Usefulness of serum cardiac troponin I concentration as a marker of survival of harbor seal (Phoca vitulina) pups during rehabilitation

Abstract

OBJECTIVE To measure serum cardiac troponin I (cTnI) concentrations in orphaned harbor seal (Phoca vitulina) pups at various points during rehabilitation in a seal rescue center and determine whether cTnI concentration was associated with survival during rehabilitation and duration of rehabilitation. DESIGN Serial cross-sectional study. ANIMALS Fifty-five 2- to 9-day-old harbor seal pups. PROCEDURES Blood samples for serum cTnI concentration measurement, CBC, and serum biochemical analysis were obtained from seal pups at admission into a seal rescue center, after 2 weeks of rehabilitation at the center, and prior to release. Serum cTnI concentrations were compared between seals that did or did not survive rehabilitation. RESULTS Median serum cTnI concentration was highest at admission (0.03 ng/mL). After 2 weeks, the median value was 0.01 ng/mL; prior to release, it was 0.01 ng/mL. Seal pups that were found to have died during or after rehabilitation (n = 7) had a significantly higher median serum cTnI concentration at admission (0.06 ng/mL) than did seal pups that survived rehabilitation (and for which the postrelease fate was unknown; 48; 0.03 ng/mL). No correlation was identified between serum cTnI concentration and duration of rehabilitation. CONCLUSIONS AND CLINICAL RELEVANCE The results of this study suggested some degree of myocardial injury was present in most of the orphaned seal pups admitted for rehabilitation. Measurement of serum cTnI concentration in seal pups at admission might provide prognostic information about their likelihood of survival during or after rehabilitation.

Sink or swim: Risk stratification of preweaning mortality in harbor seal pups (Phoca vitulina richardii) admitted for rehabilitation

“…Our hematological values were also comparable to other reported values for harbor seal pups in rehabilitation (Fonfara et al, 2016; Frouin et al, 2013; Greig et al, 2010; Lander et al, 2003; Morgan et al, 2009; Witte et al, 2014), and again we found strong relationships with survival in contrast to much previous research. Specifically, lower survival was associated with values below the reference range for WBC counts, neutrophils, lymphocytes, and platelets.…”

“…In free‐ranging harbor seals, lactation lasts only 24 to 32 days (Cottrell et al, 2002; Muelbert & Bowen, 1993) and preweaning mortality ranges from 3% to 31%, with most deaths occurring in the first two weeks (Hastings et al, 2012; Huggins et al, 2013; Steiger et al, 1989). Prerelease mortality rates for pups in rehabilitation vary from 7% to 76% (Dierauf et al, 1986; Fonfara et al, 2016; Frouin et al, 2013; Greig et al, 2010; MacRae et al, 2011; Witte et al, 2014), with most deaths also occurring within approximately 20 days of their estimated birth (Greig et al, 2010; Witte et al, 2014). Thus, both free‐ranging and rehabilitated harbor seal pups appear to be vulnerable during the early preweaning period.…”

“…Previous research has found few consistent relationships between diagnostic measures taken at admission and harbor seal pup survival to release. While body weight, serum sodium, total protein, globulin, and platelet levels at admission have occasionally been found to be higher in pups that survived (Dierauf et al, 1986; Frouin et al, 2013; Greig et al, 2010; MacRae et al, 2011), multiple studies have found no clear association between survival to release and other diagnostic measures taken at admission (Fonfara et al, 2016; Greig et al, 2010; Witte et al, 2014). Previous research of factors associated with seal pup survival has also tended to rely on generalized linear models, such as logistic regression (Greig et al, 2010; MacRae et al, 2011; Silpa et al, 2015; Witte et al, 2014), or principal component analysis (Frouin et al, 2013).…”

Exploration of serum cardiac troponin I as a biomarker of cardiomyopathy in southern sea otters (Enhydra lutris nereis)

“…Harbor seal (Phoca vitulina) pups that die during or after rehabilitation have been found to have a significantly higher antemortem serum cTnI concentration at admission than do those that survive after release. 42 Although this was not the aim of the present study, we observed that healthy managed sea otters with the highest cTnI values were those with unsuccessful releases into the wild. One died of emaciation 2 weeks after release.…”

“…39 Regardless of etiology, myocardial damage and a high serum cTnI concentration have been associated with an increased risk of death in the short and long term in various species, emphasizing the utility of serum cTnI concentration as a prognostic indicator. 16,19,33,[40][41][42] This clinical tool may be particularly useful in wildlife rehabilitation. Harbor seal (Phoca vitulina) pups that die during or after rehabilitation have been found to have a significantly higher antemortem serum cTnI concentration at admission than do those that survive after release.…”