Tilapia disease surveillance and sampling plans for epidemiological surveys and monitoring: a review

The tilapia industry has been expanding increasingly among countries on all continents, representing a major international commodity and an important source of animal protein for the global population. However, this industry has been threatened by emerging pathogens that take advantage of the highly vulnerable situation of tilapia cultures, which are increasingly subjected to super-intensive management with a high density of fish, favoring the rapid multiplication and dispersal of these agents in the environment and between farms. The aim of this study was to carry out a literature review on the general aspects of tilapia disease surveillance and the sampling plans used for epidemiological surveys and monitoring conducted in Brazil and neighboring countries, discussing the differences from the sampling plan for the Distrito Federal (Brazil). A wide variety of designs and sample sizes were observed between the different health plans and programs carried out in Brazil and other countries, with a very strong tendency to use risk-based strategies and targeted sampling. It can be concluded that there is a very wide variety of designs and sample sizes between the different health plans and programs for diseases of tilapia and other fish species. In the Distrito Federal, the only federal unit in Brazil that has a surveillance plan for tilapia diseases, the models applied were defined based on risk-based surveillance strategies and sampling of symptomatic animals to adjust logistical/laboratory costs and increase the sensitivity of epidemiological surveys.