Assessing the Effectiveness of Tuberculosis Management in Brushtail Possums (Trichosurus vulpecula), through Indirect Surveillance of Mycobacterium bovis Infection Using Released Sentinel Pigs

Table 2

Population age structure, gender, and TB lesion severity among resident wild pigs captured from Molesworth Station and Clarence Reserve between 2009 and 2012.

Molesworth Station

Clarence Reserve

Birth-year cohorts

2007 or prior

2008

2009

2010

2011

2012

Overall

2007 or prior

2008

2009

2010

2011

2012

Overall

Number (males, females)

30; (13m, 17f)

26; (12m, 14f)

66; (34m, 32f)

72; (34m, 38f)

21; (8m, 13f)

4^*1; (3m, 2f)

𝐓𝐨𝐭𝐚𝐥^∗2; 221 pigs

13; (9m, 4f)

25; (14m, 11f)

40; (20m, 20f)

16; (7m, 9f)

20; (6m, 14f)

2^*1; (1m, 1f)

𝐓𝐨𝐭𝐚𝐥^∗2; 131 pigs

Median age in months (range)

31; (11–>42)

24; (6–>42)

18; (2–38)

8; (6–28)

14; (6-7)

4.5; (3–6)

Median; 15 mo.

41; (18–>42)

25; (6–>42)

16; (3–>42)

14; (5–26)

14; (2–22)

9; (9)

Median; 18 mo.

Average lesion score in animals with culture-positive lesions (range)

3.7; (1–7)

3.1; (2–5)

2.4; (2–4)

2.1; (1–4)

2.2; (2-3)

2.5; (2.5)

Average; 𝟐.𝟖^∗3

3.6; (2–7)

3.2; (2–7)

3.0; (1–6)

2.8; (2–6)

3.7; (2–5)

3.1; (3.1)

Average; 𝟑.𝟏^∗3

∗1Pigs born in 2012 were not considered in subsequent cohort-delineated TB analyses due to too few animals.
^*2Overall totals exceed the sum of the individual males and females because pig gender was not recorded in all cases.
^*3Lesion scores were only recorded for culture-positive cases and only for those animals in which accurate lesion descriptions had been obtained; hence averages here were calculated from 102 out of a total of 221 Molesworth pigs and from 94 out of a total of 131 Clarence pigs for which lesions scores were recorded and for which the culture result was positive.