APPLICATION OF 3-HYDROXYBUTYRATE MEASUREMENT AND PLASMA PROTEIN ELECTROPHORESIS IN THE DIAGNOSIS OF ASPERGILLOSIS IN AFRICAN PENGUINS (SPHENISCUS DEMERSUS)

Abstract

New alternative laboratory means are needed to improve the options for antemortem diagnosis of avian aspergillosis. In this study, 3-hydroxybutyrate was measured in plasma samples collected from a cohort of African penguins ( Spheniscus demersus) maintained under human care. Results were interpreted in combination with those of protein electrophoresis and compared with anti- Aspergillus antibody and galactomannan antigen detection. Overall, 3-hydroxybutyrate levels were found significantly increased in Aspergillus-diseased cases versus the control penguin group ( P = 0.002). Mean absolute concentration of β-globulins was increased >20% in samples from infected birds, and α2-globublins were also found to be significantly increased versus clinically normal controls ( P < 0.001 and P = 0.001 respectively). Of note, the α2-globulins were also significantly increased versus penguins with inflammatory (non-aspergillosis) diseases ( P = 0.001). The specificity of 3-hydroxybutyrate, β-globulins, and α2-globulins for aspergillosis was 78.6%, 79.6%, and 92.2%, respectively. Using these measures in tandem resulted in high specificity (>90%) and negative predictive value (≥80%). In contrast, anti- Aspergillus antibody and galactomannan antigen did not distinguish between infected cases and controls ( P > 0.05). This study demonstrates that basic testing in tandem with the new biomarker 3-hydroxybutyrate may provide reliable evidence for the diagnosis of aspergillosis in penguins.

Protein electrophoresis of non‐traditional species: A review

“…24 In birds with aspergillosis, marked changes in albumin and globulins have been commonly observed with striking decreases in the A/G ratio. [57][58][59]65,66 Cutoff values for albumin and A/G ratios, as determined by EPH, demonstrated a 90% negative predictive value for assessing the survival of Gentoo penguins with aspergillosis. 66…”

“…In conjunction with increases in beta globulins and 3-hydroxybutyrate, the specificity was 98%. 57 In a large study inclusive of various avian species but predominating in psittacines with confirmed or probable aspergillosis, the presence of increased beta and/or gamma globulin concentrations was associated with a 73% sensitivity and 70% specificity. 53 The diverse and dramatic electrophoretic changes with aspergillosis in the African penguin can be observed in Figure 4.…”

“…51 Thus far, these types of changes have been reported mostly in avian samples with infectious processes. [52][53][54][55][56][57][58][59][60] An abnormal electrophoretogram, therefore, can demonstrate the presence of an acute-phase response but is not supportive of the presence of any one specific disease. The exception is the presence of paraproteinemia, which is most commonly observed with lymphoproliferative diseases and some infectious diseases; the latter is primarily described in mammals.…”

“…113 EPH has been used as an adjunct tool in the diagnosis of infectious diseases, including chlamydiosis, aspergillosis, sarcocystosis, bornavirus infection, and mycobacteriosis. [52][53][54][55][56][57][58][59][60]64 In a study of African penguins with presumed or confirmed aspergillosis, a significant increase in alpha 2 globulins was associated with a specificity of 92% and a negative predictive value of 81%. In conjunction with increases in beta globulins and 3-hydroxybutyrate, the specificity was 98%.…”

Capillary Electrophoresis Assessment of Plasma Protein Changes in an African Penguin (Spheniscus demersus) With Aspergillosis

“…Despite these limitations, our group has documented an electrophoretogram skewed shift observed in the plasma of an African penguin with aspergillosis . However, the composition of this shift remains largely unknown.…”