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A disease outbreak was reported in adult koi, Cyprinus carpio koi, from a fish farm in Kerala, India, during June 2015. The clinical signs were observed only in recently introduced adult koi, and an existing population of fish did not show any clinical signs or mortality. Microscopic examination of wet mounts from the gills of affected koi revealed minor infestation of Dactylogyrus sp. in a few koi. In bacteriological studies, only opportunistic bacteria were isolated from the gills of affected fish. The histopathological examination of the affected fish revealed necrotic changes in gills and, importantly, virus particles were demonstrated in cytoplasm of gill epithelial cells in transmission electron microscopy. The tissue samples from affected koi were negative for common viruses reported from koi viz. cyprinid herpesvirus 3, spring viraemia of carp virus, koi ranavirus and red sea bream iridovirus in PCR screening. However, gill tissue from affected koi carp was positive for carp edema virus (CEV) in the first step of nested PCR, and sequencing of PCR amplicons confirmed infection with CEV. No cytopathic effect was observed in six fish cell lines following inoculation of filtered tissue homogenate prepared from gills of affected fish. In bioassay, the symptoms could be reproduced by inoculation of naive koi with filtrate from gill tissue homogenate of CEV-positive fish. Subsequently, screening of koi showing clinical signs similar to koi sleepy disease from different locations revealed that CEV infection was widespread. To our knowledge, this is the first report of infection with CEV in koi from India.

Raghunath, R., Manisseri, M. K. and Sanil, N. K. 2014. Structure of the male reproductive system of the blue swimmer crab Portunus pelagicus (Decapoda: Portunidae). -Acta Zoologica (Stockholm) 95: 176-185.An attempt was made here to study the structure of the male reproductive system of Portunus pelagicus, which would improve the knowledge base on the reproductive biology of the species and also help in the maintenance of broodstock under controlled conditions. Male P. pelagicus of different sizes were collected from the Palk Bay off Mandapam (9°17′ N, 79°9′ E) and maintained under controlled conditions for the study. Tissues from testis, anterior vas deferens (AVD), median vas deferens (MVD), posterior vas deferens (PVD), ejaculatory duct and penis were fixed in Bouin's fluid and 2.5% buffered glutaraldehyde separately and processed for light and electron microscopic studies, respectively. The reproductive system consisted of testis, commissure, vas deferens, ejaculatory duct and penis. The vas deferens was divided based on the morphology and/or histology into AVD, MVD and PVD. The AVD was further divided based on histology into proximal and distal regions, and the MVD, based on diameter into major and minor coils. The testicular lobe had several lobules with a central seminiferous tubule, which continued till the penis. The seminiferous tubule was lined by a layer of cuboidal or columnar epithelium. The lining of the central tubule of the vas deferens formed several 'folds', which at times formed 'pouches'. High incidence of cell organelles in the columnar epithelial cells, aggregations of vesicles and occurrence of blebs at the luminal periphery and the projection of numerous microvilli containing electron-dense materials into the lumen from the cell lining denoted high secretory activity of the epithelial cells.

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