Systemic Iridovirus Infection in the Banggai Cardinalfish (Pterapogon Kauderni Koumans 1933)

Abstract

Abstract. Iridoviruses infect food and ornamental fish species from a wide range of freshwater to marine habitats across the globe. The objective of the current study was to characterize an iridovirus causing systemic infection of wild-caught Pterapogon kauderni Koumans 1933 (Banggai cardinalfish). Freshly frozen and fixed specimens were processed for histopathologic evaluation, transmission electron microscopic examination, virus culture, molecular virologic testing, microbiology, and in situ hybridization (ISH) using riboprobes. Basophilic granular cytoplasmic inclusions were identified in cytomegalic cells often found beneath endothelium, and hexagonal virus particles typical of iridovirus were identified in the cytoplasm of enlarged cells by transmission electron microscopy. Attempts at virus isolation in cell culture were unsuccessful; however, polymerase chain reaction (PCR)-based molecular testing resulted in amplification and sequencing of regions of the DNA polymerase and major capsid protein genes, along with the full-length ATPase gene of the putative iridovirus. Virus gene sequences were then used to infer phylogenetic relationships of the P. kauderni agent to other known systemic iridoviruses from fishes. Riboprobes, which were transcribed from a cloned PCR amplification product from the viral genome generated hybridization signals from inclusions within cytomegalic cells in histologic sections tested in ISH experiments. To the authors' knowledge, this is the first report of a systemic iridovirus from P. kauderni. The pathologic changes induced and the genomic sequence data confirm placement of the Banggai cardinalfish iridovirus in the genus Megalocytivirus family Iridoviridae. The ISH provides an additional molecular diagnostic technique for confirmation of presumptive infections detected in histologic sections from infected fish.

Megalocytivirus infection in orbiculate batfish Platax orbicularis

“…Megalocytiviruses are large, double-stranded DNA viruses with an icosahedral capsid (Kurita & Nakajima 2012). Members of the genus Megalocytivirus are pathogenic to a wide variety of freshwater and marine fishes, and have had a negative impact on ornamental and food fish aquaculture worldwide (Armstrong & Ferguson 1989, Anderson et al 1993, Fraser et al 1993, Rodger et al 1997, Sudthongkong et al 2002, Gibson-Kueh et al 2004, Jeong et al 2008a,b, Chinchar et al 2009, Weber et al 2009, Kim et al 2010, Yanong & Waltzek 2010, Zhang et al 2011. Megalocytiviruses induce lethal systemic disease at water temperatures ranging from 7.5 to 32°C (45.5 to 89.6°F) , Yanong & Waltzek 2010, Wang et al 2011, Zhang et al 2011, Waltzek et al 2012.…”

“…Megalocytivirus-infected fish may exhibit nonspecific clinical signs including lethargy, anorexia, hyperpigmentation, exophthalmos, skin lesions, unusual swimming behavior, severe anemia, and white feces , Weber et al 2009, Wang et al 2011, Waltzek et al 2012). On post-mortem examination, fish infected with megalocytiviruses may exhibit hemorrhagic lesions, renomegaly, spleno megaly, hepa tomegaly, and coelomic distension resul ting from hemorrhagic fluid accumulation , Weber et al 2009, Yanong & Waltzek 2010, Wang et al 2011, Zhang et al 2011, Waltzek et al 2012.…”

“…On post-mortem examination, fish infected with megalocytiviruses may exhibit hemorrhagic lesions, renomegaly, spleno megaly, hepa tomegaly, and coelomic distension resul ting from hemorrhagic fluid accumulation , Weber et al 2009, Yanong & Waltzek 2010, Wang et al 2011, Zhang et al 2011, Waltzek et al 2012. Histo pathologic examination typically reveals cyto megalic mesenchymal cells characterized by strongly basophilic or amphophilic granular intracytoplasmic inclusions observed in multiple organs including the spleen, kidney, liver, heart, brain, gills, intestine, eyes, and gonads , Gibson-Kueh et al 2003, Weber et al 2009, Yanong & Waltzek 2010, Zhang et al 2011, Waltzek et al 2012. Transmission electron microscopy (TEM) invariably reveals nu me rous icosahedral virus particles with a capsid diameter between 120 and 200 nm in the cytoplasm of infected cells , Weber et al 2009, Yanong & Waltzek 2010, Wang et al 2011, Zhang et al 2011, Kurita & Nakajima 2012, Waltzek et al 2012.…”

First report of Megalocytivirus in Red Piranhas (Pygocentrus nattereri) by Molecular Diagnosis in Brazil

“…This was the first report of molecular diagnosis of Megalocytivirus in Brazil in red piranhas, which draws attention due to the problems that the virus can cause. The occurrence of the nonspecific clinical signs 3,4,6,12 in red piranhas after feeding with live fish, associated with the findings in the necropsy of organ hemorrhage, have led to the suspicion of diseases of viral etiology. Further studies are needed to confirm whether fish used as food were a source of Megalocytivirus infection for native species.…”

INFEKSI PENYAKIT IKAN BANGGAI CARDINAL (Pterapogon kauderni) DALAM RANTAI PERDAGANGAN

“…Informasi, bahwa infeksi iridovirus di Amerika Serikat menyerang Banggai Cardinal dan menyebabkan kematian massal baik di importir maupun hatcheri perbenihan, sehingga menyebabkan kerugian ekonomi yang tidak sedikit (Zamrud, 2012). Kasus infeksi iridovirus ini sesuai dengan penelitian yang dilakukan oleh University of Florida Tropical Aquaculture Laboratory pada tahun 2009-2011 yang menyatakan bahwa ada strain baru dari iridovirus yaitu Banggai Cardinal Iridovirus (BCIV) yang memiliki genus Megalocytivirus (Weber et al, 2009). Mengingat rantai perdagangan Banggai Cardinal sangat kompleks, mulai dari nelayan penangkap hingga konsumen penggemar akuarium air laut dan melibatkan banyak pihak yang sebagian atau seluruh pendapatannya tergantung dari aktivitas tersebut, maka dianggap penting untuk mengetahui penyakit tersebut lebih mendalam.…”