Comparison of three diagnostic techniques for detection of rotavirus and coronavirus in calf faeces in Australia.

OBJECTIVE: Compare real-time reverse transcription polymerase chain reaction (qRT-PCR), a commercially available enzyme-linked immunosorbent assay (ELISA) and lateral flow immunochromatography assay (LAT) for the detection of rotavirus and coronavirus in faecal samples collected from diarrhoeic calves. DESIGN: Prospective survey. METHOD: Samples were tested at two separate facilities using a commercial ELISA and an in-house qRT-PCR. Simple logistic regression was performed to examine the relationship between the two tests. A subset of samples was screened using qRT-PCR, ELISA and a commercial LAT dipstick (132 faecal samples were tested for coronavirus and 122 samples for rotavirus). RESULTS: Of the 586 samples tested, 131 (22.39%) and 468 (79.86%) were positive for coronavirus and group A rotavirus, respectively, using qRT-PCR. The number of samples positive on ELISA for coronavirus and rotavirus was 73 (12.46%) and 225 (38.40%), respectively. Using LAT, 30 (22.73%) and 43 (35.35%) samples were positive for coronavirus and rotavirus, respectively. Simple linear regression revealed a statistically significant (P < 0.05) but weak (r(2) =-0.07 and -0.40) correlation between the rotavirus/coronavirus qRT-PCR and ELISA, respectively. There was also poor agreement between the LAT and qRT-PCR assays. CONCLUSION: The sensitivity and specificity of the commercial ELISA and LAT assays evaluated in this study were low compared with qRT-PCR. The low positive and negative predictive values of the assays suggests that they were of limited diagnostic benefit in the population sampled.

Epidemiology and impact of Neospora caninum infection in three Queensland tropical dairy herds.

This study investigated the epidemiology of Neospora caninum in three tropical dairy herds in North Queensland, Australia. All animals in the herds were bled, and the sera were tested by ELISA for N. caninum antibodies. Herd records were examined, and the number of calves carried to term and the number of abortions which occurred over the lifetime of each animal were recorded to determine the abortion rate for each animal. Pedigrees were constructed for two of the herds to investigate whether vertical transmission was occurring. The seroprevalence of N. caninum ranged from 23% to 34%. The abortion rate in seropositive animals was significantly (p < 0.001) higher than in seronegative animals in all three herds (12-20.1% cf. 3.6-7%). Overall, the probability of a calf being seropositive was 3.5 times higher when the dam was also seropositive than when the dam was seronegative. Subsequent selective breeding employed by one herd reduced the N. caninum seroprevalence from 23% to 5% over a 9-year period. This study shows that N. caninum infection is prevalent in North Queensland dairy cattle, and both post-natal infection and vertical transmission are common.

Prevalence of major enteric pathogens in Australian dairy calves with diarrhoea.

OBJECTIVE: Determine the prevalence of the major enteric pathogens in dairy and dairy beef calves with diarrhoea in Australia. DESIGN: Cross-sectional study. METHODS: Faecal samples from 84 Australian dairy and dairy beef properties (597 samples) were screened for rotavirus and coronavirus using real-time reverse transcription polymerase chain reaction, for Salmonella spp. using selective enrichment faecal culture, and for enterotoxigenic Escherichia coli (K99) and Cryptosporidium parvum using a commercial enzyme-linked immunosorbent assay. A logistic regression with random effects model was used to compare prevalence of pathogens in dairy and dairy beef operations. RESULTS: Enteric pathogens were isolated from 97.6% of outbreaks and 95.0% of samples. Rotavirus was the most common pathogen identified (477/597, 79.9%) followed by C. parvum (349/597, 58.5%), Salmonella spp. (142/597, 23.8%), coronavirus (129/597, 21.6%) and E. coli K99 (104/597, 17.4%). Multiple pathogens were identified on 96.4% of farms and from 71.0% of samples. Samples from dairy beef properties were more likely to have multiple pathogens than dairy properties (P < 0.05), whereas rotavirus and Salmonella spp. were more likely to be identified in samples collected from dairy beef than dairy properties (P < 0.05). CONCLUSION: Most outbreaks of calf diarrhoea in dairy and dairy beef operations involve multiple pathogens. Rotavirus and C. parvum were the most frequently identified pathogens across production systems. Salmonella spp. and rotavirus were more frequently identified in dairy beef operations.

Environmental mastitis in intensive high-producing dairy herds in New South Wales.

OBJECTIVE: To determine the prevalence of mastitis pathogens in high-producing intensive dairy herds in New South Wales. DESIGN: Field survey. PROCEDURE: Milk samples from the mastitis-affected quarter were collected from cows on five high-producing dairy farms in NSW. The 820 samples were cultured using standard microbiological culture techniques. RESULTS: Bacteria or fungi were isolated from 83.3% of samples (683/820). More than two colony types were isolated from 16.7% of samples (137/820), two types from 6.6% (54/820), and one type from 52.3% (429/820). No bacteria were isolated from 24.4% (200/820) of the primary cultures, but enrichment cultures of these samples yielded single colony type bacterial isolates from 36.5% (73/200) of samples. Environmental pathogens, including coliforms, environmental Streptococcus and Staphylococcus spp., made up 91% (555/610) of isolates and accounted for 33.6% (205/610), 41.6% (254/610) and 15.7% (96/610), respectively, of isolates. Escherichia coli accounted for 76.1% (156/205) of the coliform isolates, Streptococcus uberis and Streptococcus dysgalactiae accounted for 32.3% (82/254) and 28.0% (71/254), respectively, of the environmental streptococcal isolates. Contagious pathogens were uncommon, comprising only 2.5% (15/610) of the total isolates. CONCLUSION: The incidence and causes of mastitis are largely influenced by farm management. The relatively high prevalence of coliform mastitis in the intensive high-producing herds in this survey contrasts with the low incidence reported in surveys of pasture-based herds in Victoria. If the Australian dairy industry continues its current trend of intensification, coliform intra-mammary infections may emerge as an increasingly important cause of mastitis.

The acute abdomen: the role of computer-assisted diagnosis.

CAD has been used in over 20,000 patients in an Accident and Emergency Department. Structured documentation has replaced normal case notes and a patient record is created which includes investigations and management. A copy of the documentation acts as an immediate communication to the general practitioner. The information is held on a computer and is readily accessed to produce feedback and to allow audit of any number of parameters. The results show that an improvement in diagnostic accuracy and a reduction in admissions and unnecessary laparotomies continues over 15 years. Problems have occurred; some are inherent to the system and some have been minimized as a result of a series of studies. The savings in terms of finance and facilities are considerable and the cost is small in comparison as the programs are available and the cost of hardware has diminished. It is concluded that documentation is essential. This allows the more accurate collection of information, permits analysis, acts as a method of communication and creates a detailed patient record. The use of this part of the CADA system produces a considerable improvement in the parameters used to assess satisfactory patient management. The computer diagnostic program produces a higher level of diagnostic accuracy than that obtained by doctors who are not using the system. It does not normally exceed the accuracy of the doctors who are using the structured documentation and entering the information into the computer. Other mathematical models might lead to an improvement, particularly if they were based on the diagnostic process used by a senior clinician. The method of entry of information could be facilitated by modern technology, including light pens or word sensitive computers. This would reduce the time required for completion of the documents. A number of possible improvements in the CADA system are reported and some have been studied in detail with little evidence of significant change. The computer part of the system has an educational value and presents a stimulating challenge to the junior hospital staff seeing the patient for the first time in the Accident and Emergency Department. Rapid feedback is possible and advantageous. Possibly the greatest value of the computer is in the analysis of the value of clinical features in diagnosis, which has not been easy in the past. It has also allowed precise assessment of the value of investigations in the diagnosis of patients with a suspected disease, which leads to more appropriate management and the saving of facilities.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute abdominal pain: the value of liver function tests in suspected cholelithiasis.

Over a 4-year period, prospective data were collected on 311 patients with suspected acute cholecystitis. By identifying the diversity of conditions which can masquerade as acute cholecystitis, we have examined the role of biochemical liver function tests in the diagnosis and management of these patients. The initial clinical diagnosis of acute cholecystitis was confirmed in 229 patients (73.6%). Of those patients on whom liver function tests were performed, 76.3% (206/270) were confirmed to have cholecystitis and 69.9% (144/206) of these had some evidence of liver dysfunction. In the group of patients (64/270) with other diagnoses on whom liver function tests were performed, significantly fewer (57.8%, 37/64) had abnormal liver function tests (P less than 0.05). This is of little clinical value since normal liver function does not exclude cholecystitis (predictive value of negative test = 30.3%). In proven cases of cholecystitis, there was a significantly increased incidence of liver dysfunction when ductal calculi were present. Using the information obtained from this study, an investigative protocol is proposed which may substantially reduce the rate of misdiagnosis of patients with abdominal pain suggestive of cholelithiasis.

Anterior lesser curve seromyotomy and posterior truncal vagotomy for chronic duodenal ulcer: the results at five years.

In one surgical unit, 241 patients have undergone anterior gastric seromyotomy and posterior truncal vagotomy for chronic duodenal ulcer. The postoperative mortality rate was 0.4 per cent. Four patients (1.6 per cent) required a drainage procedure for gastric stasis. The first 66 patients (Group A) were followed prospectively and 58 were available for assessment at 5 years. Eight patients (14 per cent) had developed a recurrent ulcer. In seven of these patients this responded to conservative treatment with H2 receptor antagonists. One patient has required Polya partial gastrectomy for recurrent ulceration. At 5 years 47 patients (81 per cent) were placed in the Visick I or II categories. In the next 175 patients (Group B), the ulcer recurrence rate was 3 per cent, suggesting a learning curve in mastering the procedure. We conclude that the immediate and 5-year results of the first 66 patients are at least comparable with those of highly selective vagotomy. Anterior gastric seromyotomy with posterior truncal vagotomy is an easy and rapid procedure and may be more widely applicable than highly selective vagotomy.

Plain abdominal radiographs and acute abdominal pain.

The records of all (5080) patients presenting to a district general hospital with acute abdominal pain over a 4-year period were examined. The contribution of abdominal radiographs to the assessment of patients with suspected appendicitis, urinary tract infection, and non-specific abdominal pain was evaluated, these conditions accounting for 48 per cent of patients with abdominal pain and 32 per cent of those with abdominal radiographs. Any positive information from these radiographs was less likely to be helpful than incidental or inconsistent (and hence potentially misleading). Because of this high 'false positive' rate it is suggested that if the initial diagnosis is suspected appendicitis, urinary tract infection, or non-specific abdominal pain, there is little value in the routine use of abdominal radiographs.

Prediction of choledocholithiasis using a pocket microcomputer.

A computerized method, using a small pocket computer, has been used to predict the presence of choledocholithiasis in a prospective series of 239 patients undergoing cholecystectomy. From an initial data base of 424 patients 36 factors were evaluated and the most important 2 of these were determined by multivariate analysis for use in the prospective analysis. Satisfactory operative cholangiograms were a prerequisite to evaluation of the statistical method and were obtained in 90.4 per cent of cases. Using the computerized method a common bile duct stone would have been overlooked in only 1 patient but 17 unnecessary explorations would have been carried out. The overall accuracy of the computerized method was 92.5 per cent. When the method was applied to a further study of 97 patients from a separate centre the overall accuracy was 85.6 per cent. If the method was used to aid selective use of operative cholangiography, cholangiograms would be performed in 20 per cent and stones would be overlooked in less than 1 per cent.

Audit of surgical audit.

A clinical audit, run by surgeons with modest clerical assistance, has been incorporated into the routine clinical practice of all hospitals in a large health authority. Data on operations and deaths are integrated into routine clinical recording, and feedback is by annual report containing statistical analyses and critical commentaries and by discussions with colleagues. The results of the first five years show statistically significant falls in the number of reoperations for intra-abdominal complications, retained gallstones, arterial grafts, and amputations and in operative mortality following surgery for benign biliary and pancreatic disease, resection of large bowel for benign disease, operations on aortic aneurysms, and arterial grafts except for aneurysms. Although the audit was designed originally for monitoring and improving quality of care, other uses include monitoring of increasing specialisation and changes in clinical practice, planning surgical services and postgraduate training, and showing the effects of changes in the availability of resources.

Mortality and morbidity after anterior lesser curve seromyotomy with posterior truncal vagotomy for duodenal ulcer.

A survey has been performed of the mortality and morbidity of anterior lesser curve seromyotomy with posterior truncal vagotomy in the elective treatment of chronic duodenal ulcer. There was one death in a series of 605 patients due to a myocardial infarction, an operative mortality of 0.16 per cent. There was no case of ischaemic necrosis of the lesser curvature or fundus of the stomach. Eleven patients had symptoms of delayed gastric emptying (1.7 per cent) and seven of these underwent a drainage procedure (1.3 per cent). Postoperative dumping did not occur, significant diarrhoea was present in two patients (0.33 per cent). This operation is relatively simple, quick and extremely safe to perform. It is suggested that the more widespread use of this type of elective surgery for duodenal ulcer might reduce the mortality from the condition.