Journal of the Royal Society of Western Australia, 90(3), September 2007 
Table 1 
Results of a 12-month Salmonella recapture programme of quokkas, Setonix brachyurus, on Rottnest Island carried out in areas of 
public contact between 1984 and 1985. 
Quokkas 
Settlement 
Areas 
Camping 
Area 
Kingston/ 
Bickley 
Lighthouse 
Swamp 
Mobiles 
Totals 
No. Tagged 
344 
91 
86 
100 
49 
670 
Males 
158 
62 
38 
43 
30 
331 
Females 
186 
29 
48 
57 
19 
339 
No. Positive (%) 
71 (20.6) 
23 (25.3) 
36 (41.9) 
67 (67) 
10 (20.4) 
207 (30.9) 
Recaptures 
69 
25 
27 
75 
49 
284 
No. Swabbed once (1) 
276 
66 
59 
25 
0 
426 
Twice (2) 
56 
20 
22 
15 
26 
139 
(3) 
10 
5 
3 
25 
14 
57 
(4) 
2 
2 
7 
3 
14 
(5) 
9 
5 
14 
(6) 
8 
1 
9 
(7) 
4 
4 
(8) 
7 
7 
Total swabs 
426 
121 
120 
335 
137 
1139 
Total Serotypes 
20 
8 
15 
14 
6 
25 (25) 
Total Isolations 
81 
27 
54 
133 
14 
309 
Juveniles 
23 
4 
8 
29 
3 
58 
Results 
A total of 670 quokkas was tagged at the 4 major sites 
comprising settlement and camping area, 435; Kingston/ 
Bickley Swamp, 86; Lighthouse Swamp, 100; 'mobiles', 
49. Salmonella isolation rates over the one-year period, 
including recaptured animals, averaged 21% in the 
settlement area, 42% in Kingston and Bickley Swamp and 
67% in Lighthouse swamp, with a marked seasonal 
pattern, decreasing over the southern winter period. A 
combined total of 197 (32%) animals yielded Salmonellae 
at the four locations and 25 serotypes were identified 
from a total of 1002 swab samples (excluding mobiles) as 
shown in Table 1. A small number of faeces voided 
during collection of swab samples from adults and pouch 
young yielded an MPN (Most Probable Number) ranging 
from 10-1000 Salmonella organisms per gram. The 
efficiency of swab procedures in isolating Salmonella 
serotypes versus faecal samples for Salmonella isolations 
was 67% (Hart etal. 1982). 
The major serotypes isolated from quokkas in the 
Settlement areas and the camping area were Salmonella 
typhimurium PT 202 (21), S. muenchen 17, S. adelaide 
13, S. javiana 12 and S. wandsbek 11, with similar results 
recorded at Kingston Barracks. At Lighthouse swamp 
Salmonella adelaide, S. Chester, S. orien tails and S. 
wandsbek were the major serotypes isolated. Salmonella 
Figure 2. Seasonal variation in Salmonella percentage infection rates in quokkas (Setonix brachyurus) on Rottnest Island over a 12- 
month period from March 1984 to March 1985. Sampling locations shown are Kingston Army Barracks and Bickley swamp (Kingston), 
Lighthouse Swamp (Lighthouse), Garden Lake and the main Settlement area in Thompson Bay (Settlement). 
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