Ultrastructural features of the gametogenic and sporogonic development ofHepatozoon sipedon(Apicomplexa: Adeleorina) The applicability of ultrastructural data in differentiating amongHepatozoonspecies

Abstract

Summary :Stages of gametogony and sporogony of the haemogregarine Hepatozoon sipedon, an apicomplexan parasite of the Northern water snake, Nerodia sipedon sipedon, were studied in the mosquito, Culex pipiens, by electron microscopy. Four days after mosquitoes fed on an infected snake, microgamonts and macrogamonts were observed in syzygy in parasitophorous vacuoles within fat body cells of the haemocoel. During microgametogenesis, two biflagellated microgametes wete formed, one of which fertilized the macrogamete. After fertilization, zygotes increased rapidly in size, accumulating reserve material in the form of lipid inclusions. Beginning at 16 days post-feeding (PF), the nucleus of the immature oocyst underwent multiple divisions in the first stage of sporoblast formation. Small crystalloid bodies initially appeared in the cytoplasm of the dividing oocyst at 20 days PF. At 24 days PF, the oocyst contained hundreds of sporoblasts, each of which matured as early as 28 days PF into thick-walled sporocysts containing eight sporozoites and a large residual body. Sporozoites contained a large crystalloid body comprised of tightly-packed particles assembled in a paracrystalline array. The use of ultrastructural characters in the differentiation of Hepatozoon species is discussed in context with the current phylogenetic hypotheses of adeleorin taxa. KEY WORDS :

Ultrastructural studies on the sporogony of Hepatozoon spp. in Culex quinquefasciatus Say, 1823 fed on infected Caiman crocodilus and Boa constrictor from northern Brazil

“…(Ball et al 1969 ;Bashthar et al 1984Bashthar et al , 1991Lowichik et al 1993). In H. sipedon, also from snakes development was even slower than in H. caimani from the caiman, reaching sporozoite stages only at day 28 p.f., the ambient temperature being about the same as in the previous studies (y25 xC, Smith & Desser, 1997). In our boa-fed mosquitoes sporogonic division was first detected 9 days p.f., and in caiman-fed mosquitoes only by 12 days p.f.…”

“…The fine structure of the gamogonous process and the sporogonic development of several Hepatozoon spp. of reptiles and amphibia has been reported (Vivier, Petitprez & Landau (1972) ; Bashtar et al (1984) ; Lowichik et al (1993) ; Desser et al (1995); Smith & Desser (1997)). Here we describe the fine structure of sporogonic stages developing in mosquitoes, Culex quinquefasciatus which were allowed to engorge on an Hepatozoon-infected caiman, and an abortive development of a Hepatozoon species of the boa in the same species of mosquito.…”

“…Culicid mosquitoes are natural vectors of reptilian and amphibian Hepatozoon spp. Sporogonic development has been described in experimentally infected laboratory mosquitoes (Culex quinquefasciatus Say, 1823, Mackerras (1962), Culex pipiens, Bashtar, Ghaffar & Mehlhorn (1984), Culex tarsalis, Booden, Chao & Ball (1970), Culex territans, Desser, Hong & Martin (1995) ; Smith & Desser (1997), Aedes aegyptii, Lowichik et al (1993), Aedes togoi, Ball et al (1969) and Anopheles stephensi, Landau et al (1972)). The fine structure of the gamogonous process and the sporogonic development of several Hepatozoon spp.…”

Hepatozoon kisraen. sp. infecting the lizardAgama stelliois transmitted by the tickHyalommacf.aegyptium

“…Development of the presently described species, although taking place in ticks, occurs similarly to that seen in moquitoes, i.e. within the oocyst located in the tissue lining the haemocoel (Bashtar etal, 1984;Lowichik etal, 1993;Smith & Desser, 1997). In Hemolivia developing in ticks the sporocysts released (as sporokinetes) from the oocyst remain located inside parasitophorous vacuoles within the tick gut cells (Smallridge & Paperna, 2000b).…”

Ultrastructural Comparison of Hepatozoon ixoxo and Hepatozoon theileri (Adeleorina: Hepatozoidae), Parasitising South African Anurans

“…). The ultrastructure of parasite stages provides a diagnostic tool in the characterisation process (Siddall and Desser ) and adds reliability to taxonomic descriptions (Smith and Desser ). As intraerythrocytic gamonts are frequently found in peripheral blood, this developmental stage was used for comparison.…”