SOME ASPECTS OF THE EPIZOOTIOLOGY OF BOVINE EPHEMERAL FEVER IN AUSTRALIA

Serum samples collected from cattle in Western Australia, Northern Territory, Queensland and New South Wales in 1966 had neutralising antibodies to ephemeral fever virus, although the last major epizootic of ephemeral fever was in 1955-56. The incidence of antibodies ranged from 1.5% in Western Australia to 29.0% in Queens- land, and 57.6% of serums assayed were of low titre (2 to 5). Antibodies were not found in serums collected from cattle in Victoria, South Australia, southern Western Australia or Norfolk Island. After the 1967-68 epizootic the pro-porton of cattle with antibody ranged from 3.1% to 47.6% in herds with antibody in Victoria to 81.8% to 91.7% in herds in Queensland, and 58.2% of serums assayed had antibody titres greater than 45. Cattle with low levels of antibody in 1966 had high levels after the 1967-68 epizootic, although it is not known what pro-portion showed clinical signs of ephemeral fever during the epizootic. Serum samples collected in 1966, and which contained low levels of antibody, were fractionated by gel filtration and the neutralising activity was confined to the 7S globulin fraction. In one cow experimentally infected with ephemeral fever virus, the neutralising activity at 15 days after inoculation was confined to the 19S globulin fraction, in both the 19S and 7S fractions at 22 days but was almost totally confined to the 7S fraction by day 36. The significance of the results is discussed, and it is suggested that ephemeral fever virus remains enzootic in areas of Australia between major epizootics, but the infecting virus may be of low pathogenicity and immunogenicity for cattle, resulting mainly in subclinical infections.     

CLARIFYING SOME ASPECTS OF DIAGNOSTIC-ACCURACY RESEARCH

Evidence-based medicine is an approach to improved patient care that integrates clinical experience with basic science and clinical research in diagnostic accuracy, prognostic indicators, efficacy, and safety of treatments. Both clinical experience and methodical research assessments are essential components in this type of medical practice and underscore the importance of providing residents the opportunity to gain clinical experience as well as training them in how to perform, apply, and interpret clinical research in diagnostic imaging. The challenge for researchers is to design a study so that the data are valid and may be generalized to clinical situations where the test will be used. When assisting residents in the design of a research project for accuracy assessment of an imaging test, we consistently have observed three problem areas that if uncorrected would preclude the study results from being generalized to clinical situations where the test will be used: (1) understanding what is being measured, (2) appropriate selection of the sample population, and (3) the impact of the variability of the decision criterion. In this paper, we review these issues and suggest some solutions.     

ULTRASONOGRAPHIC EVALUATION OF BILIARY CYSTADENOMAS IN CATS

The purpose of this study was to describe the ultrasonographic appearance of biliary cystadenomas in cats and compare the findings to a similar rare form of liver tumor in humans. Biliary cystadenomas are uncommon, benign liver tumors of older cats that may occur as focal or multifocal cystic lesions within the liver. The records of 10 cats which had abdominal ultrasonography and histologic diagnosis of biliary cystadenoma were reviewed. The average age of affected cats was 13.3 years (range 10-16 years). Eight cats were neutered males and two were neutered females. In three cats, the tumors were not seen ultrasonographically due to their small size or from being obscured by near-field reverberation echoes. The remaining seven cats had solitary (4 cats) or multifocal (3 cats) masses corresponding to variable ultrasonographic patterns: multilocular masses containing thin-walled cysts, hyperechoic masses with cystic components, or masses of mixed echogenicity with cystic components. The masses had variable ultrasonographic patterns when multifocal disease was present. Recognizable cysts were evident somewhere within the tumors seen ultrasonographically, although sometimes the cysts appeared very small. The biliary cystadenomas were thought to be clinically silent. Although liver enlargement or a cranial abdominal mass was palpable in 4 cats, no consistent trend of clinical signs, CBC or serum biochemical abnormalities could be directly attributed to biliary cystadenoma. The treatment of choice is surgical resection of the tumor, as continued growth may compress adjacent vital structures within the liver. The differential diagnosis of biliary cystadenomas from other cystic liver lesions such as hepatic cysts, hematomas, abscesses, parasitic cysts, or other liver tumors is discussed.     

ECHOLARYNGOGRAPHY IN CATS

Twenty-five cats with clinical signs of upper respiratory tract disease and five cats without upper respiratory signs underwent echolaryngography. Direct inspection of the larynx under general anesthesia was undertaken in all cats and used as the 'gold standard' for the diagnosis of laryngeal diseases. The aims were to: (a) establish which anatomic structures of the larynx are visible ultrasonographically in cats without upper respiratory tract disease, (b) establish which laryngeal abnormalities can be detected and accurately localised using ultrasonography and (c) evaluate in which conditions the technique may provide complementary information or an alternative method of investigation. The ultrasound investigation accurately indicated the presence and location of cysts and masses. Abnormal laryngeal movements were also detected, although it was difficult to confirm whether these were unilateral or bilateral. Vocal cord thickening was seen but the underlying cause could not be established with this technique.     

ULTRASONOGRAPHIC EVALUATION OF GALLBLADDER WALL THICKNESS IN CATS

Ultrasonography of the gallbladder and biliary tract was performed on 42 cats: 22 clinically healthy cats (group A) and 20 cats with hepatobiliary disease and post mortem confirmation of gallbladder abnormalities (group B). The gallbladder wall was visible in 9 of 22 cats in group A and all 20 cats in group B. Additional gallbladder findings in group B included shape anomalies, biliary tract obstruction, wall thickening, polyps, neoplasia, and biliary sludge. Ultrasonographic evaluation of abdominal organs identified pancreatic disease as the predominant pathological cause of extrahepatic biliary obstruction. Hepatic parenchymal involvement was noted with inflammation and thickening of the gallbladder wall. Histologically, gallbladder walls were characterized by mucous gland hyperplasia, inflammation, infiltration, edema, epithelial detachment, and/or neoplasia. Ultrasonographic and histologic gallbladder wall measurements of 20 cats in group B agreed within 0.4 mm and all cats with a gallbladder wall thickness > or =1.0 mm had histopathologic abnormalities of the wall. Serum biochemical analysis revealed elevations of one or more parameters in all cats of group B, but was non-specific for a gallbladder lesion. The results of this study indicate that a visible, echogenic gallbladder wall can be considered a normal variant and is not always associated with hepatobiliary disease. Ultrasonography is accurate in measuring gallbladder wall thickness. Wall thickness greater than 1 mm is accurate in predicting gallbladder disease in cats, while a thickness less than 1 mm cannot rule out mild or chronic inflammation.     

大田常用杀菌剂农药对家蚕的毒性试验

本文介绍了大田常用20种杀菌剂农药对家蚕的毒性,结果表明:家蚕对其中11种杀菌剂农药有一定的毒性反应,表现轻微的症状.杀菌剂农药对家蚕的触杀毒力和残毒期因杀菌剂品种不同而有明显的差异;家蚕对杀菌剂农药的抗性因龄期大小不同而异.