Detection of Ureaplasma diversum in the upper airways of Australian feedlot cattle.

Bovine respiratory disease (BRD) exerts a major impact on the beef cattle industry nationally and worldwide, with a range of aetiological factors impacting its pathogenesis. Previous research has focussed on an increasing number of bacteria and viruses that have been shown to play a role in eliciting disease. Recently, additional agents have been emerging as potential contributors to BRD, including the opportunistic pathogen Ureaplasma diversum. To determine if U. diversum was present in Australian feedlot cattle and if that presence was linked to BRD, nasal swabs were collected from a cohort of 34 hospital pen animals and compared to 216 apparently healthy animals sampled contemporaneously at feedlot induction and again after 14 days on feed at an Australian feedlot. All samples were subjected to a de novo polymerase chain reaction (PCR) assay targeting U. diversum in combination with other BRD agents. U. diversum was detected at a low prevalence in cattle at induction (Day 0: 6.9%, Day 14: 9.7%), but in a significantly greater proportion of cattle sampled from the hospital pen (58.8%). When considering the presence of other BRD-associated agents, co-detection of U. diversum and Mycoplasma bovis was most common in hospital pen animals receiving treatment for BRD. These findings suggest that U. diversum may be an opportunistic pathogen involved in the aetiology of BRD in Australian feedlot cattle, in combination with other agents, with further studies are warranted to identify if a causal relationship exists.

Efficiency-corrected PCR quantification for identification of prevalence and load of respiratory disease-causing agents in feedlot cattle.

Bovine respiratory disease (BRD) is the most prevalent disease in feedlot cattle worldwide with Bovine alphaherpesvirus 1 (BoAHV1), Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis, Pasteurella multocida and Trueperella pyogenes accepted to be common etiological agents associated with BRD. Although these agents are common in the upper and lower airways in clinical BRD cases, some also exist as normal flora suggesting their presence in the upper airways alone is not necessarily informative with respect to disease status or risk. To determine the relationship between presence, load and disease status, we investigated the relationship between load in the upper airways at induction and active BRD cases in feedlot cattle using efficiency-corrected PCR quantification. By this approach, we were able to accurately determine the prevalence and load of the key BRD agents in the upper respiratory tract showing that cattle in the hospital pen had a higher prevalence, and load, of these agents both singly and in combination compared to cattle sampled at feedlot induction. A combination of agents was the most accurate indicator of BRD risk with cattle with four or more agents detected in the upper airway more likely to be undergoing treatment for BRD than non-BRD ailments. In addition, M. bovis was rarely detected at feedlot induction but was identified at high prevalence in cattle in the hospital pen. These findings present a potential new technological approach for the investigation, analysis and identification of BRD-associated viral and bacterial agents for Australian feedlot systems as well as for BRD disease management and treatment.

We need to pay heed to the psychosocial aspects of strabismus.

Adult strabismus surgery has long been regarded as cosmetic. This paper summarises the current evidence that this statement should be discarded. The evidence shows that strabismus surgery in non-diplopic adult patients can be beneficial in both functional and psychological situations. It is suggested that the term cosmetic would be better replaced by reconstructive.

Detection of Aphanomyces invadans and epizootic ulcerative syndrome in the Murray-Darling drainage.

Epizootic ulcerative syndrome was diagnosed, and the presence of Aphanomyces invadans confirmed, from an outbreak of clinical disease in wild-caught bony bream (Nematalosa erebi) from the Darling River near Bourke, in New South Wales, Australia, during 2008. This confirms a significant extension of the agent beyond its historical range.

Superior oblique tuck: its success as a single muscle treatment for selected cases of superior oblique palsy.

PURPOSE: To investigate the results of superior oblique tuck (SOT) for selected cases of superior oblique palsy (SOP) over a 17-year period. The results were correlated by correction of deviation; re-operation rates; rates of iatrogenic Brown's syndrome; and finally, correlation between tuck size and deviation change. Any differences between the results for congenital and acquired SOP are reported. METHODS: A retrospective, cohort study of adults with SOP-with diplopia greatest in the area of action of the paretic superior oblique-who underwent SOT between 1992 and 2009. Pre-, intra- and postoperative measurements were collected. Vertical and torsional measurements in both primary position and area of maximal deviation were analyzed. Intraoperative tuck size was measured and correlated to effect. RESULTS: We report 75 cases of isolated SOT with a mean follow-up of 8.6 months. Significant improvement in deviation in all positions measured was shown (P<0.0001 for all). Twenty-two (29.3%) cases underwent further procedures due to residual diplopia. There were no intraoperative complications. Brown's syndrome was demonstrated using a Lees screen in 10 cases but none of these were symptomatic. No patients required tuck revision. There was no correlation between tuck size and changes in either vertical or torsional deviations. 42 (56%) had acquired SOP with no significant differences in pre- or postoperative measurements to congenital cases. CONCLUSIONS: This is the largest series of SOTs reported with 71% of cases having successful outcome with the one surgical procedure. There are significant improvements in the postoperative measurements for both vertical deviation and torsion. 29.3% of cases required a further procedure consisting mainly of contralateral inferior rectus weakening although ipsilateral inferior oblique weakening was also performed. Because of the lack of correlation between tuck size and correction obtained, we would suggest that SOT should be considered as "one tightness fits all" rather than "one size fits all."

Isolation of Mycobacterium avium subspecies paratuberculosis from muscle and peripheral lymph nodes using acid-pepsin digest prior to BACTEC culture.

Meat has received little attention regarding human exposure to Mycobacterium avium subsp. paratuberculosis, a possible infectious trigger of Crohn's disease. Meat has less contamination with other organisms than gut tissues, facilitating modifications to existing decontamination protocols prior to BACTEC culture that could increase analytical sensitivity. Using spiked meat samples we trialled enzymatic and chemical digestion techniques to concentrate larger starting samples, and modifications to existing clinical mycobacteriological decontamination protocols. An acid-pepsin digestion method using a 20 g sample was considerably more sensitive (detection limit 0.88 log(10) viable organisms per gram) than previous techniques. However, it was cumbersome for routine use, and subject to frequent contamination. Modifications to an existing centrifugation protocol yielded a simple, robust technique with slightly improved sensitivity (detection limit 1.77 log(10) per gram). Use of these sensitive tests in parallel identified M. a. paratuberculosis in the muscle of 59% and peripheral lymph nodes (PLN) of 85% of clinically infected sheep. The numbers of M. a. paratuberculosis in these infected tissues were low (1.67+/-0.92 log(10) per gram in muscle and 2.06+/-0.69 log(10) per gram in PLN), such that many would not have been detected by routine methods. Fewer subclinically infected animals with gross lesions harboured M. a. paratuberculosis in meat (4.5%) or PLN (32%), and the numbers of organisms in such infected animals were lower. Because most animals raised specifically for meat production are young and unlikely to be heavily infected, and because meat is usually consumed cooked, the risk of human exposure to viable M. a. paratuberculosis via meat may be small. Measures to prevent heavily infected animals, especially those with clinical signs, from entering the human food chain would further reduce this risk.

Use of Frost sutures in an orbital trauma patient with extensive conjunctival oedema and pseudoproptosis.

Frost sutures are temporary suspension sutures conventionally used in oculoplastics. The case is presented here of a patient with multiple orbital fractures who developed worsening conjunctival chemosis and pseudoproptosis. This patient was managed successfully with Frost sutures. To the best of the authors' knowledge, there is no documented use of Frost sutures in this type of case. It is emphasized that this technique should only be considered following rigorous exclusion of retrobulbar pathology and careful attention towards early detection of raised intraocular pressure.

Genomic diversity in Mycobacterium avium: single nucleotide polymorphisms between the S and C strains of M. avium subsp. paratuberculosis and with M. a. avium.

Following identification of large genomic polymorphisms in a previous study, a polymerase chain reaction and sequencing strategy was used to identify single nucleotide polymorphisms (SNPs) in 25 genes in the sheep (S) and cattle (C) strains of Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) and between M. a. paratuberculosis and M. a. avium. From 12,117 bp of sequence representing 26 loci across 25 genes, 11 SNPs were identified between the S and C strains in eight genes: hsp65, sodA, dnaA, dnaN, recF, gyrB, inhA, and pks8. An in silico comparison of these M. a. paratuberculosis sequences and the M. a. avium 104 genome revealed 86 SNPs, which corresponded well with similar studies of SNPs in the M. avium complex.

Deletion of an mmpL gene and multiple associated genes from the genome of the S strain of Mycobacterium avium subsp. paratuberculosis identified by representational difference analysis and in silico analysis.

Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) can be divided into two major strains, sheep (S) and cattle (C), based on cultural requirements, host specificity, degree of clumping of cells in suspension and minor genomic differences including copy number of insertion elements and point mutations. Representational difference analysis (RDA) with S strain as driver and C strain as tester was used to identify unique genomic regions. Three sequences (RDA1, RDA3 and RDA4) were identified. RDA1 (229bp) contained a single base difference between S and C strains. RDA4 (163bp) was an artefact. RDA3 (206bp) was similar to several sequences in the incomplete genome sequences of M. avium subsp. paratuberculosis K10 and M. avium subsp. avium 104. In silico analysis led to the identification of a deletion that may be as large as 17kb in the sheep strain of M. a. paratuberculosis. PCR analysis of this region confirmed the deletion of 11,584bp that included 10 genes (MAP1734 to MAP1743c) of the M. a. paratuberculosis K10 genome. This included the loss of mmpL5 and mmpS5 genes and homologues of the M. tuberculosis genes: Rv2002 (fabG3), Rv2017c (lipW), Rv3132c (devS), Rv2032 (acg) and the conserved hypothetical genes Rv2005c and Rv2026c. PCR reactions designed to detect the single nucleotide polymorphism in RDA1 and the deletion in the mmpL region can be used to distinguish these strains. MmpL genes, found in M. tuberculosis and other mycobacteria are part of the resistance-nodulation-division (RND) family but contain domains unique to mycobacteria thought to play a role in cell wall biogenesis, virulence and other phenotypic characteristics. Absence of mmpL5 in the S strain of M. a. paratuberculosis is unlikely to account for the difference in clumping in suspension but may explain the difference in cultural requirements and host specificity compared to the C strain but the impact of the remainder of the deletion is yet to be ascertained.

Strabismus surgery: adjustable sutures-good for all?

AIMS: The role of adjustable sutures in strabismus surgery has mainly been limited to conditions like dysthyroid restrictive myopathy, blow-out fractures of orbit, aberrant regeneration of nerves, and certain other long-standing and complicated squints. In this clinical study, an attempt has been made to analyse the efficacy of adjustable sutures in squint surgery as a routine procedure. We also studied patients' acceptability and satisfaction following this procedure and analysed various factors that may influence the surgical outcome (age, sex, previous surgeries, injections of botulinum toxin, etc). METHODS: A total number of 443 patients, aged between 13 and 78 years, who underwent strabismus surgery in our department, from January 1996 to January 2000, were included in this study. Of these patients, 141 had surgery with adjustable sutures and 302 patients without adjustable sutures. Surgical results were followed up for a period ranging from 12 to 50 months. The main outcome measure was a need for a reoperation in the two groups. In addition, we also studied patients' satisfaction with regard to final cosmetic appearance or relief of diplopia; percentage change in angle of deviation in two groups, and influence of various factors such as age, sex, previous surgeries, and injection of botulinum toxin on the final surgical outcome. The results were statistically analysed using Levene's test for equality of variances, t-test for equality of means, and statistical significance of the results was analysed by calculating P-values. RESULTS: In total, 8.51% of the patients in the adjustable group and 27.15% in the nonadjustable group needed a reoperation. Surgical results were found to be significantly better in patients who had adjustable sutures in comparison to those who did not have adjustable sutures (P<0.005). Patients' satisfaction and percentage change in angle of deviation was also much higher in adjustable sutures group. Age, sex, number of previous surgeries, previous injections of botulinum toxin, and type and amount of deviation had no statistically significant influence on the surgical outcome. CONCLUSIONS: Strabismus surgery with adjustable sutures has a statistically significant better, final result than surgery without adjustable sutures. Patients' satisfaction and percentage change in angle of deviation is also much higher in the adjustable sutures group. As age, sex, number of previous surgeries, previous injections of botulinum toxin, and type and amount of deviation do not influence the final outcome, this type of surgery can be performed in virtually all types of patients.

Visual complications of proton beam therapy for clival chordoma.

PURPOSE: Combining maximal surgical resection with high-dose proton radiation therapy is reported to be currently the best management of patients with clival chordoma. METHOD: Since 1991, four consecutive patients from our institution with this tumour have been referred for postoperative proton beam radiotherapy. RESULT: We have experienced an unusually high complication rate (50%) of delayed radiation optic neuropathy. This has resulted in profound, bilateral visual loss at 1 and 2 years postproton beam treatment. CONCLUSION: It has served as a reminder that proton beam therapy is not an innocuous treatment option and this devastating complication should be taken into account when discussing the management of clivus chordoma. We postulate whether the optic apparatus is particularly sensitive to proton vs photon damage.

Isolation of Mycobacterium avium subsp paratuberculosis from environmental samples collected from farms before and after destocking sheep with paratuberculosis.

OBJECTIVE: To determine whether Mycobacterium avium subsp paratuberculosis could be isolated from soil-pasture, faecal, water and sediment samples on farms before and after removal of sheep with paratuberculosis. A feasibility study and subsequent field survey. PROCEDURE: First the analytical sensitivity of radiometric culture of the organism from two types of soil was determined relative to faeces. Then soil-pasture, faecal, water and sediment samples were collected for culture from a range of sites from 6 farms with paratuberculosis affected sheep and goats. Similar samples were collected from 20 farms at least 9 months after removal of infected stock. RESULTS: The analytical sensitivity of culture of M a paratuberculosis from soil samples was 2 orders of magnitude less than that from faeces, and environmental samples required longer incubation periods to yield significant growth in radiometric culture (BACTEC) medium. However, the organism was recovered from approximately 20% of 163 soil-pasture, water and sediment samples from 6 properties with clinically-affected animals with paratuberculosis. The positive samples were from a range of topographic sites, including open exposed and dry areas, however, low lying areas tended to have larger numbers of organisms. When the same sites were sampled again about 5 months later, only 1 was culture positive, and none were culture positive > 12 months later. Of 17 water and dam sediment samples collected from farm 6, which had long-standing high prevalence OJD infection, only one water sample and one sediment from the same dam were culture positive. None of the 5 water samples from the other farms were culture positive. Of 96 water samples, 90 sediment samples and 93 soil samples from farms that had been destocked of infected sheep/goats for 9 to 24 months, one sediment sample from a farm in Victoria (destocked for 12 months) and two sediment samples from a farm in New South Wales (10, 19 months) were culture positive. Recontamination from cattle or water could not be excluded as a cause of the positive cultures from the second farm. CONCLUSION: M a paratuberculosis can be detected by radiometric culture in environmental samples from farms grazed by sheep or goats with paratuberculosis. There is a relatively low likelihood of recovery of the organism from water samples from such farms, and at 5 or more months after removing stock with paratuberculosis the likelihood of positive cultures from environmental samples is very low. Although the analytical sensitivity of culture from environmental samples is less than that from faeces, surveys of environmental sites are nevertheless feasible. However, improved culture methods are needed for critical surveys and to study the movement and fate of the organism in the environment.

Rapid differentiation of Australian, European and American ranaviruses based on variation in major capsid protein gene sequence.

Epizootic haematopoietic necrosis virus (EHNV), Bohle iridovirus (BIV) and Wamena virus (WV) cause serious diseases in fish, amphibians and snakes, respectively but are restricted to Australasia. European catfish virus (ECV) and sheatfish virus (ESV) have caused epizootics in fish on farms in continental Europe. Currently there are no simple or readily available methods to distinguish these viruses, which are in the Iridoviridae. They are culturally, morphologically and antigenically very similar to Frog Virus 3 (FV3), the type species in Ranavirus in this family and Gutapo virus (GV), another amphibian ranavirus from America. The diseases caused by EHNV, ESV and ECV are so serious that they are internationally notifiable. Tests to distinguish these viruses are desirable to ensure that disease occurrences do not unnecessarily restrict trade in aquaculture products. The gene encoding the major capsid protein from two EHNV isolates from different fish species (Perca fluviatilis and Oncorhynchus mykiss) and one BIV isolate were sequenced and the data and deduced amino acid sequences were compared with those from FV3 and other iridoviruses. The sequences for the two EHNV isolates were identical, confirming suggestions from existing partial MCP sequence that the same type of EHNV infects wild redfin perch and farmed rainbow trout. Differences in restriction endonuclease patterns of specific PCR products were predicted and confirmed between EHNV, BIV, and WV and provided a basis for rapid differentiation of these viruses from each other and from ESV/ECV and FV3/GV. These simple and rapid tests to distinguish important ranaviruses from the regions of Europe, Australia and America will help regulatory authorities assess the need for disease control responses in the event of occurrence of ranavirus infection in aquaculture species.