Table 2.
Molecular evidence of rickettsiae infecting fleas collected from opossums
| Opossum | No. of flea pools (total fleas) | No. of positive pools |
MIR % (95% CI) |
|||
|---|---|---|---|---|---|---|
| Rickettsia typhi | Rickettsia felis-like | R. typhi and R. felis-like | R. typhi | R. felis-like | ||
| 1 | 3 (7) | 0 | 0 | 0 | 0 | 0 |
| 2 | 3 (8) | 1 | 0 | 0 | 12.7 (0.8–52.3) | 0 |
| 3 | 6 (17) | 2 | 0 | 0 | 12.6 (2.4–37.2) | 0 |
| 4 | 8 (35) | 1 | 2 | 3 | 13.9 (4.8–32.0) | 19.2 (7.8–41.2) |
| 5 | 16 (83) | 3 | 0 | 0 | 3.8 (1.0–10.1) | 0 |
| 6 | 2 (4) | 0 | 1 | 0 | 0 | 24.9 (1.6–82.0) |
| 7 | 5 (25) | 0 | 2 | 0 | 0 | 8.8 (1.7–27.9) |
| 8 | 3 (7) | 3 | 0 | 0 | 42.9* | 0 |
| 9 | 2 (4) | 0 | 0 | 0 | 0 | 0 |
| 10 | 6 (24) | 2 | 1 | 0 | 8.9 (1.7–27.6) | 4.2 (0.3–19.2) |
| 11 | 7 (19) | 0 | 1 | 0 | 0 | 5.3 (0.3–23.7) |
| 12 | 5 (15) | 0 | 4 | 0 | 0 | 36.3 (13.5–77.1) |
| 13 | 2 (2) | 1 | 0 | 0 | 50.0* | 0 |
| Total | 68 (250) | 13 | 11 | 3 | 7.0 (4.4–10.9) | 6.1% (3.5–9.8) |
CI = confidential interval; MIR = minimum infection rate.
*
When all pools are positive or fleas are tested individually, the likelihood methods for the estimated MIR fail. In these cases, the calculation was performed with the assumption that there is only one infected flea per positive pool.