Progress 09/01/23 to 08/31/24
Outputs
Target Audience:During the reporting period, target audiences were reached through workshops and conferences. PI Burge included a summary of results during a special session focused on OsHV-1 at the National Shellfisheries Association Pacific Coast Section in September 2023 to oyster aquaculturists, regulators, scientists, and policy makers. Co-PI Reece presented results at the Virginia Aquaculture Conference in November 2023 targeting oyster aquaculturists in the mid Atlantic but also attended by scientists, regulators, and policy makers. Co-PI Reece also presented results at the National Shellfisheries Association annual meeting in Charlotte, North Carolina attended by scientists, oyster aquaculturists, regulators, and policy makers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Several students have been trained as part of this project. M. Victoria Agnew (PhD, University of Maryland Baltimore County) received training and assisted in experimental challenges and analyses associated with this project; Dr. Agnew was co-mentored by PI Burge. Dr. Agnew defended her PhD "Disease dynamics in marine keystone species: understanding Pacific oyster-Ostreid herpesvirus-1 and eelgrass-Labyrinthula spp. interactions." Additionally, an undergraduate at the Virginia Institute of Marine Sciences was trained in molecular biology and assisted with extractions of DNA from oyster tissues. Finally, a postdoctoral scholar, Dr. Lindsay Alma assisted with analyses associated with this project, receiving training in R. How have the results been disseminated to communities of interest?Project results were presented at a special session co-led with Meganna Parikh and collaborators at the Pacific Coast Shellfish Growers Association: Burge CA, Kachmar ML, Mortensen JB, van Berkel, Parikh M. 2023 "Strengthening Support for Shellfish Health Management-OsHV-1 and the West Coast Shellfish Industry". 77th Annual Shellfish Growers Conference and Tradeshow. PCSGA/NSA-PCS Meeting, Seaside, OR September 18-21, 2023 Additionally, project results were presented at the Virginia Aquaculture Association: Reece KR. Update on OsHV1 - challenges with C. virginica and shellfish seed surveillance. Virginia Aqulaculture Conference November 10, 2023 Finally, project results were presented at the National Shellfisheries Association conference along. A discussion was also facilitated: Reece KR, Small JM, Agnew MV, MacIntyre A, Scott GP, Burge CA. 2024. Update on laboratory challanges of Crassostrea virginica families and lines with OsHV-1 microvariants. 116th National Shellfisheries Association Annual Meeting. Charlotte, NC. March 17-21, 2024 Reece KR & Burge CA. Discussion on OsHV-1 and emerging disease. 116th National Shellfisheries Association Annual Meeting. Charlotte, NC. March 17-21, 2024 What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1: Experiment 1: We completed qPCR analysis of young juvenile oysters ("spat", 10-12 mm) for 30 full sibling families and two important aquaculture lines DEBY and LOLA exposed to OsHV-1 microvar FRA. OsHV-1 viral load was determined by utilizing an OsHV-1 specific qPCR assay (as a proxy for virus infection). DNA was extracted from 0.25 mg of gill/mantle tissue of at least 15 control young juvenile "spat" oysters from Experiment 1. DNA was extracted from 0.25 mg tissue of all the dead oysters for which tissue remained and from at least 10 oysters from each of the three replicate OsHV-1 French mvar bath exposed plates for these same oyster families and lines. Overall, Eastern oyster families with high survival had low levels of viral DNA in their tissues, while those that suffered high mortality had higher levels of viral DNA, comparable to what was seen in the highly susceptible oyster species, Pacific oysters. A generalized linear model was used to compare viral load between survivors and dead oysters and among families (p<2.2e-16). Overall, animals that died had 490X OsHV-1 DNA (p< 2.e-16) in their tissues (1.10x107) than those that survived (1.59x106). Additionally, the family with the highest survival (100%) had significantly lower viral load while the lowest performing Eastern oyster families (n=3 with >45% cumulative mortality) and Pacific oysters had significantly higher viral loads (p< or equal to 0.001 for all families). Experiment 2: We completed qPCR analysis from a subset of the same oyster families (n=8 Eastern oysters, n=1 Pacific oyster stock) as juvenile oysters (30-40 mm) that had been in the field in the Chesapeake Bay for ~5 months to either a control (no virus), an OsHV-1 μvar from France, and an OsHV-1 μvar from San Diego. Similarly, 0.25 mg of gill and mantle tissue was collected from each animal for DNA extraction. Five of the control oysters from each of the three replicate tanks, and all exposed oysters, from this experiment were processed. qPCR data was non-normal for the juvenile oyster experiment, and we used a series of Kruskal-Wallis tests to compare compare viral load between 1) oysters exposed to OsHV-1 μvar from France and OsHV-1 μvar from San Diego (Chi-Squared 8.1409, df=1, p=0.004; effect size-0.013 or high) and 2) oysters that survived to the end of the experiment and those that died (Chi-Squared 332.29, df=8, p-value < 2.2X10^6; 0.445 or high) and 3) oyster families (Chi-Squared 239.6, df=1, p-value <2.2X10^-16; effect size=0.594 or high). Overall, animals that died had more OsHV-1 in their tissues (6.97X106 copies/mg) than those that survived (1.44x104 copies/mg) and a calculated effect size of 0.445 considered to be of large magnitude; these data suggest that oysters died of OsHV-1. Multiple pairwise comparisons were made using a Wilcoxon rank Sum Test with a holm probability adjustment. The lowest performing families (>38% mortality) had similar quantities of DNA in their tissues to the control C. gigas (individual pairwise comparisons p>0.05); while high performing families (~1.7-12% mortality) had similar DNA in their tissues and less than the lowest performing families and C. gigas (individual pairwise comparisons, p=<0.05). Experiment 3: We conducted a dose-response experiment utilizing a range of OsHV-1 concentration (103 - 106 copies/mL) in July of 2024. We utilized progency of C. virginica families used in Experiments 1 and 2 with a one family line predicted to be high survival (Cv-High) and the second to be moderate survival (Cv-moderate). We utilized a C. gigas "Miyagi" stock as a positive control comparison. The experiment was conducted at 25 C and 20 ppt utilizing the same methodology as Experiment 1. For C. gigas, the two populations were exposed to OsHV-1 either at salinity of 20 ppt or 35 ppt; half the animals were pre-acclimated to 20 ppt for ~10 days before the start of the experiment. A Kaplan-Meir survivorship analysis followed by pair-wise log-rank chi-square tests was utilized to compare between and families and doses. Cv-High experienced high survival at all doses (survival probability of 95-100%) while Cv-Moderate exhibited high survival in the 103-105 doses (no difference between doses and control or compared to Cv-High) and significantly lower survival probability (61%) at the 106 dose (compared to Cv-High all doses/control and Cv-Moderate 103-105 doses/controls; Chi Square Goodness of Fit with Log-Rank test pairwise comparisons p<0.001 through p<0001). The Miyagi stock had high survival probability at 103 and 104 doses and the controls (survival probability of 100%) and significantly lower survival probability at the 105 (76.7% 20 ppt; 70% 35 ppt) and 106 (39.3%; 38.3%) doses. Survival was similar between the Cv-Moderate and Miyagi at the 106 dose (p>0.05) while Cv-High had higher survival as compared to Miyagi at the 105 and 106 doses (p<0.0001) Objective 2: Using the VIMS ABC Oyster Breeding Database we were able to use full family pedigree structure and survival to run analyses using ASReml-SA or AsREML-R versions using univariate or multivariate animal models. For survival, we calculated observed h2 (broad sense) using models that assume normality of data but as these are binary data, we also calculated underlying heritability (See Table 1). We compared cumulative survival between the two trials (spat and juvenile), and examined the families challenged both as spat and as juveniles, the phenotypic correlation was very high and the calculated genetic correlation was high. The genetic correlation in survival between the spat and juvenile trial data was 0.908 ± 0.211, similar to results from simple correlation analysis (Pearson's Correlation, R=0.91, p<0.0016). This is important as it indicates that the data generated in a spat/plate trial may be a reliable predictor of performance in juveniles. For cumulative survival across both trials, lumping spat and juvenile, SD and FR microvariant trials together, heritability for survival on the observed scale was estimated to be 0.167 ± 0.104 and 0.369 ± 0.229 on the underlying scale. For Trial 1 by itself, heritability for survival on the observed scale was estimated to be 0.128 ± 0.083 and 0.300 ± 0.195 on the underlying scale. We utilized log transformed qPCR data for survivors to examine the genetic parameters associated with viral load in animal surviving Trial 1. The heritability of viral load in survivors in trial 1 has been estimated to be 0.216 ± 0.123. Finally, heritability was estimated as0.341 ± 0.165 for oysters exposed only to the French microvariant from Experiment and 2. Objective 3: Develop tools for industry preparedness in case of an OsHV-1 μvar introduction We have increased awareness of potential impacts of introduction ofOsHV-1 μvars by broadly distributing information at both the regional and national level. During the reporting period, we gave conference presentations targeted at shellfish growers in the mid-Atlantic (Virginia Aquaculture Conference) and US West Coast (Pacific Coast Shellfish Growers Association) and at the National Shellfisheries Association. PIs Burge & Reece led a discussion at the National Shellfisheries Association conference focused on emerging shellfish disease. (See below for full meeting information and authors) Additionally, we expect a FAQ sheet on OsHV-1 including results from this project to be circulated during 2025.
Publications
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Progress 09/01/21 to 08/31/24
Outputs
Target Audience:Target audiences were reached through workshops and conferences. PI Burge presented project reesults to a USDA-APHIS VHS workshop targeted at US shellfish aquacultrists (~90 individuals) in December 2022 that are directly impacted by results of the project. Co-PI Reece presented project results at the National Shellfisheries Association in a special session on OsHV-1 (Baltimore, MD 2023) that shellfish aquacultrists, scientists, students, and other interested parties. PI Burge included asummary of results during a special session focused on OsHV-1 at the National Shellfisheries Association Pacific Coast Section in September 2023 to oyster aquaculturists, regulators, scientists, and policy makers. Co-PI Reece presented results at the Virginia Aquaculture Conference in November 2023 targeting oyster aquaculturists in the mid Atlantic but alsoattended by scientists, regulators, and policy makers. Co-PI Reece also presented results at the National Shellfisheries Association annual meeting in Charlotte, North Carolina attended by scientists, oyster aquaculturists, regulators, and policy makers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Several students have been trained as part of this project. M. Victoria Agnew (PhD, University of Maryland Baltimore County) received training and assisted in experimental challenges and analyses associated with this project; Dr. Agnew was co-mentored by PI Burge. Dr. Agnew defended her PhD "Disease dynamics in marine keystone species: understanding Pacific oyster-Ostreid herpesvirus-1 and eelgrass-Labyrinthula spp. interactions." Additionally, an undergraduate at the Virginia Institute of Marine Sciences was trained in molecular biology and assisted with extractions of DNA from oyster tissues. Finally, a postdoctoral scholar, Dr. Lindsay Alma assisted with analyses associated with this project, receiving training in R. How have the results been disseminated to communities of interest?As described above in objective 3, wehave increased awareness of potential impacts of introduction of OsHV-1 μvars by broadly distributing information at both the regional and national level to shellfish growers, scientists, and regulators: In December of 2022, PI Burge presented project reesults to a USDA-APHIS VHS workshop targeted at US shellfish aquacultrists (~90 individuals) that are directly impacted by results of the project. Burge, CA. A review of OsHV-1 and OsHV-1 uvars: with focus on key knowledge for US shellfish growers. USDA-APHIS VHS Webinar. December 2022. Audience 90 Co-PI Reece presented project results at the National Shellfisheries Association in a special session on OsHV-1 that shellfish aquacultrists, scientists, students, and other interested parties. Burge CA, Small JM, Agnew MV, MacIntyre A, Reece KS. Laboratory studies on the impact of an OsHV-1 microvariant on Crassostrea virginica families and lines. 115th Annual Meeting of the National Shellfisheries Association, Baltimore, MD. March 2023. Oral Presentation. Audience 40 Project results were presented at a special session co-led by Meganna Parikh and Pi Burge and collaborators at the Pacific Coast Shellfish Growers Association: Burge CA, Kachmar ML, Mortensen JB, van Berkel, Parikh M. 2023 "Strengthening Support for Shellfish Health Management- OsHV-1 and the West Coast Shellfish Industry". 77th Annual Shellfish Growers Conference and Tradeshow. PCSGA/NSAPCS Meeting, Seaside, OR September 18-21, 2023. Audience 40 Additionally, project results were presented at the Virginia Aquaculture Association: Reece KR. Update on OsHV1 - challenges with C. virginica and shellfish seed surveillance. Virginia Aqulaculture Conference November 10, 2023 Finally, project results were presented at the National Shellfisheries Association conference in Charlotte, North Carolina. A discussion was also facilitated: Reece KR, Small JM, Agnew MV, MacIntyre A, Scott GP, Burge CA. 2024. Update on laboratory challanges of Crassostrea virginica families and lines with OsHV-1 microvariants. 116th National Shellfisheries Association Annual Meeting. Charlotte, NC. March 17-21, 2024. Audience 50 Reece KR & Burge CA. Discussion on OsHV-1 and emerging disease. 116th National Shellfisheries Association Annual Meeting. Charlotte, NC. March 17-21, 2024. Audience 75 What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1: Eastern oyster families (full sibs) and lines were produced at the VIMS ABC hatchery in Gloucester Point, Virginia and shipped to a biosecure laboratory in Tucson, Arizona for experiments. Expt 1: C. virginica (Cv) juvenile oysters or "spat" (10-12 mm) were exposed to OsHV-1 microvar FRA by bath challenge. We exposed in triplicate 30 full sibling families and two important aquaculture lines, DEBY and LOLA utilized by the US shellfish aquaculture industry. Additionally, a control C. gigas (Cg) stock was used as a positive control. Challenges were conducted in petri dishes held at 22 C with a salinity of 20 ppt; Cg challenges were conducted at both 20 ppt and 35 ppt. Viral load (based on an OsHV-1 specific qPCR assay) was determined for all families and replicates with all dead oysters analyzed in addition to select survivors. Cv families and lines exposed to the OsHV-1 microvar FRA demonstrated differential survival and viral loads. Survival over the course of the seven day experiment was higher for controls (98.5% survival probability) than Cv exposed to OsHV-1 (Cox Proportional Hazard p< 2.2e-16). For exposed families, survival ranged from 50-100% with 16 families/lines with >90% survival (<10 mortality), 8 with 80-89% survival (11-20% mortality), 3 with 70-79% survival (21-30% mortality), 2 with 60-69% survival (31-40% mortality), and 3 with 50-59% survival (41-50% mortality). A generalized linear model was used to compare viral load between survivors and dead oysters and among families (p<2.2e-16). Overall, animals that died had 490X OsHV-1 DNA (p< 2.e-16) in their tissues (1.10x107) than those that survived (1.59x106). Additionally, the family with the highest survival (100%) had significantly lower viral load) while the lowest performing Cv families (n=3 with >45% mortality) and Cg had significantly higher viral loads (p< or equal to 0.001). Expt 2. We exposed through injection a subset of the same oyster families as juvenile oysters (30-40 mm) that had been in the field in the Chesapeake Bay for ~5 months to either a control (no virus), an OsHV-1 μvar from France, and an OsHV-1 μvar from San Diego. We chose eight families representing a range of mortality from experiment 1 to determine the susceptibility of larger juvenile oysters correlates with young juvenile oysters. We measured differential survival and viral load in larger juvenile oysters. Survival was similar between OsHV-1 μvars (1.3-98.3% survival) over the course of the ten day experiment (p>0.05) was higher for controls (97% +/- .97%); with 9.5 higher cumulative hazard when exposed to either OsHV-1 microvar (p=< 2.2e-16). Mortality in juvenile oysters exposed to either the French (Pearson's R=0.91; p<0.01) or San Diego microvariants (Pearson's R=0.9; p<0.01) were highly correlated with mortality measured in spat oysters in expt 1. Additionally, mortality was highly correlated between viruses (Pearson's R=0.99; p<0.000001). qPCR data was non-normal for expt 2 and we used Kruskal-Wallis tests to determine that viral load differed in 1) oysters exposed to OsHV-1 μvar FRA and OsHV-1 μvar SD (Chi-Sq 8.1409, df=1, p=0.004; effect size-0.013/low) and 2) oysters that survived to the end of the experiment and those that died (Chi-Sq 332.29, df=8, p-value < 2.2X10^6; effect size of 0.445/high) and 3) oyster families (Chi-Sq 239.6, df=1, p-value <2.2X10^-16; effect size=0.594/high). Overall, animals that died had more OsHV-1 in their tissues (6.97X106 copies/mg) than those that survived (1.44x104 copies/mg) and a calculated effect size of 0.445 considered to be of large magnitude; these data suggest that oysters died of OsHV-1. The lowest performing families (>38% mortality) had similar quantities of DNA in their tissues to Cg (individual pairwise comparisons p>0.05); while high performing families (~1.7-12% mortality) had similar DNA in their tissues and less than the lowest performing families and Cg (pairwise comparisons, p<0.05; Wilcoxon rank Sum Test with a Holm prob. adjustment). Expt 3: We conducted a dose-response experiment utilizing a range of OsHV-1 concentrations (103 - 106 copies/mL). We used progency of Cv families used in Expts 1 and 2 with a one family line predicted to be high survival (Cv-Hi) and the second to be moderate survival (Cv-Mod). We utilized a C. gigas "Miyagi" stock (Cg) as a positive control comparison. The experiment was conducted at 25 C and 20 ppt utilizing the same methodology as Expt 1. Cv-Hi experienced high survival at all doses (surv. prob. of 95-100%) while Cv-Mod exhibited high survival in the 103-105 doses (no difference between doses and control or compared to Cv-Hi) and significantly lower survival probability (61%) at the 106 dose (compared to Cv-Hi all doses/control; Chi Square Goodness of Fit with Log-Rank test pairwise comparisons p<0.001 through p<0001). Cg had high survival probability at 103 and 104 doses and the controls (surv. prob. of 100%) and significantly lower survival probability at the 105 (76.7% 20 ppt; 70% 35 ppt) and 10^6 (39.3%; 38.3%) doses. Survival was similar between the Cv- Mod and Cg at the 106 dose (p>0.05) while Cv-Hi had higher survival as compared to Cg at the 105 and 106. Overall, our survival data suggest that selection of careful selection of Cv lines may minimize OsHV-1 mortalities and that Cv is less susceptible at lower doses than Cg. Objective 2: Using the VIMS ABC Oyster Breeding Database we were able to use full family pedigree structure and survival to run analyses using ASReml-SA or AsREML-R versions using univariate or multivariate animal models. For survival, we calculated observed h2 (broad sense) using models that assume normality of data but as these are binary data, we calculated underlying heritability. We compared cumulative survival between the two trials (spat and juvenile), and examined the families challenged both as spat and as juveniles, the phenotypic correlation was very high and the calculated genetic correlation was high. The genetic correlation in survival between the spat and juvenile trial data was 0.908 ± 0.211. This is important as it indicates that the data generated in a spat/plate trial may be a reliable predictor of performance in juveniles. For cumulative survival across both trials, lumping spat and juvenile, SD and FR microvariant trials together, h2 for survival on the observed scale was estimated to be 0.167 ± 0.104 and 0.369 ± 0.229 on the underlying scale. For Trial 1 by itself, h2 for survival on the observed scale was estimated to be 0.128 ± 0.083 and 0.300 ± 0.195 on the underlying scale. We utilized log transformed qPCR data for survivors to examine the genetic parameters associated with viral load in animal surviving Trial 1. The h2 of viral load in survivors in trial 1 was estimated to be 0.216 ± 0.123. Finally, h2 was estimated as 0.341 ± 0.165 for oysters exposed only to the French microvariant from Expts 1 and 2. Objective 3: We increased awareness of potential impacts of introduction of OsHV-1 μvars by broadly distributing information at both the regional and national level. We gave presentations targeted at shellfish growers at the national level through a webinar hosted by USDA-APHIS and presentations at the National Shellfisheries Association Annual Meeting. Additionally, we participated in workshops and presentations focused on OsHV-1 targeting shellfish growers in the the mid-Atlantic (Virginia Aquaculture Conference) and US West Coast (Pacific Coast Shellfish Growers Association). PIs Burge & Reece led a discussion at the National Shellfisheries Association conference focused on emerging shellfish disease. Additionally, we expect a FAQ sheet on OsHV-1 including results from this project to be circulated during 2025.
Publications
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Progress 09/01/22 to 08/31/23
Outputs
Target Audience:During the reporting period, the target audiences were reached through workshops and conferences. PI Burge presented project reesults to a USDA-APHIS VHS workshop targeted at US shellfish aquacultrists (~90 individuals) that are directly impacted by results of the project. Co-PI Reece presented project results at the National Shellfisheries Association in a special session on OsHV-1 that shellfish aquacultrists, scientists, students, and other interested parties. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Results have been disseminated to communities of interest, primarily the US shellfish aquaculture industry (described in objective 3 above). What do you plan to do during the next reporting period to accomplish the goals?What do you plan to do during the next reporting period to accomplish the goals? Objective 1: Conduct laboratory trials to examine differential survival and viral loads of spat and juveniles from 30 eastern oyster families and two lines exposed to two different OsHV-1 μvars We plan to finish the qPCR analysis on all families used to perform the heritability analysis including OsHV-1 viral loads. We also plan to confirm infection of tissues (viral load provides the proxy of infection) using in situ hybridization. We plan to conduct an additional dosage experiment across a range of OsHV-1 concentrations (~1x104-1x106 copies/ml) with ~10 family lines at the "spat" stage. We were unable to conduct dosage experiments at the time of experiment 1 or 2 and hope to provide additional data on the doses necessary to kill eastern oysters. Objective 2: Perform heritability analysis based on survival and OsHV-1 viral loads We expect the full heritability analysis to be completed by the end of the next reporting period. Objective 3: Develop tools for industry preparedness in case of an OsHV-1 μvar introduction 1) We will send the FAQ sheet to growers in Virginia and Maryland 2) We will develop a webinar of project results for shellfish growers to follow the initial success of the USDA-APHIS webinar 3) We will participate in the 2023 Virginia Aquaculture conference providing results and discussion of the results 4) We plan to participate in the 2023 Pacific Shellfish Growers Association/National Shellfisheries Association Meeting presenting project results in collaboration with an OsHV-1 modeling project run by Dr. Meghana Parikh at the NOAA Milford laboratory
Impacts
What was accomplished under these goals?
Objective 1: Conduct laboratory trials to examine differential survival and viral loads of spat and juveniles from 30 eastern oyster families and two lines exposed to two different OsHV-1 μvars Eastern oyster families (full sibs)and lines were produced at the VIMS ABC hatchery in Gloucester Point, Virginia and shipped to a biosecure laboratory in Tucson, Arizona for challenge experiments. Experiment 1: We exposed young juvenile oysters (10-12 mm) ready for outplant in the field: 30 full sibling families and two important aquaculture lines, DEBY and LOLA utilized by the US shellfish aquaculture industry. Cumulative mortality of exposed families and lines ranged from 0-50% with16 families/lines with <10% mortality, 8 with 11-20% mortality, 3 with 21-30% mortality,2 with 31-40%, and 3 with 41-50%. We are in process of processing of quantifying the amount of virus present or viral load (using quantitative PCR) in tissues of all families; preliminary data to date from six families representing variable mortality indicate that oysters that died at ~17% cumulative mortality or ~50% mortality viral loads that would be expected in dying individuals. This experiment indicates that eastern oysters exposed to OsHV-1 microvariants can become infected and die. Experiment 2: We exposed through injection a subset of the same oyster families as juvenile oysters (30-40 mm) that had been in the field in the Chesapeake Bay for ~5 months to either a control (no virus), an OsHV-1 μvar from France, and an OsHV-1 μvar from San Diego. We chose eight families representing a range of mortality from experiment 1 to determine the susceptibility of larger juvenile oysters correlates with young juvenile oysters. Preliminary results indicate that families experienced similar mortality as juvenile oysters when exposed to either the French (Pearson's R=0.91; p=0.002) or San Diego microvariants (Pearson's R=0.89; p=0.003) and exposures of were highly correlated between viruses (Pearson's R=0.99; p=0.0000057). We are in the process of quantifying the amount of virus present in all families; preliminary data from the same families described in experiment 1 indicates that oysters that died in susceptible families also had high copy numbers as expected in dying individuals. Initial data collected in objective 1 indicate that eastern oyster families and lines exposed to OsHV-1 microvariants demonstrate differential survival and viral load (hypothesis 1). Objective 2: Perform heritability analysis based on survival and OsHV-1 viral loads An initial heritability analysis has been conducted using survival data from experiment 1. This analysis indicates that the observed to be H2=0.128 ± 0.083 (SE) and the underlying H2=0.300 ± 0.195. The underlying H2 analysis uses a model more reflective of the true heritability. These data indicate that there may be heritable resistance to OsHV-1 microvariants but further analysis is necessary to test hypothesis 1. Objective 3: Develop tools for industry preparedness in case of an OsHV-1 μvar introduction A draft FAQ sheet is available. PI Burge lead a webinar for the USDA-APHIS Aquaculture Program (in December 2022) specifically targeted at shellfish growers
Publications
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