New Technologies for Surveillance/Monitoring on the Farm

Transcription

1 New Technologies for Surveillance/Monitoring on the Farm Prof. Alasdair JC Cook & Jimmy Wiseman Dept of Veterinary Epidemiology & Public Health School of Veterinary Medicine University of Surrey Sheep Health and Welfare Conference Wednesday 26th November 2014 Yarnfield Park Training and Conference Centre, Stone, Staffordshire, ST15 0NL Organised by the Sheep Health and Welfare Group (SHAWG).

2 Outline New approaches to delivery of surveillance Surveillance definition Purposes of surveillance Sources of information Users of information New technologies for detection and testing for disease Why do we need new tests? Desirable test characteristics LAMP tests

3 Introduction UK sheep population is approx 36 million sheep Ewe mortality estimated as 3% - 8% loss of up to one million ewes/ year Estimated ewe replacement rates approx 20% Lamb losses (birth sale) 8% - 10% Health & welfare issues include: Lameness Parasites (internal & external) Abortion & infertility Mastitis Production disease (metabolic/ nutritional etc) As Schmallenberg illustrated, sheep industry like other livestock sectors is susceptible to incursion of new diseases

4 The systematic, continuous or repeated, measurement, collection, collation, analysis, interpretation and timely dissemination of animal health and welfare related data from defined populations. These data are then used to describe health hazard occurrence and to contribute to the planning, implementation, and evaluation of risk mitigation actions. Animal Health Surveillance Terminology Final Report from Pre-ICAHS Workshop July 2013 (version 1.2)

5 Surveillance: Intelligence for Action The greatest challenge facing surveillance systems is awareness of the unexpected, recognising when things seem not quite right MacLehose L, et al (2002) Science Surveillance for the unknown requires a mindset different from surveillance of the known Vourc h G, et al (2006) EID

6 Surveillance purposes Scanning surveillance Demonstrate freedom from disease or infection Describe the level and distribution of specified diseases Describe changes in the health of the population or changes that may threaten the health of the population, this may include changes in the population at risk, changes in the occurrence of health indicators or of specified diseases Detect threats to human health Provide evidence in support of international trade Detect cases to facilitate control

7 Animal Health Surveillance and Farmed Livestock Stockperson observation includes all animals Veterinary practice records include individual clinical cases and may include herd parameters Herd / flock production data: Systematic info from many farms Laboratory data: Diagnostic; cases Screening; any animal Abattoir data healthy Fallen Stock data dead Movement records - transmission

8 The Surveillance Chain Farmer Member of the public Private Vet Veterinary Specialist Problems first spotted: 1. On farm. 2. In the habitat (wildlife). Veterinary surgeons checking for disease: 1. On farm. 2. At markets. 3. At agricultural shows 4. At slaughterhouses. Whole carcases or other samples submitted to: Whole 1. APHA. carcase 2. SAC. 3. Private Laboratories.

9 How have emerging diseases been found? Source of first alert among 117 new or re-emerging threats detected by APHA Scanning Surveillance ASSP Sustainable scanning surveillance in England and Wales: A report from the AHVLA Sustainable Surveillance Project.

10 Not a New Technology, But A pilot study on the value of fallen stock necropsy (Lovatt & Strugnell, 2013) aimed to investigate the diagnostic potential of this material and consider how such information might be applied to improve sheep health, welfare and productivity. Concluded that it is often possible to diagnose the cause of death without expensive diagnostic testing. Proposed that examination of fallen stock would lower the threshold for diagnostic investigation and thus improve best practice on UK sheep farms. For national disease surveillance and at the farm level, ongoing use of this concept may prove invaluable for livestock industries and the scope for its development is considerable.

11 From Eamon Watson, APHA

12 Private Vets & Surveillance Primary requirement for laboratory diagnosis Value determined by cost vs resolution of problem Timeliness important Secondary interest in local/ national intelligence What diseases are occurring now locally/ nationally? Are there changes in nature of endemic disease? Is this area free of conditions that are endemic nationally? Are there emerging threats elsewhere that could occur her & now? Altruistic interest in surveillance for public good What surveillance outputs are used by vets in practice? What outputs could be used? Shared interest with Defra where new disease suspected Subsidy to protect public interest not to enable producers to maximise production/ profit Added value as CPD/ education Know what it is next time Look out for new problems Inform decisions on treatment/ prevention

13 Government Farmer What are the Most Important Sheep Diseases in the UK? Well that can depend on who you ask! Varies between different regions. Depends on status and previous history of the flock. Owners of pedigree flocks may have different concerns. Scrapie Cryptosporidiosis Caseous lymphadenitis Salmonellosis Maedi-Visna Liver fluke Toxoplasmosis Clostridial disease Campylobacteriosis Parasitic gastroenteritis Enzootic abortion Lice Sheep scab Orf Lameness

14 Endemic Disease, the Overlooked Enemy! Notifiable and emerging disease threats usually take priority and, for the most part, this is justified, for economic and welfare reasons. However it should be remembered that actual losses due to endemic diseases far outweigh those from exotic or novel diseases. It is the improved control of these so-called, Known-knowns, that would allow major advances to be made. There is considerable scope to improve the control and management of endemic diseases in the livestock industry.

15 So..What Can be Done?

16 Demand for On-Farm Technologies Why do we need new veterinary tests?? More rapid, sensitive and specific tests required appropriate to purpose (surveillance vs diagnosis) and of defined quality More cost effective tests required (especially with regard to sheep) Culture-less tests Non-culturable/fastidious organisms. There is a clear need for reliable on-farm diagnostic tests that can be undertaken outside of the specialist laboratory Penside tests

17 Hallmarks of a Good Diagnostic Test Sensitive Specific Rapid & cost effective Robust

18 New test methods Test hypotheses: Is it a new threat? Why? Emergence of new agent what is it? Change in agent, host or environment New tools: Cheap & rapid screening of the usual PCR, BioSensor, LAMP Identification to sufficient level Malditof Genomics Other omics Early detection of the unusual the

19 Disadvantage of Culture Sample collection Microbiology agar, biochemical tests Result analysis Day 1 Day 2 Day 3 Day 4 Delivery Results

20 (LAMP) an Alternative Method to PCR Loop mediated Isothermal amplification - LAMP Conventional PCR Specific Sensitive Quicker than culture Requires a thermocycler Expensive instrumentation Not portable Higher power consumption LAMP Specific Sensitive Quicker than culture Isothermal Inexpensive instrumentation Portable Low power consumption

21 Options for Rapid Detection of the Target Organism Fluorometer Genie II 12v battery >1 kg Lateral flow device (LFD) Simple Unambiguous result Ideal for penside test Rapid and Cost Effective

22 LAMP - Summary Can detect as few as 4 copies of target gene Validated against a panel of 30 different bacteria species Sensitive Specific Positive result detectable in 7 minutes Rapid & cost effective Robust Can be used with extract prepared directly from clinical swabs This facilitates the efficacious and targeted treatment of infections, thereby improving the health and welfare of patients and promoting the responsible and effective use of antibiotics.

23 Rapid collection of PME data PathPal TM

24 On the Other Hand There are areas where surveillance information could potentially be collected in a cost-effective manner Ante-mortem (health and welfare) and post-mortem (gross abnormalities) examinations are already conducted on all animals at the abattoir. It is a legal requirement that fallen stock are collected by a licensed collector. Large numbers of sheep carcases are therefore collected in such sites and this presents an opportunity for examination in order to establish the cause(s) of death. Not all diagnoses require confirmatory laboratory testing.

25 Post-Mortem Examination, A Changing Service? Many AHVLA regional centres have closed and the government funded surveillance budget has been markedly reduced. As a result, many holdings are no longer within the recommended 1 hour of travel to a post-mortem facility. The Independent Surveillance Advisory Group recommended that Surveillance activities should rely less on expensive expert post mortem examinations and more on gathering, analysing and integrating different data sources to identify trends and diseases. The need for new facilities offering an efficient post-mortem examination and sample collection service is clear.

26 A new vision for surveillance Surveillance of animal health enables a healthy & sustainable food & farming industry and safeguards society from animal-related threats by the early identification of emerging disease and changes in patterns of endemic disease to inform timely action All stakeholders have the opportunity to contribute to and benefit from participation: Livestock owners Integrated enterprises Vets in practice Food processors Retailers Consumers Government

27 Key messages Surveillance is changing this brings new opportunities as well as risks Key opportunities are A greater focus on endemic disease for non-government stakeholders Integration of different sources of surveillance data to yield new information Key risk is a loss of system sensitivity if there were reduced participation by stakeholders and thus a potential for disintegration of existing systems Challenge to engage all stakeholders more completely in surveillance Increasing availability of new & sophisticated diagnostics, like LAMP, will reduce price Increase sensitivity Reduce time to diagnosis & thus benefit surveillance as well as improve service to private vets & their clients

28 Any Questions? Further queries: