Design and prospective evaluation of a risk-based surveillance system for shrimp grow-out farms in northeast Brazil

- The surveillance system evaluation prior to implementation is key to understand limitations and achievable goals.
- The model can be parameterized as seen fit to evaluate different strategies for surveillance.
- Parameter estimation is conservatively applied, as are internationally accepted methodologies.
- To our knowledge, this is the first risk-based surveillance system in shrimp aquaculture and also in the Latin American context

The farming of Pacific white shrimp Litopennaeus vannamei in northeast Brazil, has proven to be a promising sector. However, the farming of Pacific white shrimp in Brazil has been affected negatively by the occurrence of viral diseases, threatening this sector's expansion and sustainability. For this reason, the drafting of a surveillance system for early detection and definition of freedom from viral diseases, whose occurrence could result in high economic loses, is of the utmost importance. The stochastic model AquaVigil was implemented to prospectively evaluate different surveillance strategies to determine freedom from disease and identify the strategy with the lowest sampling efforts, making the best use of available resources through risk-based surveillance. The worked example presented was designed for regional application for the state of Ceará and can easily be applied to other Brazilian states. The AquaVigil model can analyse any risk-based surveillance system that considers a similar outline to the strategy here presented.