First report of a severe nasopulmonary acariasis caused by Orthohalarachne diminuata Doetschman, 1944 (Acari: Halarachnidae) in a captive South American sea lion (Otaria flavescens Shaw, 1800)

Non-invasive detection of Orthohalarachne attenuata (Banks, 1910) and Orthohalarachne diminuata (Doetschman, 1944) (Acari: Halarachnidae) in free-ranging synanthropic South American sea lions Otaria flavescens (Shaw, 1800)

“…To the best of our knowledge, current data present the first successful development and application of non-invasive sampling techniques to detect halarachnid mite infestations in free-ranging pinnipeds. Orthohalarachne attenuata and Orthohalarachne diminuata were already reported in both free-ranging and captive South American sea lions in the past ( Finnegan, 1934 ; Kutzer and Burtscher, 1983 ; Morgades et al, 2006 ; Gomez-Puerta and Gonzales-Viera, 2015 ; Seguel et al, 2018b ; Ebmer et al, 2022 ), including co-infestations with both species ( Calderón-Mayo, 2015 ). However, compared to other otariids like California sea lions, Northern fur seals or South American fur seals ( Dahme and Popp, 1963 ; Kim et al, 1980 ; Páez, 2007 ; Katz et al, 2012 ; Gastal et al, 2016 ; Kuzmina et al, 2018 , Kuzmina et al, 2021 Seguel et al, 2018a , 2018b ; Pesapane et al, 2021 ), comparably few studies specifically addressed halarachnid mites in free-ranging Otaria flavescens, so far.…”

“…Molecular identification was based on amplification of a 16S rRNA gene segment using the primer combination 16S + 1_orthohala ( Ebmer et al, 2022 ) and 16S-1 ( Black and Piesman, 1994 ). For samples with low DNA yields, the primer combinations 16S + 1_orthohala/16S-2 and 16S + 2/16S-1 were used to amplify shorter overlapping fragments as stated by Black and Piesman (1994) using the same PCR conditions ( Table 1 ).…”

“…In the current study, we aimed ( i ) to add new data on the occurrence of halarachnid mite infestations in South American sea lions and ( ii ) to develop and apply, for the first time, a non-invasive diagnostic method to sample respiratory mites in free-ranging synanthropic pinnipeds in a low-stress manner and in conformity with conservation and animal welfare aspects. By diagnosing orthohalarachnosis in both, free-ranging animals in Chile and a captive South American sea lion in the Vienna Zoo, Austria as recently published by our group ( Ebmer et al, 2022 ), we here emphasize the importance of in situ and ex situ research projects.…”

“…Mesostigmatid mites of the genera Orthohalarachne Newell, 1947 and Halarachne Allman, 1847 (Acari: Halarachnidae) represent obligatory endoparasites and the causative agents of nasopharyngeal/nasopulmonary acariasis in pinnipeds and sea otters ( Kim et al, 1980 ; Reckendorf et al, 2019 ; Rolbiecki et al, 2018 ; Seguel et al, 2018a , 2018b ; Shockling Dent et al, 2019 ). Infestations can lead from asymptomatic to strong respiratory diseases accompanied by bacterial co-infections and eventual fatal outcomes ( Dahme and Popp, 1963 ; Seguel et al, 2018a , 2018b ; Ebmer et al, 2022 ). However, direct halarachnid mite-driven detrimental effects and their role as potential vectors and/or precursors of secondary bacterial, viral, and/or fungal infections are still not well known ( Seguel et al, 2018a ; Pesapane et al, 2022 ).…”

“…However, video-rhinoscopy was applied to diagnose halarachnid mite infestations in anesthetized otters ( McDermott et al, 2013 ; Pesapane et al, 2022 ). In zoological gardens, respiratory mites have been reported as accidental findings during pathological dissections of pinnipeds ( Kutzer and Burtscher, 1983 ; Ebmer et al, 2022 ). A first diagnostic approach showed the possibility to detect Or.…”