Table 1
Description of birds before treatment, clinical signs (if any) and microscopic findings
| Case | Species/breed/sex/age in years (y) | Clinical signs | AFB in faeces | Cryptosporidium galli in faeces |
|---|---|---|---|---|
| 1 | Canary/lizard/4 y male | Chronic dyspnoea | +++ | − |
| 2 | Canary/yellow/2 y male | No signs of disease | +++ | − |
| 3 | Canary/ Raza Espanola/male 3 y | Chronic dyspnoea | +/− | ++ |
| 4 | Canary/ Raza Espanola/male 4 y | No rectrices (growth of single deformed ones, which subsequently fell out) | −/+ | − |
| 5 | Raza Espanola/Canary/ male 2 y | No signs of disease | −/+ | ++ |
| 6 | Bengalese finch/ red-brown/male 2 y | No signs of disease | +++ | − |
[i] +++ – ≥10 AFB/high-power field (HPF); ++ – 1–10 AFB/HPF; + – 10–99AFB/100 HPF; +/− – 1–9 AFB/100 HPF; − – negative result (33) ; (−/+) – dubious result
Table 2
Results of clinical, post-mortem and histopathological examinations, and PCR tests of organ tissues for M. genavense
| Case | Clinical observations during treatment | Observations after treatment | Necropsy findings | Histopathology | Results of organ qPCR for M. genavense |
|---|---|---|---|---|---|
| 1 | After three weeks of | Thirteen months | Moderate liver | Lymphoplasmacytic periportal | Negative |
| treatment, cessation of | after treatment | enlargement and | hepatitis with proliferating bile | ||
| crepitant rale at rest, | completion, placed | yellowing, grey foci up | ductules, cholestasis; chronic | ||
| occurrence of vocalisations; | in a cage with | to 1 mm on the liver | enteritis; | ||
| after two months, cessation | a female, which laid | surface, | focal myocarditis and fibrosis; | ||
| of signs of stress-induced | normal eggs. | cholecystolithiasis, | membranoproliferative | ||
| dyspnoea. | Fifteen months after | renal oedema, right | |||
| During treatment, two | treatment | ventricle dilation, | glomerulopathy, bile droplets in | ||
| periods of watery diarrhoea: | completion, | inactive testes. | tubular epithelial cells; | ||
| at the beginning | dwelling on the | splenic lymphoid depletion; | |||
| of treatment and one month | bottom of the cage, | neuronal damage and gliosis. | |||
| after treatment initiation. | hypothermia, | ||||
| Bird showing susceptibility | polyuria, | ZN-negative | |||
| to stress. | polydypsia, | ||||
| anorexia. | |||||
| 2 | One month before treatment | One month after | Moderately good | Hepatic lipidosis; chronic enteritis; | Negative |
| completion, neurological | treatment | nutrition status, loss of | fat droplets in renal epithelial cells; | ||
| signs occurred. The signs | completion, after 10 | forebrain and | splenic lymphoid depletion; | ||
| receded following | days of supportive | hydrocephalus, liver | neuronal damage, gliosis, focal | ||
| supportive treatment. | treatment, | yellowing and slight | vacuolation of neuropil and | ||
| neurological signs | enlargement, slight | oedema. | |||
| returned. The | kidney and spleen | ||||
| canary was | oedema, inactive testes. | ZN-negative | |||
| euthanised. | |||||
| 3 | Complete cessation of | Prolonged periods | Moderately good | Multifocal to coalescing hepatic | Positive |
| dyspnoea after 26 days of | of moulting. | nutrition status, | granulomas; | ||
| treatment. | Periodic post- | significant hepato- and | intestinal crypt loss, fibrosis of the | ||
| exercise dyspnoea. | splenomegaly, paleness | lamina propria, and focal | |||
| Fourteen months | of the liver and spleen, | granulomatous enteritis; | |||
| after treatment, | inactive testes. | ||||
| moderately | mesangioproliferative | ||||
| numerous AFB in | glomerulopathy, necrotic tubular | ||||
| faeces, significant | epithelial cells, lymphoid follicle | ||||
| liver enlargement. | formation in the interstitial tissue; | ||||
| splenic coalescing granulomas; | |||||
| a few mononuclear cells aggregated | |||||
| closely to the leptomeninges, | |||||
| gliosis and neuronal damage. | |||||
| ZN-positive (liver, pancreas, | |||||
| intestine, kidney, spleen and lungs). | |||||
| 4 | Good health throughout the | Prolonged periods | Not tested | Not tested | Not tested |
| treatment period. | of moulting. | ||||
| 5 | Found dead after two weeks | N/a | N/a | Fungal pneumonia; | Positive |
| of treatment. | neuronal damage and gliosis. | ||||
| A mistake in the procedure of | |||||
| fixing the remaining tissues | |||||
| prevented their histopathological | |||||
| evaluation. | |||||
| ZN-positive (liver, spleen and lungs | |||||
| in cytology). | |||||
| 6 | Good condition throughout | - | Good nutrition status | Hepatic lipidosis, proliferation of | Positive |
| the treatment period with | and musculature, | bile ducts, cholestasis fibrinoid | |||
| beak hyperplasia requiring | moderate spleen | necrosis of vascular walls; chronic | |||
| correction. Four months | enlargement, active | enteritis; | |||
| after treatment initiation, the | testes. | splenic lymphoid depletion, | |||
| bird died owing to | vascular fibrinoid necrosis; | ||||
| haemorrhage after blood | membranoproliferative | ||||
| sampling from the external | glomerulopathy, | ||||
| jugular vein. | bile droplets in tubular epithelial | ||||
| cells; | |||||
| neuronal damage and gliosis. | |||||
| ZN negative |
Table 3
Comparison of pre-treatment and post-treatment blood counts
| BT – before | WBC | Heterophils | Lymphocytes | Monocytes | Eosinophils | Basophils | |
|---|---|---|---|---|---|---|---|
| treatment, AT – after treatment | (g/L) | (%) | (%) | (%) | (%) | (%) | |
| Canary values reference (13) | 4–9 | 50–80 | 20–45 | 0–1 | 0–2 | 0–1 | |
| Case 1 | BT | 15.2 | 26 | 57 | 17 | 0 | 0 |
| AT | 10.8 | 26 | 64 | 12 | 0 | 0 | |
| Case 2 | BT | 23 | 32 | 51 | 17 | 0 | 0 |
| AT | 16.32 | 16 | 75 | 16 | 0 | 0 | |
| BT | 10.28 | 18 | 71 | 11 | 0 | 0 | |
| Case 3 | AT | 7.4 | 5 | 88 | 11 | 0 | 0 |
| Case 4 | BT | 13.75 | 6 | 87 | 7 | 0 | 0 |
| AT | 8.32 | 8 | 89 | 5 | 0 | 0 | |
| Case 5 | BT | 7 | 25 | 60 | 13 | 2 | 0 |
| Finch values reference (13) | 3–8 | 20–65 | 20–65 | 0–1 | 0–1 | 0–5 | |
| BT | 10.28 | 18 | 71 | 11 | 0 | 0 | |
| Case 6 | AT | 7.14 | 56 | 37 | 5 | 0 | 2 |
Fig. 1
Comparison of results of SG qPCR and TaqMan qPCR tests to detect M. genavense
Fig. 2
Positive SG qPCR results during the second treatment of canary 3
Fig. 3
Phylogenetic tree based on the 16S rRNA gene, including Mycobacterium strains derived from treated canaries (cases: 1, 2, 3, 5 and 6) and other avian strains selected from the GenBank NCBI database. The tree was constructed by a neighbour-joining algorithm. The bar indicates 0.001 bp sequence divergence