correct) than the compatible group. This suggests that, like humans, dogs are subject to ‘automatic imitation’; they cannot inhibit online the tendency to imitate head use and/or paw use. In a subsequent transfer test, where all dogs were required to imitate their owners'' head and paw use for food reward, the incompatible group made a greater proportion of incorrect, counterimitative responses than the compatible group. These results are consistent with the associative sequence learning model, which suggests that the development of imitation depends on sensorimotor experience and phylogenetically general mechanisms of associative learning. More specifically, they suggest that the imitative behaviour of dogs is shaped more by their developmental interactions with humans than by their evolutionary history of domestication.     

Seroprevalence of antibodies to Neospora caninum in dogs and raccoon dogs in Korea

Neospora caninum is an important cause of abortion in cattle, and dogs are its only known definitive host. Its seroprevalence among domestic urban and rural dogs and feral raccoon dogs (Nyctereutes procyonoides koreensis) in Korea was studied by indirect fluorescent antibody test (IFAT) and by the neospora agglutination test (NAT), respectively. Antibodies to N. caninum were found in 8.3% of urban dogs and in 21.6% of dogs at dairy farms. Antibody titers ranged from 1:50 to 1:400. Antibodies to N. caninum were found in six (23%) of 26 raccoon dogs. However, the potential role of raccoon dogs as a source of horizontal transmission of bovine neosporosis needs further investigation. The results of this study suggest that there is a close relationship between N. caninum infection among dairy farm dogs and cattle in Korea. This study reports for the first time upon the seroprevalence of N. caninum infection in raccoon dogs in Korea.     

Sleeping dogs

The dog genome sequence represents a landmark in the genomics era for a number of reasons.     

Juxtacardiac pressure in closed-chest dogs

We studied pressure (Ppc)-volume (Vpc) relationships of the pericardial sac by inserting air into it at constant end-diastolic heart volume in six dogs. The lungs were inflated by positive alveolar pressure while pleural pressure was monitored using the esophageal balloon technique. Ppc-Vpc relationships were measured at transpulmonary pressures (PL) of 30, 10, and 5 cmH2O in each of three states: closed chest, open chest with lung separation, and open chest with the pericardium dissected free of its mediastinal attachment. Ppc in the closed-chest condition was more positive than Ppc in the open chest with lung separation, with increase of Vpc and PL, which suggests that the lungs compress the pericardium. Ppc in the open-chest condition with lung separation was also more positive than Ppc in the pericardium after it was dissected free, which suggests that mediastinal attachment compresses the pericardium. It is suggested that lungs in the closed-chest condition as well as mediastinal attachment reduce the heart expansion by a similar magnitude.