| Summary: | Due to the increasing mass mortality of <i>Pinna nobilis</i>, mainly caused by the protozoan <i>Haplosporidium pinnae</i> along the Mediterranean Sea, it is necessary to develop rapid and effective methods to detect the pathogen. The present study describes the development and validation of a species-specific assay based on hydrolysis probe chemistry to detect <i>H. pinnae</i> DNA from faeces and pseudofaeces of <i>P. nobilis</i>. During a study campaign in the Gulf of Trieste (Italy) in the spring and summer of 2022, 18 samples (10 faeces and 8 pseudofaeces) were collected. DNA was isolated from all samples and the presence of <i>H. pinnae</i> was tested by amplifying a small portion of 18S rDNA using qPCR. The newly developed assay detected positive <i>H. pinnae</i> in the faeces of the fan mussel in the spring, while no evidence of an outbreak of <i>H. pinnae</i> was found in the summer. In addition, the method proved to be noninvasive and can be used to monitor suspected <i>H. pinnae</i> infections in the early stages when bivalves are still vital. Furthermore, fecal analysis allows the monitoring of <i>P. nobilis</i> without dissecting tissues. The presented assay can also be used to routinely monitor the progress of mass mortalities caused by <i>H. pinnae</i> and to screen for the pathogen in live fan mussels and other environmental matrices, such as water, sediment, and faeces from other species that can host the protozoan.
|
|---|