Di erent developmental stages of Artemia spp. (metanauplii, juveniles and adults) were
bath-challenged with two isolates of the Lymphocystis disease virus (LCDV), namely, LCDV SA25
(belonging to the species Lymphocystis disease virus 3) and ATCC VR-342 (an unclassified member
of the genus Lymphocystivirus). Viral quantification and gene expression were analyzed by qPCR
at di erent times post-inoculation (pi). In addition, infectious titres were determined at 8 dpi by
integrated cell culture (ICC)-RT-PCR, an assay that detects viral mRNA in inoculated cell cultures.
In LCDV-challenged Artemia, the viral load increased by 2–3 orders of magnitude (depending on
developmental stage and viral isolate) during the first 8–12 dpi, with viral titres up to 2.3 102
Most Probable Number of Infectious Units (MPNIU)/mg. Viral transcripts were detected in the
infected Artemia, relative expression values showed a similar temporal evolution in the di erent
experimental groups. Moreover, gilthead seabream (Sparus aurata) fingerlings were challenged by
feeding on LCDV-infected metanauplii. Although no Lymphocystis symptoms were observed in the
fish, the number of viral DNA copies was significantly higher at the end of the experimental trial and
major capsid protein (mcp) gene expression was consistently detected. The results obtained support
that LCDV infects Artemia spp., establishing an asymptomatic productive infection at least under the
experimental conditions tested, and that the infected metanauplii are a vector for LCDV transmission
to gilthead seabream.
