Project: Quantifying and modeling the transmission dynamics of bivalve transmissible neoplasia

NSF Award Abstract:
Cancer is not normally thought of as an infectious disease. However, several transmissible cancers have recently been found in the wild, in which the cancer cells themselves jump from animal to animal as an infectious agent, causing significant mortality on land and in the marine environment. Marine bivalves appear to be particularly susceptible. At least nine lineages of lethal transmissible cancer have been identified in eight bivalve species worldwide since they were first recognized as an infectious cancer by members of this team less than a decade ago. It is known that whole cancer cells transfer from one animal to another, but it is unclear how this infectious disease spreads at the individual level, within a single population, or between populations in the environment. The interdisciplinary team is combining sensitive field surveys of disease prevalence, laboratory inoculation, and in vitro experiments together with quantitative modeling to understand how this unique class of infectious disease spreads in nature. The team will continue to communicate the results of this project through scientific publications and meetings with commercial aquaculture and local Native American communities, including research partners in multiple Coast Salish Tribes. Understanding the disease transmission principles may help develop strategies to control this disease, which would directly help these communities. The team members are also training undergraduate students during summer research experiences at Pacific Northwest Research Institute, Western Washington University, and Bigelow Laboratory for Ocean Sciences.

To understand the basic principles of the spread of bivalve transmissible cancer, the team studies two separate lineages in geographically separated species: soft-shell clams (Mya arenaria) on the Atlantic Coast of North America, the first bivalve transmissible cancer identified; and basket cockles (Clinocardium nuttallii), a species on the Pacific Coast of North America, in which the team has just recently identified bivalve transmissible cancer. The team is developing two quantitative models, one for the spread of disease within a population over time, and a second to model the spread of cancer lineages between different populations. They are testing these models with regular disease prevalence data from wild populations from multiple sites. Laboratory work on disease progression and transmission supports development and refinement of these models by providing critical parameter values and testing whether environmental variables (such as temperature) or genetic variables (such as the relatedness of cancer and host) affect the susceptibility and timing of disease progression. This project aims to develop a quantitative understanding of disease dynamics in soft-shell clams and basket cockles. Ultimately, it will provide general principles that underlie the spread of this recently discovered class of infectious disease.

This project was funded by the Division of Environmental Biology and the Division of Ocean Sciences.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.