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Tuesday, February 7, 2017

First Zika-positive blood donations in the continental United States.

First Zika-positive blood donations in the continental United States. HT: Croft.
Zika virus (ZIKV) has spread in the Americas, including parts of the southern United States, and infection can be associated with serious complications, including congenital brain abnormalities. Probable transfusion transmission of ZIKV has been documented in Brazil. 
Preemptive testing of blood donations for ZIKV RNA was implemented in southern US states at risk of local transmission using a test approved under a Food and Drug Administration (FDA) investigational new drug application, cobas Zika. Screening was expanded after issuance of an updated FDA guidance. Donations reactive on initial screening were further tested by nucleic acid and antibody tests to determine the donor status. 
Of 358,786 donations from US states screened by individual donation testing, 23 were initially reactive on cobas Zika. Fourteen of these represented probable ZIKV infection based on reactivity on additional nucleic acid testing or anti-Zika immunoglobulin M. 
Ten of the 14 donors reported travel to an identified ZIKV-active area within 90 days before donation (median time from end of travel to donation, 25 days; range, 6-71 days). 
Three donors with travel history also had a potential sexual exposure. Only seven of the 14 donations with probable ZIKV infection were detectable upon 1:6 dilution to simulate minipool testing. The estimated specificity of the cobas Zika test was 99.997%.  

Screening of donations for ZIKV RNA can interdict ZIKV-infected donors. Donor risk factors include travel more than 4 weeks before donation and sexual exposure. Minipool screening would have detected only 50% of the RNA-positive donations.

1 comment:

  1. Until Culex are acknowledged as Zika vectors and birds (esp. red-whiskered bulbuls) are investigated as reservoir hosts of Zika, nothing will change in Florida. It will be a hotbed of infection for years to come.

    What Dr. Tom Frieden and others at the CDC failed to do was take to heart the evidence submitted by Drs. Ayres, Hunter, Guedes, and Guo et al.

    No infected mosquitoes were collected from Yap States and French Polynesia during their Zika outbreaks. They simply ASSUMED that Aedes species were vectors, although they never fulfilled the criteria: #3 and #4, i.e., “repeated demonstration that suspected vectors, collected under natural conditions, harbor the identifiable, infective stage of the pathogen” and “a biological association between clinical cases and infected mosquitoes in time and space,” respectively. Source: Dr. Walter S. Leal's paper "Zika mosquito vectors: the jury is still out".

    Now, Zika has been found in saliva a whopping 49 days (in a 41-year-old man). All it takes is a sneeze or cough on someone nearby, right? "As ZIKV [Zika virus] may persist in whole blood for 101 days [over 3 months], donors should be proactively screened for ZIKV exposure." Source: Univadis post "Zika: persistence in whole blood assists late, direct diagnosis".

    Where are the warnings? The Amercian Red Cross is sticking with a measly 28-day wait for donors who visited Zika-endemic areas; Canadian Blood Services an unconscionable 21-day wait. At least India took the evidence to heart, they have a 120-day (4 month) wait.

    Culex mosquitoes in Brazil and China are spreading Zika (which means birds are likely reservoir hosts). What's worse: Wolbachia that is acquired by any species after (or perhaps along with) a Zika infection is probably enhanced by Wolbachia.

    Source: "More Proof Wolbachia Infected Mosquito Releases Might Be Causing the Most Devastating Zika Infections"

    My open letter to Dr. Margaret Chan, director-general of WHO:


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