Defense of Sabrina Vieu's thesis

Members of the jury:

• Reviewers before defense:
  •  Emilie FREALLE, Hospital Practitioner, University Hospital of Lille, France
  • Guillaume LE LOC'H, Senior Lecturer, National Veterinary School of Toulouse, France

• President :
  • Laurence DELHAES, Professor, Bordeaux University Hospital, France
• Examiners :
  • Solène LE GAL, Professor, University Hospital of Brest, France
  • Guillaume LE LOC'H, Senior Lecturer, National Veterinary School of Toulouse, France
  • Emilie FREALLE, Hospital practitioner, University Hospital of Lille, France
• PhD Director:
  • Jacques GUILLOT, Professor, Oniris VetAgroBio, Nantes, France
• PhD co-director:
  • François BEAUDEAU, Professor, Oniris VetAgroBio, Nantes, France

Abstract:

The fungus Aspergillus fumigatus is responsible for most of the cases of avian aspergillosis, a respiratory disease often fatal due to delayed diagnosis. This thesis aimed to improve diagnostic tools through evaluation of biological tests, development of predictive models, and identification of new biomarkers by proteomics.
A first study on 118 aquatic birds evaluated several blood tests. The albumin/globulin ratio showed the best performance (sensitivity 83%, specificity 75%). A logistic regression model combining clinical signs, dosage of 3-hydroxybutyrate, and globulins achieved 95% sensitivity and specificity, demonstrating the superiority of a multiparametric approach.
A second study using mass spectrometry on blood samples from 30 falcons identified 49 differentially expressed proteins in infected birds. Some acute-phase proteins and lambda immunoglobulins were significantly increased, confirming a systemic inflammatory response. Detection of poorly characterized proteins (SRCR domains, S100 family) open perspectives for new markers.
This work demonstrates that combining biomarkers improves diagnostic accuracy of aspergillosis. Perspectives include validation on diverse cohorts of birds and development of rapid clinical tests that can be easily used by veterinary practitioners.

Keywords:

Aspergillosis, birds, diagnosis, biomarkers, predictive models, proteomics