XMRV is a new human retrovirus that was originally reported in patients with prostate cancer and chronic fatigue syndrome. Subsequent reports of failure/success to detect XMRV in similar patient populations by others have resulted in the current intense controversy related to the possible association of XMRV and these human diseases. Additionally, there are potential public health implications regarding XMRV transmission by blood transfusion. Moreover, murine retrovirus sequences related to polytropic murine leukemia viruses (MLVs) have recently been reported in some human samples.

The main focus of this special issue is presenting critical research toward development and standardization of sensitive assays for the detection of XMRV and related MLVs, understanding virus biology, and investigating virus transmission, with the important goals of investigating the risk of human infections and determining any disease associations. The special issue will be an international forum for researchers to present their most recent findings in the field, with special emphasis on results that can aid in resolving the clinical and public health concerns regarding XMRV and other MLV-related viruses in humans. The special issue will publish original research and review papers including, but are not limited to the following topics:

• Murine leukemia viruses: background
• Endogenous retroviruses: overview
• Cross-species transmission of MLVs: a historical perspective
• MLVs and host adaptations
• Biology of murine retroviruses
• XMRV: discovery and progress
• XMRV: human infections
• Gammaretroviruses: development of detection assays and standardization
• XMRV and other related murine retroviruses in vitro studies
• XMRV transmission: animal studies
• Prevalence of MLVs in humans
• Novel technologies for virus detection
• Antiretroviral drugs and MLV infection

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/av/guidelines.html. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: