http://www.cdc.gov/ncidod/dhqp/bp_xmrv_qa.html
What is XMRV?
XMRV is a newly identified human retrovirus that is similar to a mouse retrovirus that scientists have known about for years. XMRV refers to xenotropic murine leukemia virus-related virus. It was first identified in samples of human prostate cancer tissue. Some additional studies have suggested that a high percentage of persons with chronic fatigue syndrome (CFS) may be infected with XMRV, but this result needs to be confirmed by other groups of scientists.
The frequency of XMRV infection in healthy persons and the potential role of this virus in causing diseases such as prostate cancer and CFS are unknown at this time. If it is determined that XMRV may have a role in causing disease and illness, prevention recommendations can be made.
How is XMRV transmitted? Are certain individuals more likely to be infected with the XMRV virus?
The manner in which XMRV is transmitted is unknown. It is unclear whether certain individuals are more likely to be infected with XMRV. Studies of XMRV have been under way for only a short time, and therefore these and similar questions have not been answered.
If researchers find that XMRV is found in a majority of patients who have chronic fatigue syndrome, does this mean that CFS may be contagious?
One study that has been conducted on CFS and close contacts suggests that there is no evidence that CFS is contagious or spread person to person. Occurrence of CFS is not more common in family members of patients with CFS, and none of the features typical of contagious disease have been associated with CFS. These features include seasonal or regional occurrence, travel history, occupation, exposure to animals, injection drug use, and sexual behavior.
Since the recent study reported finding XMRV in healthy persons, can XMRV be transmitted through blood transfusion or organ/tissue transplantation?
This possibility will be studied carefully. At present, we do not know whether XMRV can be transmitted through blood transfusion. Since XMRV is thought to infect many types of human cells, including some blood cell types, the safety of blood could be a concern if XMRV infection is confirmed to cause human disease.
What is being done to evaluate the risk of transmission of XMRV through blood transfusion or organ transplantation?
Several studies are under way to evaluate the risk of XMRV transmission through blood transfusion. The Department of Health and Human Services (HHS) is conducting studies to determine the prevalence of XMRV in the blood donor population. In addition, HHS scientists are working with scientists in industry and academia to determine if XMRV can be transmitted by blood transfusion. If a link between XMRV and transfusion is established, action will be taken to reduce the risk.
Additionally, a Public Health Service (PHS) working group plans to coordinate testing of specimens to assess transfusion-transmissibility of XMRV. If an agent is found to be transmissible by blood, studies must begin quickly to evaluate if the agent causes disease in transfusion recipients.
Who has collections of blood samples for this research?
The National Institutes of Health (NIH) currently funds the Retrovirus Epidemiology Donor Study-II (REDS-II) which focuses on addressing critical questions in blood safety. The REDS-II laboratory sample collection, called RADAR, has specimens from blood donors and matched recipients from various regions of the country. These matched specimens can be useful in testing for the transmissibility of "new" or "emerging" infectious agents, such as XMRV.
If researchers have a test for XMRV, why cant it be used for diagnosis and screening of blood donors?
At present, although it is theoretically plausible that XMRV can be transmitted through blood transfusion, no such transmission has been identified, and there is no known evidence of XMRV infection or XMRV-related illness in transfusion recipients. Therefore, there is currently no requirement for testing of the blood supply for the presence of XMRV.
HHS scientists are working with scientists in industry and academia to determine if XMRV can be transmitted by blood transfusion. If a link between XMRV and transfusion is established, action will be taken to reduce the risk. Such a risk, if it exists, could be decreased by developing and using blood donor screening assays or other measures. The use of a donor screening assay by blood establishments would require U.S. Food and Drug Administration (FDA) approval of the test.
There are many steps between what is currently known about XMRV and the release of an FDA-approved test, if such a test were warranted. The test components and procedures must be standardized, and the test performance assessed in research studies before licensure (approval) by the FDA. However, if the risk is demonstrated, these steps could be taken more quickly, as occurred for screening approval of West Nile virus.
Is it possible to determine whether XMRV can be transmitted via blood transfusion, without waiting for it to occur in a patient?
Yes. There are several steps necessary to evaluate if a new infectious agent presents a threat to transfusion recipients. HHS scientists are taking these steps by working with scientists in industry and academia to determine if XMRV can be transmitted by blood transfusion.
The first step is to determine whether the agent is present in the blood supply by looking at the fraction of blood donors who have the infectious agent in their blood. Next, it is also important to determine the risks of the blood components themselves to spread infection, since preparation and storage may impact these risks (e.g., filtering out white blood cells or refrigerating a blood unit may decrease the risk of an infectious agent).
If the agent is found to be in the blood supply, the second step is to evaluate whether it is transmitted by transfusion. To do this, investigators can use animal studies, case report investigations, and the evaluation of biological specimens that have been collected and stored in repositories for this purpose.
Should an individual with diagnosed chronic fatigue syndrome donate blood?
At the present time, there are no specific recommendations to defer donors who have chronic fatigue syndrome. However, FDA regulations require that a donor should be in good health. Medical Directors at blood collection centers should exercise judgment in determining whether individuals with a history of CFS are in good health at the time of donation.
Should an individual who has been diagnosed, treated and currently in remission from prostate cancer donate blood?
There is no known association of prostate cancer with history of transfusion. In general, FDA has not recommended deferral of donors who have a history of cancer due to lack of such as association.
Should an individual with diagnosed chronic fatigue syndrome or in remission from prostate cancer be an organ or tissue donor?
At the present time, there are no recommendations to defer organ and tissue donations from individuals diagnosed with chronic fatigue syndrome or who are in remission from prostate cancer.
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Date last modified: February 18, 2010
Content source:
Division of Healthcare Quality Promotion (DHQP)
National Center for Preparedness, Detection, and Control of Infectious Diseases (NCPDCID)
