Newly recognizedAnaplasmasp. in erythrocytes from Gopher Tortoises (Gopherus polyphemus)

Abstract

Background In 2015, a previously unrecognized intracytoplasmic erythrocytic inclusion was discovered in anemic wild‐caught adult gopher tortoises (Gopherus polyphemus). Subsequently, molecular diagnostics revealed this inclusion to be a novel Anaplasma sp. Objectives The goal of this study was to morphologically characterize these erythrocytic inclusions by light and transmission electron microscopy (TEM). Methods Blood samples were taken from two car‐injured wild‐caught gopher tortoises for the preparation of Wright‐Giemsa stained smears and TEM specimens. CBC data were serially performed and morphologically examined during treatment periods. Results Studies revealed a moderate to severe anemia with moderate regeneration as indicated by polychromasia and the presence of immature erythroid precursors. In addition, on light microscopy, one to two variably‐sized round basophilic stippled paracentral erythrocytic inclusions were present per cell in both animals and involved 10%‐25% of erythrocytes. TEM identified the intraerythrocytic inclusions as discrete membrane‐bound cytoplasmic vacuoles (morulae) containing membrane‐bound bacterial subunits that were of variable size, shape, and electron density. Serial hematologic data indicated complete remission of the infection in response to a single long‐term course of doxycycline. Conclusions The presence of a regenerative anemia in gopher tortoises from Florida revealed a newly recognized bacterial species that has morphologic characteristics similar to members of the genus Anaplasma.

What is your diagnosis? Blood smear review in a Texas tortoise (Gopherus berlandieri)

“…The morphologic characteristics of the intra-erythrocytic inclusions observed via light microscopy and TEM in the present case were most consistent with the previously published characteristics of Anaplasma spp., particularly those described in a recent report by Raskin et al, which detailed the microscopic characterization and PCR confirmation of a novel Anaplasma species found within erythrocytes of two anemic, wild gopher tortoises (G polyphemus) in Florida. 2 The order Rickettsiales comprises three families, consisting of Rickettsiaceae, Midichloriaceae, and Anaplasmataceae, with the family Anaplasmataceae composed of five recognized genera including Aegyptianella, Anaplasma, Ehrlichia, Neorickettsia, and Wolbachia. 3 Members of the genus Anaplasma are Gram-negative, non-motile, obligate intracellular bacteria that replicate by binary fission and are found within membrane-bound inclusions inside the cytoplasm of vertebrate and invertebrate host cells.…”

“…A marginale and tends to have a more aggressive clinical course. 4 Mammals are the predominant vertebrate host for Anaplasma, but a recent report by Vanstreels et al suggests that birds can also serve as competent hosts, as evidenced by an African penguin (Spheniscus demersus) with erythrocytes that contained inclusions strikingly similar to those described by Raskin et al 2 Other organisms to consider, particularly in birds and reptiles that are similar in appearance to Anaplasma morulae with round, purple, membrane-bound inclusions 2-4 µm in diameter, are those of genus Aegyptianella (AE). The most notable species is Aegyptianella pullorum in birds, transmitted by the soft tick Argas persicus to various avian species, including chickens, turkeys, ducks, geese, and quails over a wide geographic distribution, including North America, South America, Europe, Africa, and Asia.…”

“…Although no ectoparasites were noted on physical exam, vector transmission cannot be excluded, as the gopher tortoise tick, Amblyomma tuberculatum, commonly inhabits the southeastern US. 2 The prevalence of Aegyptianella spp. in this region is unknown.…”

“…In each case of the gopher tortoises and the African penguins, phylogenetic analyses revealed that the erythrocyte inclusions were most closely related to a cluster consisting of A centrale, A capra, A marginale, and A ovis. 2,3 The diagnosis of Anaplasma spp. can be challenging since the organism is difficult to culture, and affected animals can often present with non-specific symptoms, including fever, weakness, anorexia, lameness, vomiting, and diarrhea.…”

Relative white blood cell counts, heterophil-to-lymphocyte ratio, and discovery of blood parasites in wild dugong (Dugong dugon) at Lingayan Island, Toli-toli, Indonesia

“…In the present study, the blood smear examination also demonstrated the presence of intraerythrocytic dark purple microorganisms appearing as coccoid-and pear-shaped. The coccoid-shaped intraerythrocytic parasites were generally identified as Anaplasma, bacteria belonging to the order Rickettsiales, whereas the pear-shaped microorganisms were generally identified as Babesia, protozoa belonging to the order Piroplasmida [18][19][20][21]. The genus and species of these blood parasites remain unidentified as of now.…”