Laboratory evaluation of sample collection methods (organs vs swabs) for Tasmanian salmon reovirus detection in farmed Atlantic salmon, Salmo salar L

The use of swabs relative to organs as a sample collection method for the detection of Tasmanian salmon reovirus (TSRV) in farmed Tasmanian Atlantic salmon, Salmo salar L., was evaluated by RT-qPCR. Evaluation of individual and pooled sample collection (organs vs swabs) was carried out to determine the sensitivity of the collection methods and the effect of pooling of samples for the detection of TSRV. Detection of TSRV in individual samples was as sensitive when organs were sampled compared to swabs, and in pooled samples, organs demonstrated a sensitivity of one 10-fold dilution higher than sampling of pooled swabs. Storage of swabs at 4 °C for t = 24 h demonstrated results similar to those at t = 0. Advantages of using swabs as a preferred sample collection method for the detection of TSRV compared to organ samples are evident from these experimental trials.

The GoodNEWS (Genes, Nutrition, Exercise, Wellness, and Spiritual Growth) Trial: a community-based participatory research (CBPR) trial with African-American church congregations for reducing cardiovascular disease risk factors--recruitment, measurement, and randomization

INTRODUCTION

Although cardiovascular diseases (CVD) are the leading cause of death among Americans, significant disparities persist in CVD prevalence, morbidity, and mortality based on race and ethnicity. However, few studies have examined risk factor reduction among the poor and ethnic minorities.

METHODS

Community-based participatory research (CBPR) study using a cluster randomized design--African-American church congregations are the units of randomization and individuals within the congregations are the units of analysis. Outcome variables include dietary change (Diet History Questionnaire), level of physical activity (7-Day Physical Activity Recall), lipoprotein levels, blood pressure, fasting glucose, and hemoglobin A1c.

RESULTS

Eighteen (18) church congregations were randomized to either a health maintenance intervention or a control condition. Complete data were obtained on 392 African-American individuals, 18 to 70 years of age, predominantly employed women with more than a high school diploma. Treatment and intervention groups were similar at baseline on saturated fat intake, metabolic equivalent of tasks (METS) per day, and other risk factors for CVD.

CONCLUSIONS

The GoodNEWS trial successfully recruited and evaluated CVD-related risk among African-American participants using a CBPR approach. Several logistical challenges resulted in extending the recruitment, preliminary training, and measurement periods. The challenges were overcome with the assistance of a local community consultant and a professional event planner. Our experience supports the need for incorporating non-traditional community-based staff into the design and operational plan of CBPR trials.

Physical characterisation of Tenacibaculum maritimum for vaccine development

AIMS

Tenacibaculum maritimum is a well known fish pathogen worldwide, affecting many fish species including Atlantic salmon in Tasmania, Australia. The aim of this study was to characterise and understand the similarities and differences between the isolates in order to select isolates for later pathogenicity and vaccination trials.

METHODS AND RESULTS

Several physical characterisation tests were carried out: whole cell protein profiles, lipopolysaccharide profiles (LPS), extracellular product profiles (ECP), indirect immunofluorescent antibody test (IFAT) and hydrophobicity. The Tasmanian strains of T. maritimum appear relatively homogeneous physically, but antigenically different. All isolates were hydrophobic and produce a variety of ECP profiles. There were two isolates that stand out in all assays (89/4747 and 01/0356-7) and showed great variation from the other isolates. All isolates have been confirmed as T. maritimum.

CONCLUSIONS

Based on the tests carried out three isolates were chosen for in vivo trials: 89/4747, 89/4762, 00/3280.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to characterise T. maritimum isolates from Tasmanian waters. The opportunity to develop vaccines for the Tasmanian salmonid aquaculture industry is enhanced by a greater understanding of the physical characteristics of pathogens.

Assessing Analytical Variability of Measurement of Vitamin A in Corn-Soy Blend

Two multilaboratory investigations were conducted by SUSTAIN to assess variability in the measurement of vitamin A, the marker used to verify levels of vitamin premix addition to enriched/fortified food aid products, including the widely distributed corn-soy blend (CSB). CSB specifications identify AACC Approved Method 86-06 or equivalent methods for vitamin A analysis, however there is no requirement to demonstrate equivalency. CSB samples with known and blinded levels of vitamin A and a reference standard were analyzed by 16 laboratories using their respective methods. Calculated coefficients of variation across all laboratories and methods for unknown samples and reference standard were 35 and 7.1, respectively, suggesting the largest source of variation is the vitamin extraction procedure. Laboratories generally overestimated low levels and underestimated high levels of vitamin A within the range of 6000 and 16 000 IU/lb. Only two laboratories demonstrated excellent internal precision (300 IU vitamin A/lb) and reported values within 95 confidence interval for all blinded samples. Results of this study have implications both for quality control in food aid products (due to the use of vitamin A as a marker) and for regulatory oversight of vitamin A content in commercial food products.

Assessing analytical variability of measurement of vitamin A in corn-soy blend

Two multilaboratory investigations were conducted by SUSTAIN to assess variability in the measurement of vitamin A, the marker used to verify levels of vitamin premix addition to enriched/fortified food aid products, including the widely distributed corn-soy blend (CSB). CSB specifications identify AACC Approved Method 86-06 or equivalent methods for vitamin A analysis, however there is no requirement to demonstrate equivalency. CSB samples with known and blinded levels of vitamin A and a reference standard were analyzed by 16 laboratories using their respective methods. Calculated coefficients of variation across all laboratories and methods for unknown samples and reference standard were 35 and 7.1%, respectively, suggesting the largest source of variation is the vitamin extraction procedure. Laboratories generally overestimated low levels and underestimated high levels of vitamin A within the range of 6000 and 16 000 IU/lb. Only two laboratories demonstrated excellent internal precision (+/- 300 IU vitamin A/lb) and reported values within 95% confidence interval for all blinded samples. Results of this study have implications both for quality control in food aid products (due to the use of vitamin A as a marker) and for regulatory oversight of vitamin A content in commercial food products.

An outbreak of tuberculosis affecting cattle and people on an Irish dairy farm, following the consumption of raw milk

Bovine tuberculosis is an ongoing problem in Ireland, and herd incidence has remained at approximately 5% for some years. Spillover of infection from cattle to people remains an ever-present possibility, given the ongoing pool of infection in the Irish cattle population. This paper describes an outbreak of tuberculosis affecting cattle and people on a dairy farm in southeastern Ireland following the consumption of milk from a seven-year-old cow with tuberculous mastitis. Twenty-five of 28 calves born during autumn 2004 and spring 2005 were subsequently identified as TB reactors, and five of six family members were positive on the Mantoux test. During 2005, milk from this cow had mainly been used to feed calves, and was added only occasionally to the bulk tank. Therefore, the calves each received infected milk on an almost continuous basis between birth and weaning. The family collected milk from the bulk milk tank, and consumed it without pasteurisation. This case highlights the risks associated with the consumption of raw milk. In this family, TB has had a very significant impact on the health of two young children. These risks are well recognised, and relevant information for farmers is available. It is of concern, therefore, that raw milk consumption remains prevalent on Irish farms. New strategies are needed, in partnership with industry, to address this important issue. Keywords: bovine tuberculosis, Ireland, mastitis, milk, Mycobacterium bovis, pasteurisation, TB, zoonosis

The evaluation of human papillomavirus genotyping in cervical liquid-based cytology specimens; using the Roche Linear Array HPV genotyping assay

OBJECTIVE

To ascertain the usefulness of the Roche Linear Array human papillomavirus (HPV) genotyping assay for assessing HPV genotypes in liquid-based cytology (LBC) samples and to evaluate this methodology within a cytopathology laboratory. These tests are of importance as persistent infection with high-risk HPV genotypes is considered a causal factor in the development of cervical cancer.

METHODS

A total of 175 cervical LBC samples were tested using the Roche Linear Array HPV genotyping test. The suitability of the assay use in routine cytopathology laboratory was considered. HPV genotypes were matched to the cervical cytology results, which included negative, borderline nuclear abnormalities, mild, moderate and severe dyskaryosis.

RESULTS

The assay could be applied to screening samples with the combined result available at the reporting stage. There were no test failures. All samples used after cytological analysis had sufficient DNA for testing. The results were reproducible and easily read and there was concordance of results between biomedical scientists. The results of the assay showed co-infection with multiple HPV genotypes was common in both high-grade and low-grade cytology samples. The percentage of HPV+ samples in the normal cytology samples (although in this grouping the number of samples was low) was 37%. In the cytology samples reported as severe dyskaryosis the HPV genotypes most commonly found were HPV16 and HPV51.

CONCLUSION

The assay was able to detect multiple HPV infection with a wide range of genotypes in LBC samples sent for routine cytological analysis. It would be suitable for use in a cytopathology laboratory. The results of the assay show that the genotype profile has some variation from other geographical regions, and more work is needed to determine population prevalence, to ascertain the impact of the HPV vaccine, to evaluate test for cure and HPV triage management.

Surgical treatment of malignant carcinoid tumours of the appendix

Since their first description in 1882, malignant neoplasms of the appendix still remain rare. Malignant carcinoid tumours are the most common accounting for 85% of all appendiceal neoplasms. Preoperative diagnosis is invariably difficult, and precise treatment protocols for these neoplasms remain unclear. We reviewed our experience and searched published evidence to produce management guidelines. A retrospective review of all malignant carcinoid tumours diagnosed in our hospital between April 1994 and December 2003 was performed. Patient demographics, operative details, histological types and clinical outcomes were retrieved from case notes supplemented by a questionnaire to the patient's General Practitioner. A literature search was then performed. Nine patients were identified with classical carcinoid tumours (CCT); (M = 3 and F = 6, mean age: 43, range 14-81) and two patients with goblet-cell morphology (F = 2, age 46 and 76). Mean follow-up was 63 months (range 1-125 months). Nine patients were alive at the end of follow-up. Appendicectomy was performed for acute appendicitis. Other appendiceal pathologies were identified following hemicolectomy and oophorectomy. CCT are the most common tumours and have the better prognosis. From our experience and subsequent review of the literature, we recommend right hemicolectomy as the treatment of choice for malignant carcinoid tumours. However, small CCTs less than 2 cm in diameter at the tip of the appendix, with a low proliferative index, without angiolymphatic or mesoappendiceal extension can be treated by appendicectomy. Following oncological assessment, further adjuvant therapy should be considered for patients with advanced disease.

Changes to the phenotypic profile of Vibrio harveyi when infected with the Vibrio harveyi myovirus-like (VHML) bacteriophage

AIMS

To determine if infection of Vibrio harveyi with the V. harveyi myovirus-like (VHML) bacteriophage causes a change to the phenotypic profile of this species.

METHODS AND RESULTS

Using 46 biochemical and metabolic tests, phenotypic profiles for noninfected V. harveyi and VHML infected V. harveyi were developed. Comparison of the infected and bacteriophage-infected strains of V. harveyi 645, 20 and 45 were found to have different test results for d-gluconate utilization, gamma-glutamyl transpeptidase and sulfatase activity, respectively. Using probabilistic identification, VHML infected and noninfected strains were identified as V. harveyi and had similar Willcox probability scores though the modal likelihood scores were reduced for VHML infected strains. One VHML infected strain, 642b, was misidentified as V. campbellii by phenotyping but not by PCR. It would appear that the phenotype of V. harveyi strains infected with VHML, are sufficiently altered that they occur at the margins of the known range of strain variation for V. harveyi.

CONCLUSION

Infection of V. harveyi with VHML causes the phenotypic profile of the bacterium to change. This change reduces the modal likelihood score resulting in a poorer level of assurance for an identification of V. harveyi, especially in the natural host, strain 642. The bacteriophage VHML integrates into different sites in different strains of V. harveyi.

SIGNIFICANCE AND IMPACT OF THE STUDY

The identification of V. harveyi as the causative agent of mortality in aquatic organisms is predominantly achieved through phenotyping. Since bacteriophages alter virulence in V. harveyi, understanding the effect they have on phenotype is important.

Standardization of a broth microdilution susceptibility testing method to determine minimum inhibitory concentrations of aquatic bacteria

A multiple laboratory study was conducted in accordance with the standards established by the Clinical and Laboratory Standards Institute (CLSI), formerly the National Committee for Clinical Laboratory Standards (NCCLS), for the development of quality control (QC) ranges using dilution antimicrobial susceptibility testing methods for bacterial isolates from aquatic animal species. QC ranges were established for Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp. salmonicida ATCC 33658 when testing at 22, 28 and 35 degrees C (E. coli only) for 10 different antimicrobial agents (ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, ormetoprim/sulfadimethoxine, oxolinic acid, oxytetracycline and trimethoprim/sulfamethoxazole). Minimum inhibitory concentration (MIC) QC ranges were determined using dry- and frozen-form 96-well plates and cation-adjusted Mueller-Hinton broth. These QC ranges were accepted by the CLSI/NCCLS Subcommittee on Veterinary Antimicrobial Susceptibility Testing in January 2004. This broth microdilution testing method represents the first standardized method for determining MICs of bacterial isolates whose preferred growth temperatures are below 35 degrees C. Methods and QC ranges defined in this study will enable aquatic animal disease researchers to reliably compare quantitative susceptibility testing data between laboratories, and will be used to ensure both precision and inter-laboratory harmonization.

Residues of spinosad in the tissues of sheep after aerosol treatment of blowfly myiasis

OBJECTIVE

To measure the residues of spinosad and chlorhexidine in the tissues of sheep after treatment of blowfly strike.

PROCEDURE

Fourteen sheep with natural myiasis and 12 with artificial infestations of Lucilia cuprina larvae had the wool removed over their infestations and were treated with an aerosol wound dressing containing spinosad and chlorhexidine. Sheep were killed up to 14 days after treatment and residues of the chemicals measured in tissues.

RESULTS

Chlorhexidine was not detected in any tissue. Residues of spinosad were highest in fat, lowest in muscle and intermediate in liver and kidney. The highest residue detected was 0.2 mg/kg spinosad in perirenal fat 7 days after generous treatment of a sheep with a large fly strike. Residues of spinosad in fat peaked 3 to 7 days after treatment and 1 to 3 days after treatment in liver and kidney.

CONCLUSION

These studies present a realistic worst-case in struck sheep and at the highest dose studied, equivalent to 5.8 mg spinosad per kg body weight, the maximum residue detected of 0.2 mg/kg in peri-renal fat was 20% of the Australian maximum residue limit. Muscle, liver and kidney residues of spinosad were also below the Australian maximum residue limits at all times.