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.     

EFFICACY AND TOXICITY OF AN ACCELERATED HYPOFRACTIONATED RADIATION THERAPY PROTOCOL IN CATS WITH ORAL SQUAMOUS CELL CARCINOMA

Squamous cell carcinoma (SCC) is the most common feline oral tumor. Standard radiation protocols have been reported to achieve tumor control durations of 1.5–5.5 months (45–165 days). The purpose of this study was to describe the efficacy and toxicity of an accelerated hypofractionated radiation therapy protocol in cats with oral SCC. Twenty‐one cats with histologically confirmed oral SCC and T1‐3N0M0 were treated with 10 once‐daily fractions (Monday–Friday) of 4.8 Gy. Seventeen cats had macroscopic disease and four were microscopic after incomplete excision. Acute toxicity consisted of grade 2 mucositis in all cats and this was effectively managed using esophageal or gastric tube feeding, pain medication, and antibiotics. Late toxicity effects for cats with available follow‐up data included alopecia (4 cats), leukotricia (6), tongue ulceration (1), and oronasal fistula (1). Response could be assessed in 17 cats (seven complete response and five partial response). Four cats (19%) developed metastatic disease without evidence of local progression. The median progression‐free survival (PFS) was 105 days (1 year PFS of 23%), median local progression‐free survival (LPFS) was 219 days (1 year LPFS of 41%), and median overall survival (OS) was 174 days (1 year OS of 29%). Only tumor stage was prognostic, with T1 having a median PFS of 590 days. Findings indicated that this accelerated hypofractionated radiation therapy protocol was well tolerated in cats with oral SCC, with manageable adverse events. Tumor response was observed in most cats and long tumor control durations were achieved in some cats.