GB surveillance. Pig diseases. Contents. Highlights. Date: 14 th May Quarterly Report: Vol Q1 2010

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1 GB surveillance Safeguarding public and animal health Pig diseases Quarterly Report: Vol Q Date: 14 th May 2010 The VIDA diagnoses are recorded on the VLA FarmFile database and comply with agreed diagnostic criteria against which regular validations and audits are undertaken. The investigational expertise and comprehensive diagnostic laboratory facilities of both VLA and SAC are widely acknowledged, and unusual disease problems tend to be referred to either. However recognised conditions where there is either no diagnostic test, or a clinical diagnosis offers sufficient specificity to negate the need for laboratory investigation, are unlikely to be represented. The report may therefore be biased in favour of unusual incidents or those diseases that require laboratory investigation for confirmation. VLA RLs have UKAS Accreditation and comply with ISO standard. SAC Veterinary Services have UKAS accreditation at their central diagnostic laboratory and at the Edinburgh and St Boswells Disease Surveillance Centres which comply with ISO standard. Contents Page Highlights 1 Introduction to GB Pilot Report 2 Overview 3 Pig demographics and diagnostic submission rates 6 Notifiable diseases reported 7 Farm visit investigations 8 Food Safety Incidents 8 Endemic disease surveillance 8 Scanning surveillance for new and emerging disease 19 Science update 26 Highlights No food safety incidents involving pigs were reported. An outbreak of Mycobacterium bovis in outdoor pigs with circumstantial evidence that the infection was derived from badgers is of concern. There is no evidence of post weaning catabolic syndrome in GB, which has been reported in the USA and Canada. The continued control of PCV2 associated disease (PCVAD), since the introduction of PCV2 vaccines and the probable reduction in the incidence of other diseases, as a consequence of reduced immunosuppression is very encouraging for the industry. Editor: tel: fax:

2 1) INTRODUCTION This is the eighth pig surveillance report that combines information from all areas of Great Britain into a single, integrated overview of pig health across the whole region. It has been made possible through a partnership between Defra, SEERAD, the Veterinary Laboratories Agency (VLA) and Scottish Agricultural Colleges Veterinary Services (SAC VS) Division. A key objective for any pig disease scanning surveillance system is to increase the likelihood of early detection of important changes in pig health. Any major disease occurrence, such as the FMD outbreak of 2001, can have a major impact either by threatening public health and/or animal welfare, or through its economic impact on the agricultural industry and ancillary related industries like tourism across the whole of GB. The possibility of the incursion of exotic diseases, the emergence of a new disease, or changes in known diseases are all risks which scanning surveillance seeks to mitigate. Until recently, the surveillance networks north and south of the Scottish border have reported their findings separately, which reduced the likelihood of early detection of important changes in health in this single epidemiological population. The newly unified GB-wide data resource, coupled with new collaborative analytical processes should make detection of all these scenarios both easier and quicker. The network of 14 VLA Regional Laboratories (RLs) and two Surveillance Centres (at Veterinary Schools) in England and Wales and 8 SAC VS Disease Surveillance Centres in Scotland provides a diagnostic service to private veterinary practitioners across GB. Clinical scanning surveillance information derived from diagnostic samples and carcasses is collected and analysed to determine baseline disease levels in the pig population. The aim is to provide an assessment of the current disease status of the GB pig population and to warn of potential risks from changing disease trends or new diseases and of zoonotic diseases of human health significance. Since 1975, diagnostic data from both the VLA and SAC has been merged in the veterinary investigation diagnosis analysis (VIDA) database. This database has been an invaluable source of epidemiological trends for over 30 years, but was limited in the range of data recorded and the analyses available. In 1998, the VLA started to produce a more detailed dataset within FarmFile - a powerful database, linked to the VIDA database, containing a greater amount of descriptive epidemiological data on all submissions and incorporating analysis tools used for disease surveillance purposes. These tools provide automated statistical analysis and built-in alerters which highlight statistically significant, and therefore potentially clinically significant, changes in diseases diagnosis and trends enabling more extensive analysis of data for England and Wales from 1999 onwards. The harmonisation project was initiated in 2006 to allow the extension of FarmFile analysis to cover Scotland as well. This involved the development of a single, standardised data collection system; consistent diagnostic criteria and harmonised recording, which enables the collation of the disease surveillance data from all three countries. This has been achieved by collaboration between staff and disease consultants at the VLA and SAC VS, funded by Defra and SEERAD. Detailed surveillance data from laboratory submissions for all three countries can now be collated, providing a far greater amount of data for analysis and interpretation by disease consultants at a GB level, resulting in improved disease understanding and efficient use of relevant expertise. This should enable action to be taken and resources to be appropriately targeted at an earlier stage than was previously possible, as the dataset is now much more extensive and drawn from the whole pig population of GB. Further analyses will be developed and refined to improve disease surveillance and the health and welfare of the pig population of GB. 2

3 In this report, we are pleased to include an overview on certain matters concerning the pig industry in the first quarter of The overview has been written by Professor Stan Done, International Pig Expert. The views expressed in this overview are the authors own and should not be interpreted as official statements of Defra 2) OVERVIEW The Future of Worldwide Pig Meat Production During 2009 the world pig production is thought to have increased by 2% to around million metric tons. China was responsible for most of this growth with a 5% increase to nearly 50 million tons. It is likely that the Chinese industry will become increasingly productive as more huge commercial units are established. They will become self-sufficient and the exporting countries less well able to export to China. The international trade in pig meat has fallen as a result of the increasing self-sufficiency in China and Russia (down by 10.0% in 2009 compared with 2008) and the worldwide recession. Production this year is expected to rise in China (3.6%), Russia, EU (2%) but fall in the USA by 2%. The world biofuel production continues to increase with production of ethanol rising from 73.9bn litres in 2009 to a projected 85.9 bn litres in 2010 and total biofuel to reach 1m barrels in 2010 (one barrel equals litres). This will continue to put pressure on feedstuffs for rations which ultimately will result in increased meat prices. In the future we will have to produce much more food. Although there is a much increased interest in livestock and the carbon footprint there is no doubt that livestock in general and pigs in particular are vital for future generations (Prof. Leo den Hartog, Wageningen, quoted in Pig Progress, 2010, 25, 4). Prof. Leo den Hartog, Wageningen stated at a recent conference intensive livestock farming cannot be missed in the food industry now and in the future. Especially for cattle as in this world there are vast amounts of places where nothing else but grassland can be cultivated which needs to be transferred into milk and meat. The advantage of pigs is that they are omnivores and therefore can be used as a recycling vehicle for a huge number of by-products from both the liquid and solid food industries. Swill feeding is not permitted in the UK. The United States Department of Agriculture (USDA) agricultural projections until 2018 suggest that pig numbers in the USA will fall until 2012(due to high feed prices) and will then grow again partly as a reflection of the reduced exports of Canadian pigs into the USA. The Organisation of Economic Co-operation and Development (OECD) agricultural outlook suggests a similar result for pigs until 2018 with pig meat consumption rising from 102 million tons (2009) to 120 million tons by China, Brasil and Russia continue to dominate the world pork trade scene. World trade in pig meat is likely to expand at a modest rate (+1.8% a year until 2018) with world exports reaching 7.1 million tons by Future trends will also see more computerised wet feeding with all its associated benefits (better growth rate, improved grading, improved feed conversion, less food wasted, pigs eating more, much less dust, less slurry, less stress for pigs and better hygiene in the feed systems with reductions in mycotoxin levels). There can be problems but these can be overcome by care and attention to detail. Russia continues to invest heavily in the pork industry. By 2012, it is expected that the industry will produce some 2.7million tons up from 1.87 in The imports will be reduced to 14% of the demand and by 2020 it will reach 3.97 and the country will be self-sufficient by By 2020 there may be 35-45million pigs compared with 16.2 million in

4 The other Eastern European countries newly entered into the EU are also striving for selfsufficiency. The recent invasions of CSF and ASF have not helped with the loss of large numbers of pigs through culling. The lack of veterinary expertise for large modern units can also be a factor. Energy Energy consumption is now often the third biggest cost behind feed and labour. A low cost smart-meter will tell farmers where energy is being wasted. Simply turning off lights and making sure ventilation systems work properly, before embarking on extra measures like replacing conventional lights with low energy bulbs and using low energy heat pads, will considerably reduce energy use. After this, consideration can be given to heat exchangers and sophisticated farm energy reclaiming systems. Production In Denmark the top 5% of producers are already producing weaned piglets per sow per year (the top 25% manage 29.9%). The recent targets set are for 35 weaned piglets per sow per year. Fifteen years ago the target was 25 weaned pigs per year. Over that time the sows have increased in length by 10% and the weight has increased by 20% with an increase in litter size from 10 to 14. In effect this means that pens have to be bigger. This increase has often been accompanied by a stillbirths per litter but this is not so in Danish genetics used in Eastern Europe where the higher use of labour at farrowing time enables them to control stillbirth at around piglets per litter. This level of production requires an increased level of feeding with four to six small meals a day and a consumption of 10-12kg of food a day..if fed this frequently the sow will also stand up more often and therefore have more exercise, urinate more frequently and drink more often( a sow requires as much as 40 litres of water a day delivered at a flow rate of 10 litres /minute). Last year the Dutch exported 18.5% of their weaners to Germany (over 50%), Poland, Belgium, Romania, Slovakia, and Czech Republic. About 45% of pigs born in Holland are now exported as weaners or finishing pigs (4.7million pigs), the latter also in large numbers to Germany. Environmental Enrichment Assurance scheme standards now include guidance on manipulable materials for enrichment which are closely linked to Defra s Code of Recommendations for the Welfare of Livestock: Pigs ( Chains alone are not acceptable. Environmental enrichment can include straw, hay, wood, peat, sawdust, mushroom compost, or a mixture of such which does not adversely affect the heath of the animals. However, pigs respond to novelty and get bored with the same stimuli so it is important to rotate enrichment toys or materials and to monitor their effectiveness. Guidance will be provided by the Manipulable Materials Working Group set up by the National Pig Association (NPA). There will be about two months to introduce environmental enrichment for pigs before assurance audits ensure implementation. GM Crops The rise of GM crops has been so rapid that now worldwide 50% of the cotton is GM, 25% of the maize and 70% of the soya. This makes it incredibly difficult to transport these crops worldwide without contaminating ships and storage facilities making it extremely difficult to identify GM free crops for use in the EU. 4

5 Distillers Dried Grains with Solubles (DDGS) There has been an increasing uptake of distillers dried grains with solubles (DDGS) as an ingredient in pig diets. There is some evidence that the Vitamin E and selenium in sow s milk has been falling as these substances increase. The researchers at Iowa State believe there has been a rise in mulberry heart disease over the same period which may be related to the increased use of these ingredients. They may be used to levels of 40% in gestation diets, 20% in lactation diets and 30% or greater in growing/finishing diets. The high levels of DDGS may lead to greater oxidative stress caused by a reduced absorption of selenium from the diet and exacerbated by a high sulphur content in the DDGS. Vitamin E levels in the sow may also be reduced. Careful management of the pig s oxidative metabolism is required when pigs are fed high quantities of DDGS. Pig Prices Weaner prices increased to just below 52 /head in the week ending 13 th February which is 10% higher than in the same period in Supplies of weaners were tight due to poor weather conditions in January and improved EU prices. The UK pig price is around euros/kg ( 0.85 to the Euro at the time of writing). Sow Numbers Industry figures indicate that there appear to be up to 438,000 sows in the UK. The European pig cycle (cyclical increase and decrease in sow numbers) will bottom out in 2010 with Spain and Portugal suffering the most severe cutbacks in sow numbers. Salmonella The European Food Safety Authority s (EFSA) survey of salmonella in holdings of breeding pigs, shows that the UK is fourth in the league of salmonella-positive breeding units(holdings housing and selling mainly breeding pigs) and production units (holdings housing breeding pigs and selling pigs mainly for fattening or slaughter) in the EU. It is particularly important for the top of the pyramid units to understand the situation. The EFSA report Analysis of the Baseline Survey on the Prevalence of Salmonella in Holdings with Breeding Pigs in the EU, 2008 can be found at EFSA found 54 different serovars on breeding units and 88 on production units in the European Union. Breeding units are a worry as they can provide a source of infection through pyramids. Furthermore, salmonellosis can be a disease of considerable clinical significance on some units. The EFSA website is Science Update See appendix 1 5

6 2.1 Demographics, submissions and carcases Overall the number of diagnostic carcase submissions is very similar to 2009 for Q1 and higher than 2008 and 2007 when pig prices were markedly lower. There was an increase in carcases from England and Wales and a reduction in carcases from Scotland, the reason for this is unclear. 2.2 Diagnostic submissions and carcases Table 1 Pig Diagnostic Submissions and Carcases, (Q1 only) Table 2 Pig Diagnostic Submissions for England, Scotland and Wales Table 1 Submissions Carcases Jan - Mar E&W Scotland Total E&W Scotland Total Table 2 All Years Breeding Finishing Rearing Unknown/Other Sum: Eastern England Northern England Scotland Wales Western England Unknown Sum: ,199 6

7 Figure 1: GB diagnostic submissions Jan Mar 2010 (left) 2009 (right) E Eng 2010 E Eng 2009 N Eng 2010 N Eng 2009 Scotland 2010 Scotland 2009 Wales 2010 Wales 2009 W Eng 2010 W Eng 2009 Unk 2010 Unk Breeding Finishing Rearing Unknown/Other 2.2 The Meteorological Office report January was a particularly cold and dry month: rainfall in England, Wales and Scotland was between 50% and 75% of the mean and temperatures were well below (-2.5 o C on average) the mean. February was also drier than usual in most of GB except southern England, which experienced about 130% of mean monthly rainfall. It was also colder than usual (-1-2 o C on average) Rainfall was slightly below mean and temperatures were close to mean in March throughout GB. The relatively dry weather for parts of this quarter were favourable for outdoor pig farms and although temperatures were below mean values this was of less significance given the lack of wet weather for most of the quarter. 2.3 Notifiable Disease Reported Mycobacterium bovis (TB) was confirmed in finished pigs in a high incidence area. Initially, it was thought infection had occurred through an indirect route by contact with contaminated straw at the farm premises. Further investigation revealed significant wildlife (badger) activity in the outdoor farrowing paddocks from where the pigs were sourced. Infection of young piglets appears to be via contact with contaminated ground, feed and / or straw bedding in the outdoor farrowing paddocks. 7

8 2.4 Farm Investigational and Advisory Visits Currently, farm investigatory visits by VLA Veterinary Investigatory Officers are recorded for England and Wales. For Scotland, SAC record investigations, which may or may not include a visit to a farm. Harmonisation of this information is being considered for future reports. The information below is for England and Wales only. Table 3: Farm Investigation and Advisory Visits Quarter 1 Jan - Mar Breeder Breeder Fattener Breeder Rearer Breeder / Rearer / Fattener Fattener Other Rearer Rearer Fattener Total Visits Total The visits were to investigate and advise on swine influenza, salmonellosis and antimicrobial resistant E.coli infections. One welfare visit was undertaken where mange and malnutrition were identified as significant factors. 2.5 Food Safety Incidents There were no food safety incidents involving pigs. 3) ENDEMIC DISEASE SURVEILLANCE A note about the disease trends charts. This section of the report gives information on the data collected and analysed for diseases that were especially prevalent during the quarter due to seasonal influences or are especially topical or noteworthy for the period covered. For this report, data for England and Wales and Scotland have been combined onto a single histogram. Our charts show the number of diagnoses (numerator) as a proportion of the number of submissions in which that diagnosis was possible (denominator). These proportions are represented as blocks and the GB, combined, proportion as a line. The blocks are accompanied by bars indicating 95% confidence limits generally, the greater the number of samples examined, the smaller is this range and the greater the confidence that reported figure is true. Note that the y-axis scale of the charts varies and therefore care must be taken when comparing individual charts. 8

9 3.1) Salmonella and Salmonellosis The rate of diagnosis of salmonellosis from GB diagnosable submissions increased from 4.9% in the previous quarter (Q4, 2009) to 9.6% in Q1 2010, with submission numbers tested down from 295 in Q to 249 in Q The Q1 diagnosic rate returned to a similar level to those seen in Q1 between 2003 and Higher rates were seen in 2008 and 2009 with a peak of 13% in 2009 (see figure 2). Figure 2: Percentage of submissions diagnosed with salmonellosis in Q to 2010 Salmonella Typhimurium (STM) was confirmed in 20 out of 24 Salmonella positive submissions diagnosed, with S. Derby and S. London jointly isolated from another. The remaining Salmonella positive submissions were the monophasic Salmonella Typhimurium variant 4,5,12:i:-, which in one diagnosable submission to SAC caused colitis, ill thrift and 4% mortality in 10 week-old-pigs, in combination with Brachyspira pilosicoli. A second isolate, from an 800 sow outdoor herd in Southern England, showed multidrug resistance, most likely as the result of high levels of antibiotic usage on the unit, used to control an ongoing scour problem in weaned pigs. Long-term use of antibiotics is of concern given the limited number of antibiotics available, lack of alternative control strategies and the increased resistance being recorded. This STM monophasic variant has recently become of more interest due to an increased number of human Salmonella infections associated with this organism within the EU and the USA. Monophasic STM was identified on four other occasions from bacterial cultures submitted by private laboratories. The STM phage types 193 and U 288 again dominated within the STM isolates with an almost equal split between the two. One of the U288 isolates showed multidrug resistance. STM phage type 120 was identified on one occasion. 3.2) Brucellosis The number of cultures for Brucella suis under SB4070 are shown in table 4. Brucella suis was not isolated from these cultures. 9

10 Table 4: The number of primary cultures for B.suis undertaken by Regional Laboratories under project SB4070 from 2007 to 2010 Q1 Q2 Q3 Q4 Total 2007 Data not plus Q1 available ) Streptococcal Infections Table 5: Streptococcus suis serotyping results for England and Wales for Q Year /2 UT Totals UT = Untypable SAC reported in January 2009 that there was an increase in cultures that were proving to be untypable. There was an exchange of cultures between Bury St Edmunds and SAC. Of the seven isolates received from SAC 2 were untypable but biochemically they were a poor fit for Streptococcus suis and of the other isolates one was type ½ and the others type 10. There was no significant change in the serotypes isolated from England and Wales in Q when compared with previous years (see table 5). No other bacteria isolated from pigs, that were of note, were referred to Bury St Edmunds (Bury St Edmunds is the determinative bacteriology Regional Laboratory for England and Wales). 3.4) Post Weaning Multisystemic Syndrome (PMWS) The decline in quarterly percentage of relevant diagnostic submission with a diagnosis of PMWS continued for Q1 for GB (see histogram figure 3 below) as was seen for the previous quarter. GB recorded the lowest Q1 rate of diagnosis (2.91%) since the 2003 peak in diagnostic rates. These results reflect the continued control of this disease, primarily by vaccination 10

11 Figure 3: Diagnostic rates for PMWS for first quarters of each year vertical bars indicate 95% confidence limits 3.5) Porcine Dermatitis and Nephropathy Syndrome (PDNS) Cases of PDNS remained low this quarter continuing the low level that has established recently following a downward trend between 2005 and 2008 (see figure 4). Although this disease can occur with PCVD there are other aetiologies. The widespread use of PCV2 vaccine has assisted in the control of PDNS. Figure 4: Diagnostic rates for PDNS in Q vertical bars indicate 95% confidence limits 3.6) Porcine Circovirus Associated Disease (PCVAD) There were only two cases of PCV2 associated pneumonia recorded in this quarter. A further case of the unusual circoviral hepatitis was recorded during this quarter, the diagnosis being established from fixed tissue samples. This case was in two-week-old Berkshire pigs and shows that the risk of these sporadic cases, which are almost always seen in rarer traditional pig breeds, continues despite the widespread adoption of circovirus vaccines in commercial pig units. A review of cases of PCV2 associated disease for 2009 and the use of PCV2 vaccines was reported in the last quarterly report. A continuation of this review in submissions received 1 Dec 2009 to1 Apr 2010 with a diagnosis of PMWS, PDNS and PCV2 associated pneumonia identified six new cases for which detailed information is available on five. Findings are summarised on the next page. 11

12 Summary of findings 1/6 cases were PDNS; PCV2 vaccine used in piglets but not known if used in sows 3/6 cases were PCV2 associated pneumonia; 2 x no vaccine used, 1x vaccinal status unknown. 5/6 cases were PMWS; 4 x no vaccine used, 1 x unknown vaccine status 1/6 PCV2 enteritis; no vaccine used No disease was reported in known vaccinated piglets other than a single case of PDNS. Vaccines make no specific claims to protect against PDNS the aetiology of which has not yet been established. 3.7) Porcine Reproductive and Respiratory Syndrome (PRRS) The quarterly percentage of relevant diagnostic submission with a diagnosis of PRRS showed an increase in GB and EW compared with the same quarter last year. This increase was not statistically significant and was less than the percentage detected in the 2008 peak (see figure 5). This data includes diagnoses of pneumonia associated with PRRS, systemic PRRS and foetopathy. The diagnostic rate for this quarter (6%) is up from the 3.3% reported for the previous quarter (Q4 2009). In Q it showed diagnostic rates for all quarters since 2002 and indicated a peak in diagnoses occurring in the first two quarters of the year for 2008 and It may be that this current quarter rise indicates an establishing trend for higher diagnostic rates for PRRS in the first part of the year. Figure 5: Percentage of diagnosable submissions with PRRS in Q1 of each year vertical bars indicate 95% confidence limits 12

13 3.8) Respiratory Disease Submissions with a presenting sign of respiratory disease remained at a higher level for this quarter compared to the same quarter in The diagnostic rate for pneumonia and/or pleurisy is marginally increased from the same quarter of last year (see figure 6). Of interest is the publication by NADIS commentary on BPEX data on pleurisy in pigs which has shown a general reduction in the last year from a peak in autumn 2008 and which may consequently be having some impact on the percentages of diagnosable submissions with pneumonias and pleurisy which are also running at a lower level over this period. The report notes that although there are significant variations in pleurisy scores, which can be related to different production systems, the general reduction shows a temporal correlation with the widespread adoption of PCV2 vaccination in commercial pig herds, although it is too early to say if this is anything more than coincidental. Figure 6: Percentage of diagnosable submissions with pneumonia and/or pleurisy in the first quarters of each year vertical bars indicate 95% confidence limit Pasteurellosis Despite the afore mentioned slight rise in the pneumonia and pleurisy diagnostic rate the figures for pasteurellosis fell in this quarter (although without statistical significance) as shown in figure 7. Figure 7: First quarter diagnostic rates for pasteurellosis vertical bars indicate 95% confidence limits 13

14 This is despite occasional notable cases in finishing pigs, which resulted in severe respiratory pathology. In cases of bacterial pneumonia reported towards the end of this quarter stress factors such as fighting or active PRRS virus circulation were identified as predisposing causes Actinobacillosis There has been little change in the quarterly diagnostic rates for pleuropneumonia for this quarter over the last three years (see figure 8 below). Figure 8: First quarter diagnostic rates for actinobacillosis vertical bars indicate 95% confidence limits Enzootic pneumonia GB diagnostic rates in the first quarter for enzootic pneumonia were slightly increased with the main change seen in England and Wales, although again without statistical significance and still involving low overall numbers with only 4 cases in total from England and Wales (see figure 9), most of which were from East Anglia. The diagnostic rate for enzootic pneumonia in Scotland was comparatively low this quarter with a total of two cases in contrast to the last quarter and also in previous years for this quarter. Figure 9: First quarter diagnostic rates for enzootic pneumonia vertical bars indicate 95% confidence limits 14

15 Experimental infection of piglets with M. hyorhinis has produced cranioventral pneumonic lesions resembling those usually associated with enzootic pneumonia (EP) due to Mycoplasma hyopneumoniae infection and some strains of M hyorhinis can cause EP-like disease. In view of this a VIDA code was introduced in 2009 to gather data on pneumonia associated with M hyorhinis. In the first quarter in England and Wales M hyorhinis accounted for three out of seven (43%) cases of pneumonia in pigs with histopathological evidence of cuffing pneumonia from which either M hyorhinis and Mycoplasma hyopneumoniae were identified. This compares with 61% of cases reported in ) Swine Influenza Northern Ireland VLA has provided confirmation to the Agri-Food & Biosciences Institute (AFBI), Stormont of a sixth case of pandemic (H1N1) 2009 virus in pigs in Northern Ireland. Great Britain Submissions from 12 out of 73 pig herds tested for Influenza A were positive during the period January to March 2010 in Great Britain (GB) compared with eight positive herds in the last quarter of During Q1, pandemic (H1N1) 2009 virus (ph1n1) was detected in a further six pig herds taking the GB total number of cases to nine since the pandemic began in April 2009 to the end of this reporting period. The cases during the quarter comprised of four in England (now total 7) and two in Scotland ( now total 2) with cases distributed across all three months. The remaining influenza A subtypes identified were avian-like swine H1N1 (2 herds), H1N2 (1 herd) and untyped (3 herds) due to lack of infectious virus in submitted samples (PCR positive only, negative for ph1n1). Compared to the first and last quarters of 2009 there were increases of 159% and 88% respectively in samples tested (see table 6). This is thought to be due to increased awareness. Table 6: Number of samples tested for influenza and the number positive by quarter and year from (Q1). The samples originate from a total of 503 herds. Q1 no Q2 no Q3 no Q4 no Q1 no Q2 no Q3 no Q4 no Year (%) (%) (%) (%) Total tested tested tested tested positive positive positive positive /201 (4.5%) (3.0%) (0%) (5.7%) (4.0%) /372 (4.8%) (6.3%) (2.8%) (2.0%) (3.5%) /375 (3.9%) (1.9%) (6.6%) (12.4%) (6.4%) /197 (11.7%) (11.7%) Figures in brackets are the percentage positive 15

16 Comment - Consistent with reports from across the world ph1n1 continues to be detected in pigs. In two cases of ph1n1 detected this quarter evidence suggests there were epidemiological links to other infected breeding premises. 3.9) Alimentary Disease 3.9.1) Neonatal Enteric Disease Clostridium perfringens type A was diagnosed once this quarter by VLA in one-day-old housed piglets with diarrhoea. Clostridium perfringens type C was responsible for necrotic enteritis affecting 45/1000 outdoor piglets aged two days. This quarter shows the lowest level of clostridial disease in the last 9 years for quarter one in GB. The VLA made six diagnoses of rotavirus this quarter. Two were in conjunction with colibacillosis, in pigs of one to three weeks of age and a further two cases were in older piglets (4 weeks and eight weeks old) ) Enteric Colibacillosis 6.83% of submissions tested for E. coli in GB this quarter lead to a diagnosis of E. coli infection. This equates to 14 diagnoses which is higher than in quarter one for 2009 and 2008 but lower than for quarter one from 2002 to There is no statistical significance to the increase in Both England & Wales and Scotland saw increases in this condition this quarter. Of the 11 cases diagnosed by the VLA, two involved concurrent rotavirus infection. Ages affected ranged from two days to 13 weeks. The presenting sign was usually diarrhoea but occasionally animals were just found dead ) Gastric Ulceration Only one was case diagnosed this quarter. It was found in conjunction with Mycoplasma hyopneumoniae in 14-week-old pigs where two of 25 animals were found dead ) Lawsonia intracellularis Infections Only one case of Lawsonia intracellularis was diagnosed by VLA in quarter one, continuing the downward trend in this disease. The numbers of cases in Scotland were once more higher,compared with the previous quarter, than those in England and Wales but were less than in the same quarter for the previous five years. The VLA diagnosed case involved 12-week-old pigs where 12 out of a group of 40 that were affected by wasting and diarrhoea died. The 40 affected were part of a group of 800 animals. Salmonella Typhimurium colitis was also diagnosed ) Parasitic Enteritis Coccidiosis was diagnosed once in four-week-old housed pigs with diarrhoea. Seven of a group of 25 had died and iron deficiency anaemia was also diagnosed. 16

17 3.9.6) Intestinal Torsion Seven diagnoses of intestinal torsion were made this quarter. These represented five different holdings. Pigs 12 weeks to adult were affected and in the worst case 12 of 120 gilts were found dead. The history was invariably found dead. Two units involved housed pigs whereas the other three units were outdoor setups. There were no cases of torsion of stomach and spleen recorded this quarter ) Swine Dysentery (Brachyspira hyodysenteriae) Only four diagnoses of swine dysentery were made in the first quarter of 2010, each one from a different regional laboratory. The diagnoses were made from faeces or intestinal contents in the majority of cases, and the presenting sign was diarrhoea in all cases. No diagnoses of SD were made in the east of England (where the majority of GB pigs are farmed). However, as demonstrated in Figure 10, there has been a trend of increasing diagnostic rates for swine dysentery between This data confirms clinical impression that the disease has been on the increase in the past few years. Figure 10: Annual rates of swine dysentery diagnosis of diagnosable submissions, (NB still ongoing) 3.9.8) Porcine Intestinal Spirochaetosis (Brachyspira pilosicoli) Brachyspira pilosicoli was diagnosed as a cause of diarrhoea on six occasions during this quarter. On two of these occasions it was the only diagnosis reached, although in both cases only faeces samples were submitted. It was diagnosed twice alongside PCVAD/ PMWS and twice in conjunction with Salmonella Typhimurium. The most common presenting sign was diarrhoea and wasting. Porcine intestinal spirochaetosis was diagnosed with equal frequency in Scotland and England and Wales (~4% of diagnosable submissions), and no significant trends were seen between this quarter and the corresponding quarters in previous years ) Hepatosis dietetica Hepatosis dietetica was diagnosed as the cause of death of two six-week-old piglets, which arrived at an outdoor rearing site as weaners. Animals were noted to be small on arrival. In one animal the liver had ruptured and in the other there were large blood clots in the abdomen. Massive multifocal coagulative necrosis was seen histologically, confirming the gross post mortem appearance of multifocal beige foci up to 2mm in diameter throughout the liver 17

18 parenchyma, more marked at the margins. Hepatosis dietetica is caused by a net lack of the antioxidants vitamin E and selenium, and may be triggered by intakes of higher than normal levels of oxidants e.g. rancid fats. Bitumen has also been known to precipitate the disease. 3.10) Mycoplasmas ) Mycoplasma Surveillance 167 samples from 43 cases were submitted. M. hyopneumoniae was identified five times from lung samples. In addition M. hyopneumoniae was identified mixed with M. hyorhinis seven times, six from lung samples and once from a spleen. M. hyorhinis was detected in 18 lung samples and once from a spleen and once from a joint. M. hyosynoviae was detected once from joint fluid. M. flocculare was also detected from joint fluid. M. flocculare is not often reported, none were reported last year but two were reported in M. flocculare is not thought to be pathogenic but has been isolated from the lungs and nasal cavities of healthy swine and swine with respiratory disease ) Mycoplasma News from Publications Airborne transport of Mycoplasma hyopneumoniae and PRRSV were demonstrated after being detected 9.2km from an experimentally infected herd (Otake et al., 2010). This has implications should the industry attempt eradication programmes. Mycoplasma hyopneumoniae was eradicated from a finishing herd by treating affected animals with antimicrobials and by vaccinating introduced feeder pigs originating from M. hyopneumoniae- free herds. The groups were operated with an all-in-all-out method in rooms with separate ventilation and slurry disposal systems (Heinonen et al., 2010). Dahlia et al. (2009) report on the isolation of Mycoplasma hyosynoviae from severely consolidated lungs of a piglet with severe pneumonia in Malaysia This is of interest as the VLA identified M. hyosynoviae from porcine lungs on three occasions in References Dahlia et al. (2009). Isolation of Mycoplasma hyosynoviae from pneumonic lung of swine. Trop Biomed. 26: Heinonen et al. (2010). Eradication of Mycoplasma hyopneumoniae from a swine finishing herd without total depopulation. Vet J. Mar 16 Epub ahead of print. Otake et al. (2010). Long distance airborne transport of infectious PRRSV and Mycoplasma hyopneumoniae from a swine population infected with multiple viral variants. Vet Mirobiology. doi: /j.vetmic ) Reproductive Diseases The number of submissions for investigation of reproductive diseases was similar to previous quarters (see table 7). PRRS virus and porcine parvovirus were detected in aborted foetuses on one commercial herd each, and are included in routine screening of all submissions for the investigation of abortion. 18

19 Table 7: Number of pig submissions for diagnosis of reproductive diseases. Year Abortion Other reproductive Q1 Q2 Q3 Q4 Total Q1 Q2 Q3 Q4 Total ) Nervous Diseases There were no nervous diseases of note in Q ) UNUSUAL AND NEW DISEASES There were no unusual or new diseases in Q ) SCANNING SURVEILLANCE FOR NEW AND EMERGING DISEASES IN PIGS Monitoring the trends in diagnoses of known diseases cannot, by definition, detect either new diseases, or changes in endemic diseases that would prevent a diagnosis from being reached (for example a change in the pathogen that compromised the usual diagnostic test). Such new or emerging diseases would likely first be detected by observation of increased numbers of clinical and/or pathological syndromes for which a diagnosis could not be reached in the normal way. Such submissions are regularly analysed to look for changes that could indicate the presence of a new or emerging disease, which may be reflected by an increase in undiagnosed disease. Undiagnosed disease submissions are summarised broadly by the clinical presentation of disease and, once this has been determined by further investigation, the body system affected. Both groups are investigated and trends in the levels are compared over time. This approach has been developed and refined over recent years and such analyses are now possible for data from GB. 19

20 The following is a summary of pig data analysed by VLA and SAC from diagnostic samples submitted to Regional Laboratories. The aim of this report is to review data where a diagnosis was not reached despite the sample receiving reasonable testing. This allows monitoring of this class with the aim of providing information on new or emerging syndromes. It should be noted that VLA reports prior to 2005 on undiagnosed submissions included submissions which received both adequate and limited testing. Comparisons between the figures within this report should bear this is mind. Prior years refers to pooled data for years for VLA only data, and to data for for GB VIDA data. VIDA GB data to Q1, 2010: DNR by Presenting Sign The overall percentage of pig diagnostic submissions for GB VIDA for the first 3 months of 2010 (to first quarter, Q1) where a diagnosis was not reached (DNR) was 18.5% (38/205). This was not significantly increased from data to Q1 for prior years in which DNR was 16.6% (94/566). Looking at DNR rates for submissions with different presenting signs, there was a significant increase in DNR for a presenting sign of found dead for GB data for the first quarter of 2010; 17.2% (10/58) compared to 6.7% (7/104) in prior years. In contrast, there was a significant reduction in DNR for a presenting sign of diarrhoea in the first quarter of 2010; 7.2% (2/28) compared to 25% (26/104) in prior years. This was not due to a greater proportion of carcase submissions with this presenting sign (DNR is lower for carcase submissions compared to non-carcase submissions), the proportion of carcase to non-carcase submissions remained approximately 1:2, similar to prior years. VIDA GB Rolling 12-month data: DNR by Presenting Sign As relatively low numbers of submissions are analysed in Q1 (just 3 months data) it is useful to also analyse rolling 12-month DNR rates, there was no significant increase in DNR for the 12 month period Q2, 2009 to Q1, 2010 compared to the previous 12 months; DNR was 19.6% (187/952) compared to 16.9% (199/1176). No individual presenting sign gave a significantly increased DNR for overall GB data, or for SAC or VLA data analysed separately. Drilling into the data for each presenting sign, a significant increase in DNR for submissions with wasting as a presenting sign was detected in Northern England; 36.9% (7/19) compared to 10.5% (4/38). VIDA GB data to Q1, 2010: DNR by Disease Syndrome There was a significant increase in GB data for DNR for one syndrome only in Q1, 2010 compared to prior years; this was for systemic and miscellaneous syndrome for which DNR was 15.3% (13/85) compared to 4.8% (11/228). When assessed separately, SAC data showed no significant increase in DNR for this syndrome, while VLA data did show a significant increase; 18.3% compared to 4.7%. The systemic and miscellaneous syndrome covers a wide range of diseases and it is likely that the increased DNR parallels the increased DNR observed for submissions with a presenting sign of found dead. 20

21 There was a significant reduction in DNR for enteric syndrome for VLA data; 7% (3/43) compared to 24.8% (31/125). This correlates with the reduction in DNR for submissions with a presenting sign of diarrhoea in the first quarter of 2010 for GB data. In Q1, 2010, there were three undiagnosed (with reasonable testing) enteric submissions from pre-weaned or neonatal pigs to VLA. In all three cases, they were non-carcase submissions for which it is recognised that a diagnosis is less likely to be established, especially in young piglets where histopathology and other tests are often required to achieve a diagnosis. These observations mean that there is no evidence that the unexplained neonatal pig enteric problem, described in Europe and referred to in the last quarterly report, is emerging in GB pigs. Comparing Q1, 2010 with the previous quarter Q4, 2009, DNR was significantly increased for VLA data for two syndromes: respiratory 14.3% (4/28) compared to 0% (0/35) and systemic and miscellaneous 18.3% (13/71) compared to 4.6% (3/65). These will be kept under review, a preliminary assessment of the undiagnosed submissions does not indicate common presentations or findings to suggest emergence of a new disease in either syndrome. When DNR for each disease syndrome was analysed for VIDA GB rolling 12-month there was no significant increase in DNR for any individual syndrome for GB, VLA or SAC data. Tables 9 and 10 below give GB, VLA and SAC DNR rates by syndrome and presenting sign for the first three months of 2010 compared to prior years. Increased DNR for Submissions with a Presenting Sign Found Dead The statistically significant increase in DNR for this presenting sign to Q1, 2010 was found to be associated with an increase in DNR for submissions found dead in January 2010 and in postweaned pigs. The undiagnosed submissions were from Scotland, Eastern England and Western England, two were non-carcase and eight were carcase submissions and they were from both housed and outdoor pig units. Further analysis of the data showed that whilst some are true DNR, the clinical histories and findings do not suggest a common presentation. It is clear that prompt submission of carcases is important and that antimicrobial treatment adversely affects bacteriology, follow-up submissions may be necessary to establish diagnoses if clinical disease is persisting on farm. 21

22 Table 8: Undiagnosed VLA submissions found dead as a presenting sign for the first three months of 2010 Age Summary of findings Comment 4-5 weeks 8/100 affected over one month. Anaemia and ill-thrift, iron status satisfactory, no Mycoplasma id by DGGE Histopathology suggestive of a septicaemia, cause of anaemia not established. Further pme offered free of charge 10 weeks 14 weeks 13 weeks 7/350 sudden deaths over one week. Good body condition. Fatal haemorrhage from liver rupture. One sudden death, good body condition 15/1400 affected with cough, lameness, meningitis. Two plucks. Histopathology suggestive septicaemia, no organisms isolated. Antibiotic in feed may have affected culture results. PME of further cases advised. Septicaemia suspected, on in-feed antibiotic Likely Glassers, though H. parasuis not isolated 7 weeks 13/880 dead Histopathology and findings suggestive of septicaemia, no organisms isolated but delay in submitting carcase. 4 months Valvular endocarditis Only valve lesion submitted, no significant organisms isolated = limited testing 9 weeks Berkshire cross pigs. 4/10 of litter dead in 24 hours one week post-weaning 6 months One day 10 weeks 2 months 14 weeks Pet Kune kune pig sudden death. 6/8 dead with malaise and diarrhoea and found dead 50/170 affected with chronic illthrift and scour, colitis in submitted pigs 17/500 dead over a 24 hour period, one outdoor paddock. Rest well. Histopathology indicated DIC suggestive of septicaemic/endotoxaemia as most likely cause. DNR but submitted 6 days after death Only small intestine submitted = limited testing Brachyspira positive FAT but none cultured or id by PCR. Salmonellosis in previous submission. Pigs had been treated. No diagnosis established and no feedback from farmer to PVS or VLA 1/6 found dead No cause established. Increased DNR for wasting as a presenting sign Q2, 2009 to Q1, 2010 As indicated above, there were significantly more undiagnosed submissions with wasting as a presenting sign in Northern England for VIDA GB Rolling 12-month data. The details of such 22

23 VLA submissions from all regions were reviewed, particularly in light of reports from Canada of a wasting condition in post-weaned pigs known as post-weaning catabolic syndrome (PWCS) which affects pigs immediately after weaning, usually 4-8 weeks old, for which the cause has not been established. Data from Vladimir indicates that there were 14 undiagnosed submissions from wasting postweaned pigs. In seven of these, testing was limited by sample type as they were non-carcase submissions. VLA and SAC continue to advise submission of pigs to investigate disease conditions such as wasting. In three submissions, wasting was considered likely to be a sequel to earlier enteric disease for which the cause was no longer apparent, while in three others antimicrobial treatment was considered to have affected bacteriology; in two chronic salmonellosis was suspected and in a third with bacterial polyserositis, Haemophilus parasuis was considered a likely cause. Submission of untreated pigs early in the course of disease is advised to give best chance of achieving a diagnosis. In one case, findings were not considered conclusive; mild colitis was present and Brachyspira pilosicoli was isolated. Thus, there is no evidence for emergence of a PWCS-like condition; this will be kept under review. Table 9; VIDA Overall Changes in DNR rates for Pigs by Presenting Sign to Q1 for 2010 and prior years (2008-9) GB 23

24 Red highlighting indicates a significant increase in DNR compared to prior years. Green highlighting indicates a significant decrease in DNR compared to prior years. 24

25 Table 10: VIDA Overall Changes in DNR rates for Pigs by Syndrome to Q1 for 2010 and prior years 25