In vitro and in vivo evaluation of a new zirconia/niobium biocermet for hard tissue replacement.

Metals and ceramics are commonly used in orthopaedics, dentistry and other load bearing applications. However, the use of ceramic matrix composites reinforced with biocompatible metals for heavy load-bearing hard tissue replacement applications has not previously been reported. In order to improve the reliability and the mechanical properties of biomedical implants, new zirconia-Nb composites have been recently developed. The aim of this study was to investigate the biological tolerance of these new zirconia/Nb biocermets implants with both in vitro and in vivo approaches. At first, human bone marrow derived mesenchymal stem cells were cultured on sintered biocermet discs with polished surfaces and were compared with responses to niobium metal. In vitro, the biocermets showed no deleterious effect on cell proliferation, extra-cellular matrix production or on cell morphology. Furthermore, the biocermet showed a higher percentage of cell proliferation than Nb metal. On the other hand, the bone response to these new zirconia/Nb biocermets was studied. Cylinders of biocermets, as well as commercially Nb rod were implanted in the tibiae of New Zealand white rabbits. All the animals were euthanatized after 6 months. The specimens were processed to obtain thin ground sections. The slides were observed in normal transmitted light microscope. A newly formed bone was observed in close contact with material surfaces. No inflamed or multinucleated cells were present. This study concluded that zirconia/Nb composites are biocompatible and osteoconductive. The ceramic-metal composite has even better osteointegration ability than pure Nb. In conclusion, zirconia-Nb biocermet is suitable for heavy load-bearing hard tissue replacement from the point of view of both mechanical properties and biocompatibility.

Systematic review of brucellosis in the Middle East: disease frequency in ruminants and humans and risk factors for human infection.

A systematic review of studies providing frequency estimates of brucellosis in humans and ruminants and risk factors for Brucella spp. seropositivity in humans in the Middle East was conducted to collate current knowledge of brucellosis in this region. Eight databases were searched for peer-reviewed original Arabic, English, French and Persian journal articles; the search was conducted on June 2014. Two reviewers evaluated articles for inclusion based on pre-defined criteria. Of 451 research articles, only 87 articles passed the screening process and provided bacteriological and serological evidence for brucellosis in all Middle Eastern countries. Brucella melitensis and B. abortus have been identified in most countries in the Middle East, supporting the notion of widespread presence of Brucella spp. especially B. melitensis across the region. Of the 87 articles, 49 were used to provide evidence of the presence of Brucella spp. but only 11 provided new knowledge on the frequency of brucellosis in humans and ruminants or on human risk factors for seropositivity and were deemed of sufficient quality. Small ruminant populations in the region show seroprevalence values that are among the highest worldwide. Human cases are likely to arise from subpopulations occupationally exposed to ruminants or from the consumption of unpasteurized dairy products. The Middle East is in need of well-designed observational studies that could generate reliable frequency estimates needed to assess the burden of disease and to inform disease control policies.

Spatial, demographic and clinical patterns of Angiostrongylus vasorum infection in the dog population of Southern England.

A retrospective study was carried out to provide updated knowledge of the spatial pattern of Angiostrongylus vasorum infection in Southern England and to investigate associations between selected host characteristics (age, breed, sex), risk of infection and clinical presentation (cardiorespiratory signs v haemorrhagic diathesis). One hundred and forty-one cases diagnosed between April 1999 and July 2012 were compared with a control population of dogs referred to the same hospital. A significant association was found between haemorrhagic diathesis and breed but not for other host characteristics and clinical presentations. Younger dogs and certain breeds of dog (Jack Russell terriers, Cocker Spaniels, Springer Spaniels, Cavalier King Charles spaniels and Staffordshire Bull Terriers) had significantly higher odds of angiostrongylosis than other breeds in the study. A significant cluster of cases was found in Southern England. Animals presenting with cardiorespiratory signs or haemorrhagic diathesis in Southern England, especially if they are young or of a breed associated with angiostrongylosis, should be given special consideration with regards to possible A. vasorum infestation. Our results should be interpreted bearing in mind that they are based on the retrospective exploration of dogs seen at a referral centre.

Angiostrongylus vasorum in Great Britain: a nationwide postal questionnaire survey of veterinary practices.

The lungworm, Angiostrongylus vasorum, was first reported in indigenous dogs in southwestern England in 1980 and has since been recorded in Wales, southeastern England and, more recently, in the West Midlands, northern England and Scotland. The nationwide distribution of the parasite was evaluated using a postal questionnaire sent to 3950 small animal practices during 2009. Information was sought on the location of each practice, awareness of the parasite locally, number of cases diagnosed over the past year and whether diagnosis was based on clinical signs alone or supported by additional tests. 1419 practices returned a usable response, the majority being located in a city/town. Nearly one-third of responding practices were aware of the parasite locally, 20.7 per cent had seen at least one confirmed case and 0.3 per cent >20 confirmed cases over the past year. The most widely used tests were faecal examination and any type of imaging. Existing clusters of infection were detected in southeastern England and south Wales; infection was also found to be widespread in central England, though patchy in northern England and Scotland. Using distribution of clinical cases as an indicator of parasite distribution, this study confirmed that A. vasorum has spread beyond traditional UK endemic foci.

Ruminant brucellosis in Upper Egypt (2005-2008).

Brucellosis is endemic among humans and ruminant in Egypt and recent reports suggest that its incidence may be increasing. In this study we describe the frequency of brucellosis among different ruminant species in Upper Egypt and its spatial distribution using the data generated by a large-scale control campaign undertaken between 2005 and 2008. A total of 120,090 individual animals of different ruminant species were tested during the campaign. The true proportions of brucellosis were estimated as 0.79% (CI: 0.71%-0.87%), 0.13% (CI: 0.08%-0.18%), 1.16% (1.05%-1.27%) and 0.44% (0.34%-0.54%) among cattle, buffaloes, sheep and goats respectively. We estimated that 0.2% (CI: 0.16%-0.23%) of households in the study area keep at least one seropositive animal. Spatial autocorrelation of the proportions of seropositive households and seropositive animals was assessed using Global Univariate Moran's I and Local Univariate LISA. These analyses showed that the distribution of seropositive animals has considerable spatial heterogeneity with clustering in the northern governorates of the study area. Our results show that brucellosis is widespread and heterogeneously distributed in Upper Egypt. At the current level of available resources it is very unlikely that test and slaughter could be implemented with the intensity needed to be effective and other control measures that could replace or complement the test and slaughter policy in place should be considered. Also, this study illustrates some of the challenges faced by bilateral projects that have to accommodate an externally funded intervention with an ongoing national official disease control program.

Impact of the implementation of rest days in live bird markets on the dynamics of H5N1 highly pathogenic avian influenza.

Live bird markets (LBMs) act as a network 'hub' and potential reservoir of infection for domestic poultry. They may therefore be responsible for sustaining H5N1 highly pathogenic avian influenza (HPAI) virus circulation within the poultry sector, and thus a suitable target for implementing control strategies. We developed a stochastic transmission model to understand how market functioning impacts on the transmission dynamics. We then investigated the potential for rest days-periods during which markets are emptied and disinfected-to modulate the dynamics of H5N1 HPAI within the poultry sector using a stochastic meta-population model. Our results suggest that under plausible parameter scenarios, HPAI H5N1 could be sustained silently within LBMs with the time spent by poultry in markets and the frequency of introduction of new susceptible birds' dominant factors determining sustained silent spread. Compared with interventions applied in farms (i.e. stamping out, vaccination), our model shows that frequent rest days are an effective means to reduce HPAI transmission. Furthermore, our model predicts that full market closure would be only slightly more effective than rest days to reduce transmission. Strategies applied within markets could thus help to control transmission of the disease.

Herd contact structure based on shared use of water points and grazing points in the Highlands of Ethiopia.

The use of shared common water points (WPs) and grazing points (GPs) at two different levels of administrative aggregation (village and kebelle) in a region of the Highlands of Ethiopia was explored by means of a questionnaire survey and social network analysis. Despite GPs being more abundant than WPs (208 and 154, respectively), individual GPs provide more contact opportunities for animals. There was great variability in the contact structure of the selected villages within kebelles for both networks, with this variability being higher in the GP networks for each kebelle. Contrary to the commonly held view that WPs are critical for the potential transmission of infectious diseases, intervention at GPs in the Ethiopian Highlands may have greater impact on contacts and thereby opportunities for transmission of infectious diseases between flocks. Some villages appear naturally at much lower risk of introducing disease. These findings could help the design of surveillance and control activities for directly transmitted infectious diseases.

Maxillary sinus floor augmentation on humans: Packing simulations and 8 months histomorphometric comparative study of anorganic bone matrix and ß-tricalcium phosphate particles as grafting materials.

The present study compares the behaviour of an anorganic bone matrix material and a synthetic ß-Tricalcium phosphate employed as grafting materials in a sinus floor augmentation two step protocol in humans. In order to estimate the initial occupation level for the two materials, an 'in vitro' simulation has been performed to analyse macroporosity created due to particle packing in terms of porosity and interparticle distances. Grafting in the sinus floor augmentation was performed by filling the defects only with pure grafting materials without autogenous bone addition. The new-bone generated is 100% based on the osteoconductive properties of the grafted materials in contact with physiological fluids. The implants were placed 8 months after the grafting procedure. All the implanted positions were biopsied and embedded in methacrylate resin. Histomorphometric analyses were done over thin film undecalcified sections. Packing simulations allow establishing a comparison of the resorbed volumes related to the initial occupancy of the grafting materials inside the defect. The nature of this interconnected pore network is very alike for either material so new-bone generated was similar (~35 vol.%).

Contamination of food products with Mycobacterium avium paratuberculosis: a systematic review.

Although a causal link between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn's disease has not been proved, previous studies suggest that the potential routes of human exposure to MAP should be investigated. We conducted a systematic review of literature concerning the likelihood of contamination of food products with MAP and the likely changes in the quantity of MAP in dairy and meat products along their respective production chains. Relevant data were extracted from 65 research papers and synthesized qualitatively. Although estimates of the prevalence of Johne's disease are scarce, particularly for non-dairy herds, the available data suggest that the likelihood of contamination of raw milk with MAP in most studied regions is substantial. The presence of MAP in raw and pasteurized milk has been the subject of several studies which show that pasteurized milk is not always MAP-free and that the effectiveness of pasteurization in inactivating MAP depends on the initial concentration of the agent in raw milk. The most recent studies indicated that beef can be contaminated with MAP via dissemination of the pathogen in the tissues of infected animals. Currently available data suggests that the likelihood of dairy and meat products being contaminated with MAP on retail sale should not be ignored.

Assessment and simulation of the implementation of brucellosis control programme in an endemic area of the Middle East.

Brucellosis is an important zoonosis in Middle Eastern countries. In this study we assessed the extent of the application of planned official brucellosis control programmes in Kafr El Sheikh governorate, Egypt and we used a stochastic simulation model to assess the probable impact of changes to the official control strategy on the dynamics of small-ruminant brucellosis. Our results show that <7% of female livestock were tested in any given year in the study area and that quarantine was not consistently applied to infected herds. Simulation results revealed the inability of the applied control measures to reduce the prevalence of small-ruminant brucellosis. Given our assumptions, the intensity with which infected animals are removed under the actual levels of implementation of test-and-slaughter programmes would permit brucellosis to remain endemic at a level >8% of the sheep and goat population.

Risk associated with animals moved from herds infected with brucellosis in Northern Ireland.

The movement of cattle from herds infected with Brucella abortus was investigated in order to assess the control measures for eradication of brucellosis from the cattle population of Northern Ireland. Using recorded cattle movement data, a historical cohort study was designed and carried out to quantify the risk of seropositivity in bovine animals moved from herds infected with brucellosis. The study found that 3.1% of animals, moved in the 6-month period prior to disclosure of infection in the source herd and subsequently tested, were interpreted as seropositive in their destination herds. The odds of seropositivity were approximately 19 (95% confidence interval: 7.8-46.4) times higher in this cohort compared with animals from herds with no history of infection. A multivariate logistic regression model was constructed to examine factors influencing the risk of seropositivity in the exposed cohort of animals, identifying maternal status (whether the dam had been a brucellosis reactor) and age at leaving the infected herd as the main risk factors.

Conceptual framework for avian influenza risk assessment in Africa: the case of Ethiopia.

The avian influenza (AI) epidemic is threatening Africa mainly because the flyways of migratory birds link the endemic and newly infected countries with disease-free areas in this continent and because of the risk of introduction through trade. Risk analysis provides a set of tools for supporting decision making by the veterinary services and other stakeholders, resulting in more effective surveillance and emergency preparedness. The risk assessment process could be split into three different steps: 1) risk release through the migratory birds and the official and unofficial poultry-product marketing chains; 2) risk exposure by means of studying interfaces among imported and exposed poultry and among wild and domestic birds; and 3) risk consequences for establishing the probability of AI spreading within the poultry population and the probability of it escaping detection. A conceptual framework is presented based on preliminary data and field missions carried out in Ethiopia. Field surveys and expert opinion will be necessary for the parameterization of the risk model. Spatial analysis will be used to identify high risk of exposure among wild and domestic birds. Risk communication and risk management will be based on the findings from the risk assessment model.

Effect of introducing piglets from farrow-to-finish breeding farms into all-in all-out fattening batches in Spain on productive parameters and economic profit.

A prospective study was conducted to assess the effect of introduction of piglets from farrow-to-finish farms on the global performance of all-in all-out fattening batches in Galicia (NW Spain). Two hundred and thirty-nine fattening batches from 48 fattening farms integrated in a cooperative were used in the study. All-in all-out fattening batches were classified according to the category of farm that supplied the piglets. Origin F was a fattening batch where all feeder piglets came from one or more farrow to feeder units versus origin FF, in case a group of piglets or all piglets of the batch came from farrow-to-finish farms. Productive parameters of fattening batches included in the study were recorded. Crude comparisons of performance of 37 fattening batches from origin F and 202 from origin FF were made. Mixed multiple linear regression models were used to assess the association between type of origin of feeder piglets and the following parameters: feed consumed per market hog, percentage of deaths (mortality) and time to slaughter. In all models, variables with presumable relationships with the outcomes were offered to the models as well as the biologically plausible interaction terms. Mortality was higher in fattening batches with piglets coming from farrow-to-finish farms (0.67% higher than origin F; P<0.05). Time to slaughter was longer when feeder piglets were from origin FF (3.1 days longer; P<0.05). We found a significant effect of type of origin on feed consumed per marketed hog. Additionally, a significant interaction was found: feed consumed per marketed hog was higher for fattening batches with all piglets from farrow-to-finish farms if slaughtered before 109 days and vice versa. A Monte Carlo simulation model was used to assess the economic impact of using origin F or FF as source of piglets. Results of the model indicated that the difference in expected profit per marketed hog between the types of sources of piglets was small (11.50 Euros, S.D. 1.79 for origin F versus 10.44 Euros, S.D. 2.72, for origin FF).

Space-time interaction as an indicator of local spread during the 2001 FMD outbreak in the UK.

During the 2001 FMD outbreak in the UK, decisions on the level of implementation of control measures were supported by predictive models. Models were mainly used as macro-level tools to predict the behaviour of the disease in the whole country rather than at the local level. Here we explore the use of the magnitude and characteristics of the space-time interaction as an indicator of local spread and, indirectly, of the effectiveness of control measures aimed at reducing short-range transmission during the course of a major livestock disease epidemic. The spatiotemporal evolution patterns are described in the four main clusters that were observed during the outbreak by means of the hazard rate and space-time K-function (K(s,t)). For each local outbreak, the relative measure D(0)(s,t), derived from K(s,t), which represents the excess risk attributable to the space-time interaction was calculated for consecutive 20-day temporal windows to represent the dynamics of the space-time interaction. The dynamics of the spatiotemporal interaction were very different among the four local clusters, suggesting that the intensity of local spread, and therefore the effectiveness of control measures, markedly differed between local outbreaks. The large heterogeneity observed in the relative impact of being close in time and space to an infected premises suggests that the decision making in relation to control of the outbreak would have benefited from indicators of local spread which could be used to complement global predictive modelling results. Despite its limitations, our results suggest that the real-time analysis of the space-time interaction can be a valuable decision support tool during the course of a livestock disease epidemic.

Evidence of bias affecting the interpretation of the results of local anaesthetic nerve blocks when assessing lameness in horses.

Eighteen observers were influenced to different extents in the grades of lameness they allocated to eight horses by whether they knew that a nerve block had been administered; on a scale from 0 to 10 the mean difference in grade allocated once the observer knew a horse had been nerve-blocked was increased by 0.4. The consistency of the assessments made by the individual observers was good, with a an average of 0.6 of a grade difference when grading the same horse on two occasions. The agreement between the assessments of four orthopaedic experts was reasonable (+/-1 grade), but significantly poorer for four non-experts and 10 final year veterinary students.

Use of social network analysis to characterize the pattern of animal movements in the initial phases of the 2001 foot and mouth disease (FMD) epidemic in the UK.

Aggregated movement data do not take into account the relative position of the units within a higher-level structure. Social network analysis (SNA) and graph theory provide a tool to organise and analyse relational data overcoming the limitations of standard methods where the position of individuals/observations does not affect the result of the analysis. Some recorded movements of cattle and sheep during the initial phase of the 2001 foot and mouth disease (FMD) outbreak in the UK, before the ban on animal movements was imposed, are analysed descriptively using SNA. With the data available, a directed dichotomized network with 653 nodes and 797 arches was analysed. Most of the 10 nodes with the highest betweenness (3 farms, 4 markets and 3 dealers) were identified as key players in the initial spread of the infection. Three groups of nodes with distinctive proportion of k < or = 2 neighbours would result in three different theoretical outbreak dimensions assuming that the infection is only disseminated by the movements included in the network: no spread, spread up to 7% and around 25%. There are three hierarchical clusters with 308, 215 and 130 nodes, respectively. Farms in cluster 1 appear to be more similar in their movement patterns to non-farm holdings than to farms in clusters 2 and 3. Relative betweenness, k-neighbours and structural equivalence using hierarchical clustering were able to identify key actors in the evolution of the initial phases of the FMD outbreak such as markets, dealers and farms with atypical movement patterns. Holdings with high betweenness, large number of k < or = 2 neighbours and with movement pattern as in cluster 1 should be targeted in disease control activities once primary actors like markets, dealers and slaughter houses have been contained.

Theileria (Babesia) equi and Babesia caballi infections in horses in Galicia, Spain.

The control of equine piroplasmosis is becoming increasingly important to maintain the international market open to the horse industry. The purpose of this study was to demonstrate the occurrence of equine piroplasmosis (Theileria equi and Babesia caballi) in Galicia, north-west Spain, and to compare haematological and serum biochemistry parameters between non-parasitaemic horses and horses parasitaemic with T. equi and B. caballi. Sixty serum samples (control group) were taken from healthy horses pastured on two farms, and examined for evidence of equine T. equi and B. caballi infection by indirect fluorescent antibody test (IFAT). Of the 60 samples, 24 (40%) and 17 (28.3%) samples were positive for T. equi and B. caballi, respectively. Twelve (20%) samples were positive for both parasites. Haematology and serum biochemistry were compared between controls and a series of 36 horses clinically affected by T. equi (25) or B. caballi (11). Compared with the healthy group, there was a 43% and 37% decrease in the haematocrit for T. equi and B. caballi infection, respectively. Parasitaemic horses presented an intense anaemia and serum biochemistry signs of liver damage. The anaemia was more severe in T. equi-infected than in B. caballi-infected horses. Our results suggest that equine piroplasmosis is widespread in the region and is a cause for concern.

Effect of triploidy on turbot haematology.

This study was carried out to compare key haematological features of diploid (2n) and triploid (3n) turbot as a first step towards the assessment of the ability of 3n turbot to withstand sub-optimal culture conditions. Morphometric indices of erythrocytes were determined on blood smears by light microscopy. Triploidy significantly (P<0.001) increased all morphometric indices measured in the erythrocytes, including size, surface, and volume, except for the size of minor nuclear axis. The increase in cell size was larger for the major (31.0%) than for the minor (8.3%) axis, thus rendering erythrocytes of 3n turbot more ellipsoidal. The increase in erythrocyte volume (45.9%) was close to the theoretical expected 50% increase as a result of one extra chromosome set. Haematological indices were measured automatically by a haematological Coulter Counter. Triploid turbot had lower numbers of red blood cells (RBC: 1.84 cells pL(-1) in 2n vs. 1.27 cells pL(-1) in 3n; P<0.001) but they were of a larger size (Mean corpuscular volume [MCV]: 145.51 fL in 2n vs. 181.78 fL in 3n; P<0.001). However, the decrease in RBC was not compensated by the increase in MCV, and thus, triploidy decreased the haematocrit (Hct: 26.80% in 2n vs. 23.11% in 3n; P<0.001) and total blood haemoglobin concentration (Hb: 73.74 g l(-1) in 2n vs. 67.54 g l(-1) in 3n; P<0.05). In contrast, mean corpuscular hemoglobin (MCH: 40.27 pg in 2n vs. 53.28 pg in 3n; P<0.001) was higher for 3n turbot as a result of their larger erythrocytes although MCH concentration (MCHC: 0.28 pg fL(-1) in 2n vs. 0.29 pg fL(-1) in 3n did not significantly differ. RBC, Hct and MCV were also determined manually using light microscopy. In general, discrepancies between the two methods were small (overall approximately 7%) but the Coulter Counter tended to overestimate RBC and Hct (and thus to underestimate MCV). Nevertheless, relative differences between ploidies were very similar, thus verifying triploidy-associated changes in hematological features. These changes, as determined in the present study, are essential when evaluating the feasibility of triploid turbot for intensive aquaculture systems in which unfavorable situations may occur.

A water setting tetracalcium phosphate-dicalcium phosphate dihydrate cement.

The development of a calcium phosphate cement, comprising tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD), that hardens in 14 min with water as the liquid or 6 min with a 0.25 mol/L sodium phosphate solution as the liquid, without using hydroxyapatite (HA) seeds as setting accelerator, is reported. It was postulated that reduction in porosity would increase cement strength. Thus, the effects of applied pressure during the initial stages of the cement setting reaction on cement strength and porosity were studied. The cement powder comprised an equimolar mixture of TTCP and DCPD (median particle sizes 17 and 1.7 microm, respectively). Compressive strengths (CS) of samples prepared with distilled water were 47.6 +/- 2.4 MPa, 50.7 +/- 4.2 MPa, and 52.9 +/- 4.7 MPa at applied pressures of 5 MPa, 15 MPa, and 25 MPa, respectively. When phosphate solution was used, the CS values obtained were 41.5 +/- 2.3 MPa, 37.9 +/- 1.7 MPa, and 38.1 +/- 2.3 MPa at the same pressure levels. Statistical analysis of the results showed that pressure produced an improvement in CS when water was used as liquid but not when the phosphate solution was used. Compared to previously reported TTCP-DCPD cements, the greater CS values and shorter setting times together with a simplified formulation should make the present TTCP-DCPD cement a useful material as a bone substitute for clinical applications.

Case-control study of canine infection by a newly recognised Babesia microti-like piroplasm.

We did a case-control study to identify risk factors for prevalent infection of dogs by a newly recognised Babesia microti-like piroplasm. Clinical manifestations and haematology of infected dogs also were described. Forty-three laboratory-based cases and 86 individually matched controls were studied. Information on clinical signs and on risk factors was collected by a questionnaire and telephone interviews. Haematology was carried out for all the dogs. Variables were screened in a bivariable conditional logistic regression and checked for colinearity. The final multivariable model was selected by backward stepwise elimination. The odds of a case having ticks when examined at the clinic was 4 times that of a control and the odds of a case being a hunting or a house-guarding dog were, respectively, 24.2 and 2.7 times those of a control. The most consistently reported clinical signs were weakness (79%), tachycardia (43%) and haemoglobinuria (42%). Mean red-blood-cell count, haemoglobin concentration, platelet count, and mean platelet volume of infected dogs were lower than the reference values and those of non-infected dogs-but leukocyte count, mean corpuscular volume and red-blood-cell distribution width were higher.