RESUMO
Infectious pancreatic necrosis virus (IPNV) is an aquabirnavirus that causes serious diseases in a variety of fish species worldwide. It has been isolated from a large number of healthy fresh and marine water fish. Prior to this study, there was no record of the presence of IPNV infection in Kenya. Here, the presence of IPNV in farmed rainbow trout and tilapia was examined in Nyeri County of central Kenya. Head kidney samples taken from five rainbow trout and three tilapia farms and stored in RNALater® were processed by PCR followed by sequencing of a segment A fragment covering nucleotide positions 2,120-2,343 bp. IPNV was detected in all the farms sampled with infection ratios ranging from 0.3 to 0.78 although the infections were not associated with any specific clinical signs of disease. These findings were supported by immunohistochemistry staining of the virus in the kidney and exocrine pancreas of rainbow trout. Sequence alignment and phylogenetic analysis revealed that the Kenyan isolates were identical to European isolates, suggesting a common origin. These findings highlight the need for better biosecurity procedures with more stringent surveillance programmes and control for fish diseases, especially focusing on imported breeding materials to Kenya.
RESUMO
Prostaglandin E2 (PGE2) is an important lipid mediator that plays diverse functions in mammals. Four receptor subtypes of PGE2, designated EP1-4, have been identified to mediate its signaling pathways. Extensive studies of PGE2 and its receptors have been carried out in mammals, but little is known in fish, including Atlantic salmon. In the current study, the distribution of Atlantic salmon EP4 receptor in different tissues was investigated using RT- and real-time PCR. A custom made antibody was used to investigate the distribution of this receptor in different tissues. Quantitative analysis by real-time PCR revealed that the expression was more abundant in the spleen followed by head kidney, skin and fin while it was least expressed in heart, muscles and brain. The staining intensity obtained by immunohistochemistry correlated with the RT-PCR results. EP4 expression was strongly associated with the immune cells in different tissues. To our knowledge, this is the first study to describe the distribution of EP4 receptor in Atlantic salmon tissues. Our findings suggest that EP4 may play a role in mediating immune responses as observed in mammals.