Abstract

Moniligerum blairi and Nudacotyle undicola are small intestinal trematodes of the West Indian manatee, Trichechus manatus.^1,2,3 M. blairi encysts within the small intestinal mucosa and N. undicola resides within the lumen.^1,3 Due to the small size of these two trematodes (ranging from 585 to 881 μm x 312 to 632 μm) they are often undiagnosed without histologic examination, and their significance is poorly understood.^3,4 Our goal was to determine the prevalence of these trematodes in the small intestine of Florida manatees, T. m. latirostris, from various size classes, and to describe the pathologic findings associated with their presence. Manatee carcasses necropsied at the Marine Mammal Pathobiology Laboratory had one to three portions (proximal, mid, and/or distal) of the small intestinal mucosa scraped using a #22 scalpel blade. Microscopic examinations of direct smears and samples after soap sedimentation were performed at 10x magnification to evaluate the presence of trematodes in the mucosal scrapings. Histopathology reports describing the presence of trematodes in the small intestine were evaluated. Adults and eggs of these trematodes were rarely found in the small intestine of carcasses that lacked grossly visible nodules within the mucosa. Pathology was observed in the small intestine of infected manatees. Lesions associated with these trematodes included lymphoplasmacytic, ulcerative enteritis with submucosal edema and crypt atrophy. Our study demonstrated that red and white raised nodules in the mucosa of the small intestine, found on gross necropsy, are highly suggestive of trematodiasis. Mucosal scraping of the small intestine can provide an immediate confirmation of the presence of M. blairi and N. undicola, and histologic examination can provide further support, not only of the presence of the parasite, but also the host response. To our knowledge, this is the first documentation of significant small intestinal enteritis associated with M. blairi and N. undicola in Florida manatees.

Acknowledgements

The authors wish to thank Brandon Bassett, Andy Garrett, Amber Howell, Anna Panike, and Kane Rigney of the Marine Mammal Pathobiology Laboratory in St. Petersburg, Florida and Dr. Ruth Francis-Floyd and Dr. Trevor Gerlach at the University of Florida, College of Veterinary medicine, Gainesville, Florida.

* Presenting author
+ Student presenter

Literature Cited

1.  Beck CA, Forrester DJ. 1988. Helminths of the Florida manataee, Trichechus manatus latirostris, with a discussion and summary of the parasites of Sirenians. J Parasit 74:628–637.

2.  Colon-Llavina MM, Mignucci-Giannoni AA, Mattiucci S, Paoletti M, Nascetti G, Williams EH. 2009. Additional records of metazoan parasites from Caribbean marine mammals, including genetically identified anisakid nematodes. Parasitol Res 105:1239–1252.

3.  Dailey MD, Vogelbein V, Forrester DJ. 1988. Moniligerum blairi n. g., n. sp. and Nudacotyle undicola n. sp. (Trematoda: Digenea) from the West Indian manatee, Trichechus manatus L. Syst Paras 11:159–163.

4.  Forrester DJ. 1992. Manatees. In: Forrester DJ. Parasites and diseases of wild mammals in Florida. Gainesville (FL): University Press of Florida. p 255–274.