Test for West Nile Virus in Donated Blood Approved

WASHINGTON, DC, September 4, 2007 (ENS) - The U.S. Food and Drug Administration, FDA, today announced approval of a second test for the detection of West Nile virus in blood and organs.

The cobas TaqScreen West Nile virus test, manufactured by Roche Molecular Systems Inc. of Pleasanton, California, is an automated test that is able to detect the genetic material of the virus itself early in the infection.

Such nucleic acid testing improves blood and organ safety, detecting whether donated blood and organs have been infected even before the donor's body has begun to produce antibodies against the virus.

Most often, West Nile virus is transmitted to humans by mosquitoes. But West Nile virus can also be transmitted by blood transfusion or organ transplantation from infected donors.

While West Nile virus infection is common in Africa, Asia, and the Middle East, it did not appear in the United States until 1999. Since then, West Nile virus has become endemic in most of this country, with from 1 million to 3 million cases between 1999 and 2006, according to the Centers for Disease Control and Prevention.

"This action is the culmination of the dedicated efforts of FDA, our sister agencies, blood establishments, and manufacturers to bring donor screening tests to market for this increasingly common virus," said Jesse Goodman, MD, MPH, director of FDA's Center for Biologics Evaluation and Research.

"As a result," said Goodman, "blood centers and hospitals now have a choice of two FDA approved tests to screen for West Nile Virus in donated blood and organs."

Most people infected with West Nile virus show no signs of the disease but about one in 150 to one in 350 infected people will develop serious symptoms, including encephalitis, an inflammation of the brain.

Since the introduction of the virus, the reported number of human cases of serious West Nile virus in the United States has grown steadily from 62 in 1999 to 4,269 in 2006.

WNV has been especially virulent this year, Goodman said. Although it is still early in the West Nile virus season, 58 blood donors who are possibly positive for the virus have been reported to the CDC as of August 21, 2007.

The cobas TaqScreen West Nile virus test is approved for the detection of the virus in plasma specimens from human donors of whole blood and blood components - plasma, red or white cells, platelets - and living donors of cells, reproductive cells and other tissues.

It is also intended for use in testing plasma specimens of organ donors when specimens are obtained while the donor's heart is still beating. The test is not intended for use on samples of cord blood or as an aid in the diagnosis of West Nile virus infection.

Approval comes as FDA is preparing guidance on the use of licensed West Nile virus screening tests for blood donors.

Copyright Environment News Service (ENS) 2007. All rights reserved.