Table 2.
Screening for C. burnetii DNA in animal and environmental matrices obtained from 19 dairy goat farms and 1 dairy sheep farma
| Matrix | Farm category | Total no. of samples | No. of IS1111-positive samples | No. of IS1111- + com1-positive samples | % positive samples | Mean Cq (SD) |
Categories compared |
P value |
||
|---|---|---|---|---|---|---|---|---|---|---|
| com1 | IS1111 | Fisher exact testb | Wilcoxon rank sum testc | |||||||
| Vaginal swabs | AB | 45 | 18 | 27 | 100 | 37.1 (1.0) | 33.2 (1.6) | AB and B | <0.05 | <0.01 |
| B | 55 | 30 | 15 | 81.8 | 37.3 (1.5) | 34.6 (1.8) | AB and N | <0.01 | <0.01 | |
| N | 25 | 6 | 0 | 24 | ND | 36.5 (0.8) | B and N | <0.01 | 0.02 | |
| Manure | AB | 19 | 10 | 1 | 57.9 | 37.0 (2.2) | 36.1 (1.4) | AB and B | 0.59 | 0.70 |
| B | 50 | 19 | 5 | 48 | 36.0 (3.0) | 35.7 (2.7) | AB and N | <0.01 | NA | |
| N | 25 | 0 | 0 | 0 | ND | ND | B and N | <0.01 | NA | |
| Milk unit filters | AB | 6 | 0 | 6 | 100 | 33.1 (2.2) | 27.3 (2.0) | AB and B | 1.00 | 0.02 |
| B | 33 | 9 | 23 | 97 | 34.7 (1.4) | 31.4 (3.3) | AB and N | <0.01 | 0.04 | |
| N | 13 | 2 | 0 | 15,4 | ND | 35.4 (0.9) | B and N | <0.01 | 0.09 | |
| Surface area swabs | AB | 40 | 0 | 40 | 100 | 34.1 (2.5) | 28.3 (2.4) | AB and B | NA | <0.01 |
| B | 110 | 13 | 97 | 100 | 36.0 (1.8) | 30.9 (3.1) | AB and N | <0.01 | <0.01 | |
| N | 50 | 17 | 9 | 52 | 35.1 (1.6) | 34.9 (1.5) | B and N | <0.01 | <0.01 | |
| Aerosols (stables) | AB | 15 | 1 | 14 | 100 | 36.1 (1.8) | 31.0 (1.7) | AB and B | 1.00 | 0.02 |
| B | 33 | 14 | 18 | 97 | 36.7 (1.7) | 33.7 (3.0) | AB and N | NA | <0.01 | |
| N | 15 | 13 | 2 | 100 | 35.2 (0.3) | 35.7 (1.6) | B and N | 1.00 | 0.02 | |
| Aerosols (500 m) | AB | 16 | 12 | 3 | 93.8 | 39.2 (2.3) | 36.8 (1.9) | AB and B | 0.26 | 0.14 |
| B | 42 | 30 | 3 | 78.6 | 39.0 (0.4) | 37.6 (2.0) | AB and N | 0.09 | 0.33 | |
| N | 18 | 10 | 2 | 66.7 | 37.4 (0.7) | 37.2 (1.9) | B and N | 0.35 | 0.94 | |
Farms are categorized into three farm categories (categories AB, B, and N), and for each animal or environmental matrix, the proportions of positive samples and C. burnetii DNA contents expressed by averaged Cq values are shown for C. burnetii target combinations of com1 and IS1111. Category AB, abortion wave in 2008 or 2009 (and bulk milk positive); category B, bulk milk positive only; category N, bulk milk negative and no known Q fever history. NA, not applicable; ND, not detected.
Comparison based on the proportion of positive samples, using nonparametric Fisher exact tests.
Comparison based on Cq values, using nonparametric Wilcoxon rank sum tests.