Transfusion medicine
Transfusion transmitted disease
Zika virus
Author: Kyle Annen, D.O.
Editor-in-Chief: Debra L. Zynger, M.D.
Last author update: 23 July 2019
Last staff update: 12 August 2021
Copyright: 2019-2025, PathologyOutlines.com, Inc.
PubMed Search: Zika virus[TI] pathology[TIAB] full text[sb]
Table of Contents
Definition / general | Essential features | Transmission | Symptoms | Screening | Blood donor screening | Blood donor testing | Donor deferral | Case reports | Additional references | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Annen K. Zika virus. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/transfusionmedzika.html. Accessed April 1st, 2025.
Definition / general
- Zika virus (ZIKV) is a mosquito borne virus that is transmissible via blood transfusion (U.S. Food and Drug Administration: Information for Blood Establishments Regarding FDA’s Determination that Zika Virus is no Longer a Relevant Transfusion-Transmitted Infection [Accessed 12 August 2021])
- Although most patients are asymptomatic, the disease causes severe fetal malformations (microcephaly)
- Testing and deferral periods are required by the Food and Drug Administration
Essential features
- Zika virus is a mosquito borne infectious disease
- It is also transmissible by transfusion, blood exposure and sexual intercourse
- Most infected are asymptomatic; symptoms are a flu-like illness with conjunctivitis and maculopapular rash
- Associated with severe birth defects such as microcephaly
- Donors are tested via nucleic acid testing and if positive, are deferred for 120 days
Transmission
- Primarily mosquito borne (Aedes aegypti > Aedes albopictus) (Centers for Disease Control and Prevention: Zika Virus: Prevention and Transmission [Accessed 1 July 2019])
- Other routes: perinatal, intrauterine, sexual, breast milk, laboratory acquired, transfusion transmission
- Not transmitted through saliva or urine
- First mosquito borne transmission in the United States: Puerto Rico, December 2015
- Also reported in Florida and Texas in 2016
Symptoms
- Most infected (80%) are asymptomatic or have mild symptoms lasting up to 1 week (Bull World Health Organ 2018;96:402)
- Most common symptoms are fever, conjunctivitis, maculopapular rash, arthralgia, myalgia, headache
- Usually self limiting
- Neurologic manifestations, including Guillain-Barré syndrome, have been reported
- Association of Zika infection during pregnancy and fetal malformations, microcephaly
Screening
- ZIKV can be detected in serum or plasma for 1 - 2 weeks after infection (N Engl J Med 2017;379:1234)
- Median value for ZIKV RNA persistence:
- Serum / plasma: 11 - 17 days
- Semen: 28 - 41 days
- Urine: 6 - 10 days
- Whole blood and red blood cells: up to 3 months
Blood donor screening
- If a donor volunteers a recent infection with Zika, blood or blood components must not be collected and the donor is deferred for 120 days (U.S. Food and Drug Administration: Information for Blood Establishments Regarding FDA’s Determination that Zika Virus is no Longer a Relevant Transfusion-Transmitted Infection [Accessed 12 August 2021])
- Blood donor screening questions have not been determined to be an effective method of preventing infected asymptomatic individuals from donating
Blood donor testing
- Only approved method is the individual donor nucleic acid test for Zika virus (Roche Molecular Systems)
- Minipool nucleic acid testing (N Engl J Med 2018;378:1778)
- A positive minipool nucleic acid test must be resolved using individual donor nucleic acid testing or pathogen reduction of blood components (only plasma and platelets are Food and Drug Administration approved at this time)
- Individual donor nucleic acid testing is required for defined geographic collection areas at times of higher risk (i.e. suspected or documented Zika infection) as defined by positive ZIKV testing in a nearby blood center, Centers for Disease Control and Prevention or other surveillance notification
- Converting to individual donor nucleic acid testing is required within 24 hours of notice
Donor deferral
- Donor with confirmed positive ZIKV individual donor nucleic acid test is deferred for 120 days (U.S. Food and Drug Administration: Information for Blood Establishments Regarding FDA’s Determination that Zika Virus is no Longer a Relevant Transfusion-Transmitted Infection [Accessed 12 August 2021])
- Donor must be notified and counseled regarding the medical significance of the results
- All in date blood products (including those of a prior donation) must be retrieved and quarantined
- Physicians who transfused any components from the infected donor collected during a prior donation (120 days prior) should be encouraged to notify the transfusion recipient
- Females of childbearing age should be advised that becoming pregnant is not recommended for 8 weeks from exposure
- Males should be advised that Zika is transmitted in semen; unprotected sex should be avoided for 6 months from infection
Case reports
- 25 year old woman who contracted Zika in first trimester had fetus with intrauterine growth retardation and severe microcephaly (N Engl J Med 2016;374:951)
- 44 year old man with potential sexual transmission of Zika virus (Emerg Infect Dis 2015;21:359)
- Probable transfusion transmitted Zika virus in Brazil (Hematol Transfus Cell Ther 2018;40:250)
Additional references
Board review style question #1
Postinfectious disease screening is positive for a 42 year old male blood donor who donated 2 days ago. The testing is positive for Zika virus by individual donor nucleic acid testing. You call the donor to inform him that he is now deferred. Because the donor is male, it is important to inform him of which of the following?
- Zika virus can be sexually transmitted for 6 months in semen
- Zika virus can be transmitted through urine, so he should not use a public restroom for 10 days
- Zika virus is latent and he will never clear the infection
- Zika virus is not contagious outside of blood transfusion and mosquito bites
Board review style answer #1
A. Zika virus is sexually transmitted and can cause fetal malformations in pregnancy. It is detectable in semen for 6 months.
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Board review style question #2
You receive a letter from your blood provider, stating that a donor who last donated 8 weeks ago returned and the donor is now positive for Zika virus by individual donor nucleic acid testing. The donor was negative at the time of the transfusion. The blood donor is asymptomatic. A review of records reveals this unit was transfused to a 22 year old female postdelivery of a full term male infant. When you call the recipient to inform her of the exposure, she asks you what main risk of the disease is. You tell her
- She is at an increased risk of developing Guillain-Barré disease
- She may have a flu-like illness with fever, conjunctivitis, rash and headache
- There is no risk to her since the donor was negative for Zika at the time of donation
- This virus causes birth defects, so she should avoid pregnancy for at least 8 weeks
- This virus is transmissible through breast milk, so she should talk to her pediatrician
Board review style answer #2
E. This virus is transmissible through breast milk, so she should talk to her pediatrician. The mother already delivered at the time of transfusion, so it should not have been transmitted to her infant perinatally. It is transmissible through breast milk, though in general, the benefits of breastfeeding are thought to outweigh the risk of Zika transmission in an otherwise healthy infant. She should discuss this with her pediatrician.
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