Assessment of the environmental distribution of the protozoan parasite Perkinsus olseni by next-generation sequencing, qPCR and histopathology allows the identification of alternative bivalve hosts

Perkinsus olseni is a protozoan parasite that infects wide variety of molluscs worldwide, causing economic losses in the aquaculture sector. Consequently, Perkinsosis has been catalogued by World Organization for Animal Health (O.I.E.) as notifiable disease, and international measures have established to control it (O.I.E., 2019). In present study, we analysed spatial temporal distribution transmissible stages an endemic area from 2016 2018. The pathogen was detected using high-throughput sequencing 18S rRNA gene specific real-time PCR assay (qPCR) samples water, sediment several bivalve species. Histopathological assays were also conducted on samples. P. not environmental qPCR; however, eDNA revealed its presence both water at all sampled points, showing seasonal prevalence. As expected, clams, but few cases found mussels cockles. confirmed Cerastoderma edule histology qPCR RNA evaluate proliferative life parasite. Therefore, this first time C. with low abundance infection intensity levels.