Abstract

A new upper respiratory disease syndrome, similar to upper respiratory tract disease (URTD) affecting American tortoises,^4,5 was identified in wild Eastern box turtles (Terrapene carolina carolina) from Virginia. Coincident with this discovery, turtles submitted to both the University of Virginia and the Wildlife Center of Virginia presented with tympanic bulging, oral lesions, swollen eyelids or mucopurulent nasal discharge typical of upper respiratory disease, commonly attributed to vitamin A deficiency¹ and organochlorine exposure^6,10. The present preliminary study was undertaken to determine the geographic distribution of the URTD-like disease in Virginia, to assess its prevalence in animals exhibiting the latter somewhat similar upper respiratory disease syndrome (URS), and to characterize the phylogenetic relationship of this Mycoplasma isolate to other pathogenic members of the genus.²

Results

Clinically, affected animals exhibited varied signs including unilateral to bilateral serous to mucopurulent nasal discharge, epiphora, and conjunctival injection and edema. All animals were collected from May through July, in 2001–3. Generic and agent-specific PCR detected Mycoplasma-positive nasal swabs from seven of 24 animals sampled, representing six of eleven Virginia counties where animals originated. Three specific Mycoplasma PCR-positive animals had aural bulging or oral lesions typical of URS, while four did not. A single animal without any upper respiratory signs that underwent a saline nasal flush was PCR positive, while 13 others without any upper respiratory signs, likewise flushed and screened were PCR negative. Sequence analysis based on the 16S ribosomal region from three clinical cases and a presumed carrier not exhibiting signs, representing isolates from four different counties, revealed a single unique agent. The new isolate was distinct from M. agassizii, but closely (98% 16S sequence agreement) related. Nasal swab samples from all the animals were negative for chelonian herpesviruses^11,12 and invertebrate⁷ and vertebrate (including FV3)^8,9 iridoviruses by PCR.

Discussion

These preliminary findings suggest the emergence of a new URTD-like syndrome in Eastern box turtles from Virginia. Clinically, this disease was indistinguishable from M. agassizii-induced disease in tortoises, except for a differing species predilection.^4,5 Although preliminary, no relationship was noted between Mycoplasma PCR positive tests, and URS signs common to wild turtles from this region. Similar to the description of tortoise URTD,³ preliminary observations suggest that animals may harbor the agent, but exhibit only intermittent clinical signs, and clinical signs appeared to increase the likelihood of disease detection by nasal swab/conjunctival PCR testing as in URTD (Wimsatt, unpublished data). To our knowledge, this is the first report of a Mycoplasma recovered from multiple clinically ill wild box turtles from the mid-Atlantic region of the US, a purportedly M. agassizii-free area. Further work is required to confirm that this unique Mycoplasma isolate is the causative agent of the observed disease syndrome, to map and assess the agent’s distribution and impact on wild turtle populations, to identify cofactors facilitating disease progression, and to better classify the organism biochemically and taxonomically.

Acknowledgments

We would like to thank Elliott Jacobson for helpful suggestions, and Joe Mitchell and Jean Marie Richards for their valuable contributions. Samples were collected under permits from the Virginia Department of Game and Inland Fisheries (Scientific Collection Permit number 022992), and federal permit FRSP-2003-SCI-0002 from the National Park Service.

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