Birds are highly susceptible to aspergillosis compared to mammals due to environmental contamination by Aspergillus fungi, differences in avian anatomy and physiology such as lack of macrophages in the lungs/air sacs, and a less effective avian immune response. Aspergillosis in birds can cause a variety of clinical signs depending on the infected area and species. Diagnosis relies on clinical signs, epidemiology, hematology, serology including detection of galactomannan, culture, and histopathology. Treatment involves antifungals but has a generally poor prognosis, so prevention through reducing environmental fungal levels and stress is important.

1. Jacques Guillot, Guillaume Le Loc’h, Pascal Arné,
Françoise Féménia, René Chermette
Avian
aspergillosis
UMR INRA, AFSSA, ENVA, UPVM 956, Biologie Moléculaire et Immunologie Parasitaires
et Fongiques, Ecole Nationale Vétérinaire d’Alfort, 94704 Maisons-Alfort Cedex, France

2. Introduction
Aspergillosis is considered as one of the most
important infectious diseases in birds
• early 1800s: first observations
scaup duck, jay, bullfinch, bustard and several swans
• 1898: first cases in turkey poults (Lignières & Petit in France)
• Since then, cases in a very wide range of avian species…

3. 5 key questions…
Why are birds more susceptible than mammals ?
In which circumstances does aspergillosis occur in birds ?
Is it possible to make an early diagnosis in birds ?
Is it possible to treat or prevent avian aspergillosis ?
What do the main clinical signs and lesions look like ?

4. Susceptibility of birds
Birds are much more susceptible to aspergillosis than
mammalian species
• Environmental contamination by Aspergillus spp.

5. Susceptibility of birds
• Environmental contamination by Aspergillus spp.
• Avian anatomy and physiology
40-43°C
Birds are much more susceptible to aspergillosis than
mammalian species
lungs / air sacs

6. Susceptibility of birds
• Environmental contamination by Aspergillus spp.
• Avian anatomy and physiology
• Avian immunology
Lack of resident macrophages in airways and air sacs
Heterophils without peroxydation
Birds are much more susceptible to aspergillosis than
mammalian species

7. Epidemiology
Aspergillus fumigatus / Aspergillus flavus, Aspergillus niger…
Overgrowth
Specific virulence factors ?
humidity, dampness
drying period …

8. Epidemiology
• a 600 m2 confinement building in the Center of France
• a flock comprising 4500 turkeys
females slaughtered at the age of 12 w and males at the age of 16 w
Genotyping of environmental
and clinical A. fumigatus
isolates
(2 microsatellite markers)
Bart-Delabesse et al. J. Clin. Microbiol. 1998
An epidemiological survey was conducted in France

9. Epidemiology
0
25
50
75
100
125
150
3 4 5 6 7 8 9 10 11 12 13 14 15 16
Aspergillus flavus Aspergillus fumigatus Other fungi
Lair-Fulleringer et al. Poultry Science 2006

10. Epidemiology
5 males 5 females
10 healthy chicks,
23 isolates,
1 unique genotype
Lair-Fulleringer et al. J. Clin. Microbiol. 2003

11. Epidemiology
9 healthy turkeys, 55 isolates, 17 genotypes
Lair-Fulleringer et al. J. Clin. Microbiol. 2003

12. Epidemiology
2 carcass condemnations,
36 isolates,
2 genotypes
Lair-Fulleringer et al. J. Clin. Microbiol. 2003

13. Epidemiology
362 air samples, 134 isolates
53 genotypes
16 week-sampling period
Lair-Fulleringer et al. Poultry Science 2006

14. Epidemiology
Aspergillus fumigatus / Aspergillus flavus, Aspergillus niger…
Overgrowth
Specific virulence factors ?
• Species
• Avian strains
• Individual susceptibility ?
• Age
• Sex
• Stress
• Other micro-organisms
• Toxicosis
• Therapeutics
captive environment
handling
migration…
mycotoxins ?
corticosteroids
turkeys, quails,
raptors, penguins,
parrots, waterfowl

15. Clinical signs and lesions
Different avian species
Different epidemiological situations Many clinical signs
Acute aspergillosis
= inappetance, depression, polydipsia, polyuria, dyspnoea, cyanosis
= sometimes, sudden death without any signs
Chronic aspergillosis
= signs are dependent on the area of invasion
change in voice
respiratory stridor
exercice intolerance
ataxia, torticollis, seizures
conjunctivitis, keratitis
beak malformation…
fatal evolution

16. Clinical signs and lesions
ENVA
Kaminski et al.
air sacculitis
Aspergillosis
of eggs
ENVA

17. Clinical signs and lesions
Chute
pneumonia
meningo-
encephalitis
Séguin
arthritis
Séguin
uveitis
Séguin

18. Diagnosis
Falcons, parrots, wild birds in zoological or rehabilitation centers
Clinical signs
Epidemiology
Radiology
Endoscopy
Hematology
Serology
Biochemistry
Electrophoresis
Mycological culture
PCR ?
Cytology, histology

19. Diagnosis
Clinical signs
Epidemiology
Radiology
Endoscopy
Hematology
Serology
Juliet Joseph,
Abu Dhabi Falcon Research Hospital
Falcons, parrots, wild birds in zoological or rehabilitation centers
Biochemistry
Electrophoresis
Mycological culture
PCR ?
Cytology, histology

20. Hematology
Diagnosis
Clinical signs
Epidemiology
Radiology
Endoscopy
Serology
Falcons, parrots, wild birds in zoological or rehabilitation centers
Biochemistry
Electrophoresis
Mycological culture
PCR ?
Cytology, histology
a promising approach ?

21. Diagnosis
Serology
• Immunologically, birds respond to Aspergillus infection in
the same way as mammals and a type I response appears
most beneficial
• Birds also respond with specific antibody production
similar in its kinetics to mammals
• Serological tests that may be used in birds include the
detection of specific antibodies or fungal antigens

22. Diagnosis
Serology
 detection of specific antibodies
False negative results
some birds may not be able to mount an appropriate response
some infection locations result in limited antigenic stimulation
Antibody titers not necessary correlated to clinical severity
High prevalence of seropositivity in captive penguins
Low prevalence of seropositivity in wild birds

23. Diagnosis
Serology
 detection of galactomannan
• agglutination (Pastorex Aspergillus®)
• monoclonal sandwich ELISA (Platelia Aspergillus®)
• polyclonal sandwich ELISA

24. Diagnosis
Serology
 detection of galactomannan
Cray et al. ISHAM 2006 (poster P-0011)
839 serum samples (from suspected or confirmed cases)
Galactomannan in 50% of samples from penguins
in 25% of samples from other birds
Many chronic cases = negative for antibody but positive for galactomannan
But long term chronic cases = negative for both antigen and antibody !

25. Diagnosis
Serology
 detection of galactomannan
Arca-Ruiba et al. Vet. Rec. 2006
90 serum samples (from cases in falcons)
182 control serum samples (from healthy falcons)
Galactomannan in 12% of samples from infected falcons
in 5% of samples from healthy birds

26. Diagnosis
Serology
 detection of galactomannan
Le Loch’ et al. ISHAM 2006 (poster))
Platelia®
Aspergillus
+ -
CIE
+ 17 39 56
- 20 65 85
37 104 141

27. Diagnosis
Serology
 detection of galactomannan
Many false negative results
variable release of GM
variable kinetics
according to avian species
according to physiological status of each bird
according to the level of immune complexing
Some false positive results
circulating GM from other fungi
cross reactivity with bacterial components (food supplementation ?)

28. Serology
Hematology
Diagnosis
Clinical signs
Epidemiology
Radiology
Endoscopy
Falcons, parrots, wild birds in zoological or rehabilitation centers
Biochemistry
Electrophoresis
Mycological culture
PCR ?
Cytology, histology
Hardy et al. AAV proc. 2003
Dahlahausen et al. AAV proc. 2004

29. Diagnosis
Clinical signs
Epidemiology
Turkeys, chickens, quails, ducks, ostriches…
Hematology
Radiology
Endoscopy
Serology
Biochemistry
Electrophoresis
Mycological culture
Necropsy
Cytology, histology

30. Treatment
Falcons, parrots, wild birds in zoological or rehabilitation centers
Amphothericin B
Flucytosine
Ketoconazole
Itraconazole
Terbinafine
Voriconazole (Langhofer, AAV proc. 2004)
Radiography, endoscopy or serology for the follow up
+ Supportive therapy
+ Surgical debridement of the lesions

31. Treatment
No treatment !
Turkeys, chickens, quails, ducks, ostriches…

32. Prevention
• Reduction of fungal contamination
• Chimioprevention ?
Vaccination with a heat-killed culture filtrate preparation has been reported
to reduce mortality in ducks and waterfowl
• Reduction of stress
• Vaccination
Richard (1984) reduced mortalities by 50% in turkey poults vaccinated with
germinated A. fumigatus conidia

33. Conclusions
« Avian aspergillosis »
= not a single entity but a complex of several diseases…
• importance of prophylactic procedures
• poor prognosis
• need for specific avian models of aspergillosis
• variable epidemiological situations
• several diagnostic tools required

34. References
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Le Loc’h, G., Arné, P., Bougerol, C., Risi, E., Péricard, J.M., Quinton, J.F., Bretagne, S. & Guillot, J. (2006) Detection of
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