The Florida manatee population faces numerous environmental threats, and a large number of mortalities are due to undetermined causes.1 To better understand manatee health and their environments, conservation agencies captured and examined free-ranging manatees at two locations, Crystal River (CR, Gulf coast) and Brevard County (BC, Atlantic coast). The objective of this study was to analyze and compare blood work and innate immune function in manatees of both locations to 1) develop additional tools to monitor health and 2) determine parameters that differ between the two populations to further identify underlying cellular/molecular mechanisms. Eighteen hematological and 20 biochemical analytes were analyzed in manatees from CR (n = 30) and BC (n = 12) in 2014–2015. Clinicopathologic analytes were all within normal range for wild manatees,2,3 although some significant differences between both populations were observed. Median total solids (8.1 vs. 7.5 g/dL), total proteins (8.3 vs. 7.3 mg/dL), total bilirubin (0.2 vs. 0.1 mg/dL), glucose (91 vs. 68 mg/dL), triglycerides (120.5 vs. 53.0 mg/dL), magnesium (6.9 vs. 4.9 mg/dL), and chloride (103.3 vs. 99.8 mmol/L) were significantly higher (p < 0.05), and calcium (9.6 vs. 10.2 mg/dL) was significantly lower in BC manatees compared to CR (p < 0.05). Innate immune function testing using peripheral blood mononuclear cells4 did not reveal any significant differences in neutrophil and monocyte phagocytosis between both locations (p = 0.11 and p = 0.27). Neutrophil respiratory burst (RB) was significantly higher and monocyte RB was significantly lower in BC manatees (p = 2.10-7 and p = 0.01). Cytokine cDNA levels of IL-2, IL-10, and IFN-γ were quantified using qPCR.5 Final normalized counts of IL-10 and IFN-γ were lower (p = 0.04 and 0.02 resp.) and of IL-2 cDNA were higher (p = 0.02) in BC than CR manatees. Observed differences in clinical pathology parameters and innate immune function assays may be related to different environmental conditions such water salinity, diets and/or chemical pressures between the two sites. Future comparisons and correlations with injury and illness may validate these tools for assessing and managing manatee health.
The authors wish to thank Dr. Ferrante, the Health Assessment Crew, Linda Archer, Patrick Thompson, and Kuttichantran Subramaniam of the University of Florida's Wildlife and Aquatic Veterinary Disease Laboratory for providing technical assistance.
* Presenting author
+ Student presenter
1. Runge MC, Langtimm CA, Martin J, Fonnesbeck CJ. Status and threats analysis for the Florida manatee (Trichechus manatus latirostris), 2012: U.S. Geological Survey. Open-File Report. 2015–1083:23. http://dx.doi.org/10.3133/ofr20151083.
2. Harvey JW, Harr KE, Murphy D, Walsh MT, Chittick EJ, Bonde RK, Pate MG, Deutsch CJ, Edwards HH, Haubold EM. Clinical biochemistry in healthy manatees (Trichechus manatus latirostris). J Zoo Wildl Med. 2007;38(2):269–279.
3. Harvey JW, Harr KE, Murphy D, Walsh MT, Nolan EC, Bonde RK, Pate MG, Deutsch CJ, Edwards HH, Clapp WL. Hematology of healthy Florida manatees (Trichechus manatus). Vet Clin Pathol. 2009;38(2):183–193.
4. Levin M, Joshi D, Draghi A, Gulland FM, Jessup D, De Guise S. Immunomodulatory effects upon in vitro exposure of California sea lion and southern sea otter peripheral blood leukocytes to domoic acid. J Zoo Wildl Med. 2010;46(2):541–550.
5. Ferrante JA, Wellehan JFX. Development of quantitative PCR assays to measure leukocyte cytokine levels in the Florida manatee. In: IAAAM 46th Annual Conference Proceedings. Chicago, IL; 2015.