Simulation of the economic impact of proliferative enteritis on pig production in Australia

The economic impact of proliferative enteritis (PE) on an ‘average’ pig farm was calculated using the AUSPIG decision support system. Inputs were modelled on actual cases of PE, in which affected herds suffered from depressed growth rate, decreased feed efficiency and stock losses. The costs associated with non-haemorrhagic PE and proliferative haemorrhagic enteropathy ranged from $15/sow/yr to $141/sow/yr, respectively, depending on the clinical severity of the disease, incidence of infection and the type of medication strategy used to treat and control the disease.     

Intravenous catheterisation of conventional pigs without application of antimicrobial agents

In six experiments 43 castrated male conventional pigs weighing 25-41 kg were catheterised by inserting a cannula via the jugular vein into the cranal caval vein. The catheters were taped to the spinal neck region where the tap stops were located. Antimicrobial agents were not applied. One pig died 32 hour after surgery from Porcine Stress Syndrome. The catheters remained patent for at least nine days in 38 of the remaining 42 animals (90%). In two animals the catheter by mistake was not inserted into the jugular vein. Two animals got catheters with a one-way blockage four days after surgery. In these animals autopsy revealed thrombosis and phlebitis of the occluded vein and a valve-like thrombus at the tip of the catheters. In seven of the 43 pigs the effects of anaesthesia, surgery and catherisation were followed using rectal temperature and haematological and some blood biochemical parameters for nine days after the surgery. It is concluded that this catheterisation technique, without application of antimicrobial agents, can be used well for experimental infections and pharmacokinetic studies.     

Measurement of Parity Nonconservation and an Anapole Moment in Cesium

The amplitude of the parity-nonconserving transition between the 6S and 7S states of cesium was precisely measured with the use of a spin-polarized atomic beam. This measurement gives Im(E1pnc)/beta = -1.5935(56) millivolts per centimeter and provides an improved test of the standard model at low energy, including a value for the S parameter of -1.3(3)exp (11)theory. The nuclear spin-dependent contribution was 0.077(11) millivolts per centimeter; this contribution is a manifestation of parity violation in atomic nuclei and is a measurement of the long-sought anapole moment.     

Light and transmission electron microscopy of Vibrio campbellii infection in gnotobiotic Artemia franciscana and protection offered by a yeast mutant with elevated cell wall glucan

Luminescent vibrios are amongst the most important pathogens in aquaculture, affecting almost all types of cultured organisms. Vibrio campbellii is one of these most important pathogens. In this study, the effects of feeding mnn9 yeast cell wall mutant and wild type yeast strain were investigated in the digestive tract of brine shrimp nauplii, Artemia franciscana, after experimental infection with V. campbellii (LMG 21363). Gnotobiotic A. franciscana nauplii were fed daily with dead Aeromonas hydrophila LVS3, and with either wild type strain of baker's yeast, Saccharomyces cerevisiae, or mutant strain mnn9, of which the cell wall contains elevated chitin and glucan and lower mannose levels. After three days of feeding, some nauplii were challenged with V. campbellii. Mean survival (%), individual length (mm) and total length (mm) at one day and two days after challenge were significantly higher in the group fed mnn9 than in the group fed wild type yeast (81 ± 1.50 and 63 ± 0.49, 1.56 ± 0.07 and 1.13 ± 0.02, 38.21 ± 3.11 and 21.26 ± 0.81 respectively for one day and 50 ± 2.37 and 20 ± 1.41, 2.33 ± 0.01 and 1.24 ± 0.04, 34.97 ± 5.56 and 7.45 ± 1.63 for two days after challenge). Histological examination revealed that the luminal diameter and enterocyte height of both mid- and hindgut were larger in the mnn9-fed group. Colonization of the gut lumen by V. campbellii could be observed by transmission electron microscopy for the group of nauplii fed with wild type yeast. Furthermore, it was observed that V. campbellii caused damage to the gut epithelium including shortening and disappearance of the microvilli, destruction of the apical cell membrane and cell lysis in the nauplii fed wild type yeast. The gut epithelium remained intact in challenged nauplii fed mnn9 yeast. The morphological findings of the present study further substantiate previous studies reporting a protective effect of this yeast cell wall mutant.     

A study on the pathogenesis of equine sesamoiditis: the effects of experimental occlusion of the sesamoidean artery

In this study the potential role of circulatory disturbances in the pathogenesis of sesamoiditis was investigated by studying the clinical and histological effects of experimental occlusion of the sesamoidean artery, which is the main nutrient artery of the proximal sesamoid bone (PSB). For this purpose, five adult Dutch Warmblood horses were used in which the sesamoidean artery was occluded with polyvinyl alcohol foam particles. Bone labelling was carried out with oxytetracycline and calcein. All animal were checked clinically three times a week and radiographically at days 14, 21, 28 and 35. At day 35 the animals were killed and the fetlock was dissected and macroscopically evaluated. The PSBs were isolated and radiographed and the soft tissues adjacent to the abaxial side of the PSBs were histologically examined [routine histology and for the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP)]. The PSBs were divided into bony slices which were radiographed and evaluated histologically (routine, SP, CGRP, fluorescence). All horses showed a slight lameness that gradually diminished. Radiographically enlarged vascular channels were seen in only one horse. Histological data showed that on average 60% (range 37-89%) of the total area had been deprived of vascularization. In two horses an increase in the extent of the arterial network from the basal side of the PSB was seen. Only in the horse with the greatest extent of occlusion were bone necrosis and a reactively increased uptake of fluorochromes adjacent to the occluded arteries found. Bone density did not change. The distribution of neuropeptides in the surrounding soft tissues was not affected by the occlusion. From this study, it can be concluded that a large part of the arterial supply to the PSB can be interrupted without provoking histological and/or radiographic changes that are consistent with clinical sesamoiditis. Therefore, it seems very improbable that circulatory disturbances are a primary aetiopathogenic factor in the disease.     

A REVIEW OF SMALL ANIMAL IMAGING PLANAR AND PINHOLE SPECT γ CAMERA IMAGING

Scintigraphy (positron emission tomography (PET) or single photon emission computed tomography (SPECT) techniques) allows qualitative and quantitative measurement of physiologic processes as well as alterations secondary to various disease states. With the use of specific radioligands, molecular pathways and pharmaco-kinetic processes can be investigated. Radioligand delivery can be (semi)quantified in the region of interest in cross-sectional and longitudinal examinations, which can be performed under the same conditions or after physiologic or pharmacologic interventions. Most preclinical pharmacokinetic studies on physiological and experimentally altered physiological processes are performed in laboratory animals using high-resolution imaging systems. Single photon emission imaging has the disadvantage of decreased spatial and temporal resolution compared with PET. The advantage of SPECT is that equipment is generally more accessible and commonly used radionuclides have a longer physical half-life allowing for investigations over a longer time interval. This review will focus on single photon emission scintigraphy. An overview of contemporary techniques to measure biodistribution and kinetics of radiopharmaceuticals in small animal in vivo is presented. Theoretical as well as practical aspects of planar gamma camera and SPECT pinhole (PH) imaging are discussed. Current research is focusing on refining PH SPECT methodology, so specific regarding technical aspects and applications of PH SPECT will be reviewed.     

Nematode parasites of adult dairy cattle in the Netherlands

Abomasa, blood samples and faecal samples for examination of nematode infections were collected from 125 dairy cows during the period November 1997-October 1998. Of these, 12 had no grazing history and were, therefore, excluded from this study. From the remaining 113, 88.5% had nematode eggs in the faeces. Larval identification of the positive cultures showed that Ostertagia spp. larvae were most frequent (97%), followed by Trichostrongylus spp. (29%), Oesophagostomum spp. (23%), Cooperia punctata (20%), Cooperia oncophora (4%), Haemonchus contortus (2%) and Bunostomum phlebotomum (1%). The geometric mean EPG was 2.4. Two cows excreted larvae of Dictyocaulus viviparus (0.1 and 0.6 LPG resp.). Worms were found in the abomasa of 108 cows (96%). In all these abomasa Ostertagia spp. was present (100%). Trichostrongylus axei was found in 47 abomasa (43.5%) and two cows (2%) were infected with Capillaria bovis. The geometric mean of the total abomasal worm counts was 1743 and of Ostertagia spp. alone 1615. Almost all male worms were Ostertagia ostertagi, only occasionally Skrjabinagia lyrata10,000) total worm burden.Ostertagia specific antibodies were highest in late summer and autumn and lowest in spring and early summer. The same pattern, although not so pronounced, was observed for the serum pepsinogen values. No clear seasonal pattern was found for the Cooperia specific antibodies. Antibodies against D. viviparus were detected in seven cows (6%).     

Passive immunization of guinea pigs with llama single-domain antibody fragments against foot-and-mouth disease

Foot-and-mouth disease (FMD) is a highly contagious disease that occasionally causes outbreaks in Europe. There is a need for therapies that provide rapid protection against FMD in outbreak situations. We aim to provide such rapid protection by passive immunization with llama single-domain antibody fragments (VHHs). Twenty-four VHHs binding serotype O FMDV in vitro were isolated from immunized llamas by phage display and expressed in bakers yeast for further characterization. They recognized four functionally independent antigenic sites. Six strongly FMDV neutralizing VHHs bound to a peptide representing the GH-loop of viral protein 1 known to be involved in binding to the cellular receptor of FMDV. Clone M8, recognizing this antigenic site, and clone M23, recognizing another antigenic site, showed synergistic in vitro virus neutralization. Three FMDV specific VHHs were PEGylated in order to decrease their rapid blood clearance and thus enable in vivo guinea pig protection experiments. Passive immunization with individual VHHs showed no protection, but a mixture of M8 and M23 showed partial transient protection. The protection afforded by these VHHs was however low as compared to the complete protection afforded by convalescent guinea pig serum. In contrast, these VHHs showed far more efficient in vitro FMDV neutralization than convalescent guinea pig serum. This lack of correlation between in vitro neutralization and in vivo protection lends further credence to the notion that opsonophagocytosis of FMDV is important for protection in vivo.     

Communicating the risks of handling bats: analysing approaches used by Australian stakeholders in the context of Australian bat lyssavirus

Australian bat lyssavirus (ABLV) is a member of the Lyssavirus genus of the Rhabdoviridae family and is found in Australian bat species. It is of public health concern because of the rabies-like syndrome it causes in humans, resulting in government health and wildlife agencies using varied communication approaches to inform targeted audiences about zoonotic risks associated with handling bats. Despite these warnings, the number of reports of human-bat interactions remains high. This paper details a survey conducted to analyse the approaches utilised by a range of stakeholders to educate and communicate warnings to their target audiences. The survey focused on identifying the target audiences, communication methods used, along with the message frequency, content, and perceived effectiveness. Analysis of the top three messages delivered by stakeholders revealed that over half were information-focused messages and over a third, instruction-focused. Stakeholders identified the need to balance messaging about bat handling risks with information regarding the vulnerable status of bats and their environmental significance. Whilst the most common and (perceived) effective method of communication was one-on-one discussions, it was also identified to be ineffective for targeting mass audiences leading stakeholders to recognise the need to adapt to more efficient means of communication. The outcomes of this study may be useful to improve risk communication strategies regarding ABLV in Australia.     

Sorption of perfluorinated compounds from contaminated water to activated carbon

Introduction  

Perfluorinated compounds (PFC) are toxic and bioaccumulative compounds that are ubiquitous in the environment. It is important to develop effective techniques to remove PFC from water. This study is the first to investigate sorption of PFC to activated carbon (AC) at environmentally relevant nanogram per liter concentrations.