1. Frances Cassirer Idaho Department of Fish and Game
How important are super-spreaders for disease persistence in bighorn sheep populations?
Frances Cassirer
Idaho Department of Fish and Game

3. Time series of pneumonia: 1995 - 2010 16 bighorn sheep populations
(km) km
Pneumonia in adults
Pneumonia in lambs
Pneumonia in both age classes
No pneumonia detected

4. Population dynamics post-outbreak: three Hells Canyon populations

5. Patterns of Movi shedding: Proportion of animals that tested positive for Movi at capture in 8 Hells Canyon populations,

6. Patterns of Movi shedding: consistency within individuals
Negative
Intermittent
Chronic
Lostine bighorn sheep
through 2013
WSU domestic sheep flock

7. Research hypothesis
Respiratory disease persists within bighorn sheep populations through the infection of a relatively small number of chronic or super shedders that drive disease transmission

8. Presence and implications of individual variation in disease transmission
Lloyd-Smith, Schreiber, Kopp, and Getz Superspreading and the effect of individuaal variation on disease emergence. Nature

9. Hells Canyon: Capture and sampling

10. Samples collected Sample type Media Test Nasal swab Mycoplasma broth
PCR M. ovipneumoniae
Dry, frozen
qPCR Movi
Nasal wash
50 ml saline
qPCR Movi, IgA (mucosal) antibodies, 16S PCR-sequencing
Blood
Red top
Antibodies to Movi, IgG
Oropharyngeal swab
Port-a-cul or broth
Culture for Pasteurella, PCR leukotoxin
qPCR for leukotoxin

11. Testing results Movi: Lostine

12. Testing results Movi: Asotin

13. Will removing chronic Movi shedders in the field increase lamb survival?
Experiment 1 – Remove ewes and lambs that consistently (2 or more times) test positive in at least two populations.
Experiment 2 – Translocate a group of animals that consistently test negative to a new area.
Predictions - both experiments would reduce pneumonia-caused mortality (improve summer lamb survival) and reduce Movi infection prevalence in adults.

14. Captive experiment South Dakota State University
Commingling study to monitor health and survival of lambs born to ewes of different shedding status.
Designed for three replicate populations, 10 sheep per population over three years.
Study started this year with sheep from Hells Canyon.

15. Captive experiment – Year 1

16. Captive experiment year 1 predictions

17. Captive experiment – Year 2 (breed with negative ram from the same population)
Prediction – all lambs get pneumonia and die

18. Captive experiment year 3

19. Acknowledgments