U.S. clears Roche blood test for West Nile virus

(Adds details, background on West Nile virus cases, information on competitor)

WASHINGTON, Aug 28 (Reuters) - Roche Holding AG (ROG.VX) won U.S. approval to sell a test to detect the West Nile virus in donated blood and organs, health officials said on Tuesday.

The Cobas TaqScreen WNV test is the second of its kind approved by the U.S. Food and Drug Administration, the agency said.

The test, made by Roche unit Roche Molecular Systems Inc, can detect the genetic material of the West Nile virus early in the infection, the FDA said. In March, the FDA approved a similar test made by Gen-Probe Inc (GPRO.O)

West Nile virus was discovered in the United States in 1999 and typically is spread by infected mosquitoes. It is much less common for the virus to be passed through blood transfusions and organ transplants.

Most people infected with West Nile do not get sick or have only mild symptoms such as fever and headaches. But between 1 in 150 to 1 in 350 people infected with the virus will develop serious symptoms such as brain inflammation, the FDA said. Some cases can be deadly.

The number of serious West Nile cases reported in the United States has grown from 62 in 1999 to 4,269 in 2006, the FDA said.

West Nile has been "especially virulent" this year, the agency said.

"Although it is still early in the WNV season, 58 blood donors who are possibly positive for the virus have been reported" to the Centers for Disease Control and Prevention as of Aug 21, the FDA said.

(Reporting by Lisa Richwine)

((Editing by Andre Grenon; Reuters Messaging: lisa.richwine.reuters.com@reuters.net +1 202 310-5691)) Keywords: ROCHE WESTNILE/

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