Dr. David Ebmer (Gießen / DE; Vienna / AT), Edwin Kniha (Vienna / AT), Verena Strauss (Vienna / AT), Anna Kübber-Heiss (Vienna / AT), Lukas Komornik (Vienna / AT), Folko Balfanz (Vienna / AT), Stephan Hering-Hagenbeck (Vienna / AT), Julia Walochnik (Vienna / AT), PD Dr. Ulrich Gärtner (Gießen / DE), Heinrich Prosl (Vienna / AT), Prof. Dr. Anja Taubert (Gießen / DE), Thomas Voracek (Vienna / AT), Prof. Dr. Carlos Hermosilla (Gießen / DE)
Abstract text
Introduction: Endoparasitic mites of the genera Halarachne and Orthohalarachne (Acari: Halarachnidae) parasitize different segments of the respiratory tract of pinnipeds and sea otters. Knowledge on their exact pathogenic potential and on occurrence in pinnipeds in zoological gardens is very scarce.
Materials and methods: A two-year-old South American sea lion (Otaria flavescens), born at the Vienna Zoo, died during general anesthesia for pre-transport examinations. Immediately after death, necropsy was performed and tissue samples for histological, bacteriological and parasitological analyses were taken.
Results: At necropsy, 45 adult Orthohalarachne diminuata mites were detected in the lower respiratory tract. After trepanation, 410 larval and nymphal specimens were detected in sinus paranasalis. Macroscopically, sinus mucosa showed multiple petechial hemorrhages and histopathological analyses revealed mite cross-sections, sanioserous exudate and epithelial exfoliation. For the first time, O. diminuata was molecularly characterized.
Conclusions: Our study constitutes the first record of an O. diminuata infestation in a captive O. flavescens. We present clinical and pathological data and discuss the etiology of this infestation. Further studies on pathogenic effects of these nasal/nasopulmonary parasites are essentially required for a better understanding of neglected orthohalarchniosis in pinnipeds.