Single tracheal inoculation of Aspergillus fumigatus conidia induced aspergillosis in juvenile falcons (Falco spp.)

Figures & data

Figure 1. Falcons are housed on screen perches according to standard methods in falconry.

Table 1. Definition of the clinical scores (CS) applied to 21 juvenile falcons during the 28 days of the infection trial.

CS0	0 ≥ DS < 0.4; posture 1; behaviour 1; feed 1; plumage 1
CS1	0.4 ≥ DS < 0.6 and/or one of the following points: posture 2; feed 2; behaviour 2; plumage 2–3
CS2	0.6 ≥ DS < 0.8 and/or two of the following points: posture 2; feed 2; behaviour 2; plumage 2–3
CS3	0.8 ≥ DS < 1 and/or one of the following points: posture 3–4; feed 3–4 (single day); behaviour 3, plumage 4, stridors, open-beak breathing, vomitus
CS4	DS1 &/or posture 4 and/or behaviour 4, feed 4 (several days); indication for euthanasia, central nervous signs

Notes: DS (dyspnoea score), CS (clinical score), feed (feeding behaviour), the numbers after posture, feed and plumage are scores from 1 (non-altered, physiological) to 4 (severely altered); posture: 1 (upright stance with folded wings), 2 (standing slightly stooped), 3 (standing with legs apart and slightly drooping wings), and 4 (recumbent); feed: 1 (eating fast and completely), 2 (eating slowly but completely), 3 (eating partly), and 4 (not eating); behaviour: 1 (bright and alert), 2 (nervous, restless), 3 (sleepy), and 4 (lethargic); plumage: 1 (well arranged, no ruffled feathers), 2 (mildly ruffled feathers), 3 (moderately ruffled feathers), and 4 (severely ruffled feathers).

Figure 2. Dyspnoea scores (average of abdominal respiration and tail bobbing) of falcons during the trial.

Notes: No (bird number), ID (infective dose/inoculation dose), NC (negative control), d (day), DS (dyspnoea score): 0–0.15 referred to an inconspicuous respiration, 0.2–0.35 to an increased/suspicious respiration, dyspnoea score 0.4–0.55 to a mildly affected respiration, 0.6–0.75 to a moderately affected respiration, 0.8–0.95 to a severely affected respiration, and 1 to highest grade of respiratory depression and indication for euthanasia.

Figure 3. Clinical signs of falcons following experimental inocculation of Aspergillus fumigatus intratracheally. (A) Sleeping falcon. (B) Falcon with drooping wings. (C) Falcons with open-beak breathing. (D) Falcon with sticky and dirty feathers after vomiting. (E) Mint-green urates of a falcon. (F) Falcon with ruffled feathers.

Figure 4. Clinical scores (CS) of falcons during the trial calculated by scores for respiration, posture, feeding behaviour, and plumage.

Notes: No (bird number), ID (infective dose/inoculation dose), NC (negative control), d (day), CS 0: healthy/inconspicuous status, CS 1: mildly affected status, CS 2: moderately affected status, CS 3: severely affected status, CS 4: deceased birds.

Table 2. Haematological examination of 18 falcons before and 28 days after inoculation with A. fumigatus conidia and three non-inoculated control falcons.

			d 0				d 28
No	ID	Gran	EWBC	Het	Lymp	Mono	EWBC	Het	Lymp	Mono
Reference (Wernery et al., 2004)			4280–14,580	45.7–75.1	20.1–48.6	1.0–8.4	4280–14,580	45.7–75.1	20.1–48.6	1.0–8.4
B7.2	NK	−	10,500	63	37 (*10)	0	13,125	48	48 (*12)	4
B7.4	NK	−	7000	52	47 (*9)	3	24,500	79	20 (*5)	1
B7.5	NK	−	5250	63	35 (*2)	2	17,500	45	54 (*3)	1
B1.1 (+)	10^7	+	12,250	57	42 (*3)	1	47,250	84	13 (*8)	3
B1.2	10^7	+	4375	67	32 (*6)	1	8750	66	31 (*17)	3
B1.3	10^7	+	18,375	77	23 (*2)	0	85,750	66	27 (*12)	7
B2.1	10^6	+	8750	53	43 (*6)	4	14,875	69	29 (*5)	2
B2.2 (#)	10^6	+	7000	44	56 (*4)	0	52,500	86	13 (*4)	1
B2.3	10^6	−	15,750	64	35 (*8)	0	8700	59	39 (*3)	2
B3.1	10^5	+	6125	43	53 (*4)	4	39,375	92	7 (*3)	1
B3.2	10^5	−	13,125	57	41 (*25)	2	14,875	68	26 (*8)	6
B3.3	10^5	+	7000	78	22 (*7)	0	15,750	49	47 (*0)	4
B4.1	10^4	−	14,875	63	34 (*6)	3	8750	53	45 (*2)	2
B4.2	10^4	+	5250	53	44 (*9)	3	42,875	76	17 (*3)	7
B4.3	10^4	−	7000	46	51 (*13)	3	10,500	36	58 (*10)	6
B5.1	10^3	−	14,875	62	35 (*8)	3	11,375	53	43 (*12)	4
B5.2	10^3	−	16,625	31	66 (*3)	3	14,000	73	26 (*7)	1
B5.3	10^3	−	7000	46	52 (*11)	2	8750	54	45 (*0)	1
B6.1	10^2	−	16,625	64	33 (*6)	3	10,500	40	57 (*6)	3
B6.2	10^2	−	7000	66	33 (*7)	1	10,500	36	58(*10)	6
B6.3	10^2	+	14,000	40	56 (*18)	4	91,000	74	18 (*13)	8
	Sensitivity					Specificity
Leukocytosis	88.89% (51.75–99.72)					75.00% (42.81–94.51)
Heterophilia	44.44% (13.70–78.80)					91.67% (61.52–99.79)
Lymphopenia	55.56% (21.20–86.30)					91.67% (61.52–99.79)
Lymphocytosis	0% (0.0–28.31)					66.67% (34.89–90.08)

Notes: No (bird number), ID (infective-/inoculation dose), NC (negative control), d (day), Gran (granuloma in necropsy), EWBC (estimated white blood cell count/estimated leukocyte number per µl blood), Het (percentage of heterophil granulocytes in %), Lymp (percentage of lymphocytes in %), Mono (percentage of monocytes in %), * (percentage of cells with toxic changes); # d 16; + d 22; numbers in bold exceeded the reference range, numbers in italics remained below the reference range.

Figure 5. Pathological findings in falcons after experimental infection with Aspergillus fumigatus. (A) + (B) + (C) Fungal granuloma in the air sacs of falcons of varying sizes, from pinhead-sized nodules to complete filling of the air sac. (D) Fungal granuloma at the tracheal bifurcation. (E) Fungal granuloma with active mycelium in the lung. (F) Splenomegaly and follicular hyperplasia.

Table 3. Overview of pathologic lesions, histopathologic identification of fungal structures, and fungal re-isolation in 18 falcons 28 days after experimental inoculation of Aspergillus fumigatus conidia and in three non-inoculated control falcons.

Notes: No (bird number), ID (infective dose/inoculation dose), NC (negative control), Tr (trachea), Sy (syrinx), Llu (left lung), Rlu (right lung), CrLTl (cranial, left thoracic air sac), CrRTl (cranial, right thoracic air sac), CaLTl (caudal, left thoracic air sac), CaRTl (caudal, right thoracic air sac), LAl (left abdominal air sac), RAl (right abdominal air sac), Per (pericardium), Li (liver), Sp (Spleen), GIT (gastrointestinal tract and oesophagus), Ki (kidney), Nos (nose); Pathology Score: 0 (nothing abnormal detected), 1 (mild lesion, not typical for aspergillosis), 2 (mild to medium lesion, possibly associated with aspergillosis, but not granulomatous), 3 (granulomatous lesion or other severe lesions, typical for aspergillosis, e.g. fungal mycelium), * (fungal re-isolation/culture positive), # (fungal structures identified in histopathology), § (the only fungal isolate that was proven to be not identical to the inoculated strain using the microsatellite length polymorphism).

Wernery, R., Wernery, U., Kinne, J. & Samour, J.H. (2004). Haematology and blood biochemistry. In R. Wernery, U. Wernery, J. Kinne & J.H. Samour (Eds.), Colour Atlas of Falcon Medicine (pp. 12–42). Hannover: Schlütersche Verlagsgesellschaft mbH.

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