Table 3. Real-time PCR amplification of Coxiella burnetii from environmental samples collected inside a cave, Bizkaia, Spain, March 2021–Feb 2023 (n = 122 samples).
| Sample type and sampling sitea | Cq valuesb | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 4 Mar 2021 | 22 Mar 2021 | 18 May 2021 | 2 Aug 2021 | 2 Nov 2021 | 28 Feb 2022 | 9 May 2022 | 22 Sep 2022 | 19 Dec 2022 | 2 Feb 2023 | |
| Faeces | ||||||||||
| Main entrance (F1) | 31.3 | ND | ND | ND | ND | ND | ND | ND | ND | ND |
| Main entrance (F2) | 35.7 | |||||||||
| Main entrance (F3) | 34.3 | |||||||||
| Fence (F4) | 32.3 | |||||||||
| Interior (F5) | Und. | |||||||||
| Alternative entrance (F6) | Und. | |||||||||
| Dustc | ||||||||||
| Main entrance (D1) | 31.1 | ND | 34.6 | 36.9 | 35.1 | 34.7 | Und. | 35.5 | 36.6 | ND |
| Main entrance (D2) | 31.3 | 31.3 | 26.9 | 31.8 | 27,0 | Und. | 32.1 | 35.9 | ||
| Fence (D3) | 28.7 | 25.6 | 24.9 | 28.6 | 22.5 | 29.1 | 27.7 | 30.0 | ||
| Interior 1 (D4) | 31.9 | 33.6 | 34.2 | 35.8 | 34.2 | 34.3 | 34.6 | Und. | ||
| Interior 2 (D5) | 32.5 | 35.4 | 36.7 | Und. | 33.3 | 34.6 | Und. | Und. | ||
| Interior 3 (D6) | Und. | 33.7 | Und. | 36.1 | Und. | 37.3 | Und. | Und. | ||
| Interior 4 (D7) | Und. | 34.2 | Und. | Und. | 35.1 | 36.1 | 36.8 | Und. | ||
| Interior 5 (D8) | Und. | Und. | Und. | Und. | 34.4 | 34.6 | Und. | Und. | ||
| Alternative entrance (D9) | 35.4 | Und. | Und. | Und. | 35.9 | 34.9 | Und. | Und. | ||
| Alternative entrance (D10) | Und. | 35.0 | Und. | Und. | Und. | Und. | Und. | Und. | ||
| Aerosols | ||||||||||
| Aerosol 1 (A1) | Und. | 32.2 | Und. | 33.4 | Und. | Und. | ND | 36.3 | 35.7 | Und |
| Aerosol 2 (A2) | 35.4 | 24.6 | 26.0 | Und. | 27.8 | 29.2 | 25.3 | 24.9 | 25.9 | |
| Aerosol 3 (A3) | Und. | Und. | 36.3 | Und. | Und. | Und. | 33.3 | 36.8 | 29.6 | |
| Aerosol 4 (A4) | 33.2 | Und. | Und. | Und. | Und. | Und. | 36.4 | Und. | Und. | |
| Wind direction at samplingd | South-East | North | South-West | North | South-West | South-East | North-East | North | South-East | North-West |
Cq: quantification cycle; ND: not done; Und.: undetermined (negative).
a See Figure 1 for location of sampling sites inside the cave.
b Cq interpretation as follows: Cq < 35: positive; Cq > 35 and ≤ 40: weakly positive; Cq > 40: negative. The lowest Cq value (higher bacterial load) obtained in dust during each sampling session is marked in bold. PCR target was the transposon-like repetitive region IS1111.
c On 22 March 2021 and 2 February 2023, dust samples were taken only for viability studies.
d Data were provided by the Basque Agency of Meteorology (Euskalmet, https://www.euskalmet.euskadi.eus/inicio) and collected at a meteorological station located 6.8 km from the cave.