Prolonged Zika Viremia During Pregnancy

Summary and Comment |
January 6, 2017

Prolonged Zika Viremia During Pregnancy

  1. Richard T. Ellison III, MD

Zika virus was detectable in a pregnant woman's serum samples for more than 3 and a half months after symptom onset.

  1. Richard T. Ellison III, MD

Our understanding of the natural history of Zika virus (ZIKV) infection remains limited. Recent work has indicated that ZIKV viremia is normally detectable only within the first week after the onset of illness, although viremia previously was reported to last 8 weeks after illness onset in a pregnant patient where the pregnancy was terminated due to evidence of severe abnormalities in fetal brain development.

Now, researchers report on a pregnant Colombian woman living in Spain who developed a maculopapular rash after visiting her home country at 9 weeks' gestation. She was tested for ZIKV and other flaviviruses; reverse transcriptase PCR (RT-PCR) testing identified ZIKV viremia, although urine, vaginal, and endocervical samples were negative. Maternal viremia persisted through 107 days after symptom onset, on six assays with a relatively stable viral load. The fetus had no apparent abnormalities on scans at 12 and 15 weeks but on subsequent studies had parenchymal calcifications and severe atrophy of the brain. An RT-PCR assay on the amniotic fluid at 19 weeks' gestation was positive for ZIKV with a higher viral load than in maternal serum. The infant was born with microcephaly at 37 weeks' gestation, and testing of multiple sites from the mother and newborn were all negative for the virus at that time.


The authors of this and the prior report of prolonged viremia during pregnancy hypothesize that persistent maternal viremia is related to ongoing ZIKV replication in the placenta or fetus that serves as a reservoir for the virus. If so, persistent viremia may serve as an early marker for ZIKV disease in the newborn and could help guide management of pregnant women with ZIKV infection.

Editor Disclosures at Time of Publication

  • Disclosures for Richard T. Ellison III, MD at time of publication Consultant / Advisory board Philips Healthcare Grant / Research support Philips Healthcare


Reader Comments (1)

Rose Webster Other Healthcare Professional, Ophthalmology, Hospital / Private Practice

Your finding is not surprising. I'll explain:

Re: "Zika virus was detectable in a pregnant woman's serum samples for more than 3 and a half months after symptom onset."

Our public health authorities (WHO and CDC) apparently ignored a Eurosurveillance Rapid Communication: "Detection of Zika Virus RNA in Whole Blood of Imported Zika Virus Disease Cases Up to 2 Months After Symptom Onset, Israel, December 2015 to April 2016." Source: Eurosurveillance, Volume 21, Issue 26, 30 June 2016

More recently (Dec. 2016): "detection of Zika virus RNA in vaginal secretions up to day 14 and in erythrocytes up to day 81" (almost 3 months in blood). Source: December 14, 2016 CDC post called Prolonged Detection of Zika Virus in Vaginal Secretions and Whole Blood.

Re: "ZIKV viremia is normally detectable only within the first week ..."

I wonder if this is because of the highly flawed Trioplex assay (which fails to detect 40 percent of Zika cases and all four strains of dengue). The ZIKV Detect IgM Capture ELISA test, made by InBios International has been deemed "too inaccurate" by the FDA, as well.

As of November 12th, 2016, a whopping 564,571 donations have tested positive on the cobas Zika test.
Dr. Jay S. Epstein, Office of Blood Research and Review director at the FDA, said in a statement:

"Zika virus is a transfusion transmitted disease which can cause potentially severe consequences including microcephaly and Guillain-Barré syndrome. The requirement to test blood donations for Zika virus has already resulted in interdicting contaminated collections confirming the value of testing."

Source (with citations):

Also, UC San Francisco researchers have identified fetal brain tissue cells that are targeted by the Zika virus and determined that azithromycin, a common antibiotic regarded as safe for use during pregnancy, can prevent the virus from infecting these cells.

Hope this information helps,

Rose Webster
Canadian freelance writer and activist
Education: nursing, orthotics/prosthetics, ophthalmology (as an assistant)

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