Flystrike in New Zealand: An overview based on a 16-year study, following the introduction and dispersal of the Australian sheep blowfly, Lucilia cuprina Wiedemann (Diptera: Calliphoridae)

A summary and analysis have been carried out on data from over 6000 instances of flystrike in sheep in NZ, over a 16-year period, using a self-referral system where farmers submitted larvae and related information. The study covered a period of establishment and subsequent countrywide spread of the exotic blowfly, Lucilia cuprina. Comparisons are drawn between flystrike as it was perceived by surveys carried out before the 1940s, and the current situation with L. cuprina as an added major impediment. Briefly, the main differences are an increase in the prevalence of flystrike, changes in the representation and relative influence of individual primary blowfly species, an extension of the flystrike 'season', and an apparent increase in the importance of footrot as a factor predisposing to flystrike. Otherwise, flystrike is still primarily a disease of ewe lambs that are struck predominantly around the tail and perineum, mainly because of faecal staining.     

Genotyping of Toll-like receptor 4, myeloid differentiation factor 2 and CD-14 in the horse: an investigation into the influence of genetic polymorphisms on the LPS induced TNF-alpha response in equine whole blood

The inter- and intra-species differences in the response to lipopolysaccharides (LPS) are well recognised in mammalian species. It has been hypothesized that these differences can be attributed to genetic polymorphisms in the components involved in LPS signal transduction. These components include the cluster of differentiation factor 14 (CD-14), a membrane bound protein on the surface of mononuclear cells that recognises LPS and a receptor complex consisting of Toll-like receptor-4 (TLR-4) and myeloid differentiation factor-2 (MD-2). Sequencing of these three proteins in humans and mice revealed that all three are susceptible to polymorphic alterations, influencing the response to LPS. Previous experiments in the horse showed large inter-individual variations in the response to LPS. With the aim to assess this inter-individual variation, we performed a whole blood assay in 10 healthy horses as a functional assay to study the responsiveness to LPS. In 3 out of the 10 horses, LPS-induced TNF-alpha production was significantly lower compared to the overall mean. Subsequently the entire cDNA sequence encoding for the TLR-4, MD-2 and CD-14 protein was documented for each horse. Although mutations were observed in the sequence of TLR-4, these could not be related to an altered response to LPS in the concentration used in this study, as determined in the whole blood assay. Despite the various mutations found in the TLR-4 receptor protein, no alterations could be found in either the MD-2 or CD-14 gene, which are obviously more conserved structures.     

Canine limbal melanoma: 30 cases (1992-2004). Part 1. Signalment, clinical and histological features and pedigree analysis

OBJECTIVES: (1) To review the signalment, clinical, and histological features of canine limbal melanoma; (2) to perform pedigree analysis on breeds predisposed to limbal melanoma to establish if common ancestry exists; and (3) to investigate if any ancestral relationship exists between canine limbal melanoma and canine anterior uveal melanoma (CAUM). DESIGN: Retrospective study. ANIMALS STUDIED: Thirty dogs with limbal melanoma. METHODS: Medical records of patients were reviewed. Follow-up information was obtained by re-examination of patients or telecommunications with the referring veterinary surgeons or the owners. Pedigrees were analyzed for common ancestry amongst affected dogs. RESULTS The mean age (+/- SD) at diagnosis was 6.2 (+/- 2.75) years with a range from 1 to 11 years. There was a bimodal distribution of ages with a peak at 3-4 years and a peak at 7-10 years. There was no eye predilection or predisposition for sex or coat color. Twenty-five (83%) of the limbal melanomas occurred within a dorsal arc from the dorsomedial to the ventrolateral limbus. Golden retrievers were four times more common in the melanoma group compared to the Animal Health Trust population (P < 0.0001). Labrador retrievers were three times more common in the melanoma group (P=0.01). Pedigree analysis on eight Golden retrievers [limbal melanoma (n=5), CAUM (n=2) and diffuse ocular melanosis (n=1)], revealed a pattern of inter-relatedness consistent with the condition(s) being caused, at least in part, by a genetic mutation(s). A similar level of inter relatedness was evident in six Labrador retrievers (limbal melanoma (n=2) and CAUM (n=4)). In 5/22 cases (23%), histological features suggestive of malignancy were present including intratumor necrosis in 4/22 cases (18%) and cellular atypia in 1/22 cases (5%). CONCLUSIONS: In Golden and Labrador retrievers there is evidence that limbal melanomas, CAUM and ocular melanosis are at least in part heritable and that the same genetic mutation(s) may be causally associated with melanocytic disease at different ocular sites. The same genetic mutation(s) may be present in these two breeds. Histology should be performed on all cases to identify those with greater malignant potential.     

Preliminary pharmacokinetics and cardiovascular effects of fenoldopam continuous rate infusion in six healthy dogs

Fenoldopam is a selective dopamine-1 receptor agonist that causes peripheral arterial vasodilation, increased renal blood flow, and diuresis. Enthusiasm exists for the use of fenoldopam in nonpolyuric kidney injury in dogs, although pharmacokinetic data are lacking. The purpose of this study was to collect basic pharmacokinetic and hemodynamic effect data for fenoldopam when administered to healthy awake dogs. Six healthy, awake beagles were given a 180-min fenoldopam constant rate infusion at 0.8 μg/kg per minute followed by a 120-min washout period. Citrated blood was collected during and after infusion for the measurement of plasma fenoldopam concentration by HPLC with mass spectrometry. Heart rate and indirect systolic blood pressure were concurrently measured. Mean ± SD, steady-state plasma fenoldopam concentrations of 20 ± 17 ng/mL were achieved within 10 min of starting the infusion. Area under the plasma concentration-time curve was 3678 ± 3030 ng/mL · min, and plasma clearance was 66 ± 43 mL/min per kg. Elimination was rapidly achieved in all dogs. Heart rate and systolic blood pressure were unaffected by the fenoldopam infusion. Based on the results of this study, further evaluation of the effects of fenoldopam in dogs at differing doses and in dogs with clinical conditions such as acute nonpolyuric kidney injury is warranted.     

Thermoregulation of the testicle in response to exercise and subsequent effects on semen characteristics of stallions

Stallions (n = 8) were implanted with a thermal sensory device in the muscle of the neck and the subcutaneous tissue of the scrotum and then assigned to either a nonexercise (Non-EX; n = 4) or exercise (EX; n = 4) group. A motorized equine exerciser was used to work EX stallions 30 min/d for 4 d/wk during a 12-wk period from July through October 2010. Temperatures (subcutaneous scrotal, intramuscular neck, and rectal) were recorded at 0, 22, and 30 min after the start of exercise, as well as 60 and 120 min post-exercise. Hourly ambient temperature and relative humidity data were also obtained. Semen was collected at 0, 4, 8, and 12 wk and analyzed for volume, sperm concentration, total sperm numbers, percentages of total and progressively motile sperm, sperm morphologic characteristics, and sperm DNA quality. No effect (P > 0.05) of exercise was observed on any of the measured semen variables. Implantation of thermal sensory devices had no demonstrable acute or chronic effects on the scrotal or neck tissue, indicating that the thermal sensory devices are a safe and effective way to measure subcutaneous scrotal and neck temperatures. At 22 and 30 min of exercise, rectal and neck temperatures increased (P < 0.0001) approximately 1.9 and 2.4°C, respectively, and scrotal temperatures simultaneously increased, although not significantly (P = 0.33), approximately 0.8°C. Correlations existed between scrotal, neck, rectal, and ambient temperatures, with the correlation between scrotal and rectal temperatures being greatest (r(s) = 0.76; P < 0.0001). Although moderate exercise for a short duration in extreme heat and humidity did significantly increase core body temperatures in stallions, scrotal temperatures did not significantly increase, and sperm parameters were unaffected.     

The response of monocyte derived dendritic cells following exposure to a nematode larval carbohydrate antigen

The glycolipid CarLA (carbohydrate larval antigen) is present on the epicuticle of the infective-stage larvae of gastrointestinal nematode parasites infecting livestock. The molecule is lost from the surface of the larvae in the few days post-ingestion by a host animal, and the resulting anti-CarLA antibody response has been demonstrated to be protective in vivo. Both the anti-CarLA response, and anti-parasite immunity in general, are slow to develop, and several months of natural exposure to ingested larvae is required. The current study was designed to provide information on how the anti-CarLA response develops, and focuses on the initial recognition of the molecule by human monocyte derived dendritic cells (mdDC) in vitro. Immunofluorescence and flow cytometry demonstrated that mdDC recognise and internalise both the purified and the native form of CarLA, in the case of the latter once it is shed from the larval surface. However, the recognition of CarLA did not result in classical maturation of DC, while there was only transient or minor up-regulation of CD86, CD83, HLA-DR and CD40. Exposure of mdDC to purified CarLA resulted in the increased production of the pro-inflammatory cytokines IL-6 and to a lesser extent of IL-8 and TNF-α, and a reduced production of the anti-inflammatory cytokine IL-1RA. CarLA therefore has little ability to mature and functionally alter monocyte derived dendritic cell function.     

Following a tick bite: double infections by tick-borne encephalitis virus and the spirochete Borrelia and other potential multiple infections

In Central Europe and large parts of Asia, tick-borne-encephalitis (TBE) and Lyme borreliosis caused by the spirochetal bacterium of the genus Borrelia are among the most common diseases transmitted by the bite of a tick. When in regions with overlapping TBE virus and Borrelia endemicity, a tick bite causes the victim to become ill, it is important that appropriate serological and other laboratory investigations form part of the differential diagnosis. Account must always be taken of the fact that a tick bite may be followed by a double infection with the TBE virus and Borrelia. For this reason, a comprehensive diagnostic work-up aimed at detecting co-infection by both pathogens, even when the tick bite occurs in an endemic region for both pathogens but the initial clinical symptoms suggest an infection with only one of the two pathogens. The present article discusses a number of published cases of a co-infection with TBE virus and Borrelia and other potential multiple infections.     

Polymelous layer chick displaying additional malformations of the hind gut: case report and in-depth review of related literature

A case report of a male 6-day-old male layer chick featuring incomplete polymelia of the hind limbs and hindgut malformations is presented. The chick was submitted to computed tomography (CT) examination and subsequent anatomical dissection. Apart from the two supernumerary hind limbs, the anatomical dissection revealed additional hindgut alterations: three uniform-sized caeca flanked the ileum, and the rectum branched into paired cloacae. The supernumerary hind limbs were localized caudal to the normal hind limbs in an inverted position and were attached to pelvic girdle elements and to a curtate pygostyle. They featured a prominent unpaired femur besides paired tibiotarsi, tarsometatarsi and species-specific phalanges of the toes. Additionally, two separate bones attached to the caudoventral aspect of the regular hip bones were developed. The supernumerary limbs were in part mobile and received nerve and vascular supply. Digital 3D-reconstruction based on the CT datasets revealed the osseous components of the malformed body parts. The possible morphogenesis including an in-depth literature review and the clinical implications of the reported malformations are discussed.     

Impact of regulatory perturbations to disease spread through cattle movements in Great Britain

During the past decade the British livestock industry has suffered from several major pathogen outbreaks, and a variety of regulatory and disease control measures have been applied to the movement of livestock with the express aim of mitigating the spread of infection. The Rapid Analysis and Detection of Animal-related Risks (RADAR) project, which has been collecting data on the movement of cattle since 1998, provides a relatively comprehensive record of how these policies have influenced the movement of cattle between animal holdings, markets, and slaughterhouses in Britain. Many previous studies have focused on the properties of the network that can be derived from these movements--treating farms as nodes and movements as directed (and potentially weighted) edges in the network. However, of far greater importance is how these policy changes have influenced the potential spread of infectious diseases. Here we use a stochastic fully individual-based model of cattle in Britain to assess how the epidemic potential has varied from 2000 to 2009 as the pattern of movements has changed in response to legislation and market forces. Our simulations show that the majority of policy changes lead to significant decreases in the epidemic potential (measured in multiple ways), but that this potential then increases through time as cattle farmers modify their behaviour in response. Our results suggest that the cattle industry is likely to experience boom-bust dynamics, with the actions that farmers take during epidemic-free periods to maximise their profitability likely to increase the potential for large-scale epidemics to occur.