Some coccidial parasites of the lizard Amphisbaena alba (Reptilia: Amphisbaenia: Amphisbaenidae)

Pathogenesis of Isospora amphiboluri in Bearded Dragons (Pogona vitticeps)

Isospora amphiboluri is a common coccidian found in captive bearded dragons (Pogona vitticeps). To minimize the impact of this parasite, it is important to characterize its pathogenesis so that we can develop appropriate methods for diagnosis and treatment. Forty-five juvenile bearded dragons were used for this two-part study. In the first part, ten bearded dragons were infected with 20,000 oocysts per os, while a control group of five animals received only water. Feces were collected over 45 days and screened for oocysts. In the second part, thirty bearded dragons were used to characterize the pathogenesis of I. amphiboluri. Twenty-five bearded dragons were infected as described previously, while five animals served as controls. Five infected bearded dragons and one control were humanely euthanized on days 4, 8, 12, 16, and 20 post-infection for complete necropsies. The pre-patent period for I. amphiboluri was found to be 18.6 ± 1.9 days (range 15-22 days). Histopathology confirmed that I. amphiboluri follows a homoxenous life cycle. Infections begin in the duodenum and progress to the colon over time. The findings of this study can be used to develop better quarantine and treatment protocols for captive bearded dragons.

Absence of haemoparasite infection in the fossorial amphisbaenian Trogonophis wiegmanni

Blood parasites such as haemogregarines and haemosporidians have been identified in almost all groups of vertebrates. However, very little is known about biodiversity of these parasites and their effects on some major groups of reptiles such as amphisbaenians, a distinctive group with many morphological and ecological adaptations to fossorial life. Conditions of the fossorial environment might also affect host-parasite relationships. We investigated the presence and the potential prevalence of three genera of haemoparasitic aplicomplexan blood parasites (Hepatozoon, Plasmodium and Haemoproteus) in the amphisbaenian Trogonophis wiegmanni, a fossorial worm lizard species from North West Africa. Blood parasite infection was not detected in T. wiegmanni, both in visual surveys of blood smears and using molecular methods to detect DNA of such parasites in the blood of the potential amphisbaenian hosts. We discuss how conditions of the fossorial environment might affect blood parasitaemias in amphisbaenians as well as in other fossorial reptiles.

Morphological and molecular characterization of Choleoeimeria pogonae n. sp. coccidian parasite (Apicomplexa: Eimeriidae, 1989, Paperna and Landsberg) in a western bearded dragon (Pogona minor minor)

A new species, Choleoeimeria pogonae n. sp. is described from a Western bearded dragon (Pogona minor minor) in Western Australia. Sporulated oocysts (n = 48) were cylindroidal in shape. Oocyst length, 27.0 (26.0-28.3) μm, oocyst width, 15.2 (14.0-16.5) μm, oocyst length/width ratio (L/W) 1.8 (1.6-1.9), each with 4 sporocysts (Eimeria-like) and a polar granule, but lacking a micropyle and oocyst residuum. Sporocysts are ovoidal in shape, sporocyst length, 10.0 (9.0-11.0) μm, sporocyst width 8.5 (7.0-9.5) μm, sporocyst L/W ratio, 1.2 (1.1-1.3). Stieda, substieda and parasubstieda bodies were all absent. Molecular analysis was conducted at the 18S rRNA and cytochrome c oxidase I (COI) loci. Phylogenetic analysis of 18S sequences revealed that C. pogonae n. sp. grouped together with another four Choleoeimeria spp. and exhibited 99.1%-99.4% genetic similarity. At the COI locus, C. pogonae n. sp. was in an independent clade and had the highest similarity (80.4%) to Eimeria cf. mivati from a chicken (Gallus gallus domesticus). According to the morphological and molecular data, this isolate is a new species of coccidian parasite. This study further supports the taxonomy of Choleoeimeria spp. as a new genus based on molecular phylogenetic analysis.

Considerations and conditions involving protozoal inhabitation of the reptilian gastrointestinal tract

In mammals, gastrointestinal protozoal organism inhabitation has been well studied, with hundreds of species defined as parasites. While the mammalian protozoal relationships have been identified and categorized by anatomy, tropism, pathogenicity, and life cycles, relatively few species of protozoal organism relationships have been categorized in reptiles. Species of parasites are still being segregated from each other, and conflicting information needs to be clarified to completely understand the data already available. This article presents the information available to help reptile practitioners make evidence-based decisions regarding both the determination of a pathologic parasitic condition and direct appropriate treatment of patients.

A new species of Choleoeimeria (Apicomplexa: Eimeriidae) from the lizard, Scincus hemprichii (Sauria: Scincidae)

Four out of twenty (20%) specimens of the lizard Scincus hemprichii Wiegmann, collected in Saudi Arabia were infected with a previously undescribed species of Choleoeimeria. Oocysts of Choleoeimeria jazanensis sp. n. are cylindroidal, 26 x 15 microm, with a smooth bilayered wall and a shape index of 1.7. Oocyst residuum and micropyle are absent. Sporocysts are subspherical, 10 x 7 microm, with a shape index of 1.3. The Stieda body is absent. Sporozoites are banana-shaped, 10 x 3 microm, with one refractile body and enclosed the fine granulated sporocyst residuum. The endogenous development is confined to the gall bladder epithelium, with infected cells being displaced from the epithelium layer towards lumen. Mature meronts are subspherical and estimates to produce 9-12 merozoites. Microgamonts are spherical in shape with diameter of 13 microm. Macrogamonts are subspherical with a prominent nucleus in centre and wall-forming bodies at periphery.

Redescription of Eimeria zarudnyi Alyousif & Al-Shawa, 2003 as Choleoeimeria zarudnyi n. comb. (Apicomplexa: Eimeriidae)

Coprological examination of the worm lizard Diplometopon zarudnyi Nikolskii revealed the presence of oöcysts of Choleoeimeria zarudnyi (Alyousif & Al-Shawa, 2003) n. comb. in five (17%) of the 30 lizards examined. Sporulated oöcysts were found in the faeces and the gallbladder contents. These are tetrasporocystic, ellipsoidal, 25-32 × 18-25 (mean 27 × 22) μm, with a smooth bi-layered wall. The dizoic sporocysts are ovoidal, 10-13 × 6-9 (mean 11 × 7) μm, with a granulated sporocyst residuum. Sporozoites are banana-shaped with an average size of 13 × 3 μm. Endogenous stages (meronts, gamonts and gametes) are confined to the gallbladder epithelium and the infected cells were hypertrophied. Based on the morphological features of the exogenous stages and the endogenous development of the present parasite, its generic affiliation is revised and Eimeria zarudnyi Alyousif & Al-Shawa, 2003 is transferred to the genus Choleoeimeria.

Isospora riyadhensis n. sp. (Apicomplexa: Eimeriidae) from the worm lizard Diplometopon zarudnyi Nikolskii (Amphisbaenia: Trogonophidae) in Saudi Arabia

Isospora riyadhensis n. sp. is described from the intestine of the worm lizard Diplometopon zarudnyi Nikolskii in Saudi Arabia, where its prevalence was 26.6%. Its oöcysts are spherical to subspherical and measure 23 × 20 μm. The sporocysts, which are tetrazoic and ovoid, measure 13 × 8 μm, whereas their sporozoites are banana-shaped, have anterior and posterior refractile bodies and measure 12 × 3 μm. Oöcysts are passed unsporulated, and the majority become fully sporulated within 3 days at 25 ° C. All endogenous stages develop in the cytoplasm of epithelial cells in the posterior region of the small intestine, from where meronts, microgamonts and macrogamonts are described.