DENVER (CBS4/AP) — A Colorado West Nile death has been traced to a transfusion of blood that was screened for the virus, federal health officials reported Thursday.

The 2012 death was detailed in a report by the Centers for Disease Control and Prevention. The patient died after receiving blood that was approved for use after a screening for West Nile Virus.

The patient was identified only as a Colorado man who had cancer and was in the hospital for chemotherapy and a stem cell transplant. He ended up dying of encephalitis caused by West Nile virus that the blood screening missed.

“The patient was hospitalized continuously for four weeks before illness onset without known outdoor exposure; therefore, mosquito-borne (West Nile) transmission was unlikely,” doctors wrote in the report published Thursday.

That patient died at Presbyterian/St. Luke’s Medical Center in Denver.

Bonfils Blood Center said the donor was a regular, not at Bonfils but a different location. He had given platelets and plasma seven times in three months and showed no signs of West Nile.

“The majority of people who develop West Nile Virus don’t become ill,” said Colorado Epidemiologist John Pape.

Pape said that 80 percent of people who contract West Nile show no symptoms.

The report calls for further study of the blood-screening procedure and urges physicians to consider West Nile virus when patients show symptoms compatible with the virus after receiving blood transfusions.

“This is particularly important in immunosuppressed patients, such as stem cell recipients, who might be more susceptible to (West Nile) infection at very low viral concentrations in the transfused blood product,” researchers concluded.

The first screening blood banks conduct is a pool of six donors. If that’s positive the samples are tested individually with a more precise measure.

In the 2012 case the pool sample tested positive but the more sensitive test showed negative.

That blood was then released into the blood supply.

“The virus at such a small amount the testing was not able to pick up or give consistent results,” said Bonfils Medical Director Dr. Tuan Le.

Le said it was only after the patient died that the plasma and platelets tested positive and even then the results were inconsistent. He said Bonfils did everything possible to prevent this from happening.

“They did everything strictly by the book,” said Le. “I think it’s unfortunate of course because it involved a sick patient.”

Bonfils said from now on when samples test positive all the blood will be discarded instead of conducting a second screening.

The nation’s blood supply has been screened for West Nile virus since 2003. Since then, only 13 transfusion-associated West Nile cases have been noted, the CDC reported.

Doctors traced nine other donations made by the donor of the tainted blood. They found no other cases where West Nile virus had been transmitted.

Statement from Presbyterian/St. Luke’s Medical Center regarding Fatal West Nile virus infection after probable transfusion-associated transmission: “Presbyterian/St. Luke’s Medical Center was the first to take the lead in investigating the death of a patient in October 2012 when West Nile virus was first suspected.  Our infectious disease and blood bank teams worked diligently with the family, Tri-County Health Department, Bonfils, the CDC and the FDA to determine the source of the West Nile virus.

Our investigation confirmed that Presbyterian/St. Luke’s Medical Center followed all appropriate blood donation protocols and testing procedures.

Our hearts go out to the family and friends of this patient. We will continue to work with Bonfils, the CDC and the FDA in ongoing efforts to ensure the safety of all donated blood products, and to safeguard the well-being of the patients entrusted to our care.”

(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2012 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)


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