Testing the nation's blood supply for West Nile virus began just days ago and has uncovered the first infected donation _ in Texas _ letting health workers stop the blood from reaching any patients, the Food and Drug Administration said Thursday.
The donor was a 46-year-old woman in Harris County, Texas, who was allowed to give blood because she displayed no West Nile symptoms, the FDA said.
While confirmatory testing is under way, the discovery signals that "blood is much safer than last year," said Hira Nakhasi, FDA's chief of transfusion-spread diseases.
West Nile virus is spread mostly by infected mosquitoes. But about 13 of last year's record 4,000 West Nile cases are believed to have been caused by a blood transfusion.
Last year, the only way to guard the blood supply was to turn away donors with telltale flulike symptoms. But while West Nile can kill, most people infected have such a mild case they don't experience symptoms.
So blood specialists raced to adapt a technology that detects low levels of other viruses in blood, called nucleic acid testing or NAT, hoping it could find West Nile, too.
On July 1, blood banks began using experimental West Nile NAT kits made by two competitors, Roche Molecular Diagnostics and Chiron Corp., to screen donations before they're shipped to hospitals.
Canadian report says mad cow disease might have come from the United States
TORONTO _ Canada's lone case of mad cow disease might have originated in the United States, according to a report issued Thursday by Canadian investigators, who have been unable to pinpoint the source of the infection.
In its final report on the case of bovine spongiform encephalopathy, or BSE, detected May 20 in Alberta, the Canadian Food Inspection Agency raised the possibility the disease arrived in Canada in a large 1998 shipment of pregnant U.S. cows.
The 25,000 animals were born before a ban imposed a year earlier on cattle feed containing animal protein from cows and other ruminants. Eating infected tissue is considered the most likely way that BSE is spread among cattle.
According to the report, DNA testing is under way to try to learn whether the single infected animal in Alberta, known as the index case, had links to the cows imported in 1998.
"Canada cannot, to date, exclude the possibility that the index case itself derived through this huge, unique importation," the report said.
A team of international experts that assessed Canada's investigation of the mad cow case reached no conclusion on the origin of the illness in its report, issued last week. The panel of experts had access to the final CFIA report.
Julie Quick of the U.S. Department of Agriculture said officials have been reviewing the Canadian report for several weeks. "We have absolutely no reason to believe that any cattle exported by the United States were infected," she said.
Scientists find way to increase sensitivity
Giving new meaning to "sensitivity training," scientists have developed a simple way to greatly enhance the human body's ability to feel subtle sensations.
The enhanced sensitivity, achieved with a tiny stimulating device and a single dose of a drug, has reversed fingertip numbness in older people, many of whom have trouble performing everyday tasks such as buttoning shirts or turning switches on and off.
The ability to boost sensitivity could even allow people with normal function to achieve bionic supersensitivity _ for work or recreational purposes _ scientists said.
"This indicates that the sensitivity we typically see in normal subjects is not a physical limit," said Hubert Dinse, the neuroscientist who led the work at the Ruhr-University Bochum in Germany.
The new work, described in today's issue of the journal Science, is the latest in a series of advances that have demonstrated an unexpected capacity to reverse sensory declines in the elderly and enhance those functions in younger people.
The new study shows for the first time the process involves a biochemical pathway known to play a key role in learning and memory. When scientists gave a drug that "revs up" this pathway, it vastly increased the amount of brain reorganization _ or "remodeling" _ that occurred during sensory stimulation, and significantly added to the improvement in function.
Geriatricians in particular want to understand and tinker with these biochemical pathways because the gradual loss of sensory function that comes with old age takes a huge toll on quality of life.
"The incremental loss of vision, hearing, smell and touch tips the balance eventually," said Daniel Perry, executive director of the nonprofit Alliance for Aging Research.
Germs that build fortlike colonies can lead to repeat urinary tract infections
WASHINGTON _ Millions of people have repeated urinary tract infections despite high-powered antibiotics. A new study suggests why: A germ that invades the bladder builds a fortlike colony that resists antibiotics and the body's immune system.
Researchers at Washington University in St. Louis used a powerful electron microscope to discover pods of bacteria routinely form inside the cells lining the walls of the bladder in mice that have E. coli bacterial infections of the urinary tract.
The bacteria form a structure called a biofilm inside the cells, with thousands of individual bacteria becoming unified into a colony that resists attack, said Dr. Joseph J. Palermo, a Washington University researcher and the co-author of a study appearing in the journal Science.
"The bacteria rest in a matrix like eggs in a carton," Palermo said. He said this is the first time a biofilm structure has been found within a cell, and it explains why many patients are unable to become free of urinary tract infections.