Systematic evaluation of factors controllingPerkinsus marinus transmission dynamics inlower Chesapeake Bay

Diseases of Aquatic Organisms

Christopher F. Dungan¹  Eugene M. Burreson¹  Bob S. Roberson¹  Lisa M. Ragone Calvo¹ 

关键词: Perkinsus marinus;    Crassostrea virginica;    Disease;    Parasite;    Antibody-labeled cells;    Flow cytometry;    Abundance;    Transmission dynamics;   

DOI  :  10.3354/dao056075

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: The transmission of Perkinsus marinus in eastern oysters Crassostrea virginica in relation to water temperature, host oyster mortality, and water-column abundance of anti-P. marinus antibody-labeled cells wassystematically examined for 20 mo at a site in the lower York River, Virginia, USA. Uninfected sentinel oysters were naturally exposed to the parasite at 2 wk intervals throughout the course of the study to determine the periodicity and rates of parasitetransmission. The timing and magnitude of disease-associated oyster mortalities in a local P. marinus-infected oyster population were estimated by monitoring a captive subset of the local oyster population. Flow cytometric immunodetection methodswere employed to estimate the abundance of P. marinus cells in water samples collected 3 times each week. The acquisition of P. marinus infections by naïve sentinel oysters occurred sporadically at all times of the year; however, the highestincidence of infection occurred during the months of August and September. This window of maximum parasite transmission coincided with the death of infected hosts within the captive local oyster population. Counts of antibody-labeled cells ranged from 10to 11900 cells l^-1, with the highest abundances in July and August coincident with maximum summer temperatures. A statistically significant relationship between water-column parasite abundance and infection-acquisition rate was not observed;however, highest parasite-transmission rates in both years occurred during periods of elevated water-column abundance of parasite cells. These results support the prevailing model of P. marinus transmission dynamics by which maximum transmissionrates are observed during periods of maximum P. marinus-associated host mortality. However, our results also indicate that transmission can occur when host mortality is low or absent, so alternative mortality-independent dissemination mechanismsare likely. The results also suggest that atypically early-summer oyster mortality from Haplosporidium nelsoni infection, at a time when infections of P. marinus are light, has a significant indirect influence on P. marinustransmission dynamics. Elimination of these hosts prior to late-summer P. marinus infection-intensification effectively reduces the overall number of P. marinus cells disseminated.

【 授权许可】

Unknown