Pounds ofBPA producedglobally in 2003
Americanswith detectableBPA levels
Pathogen fingered as a potential
culprit in chronic fatigue syndrome
Little-known retrovirus found in many people with condition
By Nathan Seppa
The long, fruitless search for the causeof chronic fatigue syndrome has takena curious turn. An obscure retrovirusshows up in two-thirds of people diagnosed with the condition and can infecthuman immune cells, scientists reportonline October 8 in Science.
These findings don’t establish thatthe pathogen, called gammaretrovirusXMRV, causes chronic fatigue, cautionsstudy coauthor Robert Silverman of theCleveland Clinic’s Lerner Research Institute. “Nevertheless, it’s exciting becauseit is a viable candidate for a cause.”
Roughly 1 million to 4 million peoplein the United States have chronic fatiguesyndrome, according to the Centers forDisease Control and Prevention. Characterized by unexplained mental andphysical exhaustion, memory lapses,muscle pain, insomnia, digestive distress and other health problems, chronicfatigue is often diagnosed only aftereverything else has been ruled out.
In the study, researchers tested bloodfrom 101 people diagnosed with the syndrome and found that 68 were infectedwith the retrovirus. An analysis of bloodfrom 218 healthy people showed that onlyeight had XMRV — nearly 4 percent.
“This is a very striking association —two-thirds of the patients,” says JohnCoffin of Tufts University in Boston, whowasn’t involved in the study.
Studies of its genes suggest XMRVarose from a mouse retrovirus thatsomehow jumped to humans.
Study coauthor Judy Mikovits, a cellbiologist at the Whittemore PetersonInstitute in Reno, Nev., says that theretroviral infection could result in animmune deficiency that leads to chronicfatigue symptoms in some people. Other
retroviruses, such as HIV, are known toattack the immune system. In this study,researchers showed that XMRV couldinfect immune cells in the blood.
“This may end the controversy as to whether thereis an underlying infection insome cases of chronic fatiguesyndrome but is unlikely toexplain all cases,” says DedraBuchwald of the University ofWashington in Seattle. Retroviruses can awaken latentviruses already in cells, soXMRV might affect health only indirectly,by activating other viruses, she says.
XMRV, short for xenotropic murine
leukemia virus–related virus, also shows
up in some men with prostate cancer,
particularly those with aggressive malig-
nancies, another research team reported
in September in the Proceedings of the
National Academy of Sciences.
In the new study, the researchers found
hints that the retrovirus is transmitted
by blood. But it’s probably not spreading
very fast, Mikovits says.
Further research is under way to fine-
tune testing for XMRV, and more stud-
ies are planned to clarify its
occurrence rate in the gen-
eral population. Mikovits
and her colleagues are
also investigating already-
drugs to see if these will ben-
efit people diagnosed with
A nearly 4 percent infec-
tion rate in healthy controls means that
as many as 10 million Americans may har-
bor a hidden infection, Coffin notes. But
until further studies are done, the effects
of those infections remain unclear.
is a viable
flu’s worst cases
Antivirals, ventilators help, but
fatalities show lungs hit hard
and death. In severe cases, inflammation
in the lungs leads to fluid buildup in air-
ways and lung tissues, says the University
of Toronto’s Robert Fowler, a coauthor on
t wo of the studies. “Most patients are still
able to take breaths, but these breaths are
ineffective,” he says.
In the largest of the studies, scientists inCanada monitored 168 patients deemedcritically ill with H1N1 flu. Patients averaged only 32 years of age and receivedintensive treatment, but 17 percent died.Doctors in Australia and New Zealandidentified 68 critically ill patients witha median age of 34 for the second study.The fatality rate was 21 percent. In thethird study, a team examined records of58 critically ill patients in Mexico with amedian age of 44, and found a fatality rateof 41 percent.
In Canada and Mexico, most patientsreceived mechanical ventilation, and inall three regions many were also given thedrug Tamiflu, with apparent benefit.
By Nathan Seppa
Lung inflammation and respiratory failure are largely responsible for the fatalcases of H1N1 swine flu, three new studiesshow. The findings confirm observationsthat H1N1 hits young adults hardest butcan be fought off, in many cases, with theuse of antiviral flu drugs and a mechanicalventilator that aids breathing.
Conducted between late March andlate August, the studies, reported onlineOctober 12 in the Journal of the AmericanMedical Association, find that the mostcritically ill patients suffer from oxygendeprivation in the blood, a dangerous condition that can lead to shock, organ failure