title: Ultrastructural Comparison of Hepatozoon ixoxo and Hepatozoon theileri (Adeleorina: Hepatozoidae), Parasitising South African Anurans.
abstract: To date, only two haemogregarine parasite species have been described from South African anurans: Hepatozoon ixoxo, infecting toads of the genus Sclerophrys (syn. Amietophrynus); and Hepatozoon theileri, parasitising the common river frog, Amietia quecketti. Both species have been characterised using limited morphology, and molecular data from PCR amplified fragments of the 18S rRNA gene. However, no ultrastructural work has been performed thus far. The aim of this study was to add descriptive information on the two species by studying their ultrastructural morphology. Mature gamont stages, common in the peripheral blood of infected frogs, were examined by transmission electron microscopy. Results indicate that H. ixoxo and H. theileri share typical apicomplexan characteristics, but differ markedly in their external cellular structure. Hepatozoon ixoxo is an encapsulated parasite presenting a prominent cap at the truncate pole, and shows no visible modifications to the host cell membrane. In comparison, H. theileri does not present a capsule or cap, and produces marked morphological changes to its host cell. Scanning electron microscopy was performed to further examine the cytopathological effects of H. theileri, and results revealed small, knob-like protrusions on the erythrocyte surface, as well as notable distortion of the overall shape of the host cell.
authors.affiliation: Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa.
authors.forename: Roxanne
authors.initials: R
authors.lastname: Conradie
authors.affiliation: Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa.
authors.forename: Courtney A
authors.initials: CA
authors.lastname: Cook
authors.affiliation: Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa.|South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown, 6140, South Africa.
authors.forename: Louis H
authors.initials: LH
authors.lastname: du Preez
authors.affiliation: Laboratory for Electron Microscopy, Chemical Resource Beneficiation, North-West University, Potchefstroom, 2520, South Africa.
authors.forename: Anine
authors.initials: A
authors.lastname: Jordaan
authors.affiliation: Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa.|Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Leuven, 3000, Belgium.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Netherlands
mesh_terms: D000820:Animal Diseases / Q000469:parasitology; D000818:Animals; D001001:Anura / Q000469:parasitology*; D003048:Coccidiosis / Q000097:blood / Q000469:parasitology* / Q000662:veterinary*; D016054:DNA, Protozoan / Q000235:genetics; D004912:Erythrocytes / Q000469:parasitology; D016783:Eucoccidiida / Q000145:classification / Q000235:genetics / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D045483:Rivers; D013020:South America; D013045:Species Specificity
chemical_list: D016054:DNA, Protozoan; D012337:RNA, Ribosomal, 18S
keywords: 
  SEM
  ; 
  TEM
  ; Anura; apicomplexan; blood parasite; haemogregarine; haemoparasite; morphology; ultrastructure