XMRV, a virus that has been previously linked to certain types of familial prostate cancer, has recently been cited as a potential threat to the national blood supply.
The virus can be found in measurable amounts in the blood of otherwise normal adults. It is thought that it may be transmitted in a similar fashion to HIV, thus the potential risk to the blood supply.
Researchers and public health officials still know very little about what XMRV does, how prevalent it is in the United States, or what should be done to screen for it.
Read more about the link between viruses and prostate cancer.