Search

Protozoal infections have been widely documented in marine mammals and may cause morbidity and mortality at levels that result in population level effects. The presence and potential impact on the recovery of endangered Hawaiian monk seals Neomonachus schauins- landi by protozoal pathogens was first identified in the carcass of a stranded adult male with dis- seminated toxoplasmosis and a captive monk seal with hepatitis. We report 7 additional cases and 2 suspect cases of protozoal-related mortality in Hawaiian monk seals between 2001 and 2015, including the first record of vertical transmission in this species. This study establishes case defi- nitions for classification of protozoal infections in Hawaiian monk seals. Histopathology and immunohistochemistry were the primary diagnostic modalities used to define cases, given that these analyses establish a direct link between disease and pathogen presence. Findings were sup- ported by serology and molecular data when available. Toxoplasma gondii was the predominant apicomplexan parasite identified and was associated with 100% of mortalities (n = 8) and 50% of suspect cases (n = 2). Incidental identification of sarcocysts in the skeletal muscle without tissue inflammation occurred in 4 seals, including one co-infected with T. gondii. In 2015, 2 cases of toxo - plasmosis were identified ante-mortem and shared similar clinical findings, including hematolog- ical abnormalities and histopathology. Protozoal-related mortalities, specifically due to toxoplas- mosis, are emerging as a threat to the recovery of this endangered pinniped and other native Hawaiian taxa. By establishing case definitions, this study provides a foundation for measuring the impact of these diseases on Hawaiian monk seals.

Hematology and serum chemistry reference intervals have been previously established for the endangered Hawaiian monk seal ( Neomonachus schauinslandi) as an imperative measure for health assessments. Monitoring the health of the wild population depends upon reference intervals that are context specific; hence we developed reference intervals from fresh samples, as opposed to frozen, from wild monk seals. This study builds on the number of parameters from previous efforts by using samples collected between 2004 and 2015 from wild monk seals. Blood samples were analyzed by a single veterinary diagnostic laboratory within 24 hr of collection from apparently healthy, wild seals during research activities. Reference intervals were determined based on the analytical steps outlined by the American Society for Veterinary Clinical Pathology. These comprehensive hematology and serum chemistry reference intervals enable more consistent and systematic interpretation of results, which will guide individual and population-level health assessment and decision-making research and recovery activities.