Chronic Fatigue Link to Mouse Virus Studied
A U.S. government study has uncovered a family of mouse viruses in some people with chronic fatigue syndrome, raising still more questions about whether an infection may play a role in the complicated illness.
Monday's study does not prove that having any of these viruses causes harm, stressed co-author Dr. Harvey Alter of the National Institutes of Health.
But it strengthens suspicions, and the government has additional research under way to determine if the link is real or not.
Meanwhile, a group of French and Canadian scientists said it's time to test whether antiviral medications like those used against HIV might treat at least some people with chronic fatigue.
Retrovirus Linked to Chronic Fatigue
The virus connection first made headlines last fall when Nevada researchers reported finding a specific type, named XMRV, in the blood of two-thirds of the 101 chronic fatigue patients they tested. But several other studies, including one from the Centers for Disease Control and Prevention, failed to find XMRV virus in patients, making researchers wonder if this was a false alarm.
Monday's study, published in Proceedings of the National Academy of Sciences, thickens the plot. This time, NIH and Food and Drug Administration scientists examined the blood of 37 chronic fatigue patients and again didn't find XMRV - but instead they found a group of closely related bugs named MLV-related viruses in 86 percent of the cases.
Testing of 44 healthy blood donors, in contrast, found evidence of those viruses in nearly 7 percent.
Various viruses have been linked to chronic fatigue over the years only to fall by the wayside as potential culprits in the mysterious illness thought to afflict about 1 million Americans. It's characterized by at least six months of severe fatigue, impaired memory and other symptoms, but there's no test for it and no specific treatment.
These MLV, or "murine leukemia-related viruses," are known to cause some cancers in mice, and the XMRV relative has been found in some human prostate tumors, too.
But there's no easy way to test for it, meaning studies of a link at this point must be in research labs, not doctors' offices, FDA and NIH researchers said Monday.
No one knows how people become infected, but Alter said a major study is under way to see if there's any evidence of transmission through blood.
In the meantime, federal regulations require that blood donors be in good health, said FDA's Dr. Hira Nakhasi.
© 2010 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Monday's study does not prove that having any of these viruses causes harm, stressed co-author Dr. Harvey Alter of the National Institutes of Health.
But it strengthens suspicions, and the government has additional research under way to determine if the link is real or not.
Meanwhile, a group of French and Canadian scientists said it's time to test whether antiviral medications like those used against HIV might treat at least some people with chronic fatigue.
Retrovirus Linked to Chronic Fatigue
The virus connection first made headlines last fall when Nevada researchers reported finding a specific type, named XMRV, in the blood of two-thirds of the 101 chronic fatigue patients they tested. But several other studies, including one from the Centers for Disease Control and Prevention, failed to find XMRV virus in patients, making researchers wonder if this was a false alarm.
Monday's study, published in Proceedings of the National Academy of Sciences, thickens the plot. This time, NIH and Food and Drug Administration scientists examined the blood of 37 chronic fatigue patients and again didn't find XMRV - but instead they found a group of closely related bugs named MLV-related viruses in 86 percent of the cases.
Testing of 44 healthy blood donors, in contrast, found evidence of those viruses in nearly 7 percent.
Various viruses have been linked to chronic fatigue over the years only to fall by the wayside as potential culprits in the mysterious illness thought to afflict about 1 million Americans. It's characterized by at least six months of severe fatigue, impaired memory and other symptoms, but there's no test for it and no specific treatment.
These MLV, or "murine leukemia-related viruses," are known to cause some cancers in mice, and the XMRV relative has been found in some human prostate tumors, too.
But there's no easy way to test for it, meaning studies of a link at this point must be in research labs, not doctors' offices, FDA and NIH researchers said Monday.
No one knows how people become infected, but Alter said a major study is under way to see if there's any evidence of transmission through blood.
In the meantime, federal regulations require that blood donors be in good health, said FDA's Dr. Hira Nakhasi.
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However, I think that one of the mistakes is to assume that persons with chronic fatigue who have not been proven to have some known disease have a unique condition/disease called ?chronic fatigue syndrome? and that it is a single disease with a single causative agent (the old-fashioned and outmoded principle of infectious diseases where it was claimed that a single organism casues a single disease)
(on the contrary?..see H. pylori ? it can cause ulcers, and/or it can cause gastritis, and/or it can cause stomach cancer, and/or it can cause a ?sensitive stomach? and/or it may not give much in the way of symptoms at all, and/or it may even resolve spontaneously or when the patient takes some remedy for an unrelated condition ? depending on individual susceptibility).
It is my belief that various ?stealth? infections may cause a feeling of chronic fatigue in some (but not all individuals) who carry such an untreated infection, i.e. hepatitis C carrier state, CMV carrier state, Chlamydia carrier state
(true carrier state vs. low-grade smoldering state ? similar to staph colonization of the nasopharynx ? some have no symptoms, some have only bloody crusty discharge when they blow their nose, some have a ?logy? feeling in their head and sinuses and just don?t feel right?..).
Clues to such a situation may be seen when a person is treated with Valtrex for an unrelated condition (such as herpes simplex) and their chronic fatigue improves noticeably, or with doxycycline for a skin condition, and their chronic fatigue improves noticeably, or they get a shot of gamma globulin for travel, and their persistent fatigue improves noticeably?.
There are indeed numerous such cases which may be an indirect but important clue that we should be on the alert for in considering such disease associations?? This is how the role of H. Pylori was noted. (Patient in 1970?s: ?gee, doctor, my stomach feels so much better since you gave me those antibiotics for my diverticulitis??..Doctor 1970?s: ?you are totally mistaken and must have had a placebo effect from the antibiotics ? or must have quit drinking excessively - because as we all know in the scientific medical community, there is no relationship whatsoever between a sensitive stomach and bacteria?.just look at the chapter in any authoritative gastroenterology textbook?.? Hmmm?. )