1Chicago Zoological Society, Brookfield Zoo, Brookfield, IL, USA; 2Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA; 3Division of Comparative Pathology, University of Miami, Miami, FL, USA
Serologic testing (antibody and galactomannan antigen) is commonly used for aspergillosis diagnosis. This study compared serologic data from captive and free-ranging penguins. A database was constructed using 10 yr of retrospective data from healthy penguins at three zoos and wild penguins from the Punta San Juan Reserve, Peru. Captive penguins were considered healthy based on physical examination, normal total white blood cell count, and lack of apparent clinical illness for 1 mo prior to and following the date of blood collection. Wild penguins were deemed healthy based on physical examination and total white blood cell count alone, although no cases of respiratory disease have been noted on examination of over 350 penguins at the reserve over the past 4 yr.
Antibody and galactomannan levels were determined by ELISA through the University of Miami, Miller School of Medicine. Using reference data established for psittacine species,1,2 95% of the captive (57/60) and 90% of the wild (36/40) birds were antibody positive. For galactomannan, 6% of captive penguins (2/32) were positive, while 5% of wild penguins (2/40) were positive. Using Fisher’s exact tests, no significant difference was detected for either antibody or galactomannan tests between captive and wild populations, sex, zoo, or by age classification (<15, >15 yr old). Results suggest cut-off values established for psittacines may be applicable for penguins, as exposure (with subsequent antibody production) is common in captive birds and undefined in wild populations. Thus, assessment of aspergillosis based solely on antibody indices is likely to yield high numbers of false positives. Additional work is needed to establish antibody and galactomannan reference values specific for Spheniscus penguins.
Financial support provided by the Chicago Zoological Society and Saint Louis Zoo WildCare Institute. We thank Dr. Patricia Majluf, Marco Cardeña, and other colleagues at Cayetano Heredia University for their continued collaboration on field programs in Peru that allowed for sample collection from wild penguins. We appreciate the support of Brookfield Zoo, Saint Louis Zoo, and Oregon Zoo for providing captive penguin data.
1. Cray C, Watson T, Arheart KL. Serosurvey and diagnostic application of antibody titers to aspergillus in avian species. Avian Dis. 2009;53:491–494.
2. Cray C, Reavill D, Romagnano A, Van Sant F, Champagne D, Stevenson R, Rolfe V, Griffin C, Clubb S. Galactomannan assay and plasma protein electrophoresis in psittacine birds with aspergillosis. J Avian Med Surg. 2009;23:125–135.