Two Coccidian Parasites and An Unusual Intraerythrocytic Cytoplasmic Vacuolar Inclusion from Agamid Lizard, Trapelus savignii in Egypt

Abstract

Three types of parasites, two intraerythrocytic and one Isospora species, were recorded to infect lizard Trapelus savignii (Reptilia: Agamidae) collected in summer 2019 from the Eastern Desert in Egypt. The current intraerythrocytic parasites are haemogregarine species and unusual intraerythrocytic cytoplasmic vacuolar inclusions (ICVIs). Blood stages of haemogregarine species are differentiated into three forms; trophozoite, intermediate form, and mature gamont. Trophozoites measure 7.50–8.50 (8.10±0.30) × 2.20–2.40 (2.30±0.06) μm while intermediate forms and mature gamonts measure 7.89–10.39 (9.32±0.85) × 3.9–5.18 (4.32±0.45) and 8.87–12.13 (10.25±0.90) × 2.50–4.35 (3.45± 0.58) μm,respectively. ICVIs are un- or pale-stained with Giemsa and measure 1.62–5.45 (3.64±0.87) × 1.45–5.35 (3.51±1.10) μm. At the ultrastructure level, ICVIs appeared as a membrane-bound electron-lucent matrix and contain three types of materials according to their electron density that may resemble chromatin granules. No nucleus, Golgi apparatus, mitochondria, or any apical complex structure is observed within ICVIs. Effects of haemogregarine species and ICVIs on the infected erythrocytes are recorded. Exogenous and endogenous developmental stages of the present Isospora sp. are described. Sporulated oocysts are mostly spherical, contain bilayered wall, and measure 22.48–27.71 (25.47±1.81) × 21.69–26.91 (24.37±1.73). Oocyst residuum, polar granule and micropyle are absent. Sporocysts are ellipsoidal and measure 13.79–15.84 (14.97±0.67) × 8.80–11.03 (9.97±0.70). Stieda body is nipple-like while sub-Stieda body is absent. Multinucleate meronts contain up to 34 nuclei and measure 6.29–19.83 (11.91±4.58) × 5.43–10.76 (7.57±1.75). Developed microgamonts measure 16.59–18.89 (17.74±0.94) × 15.61–18.63 (17.12±1.24) while mature macrogamonts measure 16.34–24.27 (19.95±2.98) × 12.0–20.28 (16.92±3.22).