Ultrastructure of Theileria-infected blood cells of loggerhead turtles

Abstract

The authors are grateful to Drs. Stacy and Harvey et al. for their comments concerning Caretta caretta theileriosis. It gives us an opportunity to clarify and expand our statements as well as to offer further micrographic evidence relative to understanding this condition. This report regarding theileriosis is based on observations that were made over a period of about 12 years and includes an analysis of multiple hematological parameters derived from a large number of C. caretta obtained from inhabitants of the Mediterranean Sea (see Basile et al. 2012). In spring 2011, two specimens of C. caretta, completely covered by leeches, were brought to the Turtle Center of the Zoological Station of Naples. The leeches were recognized as Ozobranchus margoi, well known as turtle leeches (see figure in Di Santi et al. 2012). The diagnostic process of theileriosis began with the detection of eosinophilic leukocytosis (Fig. 1a, Di Santi et al. 2012, and here in Fig. 1). It is well acknowledged that eosinophilia is a very frequent manifestation of parasitic infection in vertebrates. The first notable observation that was made was the presence of bacillary rodbayonet-shaped inclusions in erythrocytes (Bthe most useful guide to the genus Theileria,^ Kreir 1977) followed by their recognition in leukocytes. An abundant number of techniques were utilized to identify the parasite. The first step was to conduct weekly hemograms on the two specimens which embraced morphologic analysis of blood films for parasitized cells Figs. 2–7, 8–9, 10–12, and 13). In addition, samples were preserved in EPON preparations to study them under TEM (see enclosed unpublished photographs of Figs. 14–15, 16–17, 18–19, 20–21, 22–25, and 26–27). During the stage of infection, osmotic fragility tests were conducted to establish whether the parasitic infection resulted in an alteration of erythrocytic osmotic fragility. When the stage of infection visually affected the leukocytes in the blood smears, buffy coat preparations of both subjects were prepared and cultured. The results of these tests confirmed the presence of an