Morphological features of the vomeronasal organ of both Korean native cattle and Korean native goat were studied by gross, microscopic and histochemical examinations. Anatomical characteristics of the vomeronasal organ were similar in both Korean native cattle and Korean native goats. The vomeronasal organ is a tubular structure situated bilaterally at the base of the nasal septum, and enclosed by hyaline cartilage. Its lumen is semilunar to crescent in transverse sections. It joins with the incisive duct through narrow duct. The lumen of the vomeronasal organ is lined with sensory and respiratory epithelia. The distribution pattern of vomeronasal mucosal epithelia varied by the position. In the anterior portion joining with nasal cavity, the lumen is lined with only respiratory epithelium. In the middle portion, sensory epithelium appeared on the medial side, and respiratory epithelium on the lateral side. In the posterior, it is lined with sensory epithelium on the ventral side and lined with respiratory epithelium on the dorsal side. The vomeronasal gland composed of mucous and serous acini are distributed in the lamina propria under the respiratory epithelium, where venous sinuses are also well developed

A new sudden death in rabbits appeared in China and Korea in 1984 and 1985, respectively, and was recognized to be an acute infectious disease caused by a virus. The disease was reported as a "new viral disease", and thereafter, a tentative name of "viral hemorrhagic disease", "hemorrhagic pneumonia" or "viral hemorrhagic pneumonia" has been described in the case reports. But authors had called the viral disease "rabbit viral hepatitis" due to picornavirus infection, because the principal lesion of the disease was an acute hepatitis. The purpose of this report is to describe the electron microscopic findings on the livers in experimentally infected rabbits. All the livers of the affected rabbits were shown to have degenerative changes of a type that is characteristic of acute hepatitis. In the liver cells, there were dilation of rER and mitochondria, vacuole formation of various sizes, and appearances of many virus-like particles in the vicinity of rER, granular bodies and crystalline arrays of viral particles in the cytoplasm with necrotic changes of the nucleus. Clusters of virus-like particles and viral crystals appeared in the cytoplasm of sinusoid endothelial cells and Kupffer's cells with morphological changes of organelles. Also viral crystals were demonstrated in the cytoplasm of macrophages among the liver cells. On the whole, the liver cells had many virus-like particles and a few crystalline arrays of viral particles. Therefore, this implies that the liver cells are the main site of the viral replication in inducing the viremia. It was concluded that the liver was the primary target organ of this viral disease, and the pathological and the ultrastructural evidence suggest that the virus may belong to genus enterovirus

In order to observe the pathological changes of kidney in rabbits infected with the viral haemorrhagic disease, the kidney tissues from the 91 rabbits infected with the viral haemorrhagic disease were examined by light and electron microscopy. On light microscopic observation, the kidney lesions were identified as haemorrhagic glomerular necrosis (33.0 %), membranous glomerulonephritis (20.9 %), thrombotic glomerulopathy (19.8 %) membranoproliferative glomerulonephritis (8.8 %), mesangial proliferative glomerulonephritis (8.8 %) ischemic acute tubular necrosis (7.7 %), and acute serous glomerulitis (6.6 %). On electron microscopic observation, cytoplasmic degeneration of mesangial cells, and irregular thickening of basement membranes with electron dense granular materials were observed. In podocytes swelling of mitochondria, dilatation of endoplasmic reticulum and extensive fusion of foot processes were also observed. Nonenveloped round icosahedral picornaviral particles with a diameter of 28-33nm were detected in the cytoplasm of degenerative endothelial cells, polymorphonuclear leucocytes, and monocytes

Ixodes signatus nymphs were subjected to the scanning electron microscopy for the observation of the major physiological sense organs including Haller's organ. Funger prints and variable sensory setae were found on the body surface, and especially well developed setae were identified on the article IV and on the anal lobes. A central button-like organelle and numerous small holes were found in the spiracular plate. The Haller's organ was identified at the distal point of the tarsus I and regarded as the major sensory organ, chemoreceptor. Two types of sensory setae were observed, the shorter ones in front of the organ and the longer ones in distal front as well as behind the organ. The fully opened organ was ellipsoidal and a total of seven basiconic sensory pegs rooted deeply and shaped like well arranged hooks were found inside the organ

Five hundred and forty-eight samples of pig heart muscle were collected from the abattoirs of many regions in Korea to reveal the frequency of Sarcocystis infections and to identify the species from June 1988 to April 1989. Heart muscle of the pigs was inspected for sarcocysts by the direct detection technique and for bradyzoites by the trypsin digestion technique. For examination of development of the parasites in the final host, 5 cross bred mature dogs, 5 puppies and 5 kittens were fed 100g, 50g and 50g of the infected meat respectively, four times in 2 days. Of 402 fattened and 146 older culled breeding pigs, 3 fattened pigs and 39 culled pigs were positive for Sarcocystis. Sarcocystis cysts from heart muscle measured an average of 425 x 169 micro m and bradyzoites an average of 15.6 x 3.5 micro m. Of 15 animals, only 2 puppies were infected with Sarcocystis. The prepatent period was 11 to 12 days and patent period was not examined since the puppies were infected with some another infections and one died on day 11 and another died on day 12 after ingestion of the meat. The sporulated oocysts were detected 11 days after ingestion of the meat and sporocysts 12 days from the puppy feces. The sporulated oocysts measured an average of 16.5 x 11.5 micro m and sporocysts an average of 12.6 x 7.9 micro m. On scaping examination of the intestinal mucosa, fully sporulated oocysts were detected in the tip of the intestinal villi. Considering above all descriptions, Sarcocystis in pig heart muscle in Korea was identified with Sarcocystis suicanis

Twenty-eight porcine rotavirus were isolated from piglets with diarrhoea in Chonnam Province. According to the age, 41 to 60 day old pigs showed the highest isolation frequency among the post weaning pigs. The characteristics of the field isolates were determined by electronmicroscopy(EM), immunofluorescent assay(FA), and electrophoretic migration patterns of the genome profiles. Some of the isolates showed remarkable haemagglutination activity against rabbit and dog erythrocytes, ranging from 4 to 2848, respectively. At least 3 serotypes of porcine rotavirus were recognized by serum neutralization test using serotype specific rotavirus hyperimmune sera

In the course of studying porcine enterovirus infection in piglets, the vascular endothelial cells in the CNS of colostrum-deprived piglets with polioence-phalomyelitis were investigated by electron microscope. The experimental piglets were orally infected with the porcine enterovirus serogroup 3 isolated in Korea and necropsied at 7 days postinoculation. Crystalline arrays of viral particles were found in the vascular endothelial cells of the spinal cord and cerebellum. Aggregates of immature viral particles were occasionally observed in the vascular endothelial cells in the meninges. The rough ER was deprived of ribosomes, irregularly dilated and associated with viral crystals. There were abundant cytoplasmic filaments, dilatation of perivascular space, perivascular cuffing, and the partial disruptions of endothelial cell membrane and basal lamina