All
 B04 Viruses D014780 +
 B04.820 RNA Viruses D012328 +
 B04.820.650 Retroviridae D012190 +
 B04.820.650.375 Gammaretrovirus D017988 +
 B04.820.650.375.525 Leukemia Virus, Murine D009052 +
 B04.820.650.375.525.850 Spleen Focus-Forming Viruses D013155