Carla Correia-Gomes

Pig Abattoir Inspection Data: Can It Be Used for Surveillance Purposes?

Statutory recording of carcass lesions at the abattoir may have significant potential as a resource for surveillance of livestock populations. Food Standards Agency (FSA) data in Great Britain are not currently used for surveillance purposes. There are concerns that the sensitivity of detection, combined with other issues, may make the outputs unreliable. In this study we postulate that FSA data could be used for surveillance purposes. To test this we compared FSA data with BPHS (a targeted surveillance system of slaughtered pigs) and laboratory diagnostic scanning surveillance (FarmFile) data, from mid-2008 to mid-2012, for respiratory conditions and tail bite lesions in pigs at population level. We also evaluated the agreement/correlation at batch level between FSA and BPHS inspections in four field trials during 2013. Temporal trends and regional differences at population level were described and compared using logistic regression models. Population temporal analysis showed an increase in respiratory disease in all datasets but with regional differences. For tail bite, the temporal trend and monthly patterns were completely different between the datasets. The field trials were run in three abattoirs and included 322 batches. Pearson’s correlation and Cohen’s kappa tests were used to assess correlation/agreement between inspections systems. It was moderate to strong for high prevalence conditions but slight for low prevalence conditions. We conclude that there is potential to use FSA data as a component of a surveillance system to monitor temporal trends and regional differences of chosen indicators at population level. At producer level and for low prevalence conditions it needs further improvement. Overall a number of issues still need to be addressed in order to provide the pig industry with the confidence to base their decisions on these FSA inspection data. Similar conclusions, at national level, may apply to other livestock sectors but require further evaluation of the inspection and data collection processes.

Comparison of Respiratory Disease Prevalence among Voluntary Monitoring Systems for Pig Health and Welfare in the UK.

Surveillance of animal diseases provides information essential for the protection of animal health and ultimately public health. The voluntary pig health schemes, implemented in the United Kingdom, are integrated systems which capture information on different macroscopic disease conditions detected in slaughtered pigs. Many of these conditions have been associated with a reduction in performance traits and consequent increases in production costs. The schemes are the Wholesome Pigs Scotland in Scotland, the BPEX Pig Health Scheme in England and Wales and the Pig Regen Ltd. health and welfare checks done in Northern Ireland. This report set out to compare the prevalence of four respiratory conditions (enzootic pneumonia-like lesions, pleurisy, pleuropneumonia lesions and abscesses in the lung) assessed by these three Pig Health Schemes. The seasonal variations and year trends associated with the conditions in each scheme are presented. The paper also highlights the differences in prevalence for each condition across these schemes and areas where further research is needed. A general increase in the prevalence of enzootic pneumonia like lesions was observed in Scotland, England and Wales since 2009, while a general decrease was observed in Northern Ireland over the years of the scheme. Pleurisy prevalence has increased since 2010 in all three schemes, whilst pleuropneumonia has been decreasing. Prevalence of abscesses in the lung has decreased in England, Wales and Northern Ireland but has increased in Scotland. This analysis highlights the value of surveillance schemes based on abattoir pathology monitoring of four respiratory lesions. The outputs at scheme level have significant value as indicators of endemic and emerging disease, and for producers and herd veterinarians in planning and evaluating herd health control programs when comparing individual farm results with national averages.

How commercial and non-commercial swine producers move pigs in Scotland: a detailed descriptive analysis

BackgroundThe impact of non-commercial producers on disease spread via livestock movement is related to their level of interaction with other commercial actors within the industry. Although understanding these relationships is crucial in order to identify likely routes of disease incursion and transmission prior to disease detection, there has been little research in this area due to the difficulties of capturing movements of small producers with sufficient resolution. Here, we used the Scottish Livestock Electronic Identification and Traceability (ScotEID) database to describe the movement patterns of different pig production systems which may affect the risk of disease spread within the swine industry. In particular, we focused on the role of small pig producers.ResultsBetween January 2012 and May 2013, 23,169 batches of pigs were recorded moving animals between 2382 known unique premises. Although the majority of movements (61%) were to a slaughterhouse, the non-commercial and the commercial sectors of the Scottish swine industry coexist, with on- and off-movement of animals occurring relatively frequently. For instance, 13% and 4% of non-slaughter movements from professional producers were sent to a non-assured commercial producer or to a small producer, respectively; whereas 43% and 22% of movements from non-assured commercial farms were sent to a professional or a small producer, respectively. We further identified differences between producer types in several animal movement characteristics which are known to increase the risk of disease spread. Particularly, the distance travelled and the use of haulage were found to be significantly different between producers.ConclusionsThese results showed that commercial producers are not isolated from the non-commercial sector of the Scottish swine industry and may frequently interact, either directly or indirectly. The observed patterns in the frequency of movements, the type of producers involved, the distance travelled and the use of haulage companies provide insights into the structure of the Scottish swine industry, but also highlight different features that may increase the risk of infectious diseases spread in both Scotland and the UK. Such knowledge is critical for developing more robust biosecurity and surveillance plans and better preparing Scotland against incursions of emerging swine diseases.

Nuclear pleomorphism: role in grading and prognosis of canine mammary carcinomas

Canine mammary tumours are highly heterogeneous in morphology and behaviour and successful clinical management requires robust prognostic factors. Histological grade, determined by the Nottingham nuclear pleomorphism scoring method, has been considered one of these factors. Despite the adoption of this method, it is unknown whether inter-observer agreement exists regarding the assessment of its parameters in canine mammary carcinomas (CMC). In this study, the agreement between two observers in scoring nuclear pleomorphism using the Nottingham method was evaluated in 89 cases of CMC. Histological evidence of vascular invasion and/or lymph node metastases (both early signs of tumour aggressiveness) was recorded. For 48 animals, two years of follow-up data were available. Nuclear pleomorphism was quantitatively assessed using a stereological method that allowed for an unbiased estimation of nuclear size and its variability by determining the volume-weighted mean nuclear volume (v¯v). Differences between the v¯v estimations and nuclear pleomorphism scores were evaluated. Additionally, the prognostic significance of clinicopathological features including nuclear score and v¯v was evaluated. A poor agreement between the two observers was obtained (κ value 0.46). Tumours scored as 1 and 2 presented similar v¯v values and only tumours that scored 3 presented significantly higher estimates. The v¯v value was not associated with vascular invasion and/or lymph node metastases, but was higher in tumours that progressed during follow-up. In multivariable analysis, only tumour size was an independent factor regarding evidence of aggressiveness and an optimal cut-off of 2.9 cm was defined.

Stereological assessment of sexual dimorphism in the rat liver reveals differences in hepatocytes and Kupffer cells but not hepatic stellate cells

There is long‐standing evidence that male and female rat livers differ in enzyme activity. More recently, differences in gene expression profiling have also been found to exist; however, it is still unclear whether there is morphological expression of male/female differences in the normal liver. Such differences could help to explain features seen at the pathological level, such as the greater regenerative potential generally attributed to the female liver. In this paper, hepatocytes (HEP), Kupffer cells (KC) and hepatic stellate cells (HSC) of male and female rats were examined to investigate hypothesised differences in number, volume and spatial co‐localisation of these cell types. Immunohistochemistry and design‐based stereology were used to estimate total numbers, numbers per gram and mean cell volumes. The position of HSC within lobules (periportal vs. centrilobular) and their spatial proximity to KC was also assessed. In addition, flow cytometry was used to investigate the liver ploidy. In the case of HEP and KC, differences in the measured cell parameters were observed between male and female specimens; however, no such differences were detected for HSC. Female samples contained a higher number of HEP per gram, with more binucleate cells. The HEP nuclei were smaller in females, which was coincident with more abundant diploid particles in these animals. The female liver also had a greater number of KC per gram, with a lower percentage of KC in the vicinity of HSC compared with males. In this study, we document hitherto unknown morphological sexual dimorphism in the rat liver, namely in HEP and KC. These differences may account for the higher regenerative potential of the female liver and lend weight to the argument for considering the rat liver as a sexually dimorphic organ.

Voluntary monitoring systems for pig health and welfare in the UK: Comparative analysis of prevalence and temporal patterns of selected non-respiratory post mortem conditions

Collection of abattoir data related to public health is common worldwide. Standardised on-going programmes that collect information from abattoirs that inform producers about the presence and frequency of disease that are important to them rather than public health hazards are less common. The three voluntary pig health schemes, implemented in the United Kingdom, are integrated systems which capture information on different macroscopic disease conditions detected in slaughtered pigs. Many of these conditions have been associated with a reduction in performance traits and consequent increases in production costs. The schemes are the Wholesome Pigs Scotland in Scotland, the British Pig Health Scheme in England and Wales and the Pig Regen Ltd. health and welfare checks in Northern Ireland. In this study, four post mortem conditions (pericarditis, milk spots, papular dermatitis and tail damage) were surveyed and analysed over a ten and half year period, with the aim to compare the prevalence, monthly variations, and yearly trends between schemes. Liver milk spot was the most frequently recorded condition while tail damage was the least frequently observed condition. The prevalence of papular dermatitis was relatively low compared to liver milk spot and pericarditis in the three schemes. A general decreasing trend was observed for milk spots and papular dermatitis for all three schemes. The prevalence of pericarditis increased in Northern Ireland and England and Wales; while Scotland in recent years showed a decreasing trend. An increasing trend of tail damage was depicted in Scotland and Northern Ireland until 2013/2014 followed by a decline in recent years compared to that of England and Wales with a decreasing trend over the full study period. Monthly effects were more evident for milk spots and papular dermatitis. Similarity of the modus operandi of the schemes made the comparison of temporal variations and patterns in gross pathology between countries possible over time, especially between countries with similar pig production profile. This study of temporal patterns enables early detection of prevalence increases and alerts industry and researchers to investigate the reasons behind such changes. These schemes are, therefore, valuable assets for endemic disease surveillance, early warning for emerging disease and also for monitoring of welfare outcomes.

Using national movement databases to help inform responses to swine disease outbreaks in Scotland: the impact of uncertainty around incursion time

Modelling is an important component of contingency planning and control of disease outbreaks. Dynamic network models are considered more useful than static models because they capture important dynamic patterns of farm behaviour as evidenced through animal movements. This study evaluates the usefulness of a dynamic network model of swine fever to predict pre-detection spread via movements of pigs, when there may be considerable uncertainty surrounding the time of incursion of infection. It explores the utility and limitations of animal movement data to inform such models and as such, provides some insight into the impact of improving traceability through real-time animal movement reporting and the use of electronic animal movement databases. The study concludes that the type of premises and uncertainty of the time of disease incursion will affect model accuracy and highlights the need for improvements in these areas.

Liver and gender: are there differences in fibrous tissue before the onset of fibrosis?

important, the operators of performing an AUS in a local community setting were well trained by the two senior experts in gastroenterology (Dr. Tsung-Hui Hu, the second author, and Dr. ChaoSheng Liao, the last author), both of whom have practiced AUS for over 20 years. We think that quality control for screening with AUS would not be a serious problem. Indeed, large samples would be suggested for better operator reliability in the future before conducting such a mass screening. Indeed, in our risk score assessment, we did not include nonalcoholic fatty liver disease or alcoholic steatohepatitis alcoholic, as we did not have such information. We understand this plays an important role in HCC cases resulting from those free of hepatitis viral infection. This may be considered in our Group B (free of hepatitis viral infection). In the current scenario, not including this factor may have little effect, as our HCC cases in Taiwan so far are still dominated by hepatitis viral infection. Finally, on the basis of evidence-based medicine (EBM), we do agree with Cui et al. in pointing out that a randomized controlled trial (RCT) with long-term follow-up, evaluation of the sensitivity and specificity of US (several previous studies have been provided), and the aspect of an economic appraisal should be required before HCC screening with AUS is recommended. Our observational cohort study cannot replace the RCT but it provides a new insight into the possibility of considering mass screening for HCC with AUS in places with a high incidence HCC. HSIU-HSI CHEN, PH.D. YEN-PO YEH, PH.D. CHAO-SHENG LAO, PH.D. TSUNG-HIU HU, PH.D. AMY MING-FANG YEN, PH.D. WENDY YI-YING WU, PH.D. National Taiwan University School of Public Health Institute of Epidemiology and Preventive Medicine Taipei, Taiwan

Use of the optical disector in canine mammary simple and complex carcinomas

Grading of canine mammary carcinomas (CMC) is associated to subjective assessments made by the pathologists. Due to its unbiased nature, stereology can be used to objectively quantify morphological parameters associated with grading and malignancy. However, the use of stereology in CMC has not been fully disclosed. The nuclear numerical density [NV (nuclei, tumor)] is a cellularity‐associated parameter that can be estimated by the optical disector. Herein, it was estimated in 44 CMC and its association with clinicopathologic factors – such as tumor size, histological subtype and grade, vascular/lymph node invasion, nuclear pleomorphism, and survival – was evaluated. Considering all the cases, the mean NV (nuclei, tumor) was 1.6 × 106 ± 0.5 × 106 nuclei/mm3. Lower values were attained in complex carcinomas, comparing to simple carcinomas, in tumors smaller than 5 cm, with low mitotic activity and in those with high nuclear pleomorphism. No statistically significant association with grade or vascular/lymph node invasion was observed, but tumors with disease progression had lower nuclear densities. The NV (nuclei, tumor) and the correlated parameters mirror to some extension those in human breast cancer, suggesting an interesting interspecies agreement. This first estimation of the nuclear numerical density in CMC highlights the feasibility of the optical disector and their utility for objective morphological assessments in CMC. The association between nuclear numerical density and disease progression warrants future studies.

Detecting and managing new animal health threats: how vulnerable are we?

IN an ideal scenario, disease surveillance is nearly invisible. If all goes well, you can almost forget it’s there. However, when things don’t go well it represents the only way to quantify, prevent and mitigate disease outbreaks. The vulnerability of animal agriculture worldwide to notifiable and emerging diseases is regularly demonstrated, with significant impacts on food security and economic stability. The UK is not immune to this, as recent incursions of avian influenza have reminded us. Official authorities must be wary of such incursions and possess processes to respond to and manage such events, including preventing the introduction of exotic and emerging animal pathogens, detecting and managing outbreaks of exotic disease, and having an appropriate response system to control and eradicate disease in case of introduction (Torres and others 2002). The paper by Kosmider and others (2017), summarised on p 67 of this week’s issue of Veterinary Record , describes in detail how animal-related threats and vulnerabilities are identified in the UK, and how these threats are assessed and managed. The risk management cycle starts with the UK Veterinary Risk Group (VRG), which represents a network of teams across animal and public health throughout the UK that …