In vitro infectivity and immunofluorescence assays All samples in which a RT-qPCR signal was detected (either confirmed [above LOD], or at a very low level [below LOD]) were submitted to an in vitro infectivity assay. The presence of infectious viral particles for all fluids except semen was considered positive for values exceeding the LOD of 10 CCID 50 /well (with 95 % probability). Nevertheless, the assay was designed to detect one infected cell that propagates the virus to its adjacent cells, resulting in a plaque forming unit (as aided by the presence of agarose in the culture medium). Therefore, it was assumed that the system was able to detect 1 CCID 50 /well (but with a probability of detection of less than 95 %). However, for this to occur at least 10 CCID 50 should be present in the inoculum, in order to allow the adsorbtion onto the cells. For semen, validation of the infectivity assay could not be conducted due to high bacterial contamination.