<qa>  What is the RT-PCR used to test peritoneal aspirate?Peripheral blood mononuclear cells are collected at baseline and periodically during and after treatment to assess viremia. Throat gargle and urine specimens are assessed periodically during course 1 for viral shedding by reverse transcriptase-polymerase chain reaction RT-PCR. Peritoneal aspirate is tested at baseline and periodically during treatment for viral replication by RT-PCR, co-culture with Vero cells, and measles virus N-specific mRNA in situ hybridization. 