The efficacy of three pretreatment techniques for the detection of prion protein (PrP) in formalin-fixed, paraffin-embedded bovine spongiform encephalopathy (BSE)--affected brain tissue were compared using automated image analysis. The most abundant immunostaining was in the form of particulate expression observed in sections pretreated with hydrated autoclaving for 30 min. Considerably less immunostaining occurred in sections pretreated with formic acid and no specific particulate immunostaining was detected in sections pretreated with hydrolytic autoclaving. Hydrated autoclaving pretreatment of sections prior to PrP immunolabelling gives visualisation of widespread sites of abnormal PrP deposition in the brain, allowing detailed study of the form and distribution of the protein in routinely fixed bovine central nervous system affected with BSE.

Two outbreaks of gizzard erosion in slaughtered broiler chickens in Japan were examined pathologically and microbiologically. The prevalences of such lesions were 9%-11% and 4%-50% in the affected flocks. Affected chickens had no clinical signs. Group I fowl adenovirus (FAV) serotype 1 was isolated from gizzard lesions. Histologically, gizzard mucosa were necrotic. Intranuclear inclusion bodies were seen in the enlarged nuclei of degenerating epithelial cells of the gizzard. The keratinoid layer in the erosion was edematous and desquamated and contained degenerative cells. Moderate to marked inflammatory cell infiltration was observed in the lamina propria and perivascular connective tissue in the submucosa and muscle layer. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies within degenerating epithelial cells. Ultrastructurally, numerous viral particles were demonstrated in the inclusions.

Abstract. We occasionally encounter feline cervical or mesenteric lesions diagnosed histopathologically as abscess or inflammatory granulation tissue with eosinophil infiltration. Gram-positive cocci accompany the lesions. In the present study, such lesions obtained from 27 cats were examined to evaluate the histopathologic features and the nature of the causative bacteria. The average age was 7.3 Ϯ 3.5 years. No sex predilection was observed. Most frequent locations of the lesions included the abdominal cavity with/without mesenteric lymph nodes (11/ 27, 41%) and subcutaneous tissue or lymph nodes of the neck (9/27, 33%). Common clinical presentation was a localized mass. Grossly, the lesions contained abscesses in the center and were surrounded by fibrous tissue. Microscopically, the necrotic zone contained bacterial colonies. Large numbers of eosinophils and macrophages infiltrated the area surrounding the necrotic tissue. The surrounding connective fiber-rich granulation tissue demarcated the eosinophilic abscess. The bacteria were Gram-positive cocci in 23 of the 27 cats and were positive for anti-staphylococcus antiserum in 19 of the 23 cats. In 15 out of 17 lesions, the colonies expressed immunoreactivity to penicillin-binding protein 2Ј, which is a drug-resistance gene product of methicillin-resistant Staphylococcus (MRS) species. These findings suggest strongly that MRS causes this type of infectious lesion.

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ABSTRACT. Primary culture of bovine brain cells was examined for its susceptibility to Neospora caninum infections, and this model was used to investigate the effects of bovine interferon gamma (IFN-γ) and tumor necrosis factors alpha (TNF-α) on tachyzoite growth. Tachyzoites of N. caninum grew well in this culture, and tachyzoite growth in astroglia and microglia were confirmed by immunocytochemical staining. IFN-γ inhibited the tachyzoite growth, and this inhibition was not reversed by the addition of nitric oxide antagonist. TNF-α, to a lesser extent, also inhibited the tachyzoite growth. Th-1 type cytokines may play an important role in host defense mechanisms in N. caninum infection.-KEY WORDS: brain culture, cytokine, Neospora caninum.

Abstract. Neospora is a cyst-forming coccidian parasite that causes abortions and neuromuscular disorders in a wide variety of mammals. Japanese bovine isolate JPA1 was inoculated intraperitoneally into BALB/c nu/ nu (athymic nude) and BALB/c (congenic wild type) female mice to examine the distribution of parasites and resistance mechanisms to Neospora infection. All the athymic nude mice died within 28 days after intraperitoneal injection of 2 ϫ 10 5 JPA1 tachyzoites, whereas all the congenic wild type mice survived without exhibiting any clinical signs. Tachyzoites were identified in the uterus and pancreas and later spread to many other organs. Most tachyzoites identified in the necrotic foci were localized in the epithelium of the venules and capillaries. Nude mice developed high level of serum interferon-␥ and interleukin-6 as infection proceeded. Inflammatory response to Neospora infection might be mediated by Th1-type dependent cellular immunity.

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Abstract. Between August and September 2000, five 2-7-year-old cows in Korea exhibited neurologic signs and were diagnosed as infected with Akabane virus based on the results of histopathology, immunohistochemistry, serology, and reverse transcription polymerase chain reaction (RT-PCR) analysis. Immunohistochemistry and RT-PCR were equally effective and sensitive for diagnosing Akabane virus infection during the early stage of infection. Typical lymphohistiocytic inflammation characterized by perivascular mononuclear cell infiltration, gliosis, neuronophagia, and neuronal loss was noted in the brain and the ventral horn gray matter of the spinal cord. The lesions in the brain were most prominent in the pons and medulla oblongata. Akabane virus antigen was detected in the brain and spinal cord, mainly in degenerating neurons and glial cells. RT-PCR analysis revealed a target band of expected size in four cows. This is the first report on an outbreak of natural Akabane virus infection in adult cattle.Key words: Akabane virus; cattle; immunohistochemistry; RT-PCR.Akabane disease (AD) is an arthropod-borne bunyaviral disease associated with abortion, stillbirth, and various congenital abnormalities in cattle, goats, and sheep. Akabane virus (AV) is a member of the Simbu group, genus Bunyavirus, family Bunyaviridae, and was first isolated from Aedes vexans and Culex triaeniorhynchus in 1960 and 1964, respectively, in Japan. 4,11 Sporadic outbreaks of AD have been reported in Japan, Taiwan, Australia, and Israel. 1,8,18 In Korea, the first AD outbreak was reported in 1980. 2 The pathogenesis of AV infection in cattle is well understood. Pregnant cows infected by AV through vectors generally do not develop any apparent clinical signs. However, during the early and mid to late gestation periods infection results in abortion and congenital arthrogryposis-hydranencephaly syndrome (AHS), respectively. 4,10 Although nonsuppurative encephalomyelitis may be observed in the late gestation infection in calves without AHS, encephalomyelitis induced by AV is unusual in cattle after birth. A few case of this condition caused by a highly virulent AV strain known as Iriki strain were reported in Japan and Taiwan, suggesting that AV may cause nonsuppurative inflammation in the brain and spinal cord of cows through horizontal rather than vertical transmission. 12,15 In July 1998, a severe outbreak of congenital abnormalities in calves was reported in most areas of Japan; a 5-month-old bull calf and 27 calves ranging from 1 to 27 days of age were examined, and their cases were diagnosed as AV infection. 19 Here, we describe an outbreak of natural AV infection in adult cows as revealed through histopathology, immunohistochemistry, neutralizing antibody assay, and reverse transcription polymerase chain reaction (RT-PCR) analysis.Between August and September 2000, 5 adult cows in Wonju City ranging from 2 to 7 years of age developed neurologic signs, including hypersensitivity, tremor, locomotor ataxia, or lameness. The cows were from fiv...