Gaber Ahmed Saad^1,2

1. Department of Biology, Deanship of Preparatory Year and Supporting studies, Dammam University, Saudi Arabia, KSA
2. Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
Author    Correspondence author
International Journal of Marine Science, 2016, Vol. 6, No. 18   doi: 10.5376/ijms.2016.06.0018
Received: 29 Feb., 2016    Accepted: 26 Apr., 2016    Published: 26 Apr., 2016

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Saad G.A., 2016, A Coccidian Parasite Inhabiting The GI Tract and Leucocytes of Styela plicata (Lesuaer, 1823) and Ciona intestinalis (Linnaeus, 1767) Sampled from the Arabian Gulf (Saudi Arabia), International Journal of Marine Science, 6(18): 1-14 (doi:10.5376/ijms.2016.06.0018)

Styela plicata and Ciona intestinalis were collected from the shallow water of the Arabian Gulf, Saudi Arabia during 2011 – 2014.  Breeding and non breeding seasons were considered. Specimens were dissected alive in seawater and isolated parts from the intestine were sampled. In a previous study, a sporocyst of a coccidian was observed completely embedded in the intestinal epithelial cells of Styela plicata. Since that time, the author tried to find all stages of the life cycle of this coccidian parasite and describe them. Ascidians may obtain parasites from their food through water filtration, or directly swallow an unsporulated oocyst with incurrent water. Sporozoites initiate infection probably homoxenously or heteroxenously. Sporozoites then enter host intestinal epithelial cells and there transform into meronts. Merozoites of the final merogony enter blood cells to initiate the gametic cycle, and become either macrogamonts or microgamonts. Microgamontes became trophozoites (uninucleated zoite). These divide by multiple fission to produce large numbers of flagellated microgametes. Macrogamonts develop into macrogametes without further division. Syngamy produces zygotes, then merogony proceeds to form merozoites which enter new host cells extraintestinal like blood cells to produce more merogonous cycles. The present study concluded that the investigated parasite may belong to Genus Isospora (schneider, 1881). Since in isosporans sporogony leads to the formation of four sporozoites inside each sporoblast and this agametic phase develop extraintestinal.

Ascidians; Filter feedin; Homoxenous or heteroxenous infection; Uninucleated zoite; Sporozoites; Merozoites