Herpetological Review 49(1), 2018
AMPHIBIAN AND REPTILE DISEASES 47
Herpetological Review, 2018, 49(1), 47–49.
© 2018 by Society for the Study of Amphibians and Reptiles
Seroprevalence of Mycoplasma agassizii and
Mycoplasma testudineum in Wild and Waif Gopher
Tortoises (Gopherus polyphemus) in Miami-Dade
County, Florida, USA
Gopher Tortoises (Gopherus polyphemus) are subject to a
variety of natural and anthropogenic stressors including habitat
loss and degradation, chemical contaminants, overexploitation,
and diseases (Rostal et al. 2014). Risk assessment and abatement
is especially critical for this species because Gopher Tortoises are
classified as a candidate species (Eastern population, including
all of Florida, USA) for listing as Threatened under the US
Endangered Species Act (USFWS 2014), Florida State Threatened
(FWC 2013), and globally Vulnerable by the International Union
for the Conservation of Nature Red List (Tortoise & Freshwater
Turtle Specialist Group 1996). In particular, Gopher Tortoises are
increasingly threatened by emerging infectious diseases (Berish
et al. 2010; Jacobson et al. 2014), including Upper Respiratory
Tract Disease (hereafter, “URTD”), an infection typically caused
by Mycoplasma testudineum or M. agassizii. URTD has been
detected in populations of Gopher Tortoises throughout much of
Florida (Berish et al. 2000, 2010), and is a health concern both for
individual Gopher Tortoises and entire populations (Jacobson et
al. 2014; McGuire et al. 2014). In some cases, URTD may cause
high mortality and morbidity in Gopher Tortoise populations,
with up to 50% of individuals in a population dying in a single
acute outbreak (Jacobson et al. 2014). However, infection by
Mycoplasma is not necessarily associated with symptoms of
disease. Herein, we report seroprevalence for wild and waif
Gopher Tortoises from Miami-Dade County, Florida. Our aim
is to expand surveillance of tortoise Mycoplasma exposure to
the southern end of the species’ distribution, and to provide
information relevant for management of the species within
highly urbanized environments.
We sampled wild and waif Gopher Tortoises for Mycoplasma
testudineum and M. agassizii within Miami-Dade County,
between September 2015 and April 2017. Our sampling of wild
tortoises focused on the Richmond Tract—an isolated 4.5-km
2
patch of critically endangered pine rocklands habitat (Diamond
and Heinen 2014; Possley et al. 2016) that harbors one of the
few Gopher Tortoise populations within Miami-Dade County
and extreme southern Florida (Kushlan and Mazotti 1984; Enge
et al. 2004; Rostal et al. 2014). The Richmond Tract consists
of several contiguous parcels (including Zoo Miami, Larry &
Penny Thompson Memorial Park, Martinez Pineland Preserve,
Gold Coast Railroad Museum and several other private and
government landowners). We located tortoises sampled in this
study by opportunistic encounters of tortoises, and through
monitoring apparently active burrows using camera traps and
Havahart traps at burrow entrances to capture tortoises from
within occupied burrows. In addition to sampling within the
Richmond Tract, we also opportunistically sampled two waif
tortoises that were brought to Zoo Miami by local residents. Here,
we define “waif” tortoise as any tortoise of unknown geographic
origin found outside of a natural area or one that had been
held for some time in captivity. Waif tortoises are of particular
interest because long-distance movement of tortoises may be
an important route for pathogen transmission between isolated
populations, and with the uncertain origin of waifs, they may
represent these types of vectors. In contrast to waif tortoises, we
define “wild” tortoises as any tortoise found within a natural area
at the Richmond Tract, although it is possible that some tortoises
within the Richmond Tract were at some point displaced by
people. As one of the few large protected areas of natural habitat
within urbanized Miami-Dade County, the Richmond Tract
properties are a popular site for illegal release of unwanted
exotic pets by Miami-Dade residents (Whitfield, pers. observ.).
All tortoises sampled in this study were adults or sub-adults.
To test for exposure to pathogens, we extracted up to 2-mL
blood from the brachial vein of tortoises. We held plasma or
serum from blood draws at -20°C until processing. Samples
were analyzed by the University of Florida Tortoise Mycoplasma
Testing Lab using enzyme-linked immunoassay tests (ELISA) for
M. testudineum and M. agassizii (Wendland et al. 2007).
Exposure to M. testudineum was supported for 2 of 12 (17%)
tortoises and another two tortoises showed suspect ELISA results
(Table 1). Exposure to M. agassizii was supported in 1 of 12 (8%)
tortoises and a further two tortoises showed suspect ELISA
results for exposure to this pathogen (Table 1). Two tortoises
tested positive for exposure to M. agassizii and suspect for M.
testudineum. None of the tortoises examined showed clinical
symptoms of URTD (e.g., dyspnea, rhinorrhea, epiphora,
mucopurulent ocular and/or nasal discharge, conjunctivitis).
We are not aware of any reports of disease-associated mortality
in Gopher Tortoises in Miami-Dade County. Individual wild
tortoises included individuals with both exposure to M. agassizii
and M. testudineum, while neither of the two waif tortoises
showed exposure to M. agassizii and only one of two tested
suspect for exposure to M. testudineum.
The ELISA assays for M. agassizii and M. testudineum
indicated exposure to a pathogen, not the sustained presence
of the pathogen in the Gopher Tortoise population within the
Richmond Tract. The sample sizes in this study were low, in
particular for waif tortoises. Small sample sizes limit our ability
STEVEN M. WHITFIELD
Zoo Miami, Conservation and Research Department,
Miami, Florida 33177, USA; e-mail: steven.whitfield@miamidade.gov
FRANK N. RIDGLEY
Zoo Miami, Conservation and Research Department,
Miami, Florida 33177, USA
DANIEL VALLE
Florida International University, Department of Earth and
Environment, Miami, Florida 33199, USA
NICOLE ATTEBERRY
Zoo Miami, Department of Animal Sciences,
Miami, Florida 33177, USA