Applicability of the Platelia EIA® Aspergillus test for the diagnosis of aspergilosis in penguins

Abstract

Even today, an effective diagnostic test for aspergillosis in penguins is unknown, being the gold standard post-mortem examinations. The fungal antigen galactomannan (GM) has been used as a biomarker of disease in humans and is detected by the Platelia Aspergillus EIA (BioRad)®, a commercial kit based on the sandwich ELISA technique. It is standardized for use in neutropenic patients, however studies have demonstrated its usefulness also possible for birds. The aim of our study was to evaluate the effectiveness of Platelia Aspergillus EIA® test (BioRad-US) in the diagnosis of aspergillosis in Magellanic penguins, determining sensitivity, specificity, and positive and negative predictive values for different cut-off points. Were included in the study, blood serum samples (n = 29) Magellanic penguins in captivity that died by aspergillosis. Detection of GM was performed following manufacturer's instructions and the GM index was obtained by dividing the average value of OD of the duplicate of the clinical sample by duplicate OD of the average value of the cut-off sample provided by the kit. Through information database results were obtained for the presence of anti-Aspergillus fumigatus antibodies detected by agar gel immunodiffusion (AGID) for all serum samples. Results were analyzed using chi-square test and Kruskal-Wallis from SPSS 20.0, IBM®. ROC curve was obtained and from this, rates of sensitivity, specificity, positive and negative predictive values were also calculated based on four different cutoff points (0.5, 1.0, 1.5 and 2.0). The serum GM index did not differ between animals of the case and control group (pkw =0.097). In determining the ROC curve for serum GM detection the value of area under the curve was 0.635. From the values ​​determined by the coordinate of the curve, four different cut points (0.5, 1.0, 1.5 and 2.0) were analyzed, resulting in sensitivity rates ranging from 86.2 to 34.5% % and specificity between 87% and 26.1%. By comparing the serum GM index in group case as the presence or absence of antibodies detected by AGID was found p=0.503. The detection of GM the Platelia Aspergillus EIA® test seems is not be useful for the diagnosis of aspergillosis in naturally infected penguins.

Diagnosis of Aspergillosis in Horses

“…GM detection for the diagnosis of systemic fungal infections in animals has been used with conflicting results. GM concentration in the serum of Magellanic penguins was shown to not discriminate healthy birds from those with pulmonary aspergillosis [ 32 ]. On the contrary, serum Aspergillus GM appeared as a noninvasive marker for the diagnosis of disseminated aspergillosis in dogs with a sensitivity of 92% and a specificity of 86% [ 33 ].…”

Assessment of the Safety and Efficacy of an Oral Probiotic-Based Vaccine Against Aspergillus Infection in Captive-Bred Humboldt Penguins (Spheniscus humboldti)

“…For these reasons, capillary zone electrophoresis assay and measurement of 3-OHB levels were added to the diagnostic panel in this study. Despite being a sometimes-useful assay in selected avian species such as psittacine birds (53,80,84) the s=galactomannan assay is not reliable in penguins (85) and was not used in the study.…”

Aspergillosis, Avian Species and the One Health Perspective: The Possible Importance of Birds in Azole Resistance

“…For certain avian species, such as penguins and albatrosses being treated in rehabilitation centers [12,55], and poultry (i.e., turkeys and chicks) in production settings [51,59] the management of flocks is more common than an individual bird, and therefore an earlier diagnosis can be an even bigger challenge. In this context, early diagnosis is essential for determining treatments, and serological assays seems to be the most promising so far [59][60][61][62][63][64][65]. However, since an efficient and financially accessible method for making an early diagnosis is not available, the diagnosis of aspergillosis in birds is commonly made only on post-mortem examination.…”