Report on the first outbreaks of the porcine reproductive and respiratory syndrome (PRRS) in France. Diagnosis and viral isolation.

We describe the first known occurrence in France of the porcine reproductive and respiratory syndrome (PRRS), a new porcine disease that first appeared in Germany in November 1990. Outbreaks of the disease appeared in November 1991 in Brittany (France), with comparable clinical features to those observed in other countries, were definitively confirmed by a serological analysis from the affected animals using an immunoperoxidase monolayer assay with PRRS-virus infected alveolar macrophages. Furthermore, we report the isolation from one serum of a filtrable agent that, in view of its cytopathic effect for porcine alveolar macrophages and of the serologic reactivity of the infected cells, appears similar to the Lelystad virus that has been implicated in the etiology of the disease.