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Tracking animal movement: Implications for Emerging Disease

Tracking animal movement: Implications for Emerging Disease. Dr. John Campbell Dept. of Large Animal Clinical Sciences Western College of Veterinary Medicine. Animal Movement and Disease Emergence. Animal Movement/Travel is a potent force in disease emergence and spread

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Tracking animal movement: Implications for Emerging Disease

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  1. Tracking animal movement: Implications for Emerging Disease Dr. John Campbell Dept. of Large Animal Clinical Sciences Western College of Veterinary Medicine

  2. Animal Movement and Disease Emergence • Animal Movement/Travel is a potent force in disease emergence and spread • The current volume, speed, and extent of movement of domestic animals and their products is unprecedented! • Our knowledge of movement is limited at best!

  3. Basic Concepts in Disease Emergence • Emergence of infectious diseases is complex • Infectious diseases are dynamic • Human activities are the most potent factors driving disease emergence Wilson, ME; Emerging Infectious Diseases Vol 1:39-46; 1995

  4. Basic Concepts in Disease Emergence • Social, economic, political, climatic, technologic and environmental factors shape disease patterns and influence emergence • Understanding and responding to disease emergence requires a global perspective, conceptually and geographically Wilson, ME; Emerging Infectious Diseases Vol 1:39-46; 1995

  5. Factors Contributing to the Emergence of Zoonotic Diseases • Host Population Determinants • Host behavioural characteristics • Ecologic/Climatologic influences • Societal/Transport/Commercial Factors Murphy, Emerging Infectious Diseases Vol 4: 1998: 429-510

  6. Travel and Disease Emergence • Smallpox • 1st epidemics in New World followed European explorers • Population of central Mexico dropped by 1/3 in the decade after Europeans arrived • Influenza • 1918 influenza pandemic was concentrated in military bases throughout US • Arguably the most mobile population of the time

  7. Animal Movement and Emerging Disease Examples

  8. Active trading of pigs and movement of pigs over long distances facilitated virus spread during outbreak of Nipah virus in Malaysia

  9. Machupo Virus(or How Cats Saved the World)

  10. Machupo Epidemiology • New villages disturbed natural habitat of Calomys • Provided mice with new food source (corn in village) • Mice migrate from forest to villages • Mice urinate in homes throughout night • Villagers inhale aerosolized urine or ingest urine contaminated food

  11. June 1964 • Following a successful trial utilizing mouse traps: • Hundreds of cats are airlifted into San Joaquin • Epidemic ends completely shortly thereafter

  12. Research: Elk Movement Study • Information continues to be gathered on approx. 50 elk using both VHF and GPS collars. • Analysis of the data is on-going, however indications are that some elk spend considerable time outside the Park, and three elk have moved between Riding Mountain and Duck Mountain Provincial Forest.

  13. Courtesy: Ryan Brook

  14. BSE: A Political Disease!

  15. The Movement of Domestic Animals and Animal Products is at an unprecedented level! • Globalization of world’s economy • The value of food trade in 1994 was $266 billion dollars (US) • 300% greater than 20 years ago and continues to grow rapidly

  16. How did BSE get to North America? • Was there a similar mutation of scrapie in sheep? • Was it CWD? • Was it spontaneous BSE? • Molecular analysis of prions would suggest that these are unlikely • Was it imported pre-ban MBM? • Did we import an infected bovine from the UK or elsewhere?

  17. Meat and Bone Meal Movement • Meat and Bone meal is simply a commodity • It is traded and moved across borders like many other commodities • Commodity Brokers look for opportunities to buy and sell this product • Once it moves into another country it quickly loses it’s identity of origin!

  18. When did it really all start? • Current evidence from a number of epidemiological studies suggests that the first case probably occurred in the late 1970s • British dairy rations typically contained rendered meat and bone meal (MBM) at this time

  19. Why was the feeding of MBM so widespread? • It was freely available • At this same time there was a massive reduction in the UK sheep flock, there is no market for cull sheep beyond rendering • It was needed • There is no easily available cost effective source of protein feed in the UK • It was a common ingredient in calf-starter rations

  20. The British Epidemic

  21. Canadian Imports of Meat Meal (1990-1995) • Canada did not import from UK • Most of our imported MBM originated from U.S.A. • USA: 75.4 million kg • New Zealand: 176,000 kg • Australia: 38,000 kg • Denmark: 26,000 kg

  22. The UK Imports • 1993: First Canadian case of BSE in Alberta • An Saler cow from UK imported in 1987 • The herd and all offspring were destroyed • CFIA began searching for all imported cattle from UK between 1982 and 1989 • 182 animals from UK and Ireland were imported between 1982 and 1989

  23. 182 UK imports 1982-1990 1993 Saler cow in Alberta Diagnosed with BSE Subsequent CFIA cull removes remaining UK imports in Canada (incineration or removed) 68 of these animals were already dead Rendering Plant

  24. UK Imports Geographic Distribution 7 30 2 1 3 5 20

  25. Tracking Movement as an Aspect of Risk Analysis • If a BSE infected animal dies in a certain geographical location: • Where does the rendered product travel to? • What is the risk of that product moving into another geographical area? • Eg: Western Canada to Eastern Canada?

  26. Describing the “Watershed” of Meat and Bone Meal • Collection area includes both: • Deadstock pickup • Rendered product from packing plants • What is the collection area for a packing plant? • Almost no information….. • Watershed of product is somewhat easier to describe but is still difficult

  27. Animal Movement Aspects of BSE Risk Analysis • How likely would a potentially infected BSE cow move out of the MBM collection area and watershed? • Move to another area for slaughter? • Move to another area for another segment of industry (eg: feedlot) • Move to another area as a mature cow? • There is very little data available • Brand inspections etc…

  28. Gaps in Risk Analysis • Some limitations in our ability to describe the “watershed” of meat and bone meal • Cattle Movement within Canada is not well described! • What was the probability that infected animals would move inter-provincially? • This has obvious implications for other emerging diseases or foreign animal diseases • A research priority of the CAHC

  29. The Future • CCIA tag systems now allow trace-back to farm of origin • New RFID tags should enhance the ability to actively track cattle movements • Animal Movement is an important and somewhat neglected component of infectious disease research! • Tools such as Network theory may help with this type of research

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