"When human fluid and tissue samples are applied to the chip, these probes will stick to any closely related genetic material in the samples," the U.S. National Institute of Allergy and Infectious Diseases, which helped develop the chip, said in a statement.

Doctors have been asking for such a tool for years, although widespread availability of the chip will require more work. An estimated half of all upper respiratory infections in the United States are never diagnosed, in part because it is so cumbersome, expensive and time-consuming to test patients for every single virus or bacteria that might be the cause.

Dr. Ian Lipkin, director of the Greene Infectious Disease Laboratory at Columbia University in New York, noted that hundreds of different infectious agents all can cause similar symptoms.

"Methods that simultaneously screen for multiple agents are important, particularly when early accurate diagnosis can alter treatment or assist in containment of an outbreak," Lipkin said in a statement. The chip is named for his lab.

The researchers tested their chip on samples from patients with respiratory disease, hemorrhagic fever, tuberculosis and urinary tract infections.

The GreeneChip diagnosed the infectious agent as accurately as older and slower methods, such as culturing or growing the bacteria or virus, or using polymerase chain reaction to look at the genetic material and identify the infectious agent that way.

"In addition, the GreeneChip was used in the analysis of an unknown sample from a patient with a viral hemorrhagic fever (VHF)-like syndrome," Columbia University wrote in a statement.

The researchers tested samples from a health care worker who died during an outbreak of deadly Marburg virus in Angola, which ended up killing 90 percent of its 252 victims.

A PCR test showed no evidence of Marburg virus, and neither did the GreeneChip. But the chip then identified Plasmodium -- the parasite that causes malaria.

Had the GreeneChip been available then, the worker could have been treated for malaria.

Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.

Third U.S. human 'mad cow' case reported in Virginia, CDC says

Last Updated: 2006-12-06 10:33:25 -0400 (Reuters Health)

WASHINGTON - A Saudi-born man living in Virginia has been identified as the third reported U.S. case of a human form of mad cow disease, according to the Centers for Disease Control and Prevention.

The man, whose case was reported to the CDC by the Virginia Department of Health, has variant Creutzfeldt Jakob Disease, or vCJD, the CDC said on its Web site.

This is a carefully diagnosed, brain-destroying illness that scientists believe is caused by eating beef products from cattle infected with bovine spongiform encephalopathy, also known as BSE, or mad cow disease.

"This U.S. case-patient was most likely infected from contaminated cattle products consumed as a child when living in Saudi Arabia," the CDC said in its report, posted on the Internet at http://www.cdc.gov/ncidod/dvrd/vcjd/other/vCJD_112906.htm.

"The current patient has no history of donating blood and the public health investigation has identified no risk of transmission to U.S. residents from this patient."

BSE swept through British herds in the 1980s, and people began developing an odd, early-onset form of CJD a few years later. CJD normally affects one in a million people globally, usually the elderly, as it has a long incubation period.

There is no cure and it is always fatal.

It is related to BSE and other transmissible spongiform encephalopathies, or TSEs, including scrapie in sheep and chronic wasting disease in deer.

"As of November 2006, 200 vCJD patients were reported worldwide, including 164 patients identified in the United Kingdom, 21 in France, 4 in the Republic of Ireland, 3 in the United States (including the present case-patient), 2 in the Netherlands and 1 each in Canada, Italy, Japan, Portugal, Saudi Arabia and Spain," the CDC said.

"Of the 200 reported vCJD patients, all except 10 of them (including the present case-patient) had resided either in the United Kingdom (170 cases) for over six months during the 1980-1996 period of the large UK BSE outbreak or alternatively in France (20 cases)."

The disease may have first started to infect cattle when they were fed improperly processed remains of sheep, possibly sheep infected with scrapie. Although people are not known to have ever caught scrapie from eating sheep, BSE apparently can be transmitted to humans.

There are now global bans on such cattle feed.

Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.