Antemortem diagnostic tests for the detection of Aspergillus infection in birds: A systematic review

Aspergillosis remains a common and life-threatening disease in captive and wild birds all over the world. The diagnosis is currently based on clinical signs or lesions, diagnostic imaging, and a variety of biological tests. This systematic review aimed to compare the accuracy of antemortem diagnostic tests for Aspergillus infection in birds. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a search was conducted on PubMed, Scopus, Web of Science, and CAB until January 2024. The methodological quality was assessed with QUADAS 2 risk of bias tool. The 13 studies, selected for the review, included results from a wide variety of birds (mainly Spheniciformes but also Falconiformes, Psittaciformes, and Galliformes) from wildlife rehabilitation centers, zoological parks, or veterinary practices. Aspergillus infection was mainly confirmed by fungal culture and/or histopathology. Serum markers included Aspergillus components (galactomannan, β-d-glucan, mannoproteins, and gliotoxin), anti-Aspergillus antibodies, 3-hydroxybutyrate, as well as protein electrophoresis and acute phase molecules. Sensitivity and specificity displayed a large amount of variation despite threshold arrangement. Disparities in the number of individuals per study did not allow for reliable comparison. Platelia Ag Assay (Bio-Rad), the most commonly used test in the studies, demonstrated moderate specificity and low sensitivity. Overall, non-specific tests demonstrated more consistent performance, whereas specific tests showed greater variability. Based on current knowledge, none of these tests provide sufficient accuracy to reliably detect Aspergillus infection in birds in clinical practice.