Novel Anaplasma sp. and Helicobacter sp. in gopher tortoises (Gopherus polyphemus) in Florida

Gopher tortoises (Gopherus polyphemus), protected under the Endangered Species Act in the western part of their range, are under significant pressure from anthropogenic habitat loss. Aside from Mycoplasma agassizii and Frog... [ view full abstract ]

Gopher tortoises (Gopherus polyphemus), protected under the Endangered Species Act in the western part of their range, are under significant pressure from anthropogenic habitat loss. Aside from Mycoplasma agassizii and Frog Virus 3, little is known about infectious diseases of gopher tortoises. Three gopher tortoises injured in 2015-2016 in north central Florida presented with anemia and intracytoplasmic inclusions in red blood cells. Pan-bacterial 16S rRNA PCR and sequencing of blood resulted in sequence consistent with a novel Anaplasma sp. that is most closely related to but basal to the clade containing A. marginale, A. ovis, and A. centrale, all of which cause clinically significant anemia in ruminants. Anaplasma are arthropod-borne obligate intracellular bacteria in the class Alphaproteobacteria, order Rickettsiales. Bacteria morphologically similar to A. marginale grew within parasitophorous vacuoles on ISE6 tick cells. Electron microscopy of blood was consistent with Anaplasma sp. After treatment with doxycycline (10 mg/kg) for up to 200 days, anemia resolved. Archived gopher tortoise blood samples with low packed cell volumes were available from a 2003-2006 study in North and Central Florida. Bacterial 16S rRNA sequences from 14 animals were identical to the Anaplasma species seen in the first three tortoises. Two additional gopher tortoises presented in 2014-2016 initially healed from traumatic wounds, but later developed severe upper respiratory tract disease. Cytologic examination of nasal discharge revealed large numbers of spirilliform bacteria and marked rhinitis. Pan-bacterial 16S rRNA PCR and sequencing of nasal discharge resulted in sequence consistent with a novel Helicobacter sp. related to the two previously sequenced Helicobacter sp. from other tortoise species. Culture attempts were unsuccessful. Both tortoises were also Mycoplasmaagassizii positive by specific PCR/sequencing. Select coinfections may significantly exacerbate mycoplasmal respiratory disease in other species.