title: JJSD
design: Enrichment of pathogen RNA; reverse transcription of cDNA after pausing; after end repair, A-addition and ligation steps, sequencing junctions are added to both ends of the cDNA fragments; after junction ligation is complete, fragment screening is performed using magnetic bead purification (0.6-0.11X magnetic bead screening); magnetic bead purification and screening result in a library of target fragments; after enrichment and magnetic bead purification, the library is obtained on the machine.