Fig. 3. Host reaction and pathology related to APXSc. (A–E) Granulomatous swirl lesions within the Tehuelche scallop, a common host reaction to APXSc infection. (A) Semithin section stained with toluidine blue, showing typical swirl-like lesion, where fibroblast-like hemocytes (black arrowheads) surround groups of parasites, commonly 4–8 (black arrow). A larger granuloma is then formed around a cluster of these groups, forming a kind of double granuloma. (B) ISH sections of a similar swirl lesion as in (A), note the formation of numerous groups of parasites, each group apparently within one hemocyte (host nuclei: white arrowheads) and surrounded by fibroblast like hemocytes (black arrowheads). The insert shows a higher magnification of a cluster of the parasites. (C–E) Granulomatous swirl lesions with apparently degenerating parasites (*), surrounded by fibroblast like hemocytes (arrowheads). (C) = HE) = ISH.. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Published as part of V, Nuria, azquez, Freeman, Mark A., Cremonte, Florencia, Gilardoni, Carmen, Arni & Kristmundsson, 2022, A phylogenetically unresolved apicomplexan (APXSc) causing swirl lesions in the Tehuelche scallop, Aequipecten tehuelchus, from the Southwest Atlantic coast, pp. 295-307 in International Journal for Parasitology: Parasites and Wildlife 17 on page 297, DOI: 10.1016/j.ijppaw.2022.03.009, http://zenodo.org/record/13288099