Life Science Journal, 2011;8(3) http://www.lifesciencesite.com http://www.sciencepub.net/life lifesciencej@gmail.com 523 Histopathological and Ultrastructural Study of Experimental Spring Viraemia of Carp (SVC) Infection of Common Carp with Comparison between Different Immunohistodignostic Techniques Efficacy A.Y. Gaafar 1* , Tomáš Veselý 2 , T. Nakai 3 , E.M. El-Manakhly 4 , M.K. Soliman 5 , H. Soufy 1 , Mona S. Zaki 1 , Safinaz G. Mohamed 6 , Amany M. Kenawy 1 , M. S. El-Neweshy 4 and A. Younes 1 . 1 Veterinary Research Division, National Research Centre, Cairo, Egypt. 2 Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic. 3 Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima 739-8528, Japan. 4 Faculty of Veterinary Medicine - Alexandria University, Edfina, Egypt. 5 Faculty of Veterinary Medicine - Damanhour University, Bostan City, Egypt. 6 National Institute of Oceanography and Fisheries, Alexandria, Egypt. * Correspondence to A.Y. Gaafar, (e-mail: alkhateibyg@yahoo.com ). Abstract: Spring viremia of carp (SVC) is an important disease affecting cyprinids, mainly common carp Cyprinus carpio. The disease is widespread in European carp culture, where it causes significant morbidity and mortality. This study describes some Histopathological, Immunohistological, and Ultra-microscopical characteristics of infection by this virus in experimentally infected target species; common carp. In this study the pathological changes in naturally and experimentally infected fish existed mainly in the hepatopancreas, kidney, spleen and gills. On the other hand, the changes were evoked to a lesser extent in the intestine and brain. The alterations were ranging between minor degenerative changes to severe necrotic picture. Immunostaining and immunoflourescence studies revealed the presence of antigen in SVCV infected tissue specimens. Transmission Electron Microscopy studies of liver, kidney and spleen samples revealed the presence of pullet-shaped electron-dense intra-cytoplasmic particles, with approximate length of 180-200 nm and approximate width of 90-100 nm. These particles resemble the characteristics of Rhabdovirus viral particles. [A. Y. Gaafar, Tomáš Veselý , T. Nakai, E.M. El-Manakhly, M.K. Soliman, H. Soufy, Mona S. Zaki, Safinaz G. Mohamed, Amany M. Kenawy , M. S. El-Neweshy and A. Younes. Histopathological and Ultrastructural Study of Experimental Spring Viraemia of Carp (SVC) Infection of Common Carp with Comparison between Different Immunohistodignostic Techniques Efficacy. [Life Science Journal. 2011; 8(3):523-533] (ISSN: 1097- 8135). http://www.lifesciencesite.com . #82 Keywords: Spring Viraemia of Carp, SVC, Rhabdovirus carpio, common carp, Cyprinus carpio, Histopathology, Immunohistochemistry, Immunoflourescence, TEM. 1. Introduction Spring Viraemia of Carp (SVC) is an acute, systemic, contagious disease caused by Rhabdovirus (Bootsma and Ebregt, 1983; Wolf, 1988; Ahne et al., 2002 and Saad 2005). The term SVC and Rhabdovirus carpio (RVC) were firstly introduced by Fijan et al. (1971). Tropism and replication of virus are confined to capillary endothelium, as well as in haemopoietic and excretory kidney tissues, causing an impaired salt–water balance, which is often lethal (Fijan et al., 1971). The systemic character of Spring Viraemia of Carp virus (SVCV) infection has been demonstrated by experimental infection of specific pathogen free (SPF) carp (Ahne 1977, 1978). It affects primarily common carp (Cyprinus carpio), while other cyprinids and non-cyprinid species are also susceptible including Koi carp (Cyprinus carpio koi), Crucian carp and Goldfish (Carassius auratus), Bighead carp (Aristichthys nobilis), Grass carp (Ctenopharyngodon idella), Silver carp (Hypophthalmichthys molitrix), Sheatfish, (Silurus glanis), Orfe (Leuciscus idus), Tench (Tinca tinca) and Roach (Rutilus rutilus) as stated by Haenen & Davidse (1993), And Oreochromis niloticus (Abo Eisa 2008). SVC disease is very important fish disease because of its world-wide distribution. The disease was firstly discovered in Yugoslavia 1969 (Fijan et al., 1971), then Czechoslovakia (Tesarcik et al., 1977), Scotland (Richards and Buchanon, 1978), Malaysia (Armstrong and Ferguson, 1989), Spain (Lupiani et al., 1989), Indonesia (Glazebrook et al., 1990), Russia (Oreshkova et al., 1995), Brazil (Alexandrino et al., 1998), Hawaii (Johnson et al., 1999), Northern Ireland (Rowley et al., 2001), United States in North Carolina and Virginia (APHIS, 2003), China (Liu et al., 2004), Egypt (Saad et al., 2005), Canada (Garver et al., 2007) and Iran (Haghighi et al., 2008) In European countries including Russia where the Carp is an important fish, SVCV causes high mortalities among carp farms with reduction of total returns from fish selling leading to severe economic