Nasal mites in wild Magellanic penguins (Spheniscus magellanicus) in Chubut, Argentina

RALPH E.T. VANSTREELS; LUCIANA GALLO; GABRIELA BLANCO; HILTON ENTRINGER JR; MARCELA M. UHART

Viña del Mar

Congreso; XI International Penguin Congress; 2023

Rhinonyssids (Mesostigmata: Rhinonyssidae) are haematophagous mites that parasitize the upper respiratory tract of vertebrates. These minuscule spider-like parasites (approx. 1 mm) can cause significant discomfort, itching, sinusitis and may contribute to secondary respiratory infections. Two species of nasal mites are known from penguins: Rhinonyssus sphenisci parasitizes Humboldt (Spheniscus humboldti) and Magellanic penguins (Spheniscus magellanicus) and Rhinonyssus schelli parasitizes Adélie (Pygoscelis adeliae) and Gentoo penguins (Pygoscelis papua). Additionally, Rhinonyssus sphenisci sensu lato has been reported parasitizing African penguins (Spheniscus demersus). We examined the upper respiratory tract of 30 juvenileplumaged and 18 adult-plumaged Magellanic penguin carcasses collected from April to November 2022 at Chubut province, Argentina. Nasal mites were found in the nasal cavity and paranasal sinuses of 8 individuals (16.7%), comprising 4 juveniles (13.3%) and 4 adults (22.2%). Average abundance was 1.6±5.8 parasites/examined host, and average intensity was 9.4±12.1 parasites/infected host (median = 4, range = 1–34). No significant differences were detected in the prevalence of these parasites among categories of age, sex, carcass collection context (beach-cast, colony survey), carcass preservation (fresh, moderate decomposition, advanced decomposition, severe decomposition), or cause of death (paralytic shellfish poisoning, predation, starvation, other). The prevalence in this study was comparable to that reported in previous surveys on Magellanic penguins beach-cast in southern Brazil (juveniles 17.6%, adults 12.5%) and in African penguins in South Africa (juveniles 29.4%, adults 26.7%). Morphological and genetic characterization of these parasites is under way in order to clarify the taxonomy and evolutionary relationships of the nasal mites from different penguin species.