Abstract

Infections with digenetic trematodes Moniligerum blairi and Nudacotyle undicola are associated with severe enterocolitis and have been identified as an emerging cause for Florida manatee (Trichechus manatus latirostris) calf mortality.^1–2 It is currently unknown if one or both trematode species can cause disease. Antemortem diagnosis requires the identification of trematode ova on standard fecal parasitological screening, however an unknown prepatent period, intermittent shedding of ova, and varying parasitic burden reduces diagnostic sensitivity.³ Further, morphological similarities between ova complicates discrimination between trematode species.⁴ Molecular characterization of trematodes could facilitate development of an assay with greater sensitivity and specificity compared to traditional methods. The objective of this study was to obtain molecular sequence data from adult M. blairi and N. undicola.

Adult trematodes were collected from the small intestines of infected manatee calves presenting for gross necropsy in Florida. Adult worms were identified grossly using light microscopy based on morphological features.⁵ Twenty-five worms from four manatees were screened by targeting the 18S small subunit ribosomal RNA gene. A 1,767 base pair fragment from nineteen presumptive M. blairi showed 96.9% homology to Taprobanella bicaudata, 96.9% homology to Notocotylus sp. DTJL-2000, and 95.5% homology to N. undicola. A 737 base pair fragment from six presumptive N. undicola showed only 97.4% homology to previously identified N. undicola and 94.7% homology to T. bicaudata. This is the first partial molecular characterization of M. blairi and also the first report for this potentially novel Nudacotyle species.

Acknowledgements

The authors wish to thank the staff and volunteers at the FWC Marine Mammal Pathobiology Lab, SeaWorld Orlando, and ZooTampa for their assistance with sample collection as well as Dr. Heather Walden and Nina Thompson for their help with processing.

Literature Cited

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