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. Anaplasma are arthropod-borne obligate intracellular bacteria in the class Alphaproteobacteria, order Rickettsiales. 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. For further phylogenetic characterization, novel consensus PCR assays targeting the groEL and sucB genes were designed. Bayesian and maximum likelihood phylogenetic analyses found that this agent was the most basal member of the Anaplasma clade tropic for erythrocytes, containing A. marginale, A. ovis, and A. centrale, all of which infect erythrocytes and cause clinically significant anemia in ruminants.1 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. Specific TaqMan assays for the tortoise Anaplasma groEL and sucB genes were designed and validated, enabling rapid, specific, sensitive, and quantitative testing. Archived gopher tortoise blood samples with normal and low packed cell volumes were available from a 2003–2006 study in North and Central Florida. The clinical presentation of significant anemia associated with Anaplasma may have conservation implications.
1. Brown WC, Barbet AF. 2016. Persistent Infections and Immunity in Ruminants to Arthropod-Borne Bacteria in the Family Anaplasmataceae. Annu Rev Anim Biosci. 4:177–197.