Abstract
Coagulation disorders have recently been investigated in the roles of several health issues in rehabilitated Florida manatees (Trichechus manatus latirostris). Clinical evidence has suggested that thromboembolic disease (TE) may have a significant role in cold stress syndrome (CSS)1 while brevitoxicosis appears to have features consistent with bleeding tendencies. D-dimer (ng/ml), fibrinogen (mg/dl), prothrombin time (PT, sec), partial prothrombin time (PTT, sec), and platelets (10^3/µl) of manatees received for rehabilitation to Tampa's Lowry Park Zoo (TLPZ) were evaluated. Healthy values were determined from manatees that were being prepared for release and were considered healthy based on physical exam, complete blood cell counts (CBC) and serum biochemistry panels. Abnormal animals were all manatees presented for CSS, brevetoxin exposure, and trauma of any type. Some manatees may have contributed to several samples while still clinically affected with the presenting problem, but each manatee could only contribute one healthy sample if they were deemed healthy enough for release. Means, standard deviations, and 95% confidence intervals for D-dimer, PT, PTT, fibrinogen, platelet count were all calculated. Student T-test (α = 0.05) between healthy manatees and debilitated manatees as well as subsets of specific health problems were compared as well. Twenty-eight clinically healthy manatees and 43 debilitated animals were included in the study. Results are summarized in Table 1.
When results were compared between healthy and all debilitated animals, the D-dimers were found to be statistically significantly increased in debilitated manatees (p = 0.0039), PT (p = 0.379), PTT (p = 0.293), platelet count (p = 0.315), and fibrinogen (p = 0.172) were not found to be statistically different. The confidence interval (CI) of D-dimers in manatees with brevetoxicosis (87.5–109.0 ng/ml) falls within that of healthy manatees (50.9–159.42 ng/ml). Traumatized manatees had higher levels compared to healthy manatees (p = 1.35*10-06), CI 444.9–547.6 ng/ml), and CSS afflicted manatees had the highest D-dimers compared to healthy manatees (p = 0.0008, CI 755.4–904.8 ng/ml). The CI of D-dimers for healthy manatees is consistent with what has been reported in domestic companion animals2 and has been adopted as normal in manatees.1 The trend of elevated D-dimers in CSS and normal levels in manatees with brevetoxicosis is consistent with the clinical presentation of TE disease in CSS and possible bleeding tendency in brevetoxicosis. Manatees with trauma also had higher fibrinogen (p = 0.05) than healthy manatees.
Comparing the groups of debilitated manatees to each other finds CSS manatees having elevated D-dimer compared to brevetoxicosis affected manatees (p = 0.025), CSS manatees have higher platelets than traumatized manatees (p = 0.014), and traumatized manatees have higher D-dimer than brevetoxin affected manatees (p = 0.0004). One notable trend seen was than CSS manatees have shorted PTT than manatees with brevetoxicosis (p = 0.07). There is a trend in platelets in CSS manatees to be elevated compared to healthy manatees (p = 0.065). This elevation in platelets is believed to be due to coagulation activation and not a reflection of chronic inflammation as other chronic inflammatory diseases in manatees (trauma) does not have elevations in platelets. Additional testing will continue to determine if these trends becomes significant.
Table 1. Mean, standard deviation (SD), number (N), and 95% confidence intervals of healthy released manatees, debilitated manatees, and manatees with specifically diagnosed issues; cold stress syndrome (CSS), brevetoxicosis, and trauma from any source
| |
D-dimer (ng/ml)
|
Fibrinogen (mg/dl)
|
PT (sec)
|
PTT (sec)
|
Platelets (x103/µl)
|
|
Released
|
|
Mean
|
105.17
|
350.90
|
9.59
|
12.94
|
340.35
|
|
SD
|
146.46
|
54.08
|
1.90
|
4.12
|
226.31
|
|
N
|
28
|
21
|
28
|
28
|
14
|
|
95% CI
|
50.9–159.42
|
327.7–374.03
|
8.88–10.29
|
11.42–14.47
|
221.8–458.9
|
|
Debilitated
|
|
Mean
|
497.51
|
399.83
|
9.21
|
17.57
|
418.65
|
|
SD
|
668.53
|
153.65
|
1.45
|
22.48
|
247.68
|
|
N
|
43
|
35
|
37
|
37
|
38
|
|
95% CI
|
297.69–697.33
|
348.9–450.7
|
8.74–9.68
|
10.32–24.81
|
339.9–497.4
|
|
CSS
|
|
Mean
|
830.13
|
383.14
|
8.96
|
10.73
|
529.21
|
|
SD
|
971.73
|
150.57
|
1.43
|
1.39
|
271.62
|
|
N
|
15
|
7
|
10
|
10
|
14
|
|
95% CI
|
755.4–904.8
|
333.0–433.2
|
2.79–15.12
|
3.99–17.46
|
494.3–564.0
|
|
Red tide
|
|
Mean
|
98.27
|
351.18
|
9.54
|
14.05
|
563.33
|
|
SD
|
100.14
|
42.25
|
1.61
|
5.17
|
216.04
|
|
N
|
11
|
11
|
11
|
11
|
3
|
|
95% CI
|
87.5–109.0
|
315.6–386.78
|
3.86–15.22
|
6.49–21.61
|
*
|
|
Trauma
|
|
Mean
|
496.27
|
445.73
|
8.95
|
26.00
|
311.39
|
|
SD
|
296.26
|
197.83
|
1.28
|
34.55
|
183.89
|
|
N
|
15
|
15
|
14
|
14
|
18
|
|
95% CI
|
444.96–547.56
|
391.38–500.08
|
2.67–15.22
|
6.40–45.61
|
262.59–360.19
|
* Unable to calculate statistic
Acknowledgements
The authors wish to thank Drs. Lizzy Arnett, Lauren Smith, and Nico Maldonado; the Veterinary Clinic Staff of Heather Henry, CVT and Michelle Devlin CVT, and the Manatee Rehabilitation Team led by Virginia Edmonds from Tampa's Lowry Park Zoo.
* Presenting author
Literature Cited
1. Ball RL. Thromboembolic disease as a component of health issues in the Florida manatee (Trichechus manatus latirostris). IAAAM 27th Annual Conference Proceedings, Sausalito, CA; 2013.
2. Nelson OL, Andreasan C. The utility of plasma D-dimer to identify pathologic thromboembolic disease in the dog. J Vet Intern Med. 2003;17:830–834.