Date of Award
Master of Science
Wildlife and Fisheries Science
Debra L. Miller, Richard Gerhold
Toxoplasma gondii is a protozoan parasite of felids reported to cause morbidity and mortality in the two subspecies of the West Indian Manatee (Trichechus manatus): the Antillean manatee (Trichechus manatus manatus) in Puerto Rico and the Florida manatee (Trichechus manatus latirostris). Sera or plasma (n=343) were collected from live-capture T. m. latirostris through the US Geological Survey (USGS) manatee health assessment program and serosanguinous fluid (n=10) were collected from necropsies conducted by the Marine Mammal Pathobiology Laboratory (MMPL). Additionally, serum or serosanguinous fluid samples (n=5) were collected from rehabilitated or necropsied T. m. manatus at the Manatee Conservation Center (MCC) of Puerto Rico. Free-roaming cat (Felis catus) serum samples (n=25) from Puerto Rico were collected for T. gondii testing. All serum, plasma, and serosanguinous fluid samples (n=383) were screened using the Modified Agglutination Test (MAT) to determine T. gondii seroprevalence in manatee and cat. All manatee samples tested on the MAT were seronegative for T. gondii except for one Antillean manatee which was inconclusive. Nested PCR on the blood clot of this animal was negative. Seroprevalence of T. gondii in cat sera was 16%. Fecal samples (n=79) from free-roaming cats in Florida were collected to determine the shedding prevalence of T. gondii oocysts. No oocysts consistent with T. gondii morphology were detected in any felid samples. This is the first attempt to connect T. gondii genotypes in manatees to the hypothesized contamination source, feral cat populations. To determine manatee habitat contamination, 33 seagrass samples (Thalassia testudinum, Syringodium filiforme, and Halodule wrightii) from 19 sites on the main island of Puerto Rico were collected for concentration and PCR detection of T. gondii oocysts. No T. gondii oocysts were detected in any of the seagrass samples. Freshly defecated fecal samples (n=24) were also collected from T. m. latirostris (n=21) and T. m. manatus (n=3) for parasite surveillance. Parasite ova found included: 2 Chiorchis spp., Pulmonicola cochleotrema, Moniligerum blairi, Nudacotyle undicola, 2 Eimeria spp., Heterocheilus tunicatus, and several unidentified eggs, cysts, and larvae. To the author’s knowledge, this is also the first report of Eimeria spp. in T. m. manatus from Puerto Rico.
Wyrosdick, Heidi Lynn, "Epidemiology of Toxoplasma gondii and a survey of other parasites in the West Indian manatee (Trichechus manatus). " Master's Thesis, University of Tennessee, 2016.