A sampling of results and impacts from completed New York Sea Grant-funded research projects, written during the period February 1, 2009 – January 31, 2010

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Isolation of the Pathogen from New York Clams and Genetic Variability in the Host-Parasite System of QPX Disease in Mercenaria mercenaria
R/FBF-17, Allam / Dove / Collier / Smolowitz / Ragone Calvo

Quahog Parasite Unknown (QPX) is a protistan parasite that causes significant mortalities in hard clams, Mercenaria mercenaria, in the northeastern states of the United States and Canada. Little has been known about the organism and about the factors involved in the transmission of the disease.

Observations suggest that genetic variability in the host and/or in the QPX pathogen could be responsible for differences in susceptibility toward the infection and in the presentation of the disease.

This project used both molecular and genetic tools and infection transmission experiments to address the genetic variability in the QPX disease system. The results showed that QPX is a direct pathogen and that it does not need an intermediary host to cause infection.

The findings also showed that the presence of QPX in the environment is not sufficient to cause disease and clam mortality, and that other factors (like prevailing environmental factors) play a role in disease development. In addition the project also revealed differences among clam strains with regard to susceptibility toward QPX disease.

The genetic information generated by this project allowed the development of a new quantitative Real-Time Polymerase Chain Reaction technique to quantify QPX in clams and environmental samples.

Project findings were used by NYSDEC to evaluate the Shellfish Transplant Program in Raritan Bay and to obtain information on the distribution and prevalence of QPX in Raritan Bay and other locations in the marine district, which is vitally important for the management of these resources and support of our shellfish industry.

This technology will be used by the state's QPX monitoring program to help maximize the areas available for shellfish harvesters and at the same time minimize the risk of disease transmission to natural clam resources.

The researchers have received further funding from NYSDEC and have gone on to receive NYSG support for more projects to further study QPX disease.