Detection of Avian Malaria Infections in Wild and Captive Penguins

Sera from wild African black-footed penguins (Spheniscus demersus L., 1758), Adelie penguins (Pygoscelis adeliae Houbron, 1841), Gentoo penguins (Pygoscelis papua Forster, 1781), king penguins (Aptenodytes patagonicus Miller, 1778), and little blue penguins (Eudyptula minor Forster, 1781) and from captive yellow-eyed penguins (Megadyptes antipodes Houbron, 1841) and Magellanic penguins (Spheniscus magellanicus Forster, 1781) were tested by enzyme-linked immunosorbent assays for the presence of avian malaria antibodies (Ab). Plasmodiurn falciparum sporozoite (R32tet32) and gametocyte (P.F.R27) antigens were used. Specificity of anti-5". demersus, anti-duck, anti-chicken, and anti-turkey IgG labeled with alkaline phosphatase was determined for homologous and heterologous sera of 8 avian species (including 6 penguin species). The penguin conjugate was the most specific for the various penguin species immunoglobulins. It was possible to detect penguin immunoglobulins at a dilution of 10~4•". The relative binding of anti-S. demersus IgG was equal to relative binding of commercial conjugates. Kinetic profiles and overall magnitudes of malarial Ab detected by the 2 antigens were not significantly different. Antarctic P. adeliae were negative for malarial Ab, all New Zealand M. antipodes were positive, and the positivity prevalence of the remaining penguins ranged from 33 to 92%. Antibody titers and the prevalence of infection of wild S. demersus were significantly lower than those reported for captive North American S. demersus.