Gastrointestinal macroparasites of chinstrap penguin in Deception Island (Antartida)

VIDAL, V.,; ORTIZ, J.,; DIAZ, J.I.,; RUIZ DE IBÁÑEZ, M.R.,; AMAT, M.T.; PALACIOS, M.J.,; BENZAL, J,; VALERA, F.,; DE LA CRUZ, C.; BARBOSA, A.

Lisboa, Portugal

Congreso; IX Congreso Ibérico de Parasitología; 2009

Sociedad Portuguesa y Sociedad Española de Parasitologica

INTRODUCTION The present work is carried out under the research project “Parasitic-host interaction and immune response in three species of Antarctic penguins: effect of global change” (CGL2004-01348 and CGL2007-60369; Pinguclim I and II). Part of the objectives is to determine the effect of the climatic change on the parasitic agents through a short term study, establishing a simulation model based on latitudinal gradient, and a long term study, creating a data base that can be used in the future. The first step consists of the determination of gastrointestinal macroparasites in one of the most frequent pygoscelid species in Antarctica, the chinstrap penguin (Pygoscelis antarctica). MATERIALS AND METHODS In this study 34 gastrointestinal packages of chicks and/or adults Chinstrap penguin (Pygoscelis antarctica) were analyzed. They were collected along two campaigns of sampling (2006: 13 individuals and 2007: 21 individuals), during the austral summer. Penguin carcasses were collected in Deception Island (63º00´S, 60º 40´ W), a volcanic island of the South Shetland Islands, in the Antarctic Peninsula. Samples were identified and frozen at -20ºC. The parasitic necropsies of the different sections of the digestive apparatus were made studying the mucosa under the stereoscopic microscope, and collecting their content, along with superficial scraping of the mucosa in sedimentation cups. Finally the present parasites in the penguin were isolated by means of stereoscopic microscope. Specimens were conserved in ethanol 70%. Nematodes identification was based on morphological study by means of optical microscopy (clarifying some specimens with lactofenol of Amman). Cestodes were dyed for a detailed study with the Carmine acetic technique of Semichon. Acanthocephalans were observed in fresh. All of them were studied under Scanning Electron Microscopy, previous drying with the Critical Point Dryers technique.    RESULTS   91.2% of the penguins turned out to be parasitized. About the identification of the macroparasites, we found one species of nematode (Stegophorus macronectes), two of cestodes (Tetrabothrius sp. and Parorchites zederi) and one species of acanthocephala (Corynosoma sp.).  The greater numbers of prevalence and mean intensity presented were S. macronectes, 85.3%, and 34.0 respectively, followed by Tetrabothrius sp. (23.5%, 1.2), Parorchites zederi (2.9%, 12.0) and Corynosoma sp. (2.9%, 7.0). CONCLUSIONS    As it was predicted from such a stenophagic species like Chinstrap penguin that feeds almost exclusively on Krill, we found a low number of species of macroparasites. Nevertheless, the high prevalence observed, even when the analyzed specimens were mostly chicks, gives an idea of the high rates of the infection present in this species. The most prevalent parasite, Stegophorus macronectes, has been reported in other species of Antarctic birds, including penguins like Pygoscelis papua (gentoo penguin), and Pygoscelis adeliae (Adelie penguin). Nevertheless it is the first report of S. macronectes in Pygoscelis antarctica. The remaining species and genera found are of wide presence in Antarctic birds, including the Chinstrap penguin in other South Shetlands Islands.