Experimental infection of Atlantic halibut Hippoglossus hippoglossus with nodavirus: tissue distribution and immune response.
Atlantic halibut Hippoglossus hippoglossus, age 8 mo and weighing 20 g, were challenged by either intraperitoneal injection (i.p.) or by bath exposure using nodavirus isolated from Atlantic halibut. Fish were sampled at intervals over a 41 d period, starting on Day 5 post-challenge. Although no clinical disease or mortality was recorded, the data show that nodavirus did successfully propagate in i.p.-challenged fish. Using conventional end-point reverse transcription (RT)-PCR, nodavirus was detected in the kidney of all examined i.p.-challenged fish, and further in the head, heart, liver and posterior intestine of most of these individuals. Quantitative real-time RT-PCR revealed that the amount of virus in head samples from the i.p.-challenged group increased during the experiment. The presence of nodavirus in nervous tissue of i.p.-challenged fish was detected by immunohistochemistry from Day 13 post-challenge. In the retina, virus positive cells were found adjacent to the circumferential germinal zone at the ciliary margin towards the iris. In the brain, a few positive cells were detected in the tectum opticum. An ELISA was developed to detect anti-nodavirus activity in plasma. The method included an optimized coating procedure, which allowed the use of non-purified nodavirus as the coating antigen in a simple indirect ELISA. An anti-nodavirus antibody response was detected from Day 19 post-challenge in i.p.-challenged fish, while a response was not detected in the bath-challenged or control fish. This experiment demonstrates a subclinical nodavirus infection in Atlantic halibut at a post-juvenile stage induced by i.p. injection of virus.
Grove
S
S
National Veterinary Institute, PO Box 8156 Dep., 0033 Oslo, Norway. soren.grove@vetinst.no
Johansen
R
R
Dannevig
B H
BH
Reitan
L J
LJ
Ranheim
T
T
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D001921:Brain / Q000473:pathology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005393:Fish Diseases / Q000276:immunology / Q000821:virology*; D005432:Flounder; D005880:Gills / Q000821:virology; D006321:Heart / Q000821:virology; D007121:Immunocompetence; D007150:Immunohistochemistry / Q000662:veterinary; D007274:Injections, Intraperitoneal / Q000662:veterinary; D007422:Intestines / Q000821:virology; D007668:Kidney / Q000821:virology; D008099:Liver / Q000821:virology; D030381:Nodaviridae / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology*; D012327:RNA Virus Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D012160:Retina / Q000473:pathology / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
D000914:Antibodies, Viral