Table 1.
Zebrafish were injected with Mycobacterium marinum or Mycobacterium chelonae or distilled water (DW; sham-injection) and some were exposed to stressors over an 8-week period
| Positive (culture or histology) |
Diffuse infections |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Injection | Tank | Inoculum (×102) | Stressor | Moribund | Week 4 PI | Week 8 PI | Moribund | Week 4 PI | Week 8 PI | Moribund | Pseudoloma positive |
| Mycobacterium marinum | A | 1 | Y | 1/15 | 5/5 | 8/9 | 1/1 | 3/5 | 5/9 | 1/1 | 13/15 |
| B | 1 | Y | 3/14 | 5/5 | 6/6 | 3/3 | 2/5 | 5/6 | 3/3 | 14/14 | |
| A | 1 | N | 0/14 | 5/5 | 9/9 | NA | 1/5 | 2/9 | NA | 10/14 | |
| B | 1 | N | 0/15 | 5/5 | 10/10 | NA | 1/5 | 2/10 | NA | 10/15 | |
| DW | A | 0 | Y | 1/15 | 0/5 | 0/5 | 0/1 | NA | NA | 0/1 | 5/15 |
| B | 0 | Y | 0/15 | 0/5 | 0/5 | NA | NA | NA | NA | 9/15 | |
| A | 0 | N | 1/15 | 0/5 | 0/5 | 0/1 | NA | NA | 0/1 | 10/15 | |
| B | 0 | N | 0/15 | 0/5 | 0/5 | NA | NA | NA | NA | 9/15 | |
| Mycobacterium chelonae | A | 500 | Y | 0/18 | 4/9 | 9/9 | NA | 3/9 | 9/9 | NA | 0/17 |
| B | 500 | Y | 0/16 | 4/7 | 8/9 | NA | 4/7 | 7/9 | NA | 0/18 | |
| A | 500 | N | 0/14 | 5/7 | 4/7 | NA | 5/7 | 2/7 | NA | 0/14 | |
| B | 500 | N | 0/18 | 5/8 | 5/10 | NA | 5/8 | 5/10 | NA | 0/18 | |
| DW | A | 0 | Y | 0/21 | 1/10 | 0/11 | NA | 0/10 | NA | NA | 0/21 |
| B | 0 | Y | 11/21* | 0/10 | 0/11 | NA | NA | NA | NA | 0/10 | |
| A | 0 | N | 0/21 | 0/10 | 0/11 | NA | NA | NA | NA | 0/21 | |
| B | 0 | N | 0/21 | 0/10 | 0/11 | NA | NA | NA | NA | 0/21 | |
Y, yes; N, no; NA, not applicable.
Replicate tanks of the same treatment are indicated by the letters A and B. Morbidity (proportion of fish) was measured over an 8 week period. The prevalence of infection was evaluated by culture or histology at weeks 4 and 8 post-injection (PI). The proportion of fish with diffuse infections was measured at weeks 4 and 8 PI. The proportion of fish which were positive for Pseudoloma neurophilia via histology was measured.
*
Unexplained mortality of a sham-injected tank in Mycobacterium chelonae study at week 5 PI (no mycobacteria present).