Mighty surprising mites: Nasopulmonary mite infestations and implications for marine mammal health

Nasopulmonary mites (NPMs) of the family Halarachnidae are obligate endoparasites that colonize the respiratory tracts of mammals. Although sometimes mistakenly regarded as benign, NPMs can damage surface epithelium resulting in mucosal irritation, respiratory illness, and secondary infection in pinnipeds and lutrinids. NPM also harbor numerous bacterial pathogens associated with fatal lesions in marine mammals suggesting they may also aid in bacterial invasion. Nasopulmonary acariasis is now recognized as an underappreciated contributor to morbidity and mortality of southern sea otters (Enhydra lutris nereis), a threatened species. Captivity may permit or facilitate the proliferation of nasopulmonary mites since a history of rehabilitative care is strongly associated with the likelihood of infestation for otters and infestations of captive marine mammals can be especially severe. To investigate the potential for environmental survival of NPM, we placed live mites in microcosms simulating environmental conditions and disinfectant protocols used in captive facilities. NPM survived for long periods on surfaces and in pools that mimicked captive enclosures and were resilient against existing disinfectant procedures. We discuss these findings and the growing body of knowledge of NPM pathology in the context of marine mammal rehabilitative care, population health, and proposed management plans.