1.1.3.1. International examples
The principles of surveillance are the same around the world; however, different countries may adopt different approaches to organise their surveillance systems. One of the main differences is how surveillance is funded. The majority of surveillance systems across European countries are publicly funded; however, some base their surveillance only on private systems (Häsler et al., 2014). The latter is the case for Denmark, where it was decided that, due to the small amount of imports the risk of introducing new diseases was very low and it did not justify a government funded laboratory (The Scottish Government, 2011). The organisation of laboratories and institutions performing surveillance activities also varies across the world. In the USA and Canada, surveillance for non-notifiable conditions relies on state and provincial organisations, but a national network coordinates the surveillance activities carried out by the different centres (Kloeze et al., 2010; United States Department of Agriculture, 2016). In Finland, four government-funded laboratories are localised in the areas with highest livestock density (The Scottish Government, 2011), whereas in The Netherlands only one laboratory is responsible for the testing of samples that generate surveillance data. The latter is located in the geographical centre of the country, which has been shown to not affect case submission rates. Animal health surveillance there is supplemented by a telephone helpdesk that offers advice to veterinarians and may start follow-up investigations when needed (GD Animal Health, 2014). This system allowed the early detection of Bluetongue virus serotype 8 and Schmallenberg virus (van Wuijckhuise et al., 2006; Elbers et al., 2012). In addition, The Netherlands also collects data from many other sources including production and husbandry data and abattoirs (GD Animal Health, 2014). This is also the case in the Scandinavian countries, where data regarding drug usage is used especially for the monitoring of antimicrobial resistance (Stege et al., 2003).
1.1.3.2. The United Kingdom system
Examples of how surveillance is organised in the UK have already been given in previous sections. To finish with the surveillance part of this literature review, an overview of the delivery of surveillance in the UK and Scotland is given in this section, with emphasis on the recent reviews and changes in its organisation.
In addition to active or targeted surveillance campaigns for notifiable diseases, the main source of surveillance in the UK is the publicly subsidised testing performed at the APHA VI centres in England and Wales, the SRUC DSC in Scotland and the AFBI laboratories in Northern Ireland. Private laboratories and livestock health schemes represent additional surveillance initiatives, although due to privacy and commercial reasons, very few data are publicly available (Drewe et al., 2014). In 2012 it was calculated that approximately 14% of cattle herds were included in the Cattle Health Certification Standards (CHeCS) that regulates health schemes across the UK and the Republic of Ireland (Brigstocke, 2012). These include important diseases like BVD and Johne’s disease and represent a missed opportunity to benefit from information regarding the prevalence of these conditions in the UK. Overall, cattle are the focus of most surveillance activities in the UK, involving nearly 94% of the public and private surveillance expenditure. By contrast, sheep represent up to 70% of the British livestock population and only receive 2% of the surveillance funds (Drewe et al., 2014; The Scottish Government, 2016b).
The diagnoses reached at the VI centres and DSC are collated in the VIDA database. The VIDA system was developed in 1967 (Hugh-Jones et al., 1969) and re-designed in 1973 (Hall et al., 1980). This was the first veterinary diagnostic centralised recording system in the UK. The VIDA codes were adapted from the Veterinary Medical Data Processing Scheme (VMDP) created by the US National Cancer Institute and have been periodically reviewed since then (Hugh-Jones et al., 1969; Hall et al., 1980). The individual diagnoses are grouped under nine body system groups which have been in use since VIDA was developed (Hugh-Jones et al., 1969). Initially, information was stored using card tabulators, but these were replaced by computers in the early 70s. Data were analysed annually. The main disadvantage of the VIDA database was that a category or detection system was not included for unknown emerging conditions. Therefore, after the bovine spongiform
encephalopathy (BSE) crisis, the system was reviewed in 1999. A new database called FarmFile was created to record additional information (Gibbens et al., 2008). Since 2004 data are analysed every four months and syndromes (diseases grouped by systems) and ‘diagnosis not reached’ (DNR) cases are analysed to detect any clusters that may suggest emergence of new or re-emergence of existing conditions (Gibbens et al., 2008). Bovine neonatal pancytopenia (‘bleeding calf syndrome’) and Schmallenberg virus are two examples of emerging diseases whose incursions in the UK were first detected by the APHA network of VI centres (Veterinary Laboratories Agency, 2009; Anon, 2012). During the first years of the database, about 150,000 samples were processed each year (Hall et al., 1980). Between 43,000 and 63,000 samples have been submitted to the database over the last eight years, with a progressive decrease in numbers since 2012 (Animal and Plant Health Agency, 2015c).
The first national laboratories in the UK were established in 1922 and since then the delivery of surveillance and the organisation of the laboratories have undergone many reviews (Bradley, 2000; The Scottish Government, 2011). After the BSE and FMD crises, the whole UK surveillance strategy was reconsidered in 2003 (Department for Environment Food and Rural Affairs, 2003). As a consequence, both the delivery of surveillance in England and Wales and Scotland were reviewed in 2012 and 2011 respectively (The Scottish Government, 2011; Surveillance Advisory Group, 2012). After the recommendations made by both reports, changes to the organisation of surveillance are still being debated. The need for more cost-effective approaches to veterinary surveillance was identified in both reviews. In England and Wales the APHA funding has been reduced from £10.2 to 7.2 million between 2010 and 2015 and in 2014 the first changes were applied to the delivery of PM examinations, with the closure of eight PM facilities. The provision of PM examinations was then supplemented by the RVC, the University of Bristol, the University of Surrey and the SRUC in North East England (Animal Health and Veterinary Laboratories Agency, 2013). A triage of samples has been added to the submission process and only those samples with potential use as surveillance material receive subsidised testing (University of Surrey, 2015) and a carcass collection service was introduced for those farms located more than one hour away from the PM examination facilities (Animal and Plant Health Agency, 2014a). In Scotland, an outcome of the 2011 review in Scotland was the creation of a ‘Strategic Management Board’ which was established in 2012 and is responsible for advising the
Scottish Government in the field of animal health surveillance. The review also recommended the closure of SRUC DSC, the centralisation of the laboratory services into one facility and the incorporation of existing animal health data streams to the current surveillance system (e.g. abattoir and CTS data) (The Scottish Government, 2011). The closure of the Inverness and Ayr DSC was discussed. A consultation process took place in which it was suggested that the Ayr DSC services could have been transferred to the School of Veterinary Medicine of the University of Glasgow. However, after the consultation with farmers, veterinarians and stakeholders it was decided to maintain both centres with some reorganisation.
The Scottish Centre for Production Animal Health and Food Safety (SCPAHFS) of the School of Veterinary Medicine of the University of Glasgow receives uneconomic cases donated by farmers and veterinarians in Scotland and Northern England. Animals receive full diagnostic work ups, including gross PM examinations and therefore represent an important source of animal health data. This data stream could potentially contribute to the existing surveillance system in Scotland and one of the aims of this thesis is to assess this possibility.