Transfusion‐transmitted West Nile Virus infection (platelets)

Ready to upload
Record number: 
Adverse Occurrence type: 
MPHO Type: 
Estimated frequency: 
Since the implementation of WNV NAT in 2003 through the end of 2015 in the US, there have been 13 reports of WNV transfusion‐transmitted recipient infections. Of the 13 implicated donations, 12 were associated with false‐negative test results (none were attributed to donations from American Red Cross donors), and one was attributed to an untested granulocyte collected by the ARC during a period of WNV activity in 2012, when WNV screening of blood donors is implemented. Transfusion‐transmitted WNV is rare but possible due to low, short viraemia in donor.
Time to detection: 
The patient was admitted for chemotherapy and an autologous stem cell transplant for lymphoma. On posttransplant day 14 the patient received an apheresis platelet transfusion from a donor later shown to have an asymptomatic WNV infection. Four days after transfusion of the implicated platelets, the patient became symptomatic.
Alerting signals, symptoms, evidence of occurrence: 
Following his autologous stem cell transplant he received allogenic, leukoreduced, irradiated blood products during hospital days 13–30. He developed gastrointestinal symptoms on hospital day 18, followed by fever and hypotension on hospital day 28. On hospital day 29, he developed altered mental status, somnolence, and respiratory failure; need for sedation and mechanical ventilation precluded a full neurologic assessment. The patient’s mental status did not improve after discontinuation of sedation; support was withdrawn, and he died on hospital day 47. WNV encephalitis was diagnosed at autopsy, 33 days after the transfusion on posttransplant day 47.
Demonstration of imputability or root cause: 
The patient tested negative for WNV RNA 22 days before hospital admission. On posttransplant day 14 he received a platelet transfusion from a donor who later was shown to have had a recent asymptomatic WNV infection (80% of WNV infections are asymptomatic). Blood from the donor drawn at the day of donation was pooled with 5 others and the minipool tested positive for WNV RNA; however, each donor tested negative for WNV RNA when tested individually. Retrospectively it was shown that the implicated donor had WNV IgM antibodies in stored frozen plasma obtained on the day of platelet donation and that he had a history of mosquito bites. The donor was retested 56 days after donation and found to have WNV IgM and neutralizing antibodies. An editorial accompanying the case report (MMWR, 2013) called this case a transfusion-associated transmission: "It is likely that this transfusion-associated transmission occurred because the donor had a waning viremia that was sufficiently low to be inconsistently identified" and "This case demonstrates the potential for transmission of WNV through blood products tested nonreactive for ID-NAT". The time sequence from transfusion to development of typical WNV infection symptoms and death from WNV encephalitis is consistent with transfusion being the cause.
Imputability grade: 
3 Definite/Certain/Proven
Suggest references: 
Fatal West Nile virus infection after probable transfusion-associated transmission--Colorado, 2012. MMWR Morb Mortal Wkly Rep. 62(31):622-4, 2013 Aug 9.
PROBABLE IMPUTABILITY (6 existing records for WNV+blood, imputability certain) (EP) need to enter key words and go through the paper to pick up a few more details (IUL) - ok done (EP) --------------------------------------------------------------------------------------------- TE ------------------------------------------------------------------------------ I have recommended changing imputability to a DEFINITE PROVEN case classification because the donor clearly had a recent WNV infection (inconsistent donor testing for WNV RNA but positive WNV IgM and neutralizing antibodies in a donor who had been bitten by mosquitos) and the recipient clearly died of WNV infection. (TE) In addition the editorial author called it a "transfusion-associated case". in at least one sentence.
Expert comments for publication: 
This rare case of WNV transmission through a blood transfusion is the first where WNV RNA testing of the infected blood donor was inconsistent; positive when tested in a pool with five others but negative when tested individually.