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Environmental distribution of M. paratuberculosis on cow-calf farms with clinical Johne’s disease in Western Canada. Dale Douma DVM Western College of Veterinary Medicine. Outline. Introduction to the Johne’s Disease Research Prevalence Study Wildlife Study Environment Study Conclusions.
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Environmental distribution of M. paratuberculosis on cow-calf farms with clinical Johne’s disease in Western Canada Dale Douma DVM Western College of Veterinary Medicine
Outline • Introduction to the Johne’s Disease • Research • Prevalence Study • Wildlife Study • Environment Study • Conclusions
What is Johne’s disease? • Chronic granulomatous enteritis of ruminants • Signs include: • Profuse diarrhea • Severe weight loss • Altered lining of the intestine • Thickened and corrugated mucosa • Caused by Mycobacterium paratuberculosis http://www.johnes.org
Bacterial cause discovered by Dr. H. Johne and Dr. L. Frothingham in 1895 in Germany Acid fast bacteria similar to M. avium and pathology similar to intestinal tuberculosis in cattle First found in North America in 1908 History of Johne’s http://www.johnes.org/history/index.html
M. paratuberculosis • aka M. avium paratuberculosis “Map” • Virtually identical to M. avium genetically (>99%) • Behaves differently • Mycobactin dependant for iron transport • Slower growing • Primarily infects ruminants but not exclusively
M. paratuberculosis • Small Gram-positive rod-shaped bacterium • Acid Fast positive • Tendency to clump together • Waxy rough cell wall • Can survive outside of host • Replicates inside of macrophages
Johne’s Disease Transmission Cycle: Pictures from: http://www.johnes.org
Why present at ADED? • Cattle prevalence increasing • Host range expanding? • Other ruminants • Non-ruminants • Primates • Zoonotic concern • Crohn’s disease • Positive association evident http://www.johnes.org/zoonotic/index.html
Research Objectives • Determine the seroprevalence of Map in Canadian beef cow-calf herds • Survey wildlife present on cow-calf farms that may be infected with Map • Characterize the distribution of Map within the environment of these cow-calf herds • Evaluate the potential of using environmental sampling as a economical herd test
Seroprevalence Study • Production Limiting Disease Committee research project • Collected 4778 serum samples from 179 cow-calf herds across Canada in 2003 • excluding Manitoba and Quebec
Wildlife Survey • Trapped wild rodents and birds on 6 cow-calf herds with clinical Johne’s disease • 4 rounds of trapping • One round every 3 months for one year
Wildlife Survey • Results – all 4 rounds • 202 Birds (sparrows, junco, swallows, etc) • 236 Rodents (house mice, deer mice, RGS, etc) • No positive samples • Birds and rodents appear to be non susceptible or unaffected by Map due to low exposure on cow-calf farms
Coyote Survey • Part of tuberculosis study by Dr. Gary Wobeser and Dr. Cheryl Sangster • Lymph nodes collected from 82 trapped coyotes around Riding Mountain National Park and submitted for culture to the CFIA • 0 positive for tuberculosis • 3 positive for Map (3.7%; 95% CI 0-7.7) • Significance • First report of Map cultured from multiple coyotes at one location • Further research required
Map of trapped coyote locations RMNP Blue – Map Negative Red – Map Positive
Environmental Study • Method • Enrolled 27 herds with a history of clinical Johne’s disease • Collected approx. 15 environmental samples per herd during the calving season • Collected manure from up to 150 cattle per herd to estimate prevalence • Cultured in pools of 5 • Compared results of test methods
Environmental Study • Results • Water Samples • 26 biofilm samples, 54 samples from waterers, 21 dugout samples, and 13 farm drainage samples including creeks and rivers • 0 culture positive for Map
Environmental Study • 243 non-water environmental samples were collected • 15 (6.2%) were positive for Map • chute systems: 4/26 (15.6%) • outside cattle feeders: 3/21 (14.3%) • inside cattle feeders: 2/21 (9.5%) • mothering-up pens: 2/13 (15.4%) • bullpens : 1/7 (14.3%) • turnout pens: 1/10 (10.0%) • calf shelters: 1/18 (5.6%) • calving pens: 1/26 (3.8%) • No Map was detected in 101 samples from: pastures (24), hospital pens (19), manure storage areas (17), young stock pens (10), creep feeders (7), mineral supplements (4), calf pens (2), and other areas of owner concern (18).
Environmental Study • Results for Environmental Testing as a Herd Test • 8 of 27 (29.6%) herds had at least one positive environmental sample • 17 of 27 (63.0%) herds had at least one positive fecal pool • 2 of 27 (7.4%) herds were positive only on environmental sampling • 9 of 27 (33.3%) herds were positive only with fecal pool cultures
In Conclusion • At this time: • Johne’s prevalence in cow-calf herds in Canada is relatively low • Environmental contamination of Map on cow-calf farms is low • The time to act is now • Environmental sampling as done in this research study is not sensitive enough at this time to replace animal sampling
Thank you! • Funding Agencies: • Agriculture Development Fund of Saskatchewan • Beef Cattle Research Council • Beef Development Fund of Saskatchewan • Wildlife Health Fund • Interprovincial Graduate Student Fellowship