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
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Outline
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Introduction to the Johne’s Disease
Research
Prevalence Study
 Wildlife Study
 Environment Study
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Conclusions
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What is Johne’s disease?

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Chronic granulomatous enteritis of ruminants
Signs include:
Profuse diarrhea
 Severe weight loss
 Altered lining of the intestine

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Thickened and corrugated mucosa
http://www.johnes.org
Caused by Mycobacterium paratuberculosis
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History of Johne’s
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
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
http://www.johnes.org/history/index.html
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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
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M. paratuberculosis
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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
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Pictures from: http://www.johnes.org
Johne’s Disease Transmission Cycle:
Why present at ADED?
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Cattle prevalence increasing

Host range expanding?
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Other ruminants
Non-ruminants
Primates
Zoonotic concern

Crohn’s disease

Positive association evident
http://www.johnes.org/zoonotic/index.html
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Research Objectives

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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
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Seroprevalence Study


Production Limiting Disease Committee
research project
Collected 4778 serum samples from 179 cowcalf herds across Canada in 2003

excluding Manitoba and Quebec
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Table 1. Summary of the results of cow and herd level seroprevalence by
province.
Animal Level Prevalence
Herd Level Prevalence (≥2 pos.)
Region
No. of cows
tested
positive
No. of
cows
tested
Apparent
Prevalence %
(95%CI)
No. of
herds
tested
positive
Alberta
7
833
0.8% (0-1.7)
2
29
6.9% (0-16.3)
British Columbia
3
1196
0.3% (0-0.5)
0
44
0.0%
Ontario
11
1037
1.1% (0-2.1)
3
40
7.5% (0-15.8)
Saskatchewan
5
880
0.6% (0-1.1)
1
32
3.1% (0-9.3)
Maritimes
(NB,NS,PEI)
11
832
1.3% (0-2.6)
2
34
5.9% (0-13.9)
Overall
37
4778
0.8% (0.4-1.1)
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179
4.5% (1.4-7.5)
No. of
herds
tested
Prevalence %
(95%CI)
Serologic results determined by Elisa testing using the optical density cutoff of 0.100 above the
mean of two negative controls
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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
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Wildlife Survey

Results – all 4 rounds
202 Birds (sparrows, junco, swallows, etc)
 236 Rodents (house mice, deer mice, RGS, etc)
 No positive samples
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Birds and rodents appear to be non susceptible or
unaffected by Map due to low exposure on cow-calf
farms
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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)
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Significance
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First report of Map cultured from multiple coyotes at one location
Further research required
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Map of trapped coyote locations
RMNP
Blue – Map Negative
Red – Map Positive
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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
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Cultured in pools of 5
Compared results of test methods
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Environmental Study

Results
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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
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Environmental Study
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243 non-water environmental samples were collected
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15 (6.2%) were positive for Map
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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).
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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
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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


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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
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Thank you!
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Funding Agencies:
Agriculture Development Fund of
Saskatchewan
 Beef Cattle Research Council
 Beef Development Fund of Saskatchewan
 Wildlife Health Fund
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