title: A herpes-like virus in king crabs: Characterization and transmission under laboratory conditions.
abstract: A herpes-like virus was found infecting the antennal gland and bladder epithelium in the blue king crab Paralithodes platypus from the eastern area of the Sea of Okhotsk. Electron microscopic analysis of antennal gland samples from blue king crabs with histologically confirmed signs of disease revealed virus particles, which were mostly hexagonal in shape and located primarily in the nucleus; these particles were rarely observed in the cytoplasm of infected cells. Most virus particles ranged in size from 115 to 125nm. Hemocytes of the red king crab Paralithodes camtschaticus in cell culture could be experimentally infected with virus from thawed antennal gland samples of the blue king crabs with histologically confirmed signs of viral infection. Clear signs of infection were observed in hemocyte cultures at 3-4days post-inoculation as small foci of highly vacuolated formations. These formations included several nuclei and were surrounded by a halo of small cytoplasmic bubbles containing actin and tubulin. As demonstrated by electron microscopic studies, no virus-like particles were found in the cells 1day post-inoculation, but particles become abundant at 7days post-inoculation. We developed a consensus primer PCR method for amplification of a region of the herpesviral DNA-directed DNA polymerase. Primers were designed to target sequences encoding highly conserved amino acid motifs covering a region of approximately 800bp. Thus, macroscopic, histological and ultra-structural examinations of blue king crabs infected with a virus and the molecular identification of the pathogen revealed the presence of herpesviruses. The frequency of the herpes-like viral infection in natural populations of blue king crabs in the Sea of Okhotsk ranged from 0% to 3% in different years.
authors.affiliation: Kamchatka Research Institute of Fisheries and Oceanography, Petropavlovsk-Kamchatsky 683002, Russia. Electronic address: yashma_777@mail.ru.
authors.forename: T V
authors.initials: TV
authors.lastname: Ryazanova
authors.affiliation: A.V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, Palchevsky Str. 17, Vladivostok 690041, Russia. Electronic address: meliseikina@yandex.ru.
authors.forename: M G
authors.initials: MG
authors.lastname: Eliseikina
authors.affiliation: National Research Institute for Veterinary Virology and Microbiology of Russia, The Russian Academy of Agricultural Science, Pokrov 601120, Russia. Electronic address: ismil@yandex.ru.
authors.forename: I M
authors.initials: IM
authors.lastname: Kalabekov
authors.affiliation: A.V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, Palchevsky Str. 17, Vladivostok 690041, Russia; Far Eastern Federal University, Sukhanova Str. 8, 690950 Vladivostok, Russia. Electronic address: nelodin54@yahoo.com.
authors.forename: N A
authors.initials: NA
authors.lastname: Odintsova
mesh_terms: D000818:Animals; D003386:Brachyura / Q000821:virology*; D004279:DNA, Viral / Q000032:analysis; D006564:Herpesviridae / Q000472:pathogenicity / Q000502:physiology*; D046529:Microscopy, Electron, Transmission; D016133:Polymerase Chain Reaction; D015995:Prevalence
chemical_list: D004279:DNA, Viral
keywords: Crustacea; Hemocyte culture; PCR; Paralithodes camtschaticus; Paralithodes platypus