Aegyptianella Ranarum Sp. N. (Rickettsiales, Anaplasmataceae): Ultrastructure and Prevalence in Frogs From Ontario

Abstract

Aegyptianella ranarum sp. n. (Rickettsiales, Anaplasmataceae) was recorded from bullfrogs (Rana catesbeiana Shaw), green frogs (Rana clamitans Latreille) and mink frogs (Rana septentrionalis Baird) from five sites in southern Ontario. The rickettsia occurs within membrane-bound vacuoles in the cytoplasm of erythrocytes with up to 120 organisms in mature inclusions. The pattern of replication of A. ranarum in host erythrocytes and its prevalence over a 3-yr period in frogs from Algonquin Park, Ontario are discussed.

New Findings from an Old Pathogen: Intraerythrocytic Bacteria (Family Anaplasmatacea) in Red-Backed Salamanders Plethodon cinereus

“…Early studies cited by Hegner (1921) reported a parasite meeting this description in amphibians from Africa and Brazil. Werner (1993) and Chutmongkonkul et al (2006) reported infected amphibians from China and Thailand, while Desser (1987) and Barta and Desser (1984) describe the organism in frogs from Ontario, Canada. Desser and Barta (1989) also report it from ranid frogs in Corsica.…”

“…Morphologically, the organisms and inclusion are consistent with members of the family Anaplasmataceae (order Rickettsiales), for which all known species are all obligate, intracellular bacteria transmitted by vectors (Rikihisa, 2006). At one point this organism of frogs, as well as other morphologically similar organisms (Tunetella emydis) from turtles, were all transferred to the genus Aegyptianella, due to similarities with A. pullorum of birds (Gothe and Kreier, 1978;Desser, 1987). Recently though, molecular characterization of an Aegyptianella-like organism from a bullfrog (Rana catesbeiana) from Canada indicated that the bacteria were actually members of the family Flavobacteriaceae (Zhang and Rikihisa, 2004).…”

“…They appear as a violet or purple membrane-bound structure within red blood cells, and have rod-shaped granules visible inside some inclusions. Initially, the parasite was believed to be an amoeba (Hegner, 1921;Lehmann, 1961Lehmann, , 1964, but ultrastructural studies have since demonstrated the ''organism'' is a membrane-bound, violet-staining valuole containing numerous bacteria (Desser, 1987).…”

Intraerythrocytic rickettsial inclusions in Ocoee salamanders (Desmognathus ocoee): prevalence, morphology, and comparisons with inclusions of Plethodon cinereus

“…They were once thought to be protozoal in origin and given the name Cytamoeba bacterifera (Hegner 1921). This designation continued until later investigations using electron microscopy suggested that the organism was a rickettsia-like bacterium that was segregated from the host-cell cytoplasm within a membranebound vacuole, and based on this evidence, Desser (1987) argued that it belonged to the genus Aegyptianella. However, a recent investigation using gene sequencing of blood from infected red-backed salamanders (Plethodon cinereus) indicated that the bacteria, at least in that host, was only distantly related to the Aegyptianella genus and in fact belonged in a new, as yet unnamed, genus of Rickettsia (Davis et al 2009a).…”

Parasites of the Mink Frog (Rana septentrionalis) from Minnesota, U.S.A

“…Bacterial (Aegyptianella ranarum [Desser, 1987], Aeromonas spp. [Hedeen, 1972a]), viral (icosahedral viruses [Gruia-Gray et al, 1989;Desser, 1992]), and fungal (Batrachochytrium dendrobatidis [Longcore et al, 2007]) pathogens have been reported from mink frogs.…”