Abstract
Nasal mite infestations of the upper respiratory tract in pinnipeds are sparsely reported.1,2,3 Some anecdotal information suggests that there is not a common practice to open and examine nasal passages of the pinnipeds at the time of necropsy, especially in cases where the clinical reports do not report nasal discharge. As we studied the incidences of nasal mite infestations over a course of 3 years in the Los Angeles area, we found predominantly two representative species from the family Halarachnidae in the nasal passages, and occasionally in trachea and bronchioles of California sea lions (Zalophus californianus) and Northern elephant seals (Mirounga angustirostris): Orthohalarachne attenuata and O. diminuta.4 Previous clinical reports suggest that these infestations do not result in serious clinical disease for the pinnipeds.2,3 However, our gross and histopathological findings show that the affected animals at the time of necropsy often presented with a heavy parasitic load in the nasal passages and nasopharynx associated with the inflammatory response that ranges from mild to severe. Prevalence of disease ranged from 50% (2013) to 84% (2015) to 100% (2016) with the recent trend for adult mites to be affecting juvenile animals, unlike previously reported.5,6 Additionally, although most prevalent in our studies were adults and larvae of Orthohalarachne attenuata, mites of the Orthohalarachne diminuta were present in elephant seals also found in mucus from the trachea and small bronchioles, especially in heavy infestations. In contrast to the previous reports, we suggest that such heavy infestation of nasal mites can impair respiration in the affected hosts, which will superimpose to other infections and aggravate the general health condition of the affected animal, especially in the case of UME that bring other debilitating conditions as primary.7,8 Our data suggest that a detailed pathological evaluation of nasal passages and nasopharynx in the stranded pinnipeds is warranted regardless of the presence of clinical disease or discharge in order to scientifically assess and monitor the epidemiological status of nasal mite infestations.
Acknowledgment
This work is approved by NOAA and supported by the intramural summer student research grant by Western University of Health Sciences.
* Presenting author
Literature Cited
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