Supplementary material from "Shedding of OsHV-1 from infected Pacific oysters depends on viral variant"

Ostreid herpesvirus-1 (OsHV-1) can cause massive economic losses of Pacific oysters, Magallana gigas. Breeding resistant oysters in the USA is difficult due to lack of oyster hatcheries within disease endemic locations. Without resistant oysters, understanding transmission dynamics is useful to assess the risk of spread to aquaculture farms. This research aimed to quantify OsHV-1 shedding from M. gigas of varying OsHV-1 susceptibility. Oyster spat were challenged with OsHV-1 to determine high and low surviving lines. Siblings were exposed to either an OsHV-1 variant from France or San Diego, California USA as juveniles. Oysters were injected with a known concentration of OsHV-1 and placed in individual containers. Water was sampled periodically for 6d to monitor the amount of virus shed over time. Both family lines maintained high survival (53.3%-66.7% survival) when exposed to either variant as juveniles, indicating differences in susceptibility between ages of the same genetic line. OsHV-1 in water containing oysters exposed to the French variant was detected earlier and in significantly higher amounts overall (~2.7x) than those exposed to the San Diego variant. Peak shedding of OsHV-1 was confirmed at 24-120h post injection from oysters exposed to either microvariant, which improves our understanding of OsHV-1 transmission dynamics.