Disease in wildlife or exotic speciesRetrospective Survey of Amphibian Pathology Cases at Texas A&M University System (2016–2020)
Introduction
Amphibians (∼7,600 species) are widespread vertebrates that include the orders Anura (frogs and toads), Caudata (salamanders and newts) and Gymnophiona (caecilians). Rapid declines in populations worldwide have led to increased interest in amphibian epidemiology and disease (Grant et al, 2020). Environmental pollution, habitat loss, introduction of prey species, climate change, overexploitation and infectious diseases are their main threats worldwide (Earl et al, 2016; Scheele et al, 2019). Therefore, ex-situ conservation and research programmes using wild-captured specimens have increased significantly (Biega et al, 2017; Jacken et al, 2020). An increased understanding is essential to improve management and maximize amphibian conservation efforts. In this study, we evaluated and delineated the main pathologies and causes of mortality in amphibians submitted to the Texas A&M University System between 2016 and 2020.
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Materials and Methods
The databases of the Texas A&M Veterinary Medical Diagnostic Laboratory and the Department of Veterinary Pathobiology were interrogated on the basis of defined selection criteria. Key words employed were ‘amphibian’, ‘frog’, ‘toad’, ‘salamander’ and ‘newt’. Records from January 2016 to August 2020 were analysed. Epidemiological and biological data, necropsy reports, photographic material and ancillary diagnostic results were retrieved and further evaluated, with special emphasis on the type and
Results
A total of 532 amphibian records representing 64 species were evaluated: 502 anurans (order Anura) (157 frogs [44 species] and 345 toads [10 species]) and 30 caudatans (order Caudata) (23 salamanders [6 species] and 7 newts [4 species]). The most commonly submitted species were the Houston toad (Anaxyrus houstonensis; n = 325), African clawed frog (Xenopus laevis; n = 16), Lemur leaf frog (Hylomantis lemur; n = 16) and Barton spring salamander (Eurycea sosorum; n = 15). Sex distribution for
Discussion
Very few studies have reported causes of death in large amphibian cohorts (Reiehenbach-Klinke and Elkan, 1965; Elkan, 1976; Green and Sherman, 2001; Eustace et al, 2018; Flach et al, 2020). Our findings indicate that infectious diseases are the main disease threats to captive amphibians in Texas. The Houston toad, an endangered species, is severely impacted, with mycobacteriosis and chlamydiosis as the leading causes of morbidity and mortality.
Amphibian mycobacteriosis has a worldwide
Acknowledgments
The authors would like to thank the dedicated staff at the Houston Zoo for their remarkable care for these animals and the histology technicians at Texas A&M Veterinary Medical Diagnostic Laboratory for their professionalism and commitment.
References (29)
Pathology in the Amphibia
In: Physiology of the Amphibia, B Lofts, Ed, Academic Press, New York pp
(1976)- et al.
Amphibian mycobacteriosis
Veterinary Clinics of North America: Exotic Animal Practice
(2012) Amphibians
- et al.
Practical gross necropsy of amphibians
Seminars in Avian and Exotic Pet Medicine
(2003) - et al.
Amphibian oncology
Veterinary Clinics of North America: Exotic Animal Practice
(2004) - et al.
Tumors in Amphibia
Zoological Science
(1987) - et al.
Global representation of threatened amphibians ex situ is bolstered by non-traditional institutions, but gaps remain
Animal Conservation
(2017) Mycobacteriosis
- et al.
Diseases of amphibians
ILAR Journal
(2007) - et al.
Ranavirus could facilitate local extinction of rare amphibian species
Oecologia
(2016)