Skip to content

Advertisement

  • Case report
  • Open Access

Zika virus infection in a pregnant Canadian traveler with congenital fetal malformations noted by ultrasonography at 14-weeks gestation

  • 1, 2, 3,
  • 4,
  • 5,
  • 6, 7,
  • 6, 7,
  • 8,
  • 1, 4, 9 and
  • 1, 4, 10Email author
Tropical Diseases, Travel Medicine and Vaccines20184:2

https://doi.org/10.1186/s40794-018-0062-8

Received: 31 August 2017

Accepted: 27 March 2018

Published: 4 April 2018

Abstract

Background

Following emergence of Zika virus in the Americas, a devastating new congenital syndrome has been documented, leading to significant morbidity among Zika-infected fetuses and neonates.

Case presentation

A 29-year-old pregnant woman infected with Zika virus at 9-weeks gestation in Trinidad presented with one-month of fever, headache, and myalgia with persistent viremia. Significant fetal abnormalities were identified at 14-week ultrasound, which is the earliest ultrasound to describe a severely affected fetus following Zika virus infection to our knowledge.

Conclusions

We discuss the implications of prolonged maternal viremia and the spectrum of congenital Zika syndrome detectable by fetal ultrasound.

Keywords

  • Arbovirus
  • Congenital infections
  • Fetal sonography
  • Pregnancy and travel
  • Zika virus

Background

Following reports of associations between congenital microcephaly and Zika virus (ZIKV) infection in pregnancy, the World Health Organization (WHO) declared ZIKV a Public Health Emergency of International Concern. ZIKV was first described over 70 years ago with limited spread outside Africa and no description of congenital abnormalities. There had been no newly discovered congenital infectious disease since cytomegalovirus and rubella in the mid-twentieth century [1, 2].

ZIKV is primarily transmitted through the bite of the day biting Aedes species of mosquito. Symptoms most commonly associated with ZIKV infection include diffuse or focal rash, conjunctivitis, fever, myalgia, and arthralgia [3]. Approximately 80% of ZIKV infections are asymptomatic [4].

Identification of this emerging arboviral congenital infection has led to justifiable concern among patients, physicians, and public health officials. In the absence of a licensed vaccine and specific treatment, the focus has been on prevention and calls for enhanced understanding of the epidemic. We report a case of a pregnant woman infected with ZIKV during the first trimester with prolonged viremia and significant fetal neurological compromise identified at 14-weeks gestation.

Case presentation

A 29-year-old pregnant woman from Canada, gravida 4 para 3, developed a low-grade fever and a generalized rash at 9-weeks gestation while visiting friends and relatives in Trinidad. Symptom onset occurred 6-weeks after arriving in Trinidad and all symptoms lasted for 4 days, followed by approximately one month of fever, myalgia, and retro-orbital headaches. Seven days after symptom onset she sought medical care in Trinidad with her 4-year-old child who was experiencing similar symptoms. Her blood tested negative in Trinidad by real-time reverse transcription polymerase chain reaction (PCR) for dengue and chikungunya viruses, but was positive for ZIKV. An ultrasonographic examination was not performed locally in Trinidad. One month after symptom onset she returned to Canada for further evaluation.

The patient was evaluated in our centre at 13 weeks 6 days gestation, which corresponded to one month post-symptom onset. Past medical history was significant for mild cerebral palsy and scoliosis. Her only medication was a prenatal multivitamin. She denied substance use during pregnancy. On examination, temperature was 38.1 °C. Heart rate and blood pressure were normal. There was no conjunctivitis, lymphadenopathy, or organomegaly. Cardiorespiratory exam was normal. The previously mentioned diffuse rash had resolved.

Blood was drawn, and at 30 days post-symptom onset, ZIKV PCR, performed by Public Health Ontario Laboratory (PHOL), was positive at a cycle threshold (CT) of 31.85 using a commercial assay [RealStar® Zika Virus RT-PCR Kit (Altona Diagnostics, Hamburg, Germany). Urine ZIKV PCR was negative by the same assay. Dengue IgM and IgG were reactive, and chikungunya IgM and IgG were non-reactive. ZIKV IgM ELISA and plaque reduction neutralization test (PRNT) serology was performed at Canada’s National Microbiology Laboratory (NML) as previously described [5]. The ZIKV IgM ELISA was positive, however, the PRNT was inconclusive. Similar neutralization titres were demonstrated for both ZIKV and dengue virus (ZIKV titer 320, dengue virus titer 160) and were consistent with a previous exposure to a non-ZIKV flavivirus.

Fetal ultrasound performed at 14-weeks gestation revealed a single live intrauterine pregnancy with bilateral fluid collections in the fetal neck likely representing dilated jugular lymph sacs. The larger collection was 6-mm in size. Abnormal fetal intracranial anatomy was identified. There was asymmetry in the appearance of the lateral cerebral ventricles (Figure 1), the right ventricle appeared dilated especially in the frontal horn, and the left ventricle appeared small. The left choroid plexus was prominent in the frontal horn region and the third ventricle appeared slightly dilated. Head circumference was 14.5 weeks by size. No intracranial calcifications were seen.
Figure 1
Fig. 1

Asymmetrical cerebral ventricles. Dilated right ventricle with prominent, irregular choroid plexus

Therapeutic termination of the pregnancy was performed by dilation and curettage at 15-weeks gestation. Initial molecular testing of fetal tissue was performed at PHOL. ZIKV RNA was detected in the umbilical cord (CT 31.70), placenta (CT 24.89), liver (CT 24.62), and fetal neural tissue (CT 17.42) using the RealStar® Zika Virus RT-PCR Kit. In addition, ZIKV sequence was confirmed in all fetal samples by RT-PCR and Sanger amplicon sequencing targeting 192 nucleotides of the ZIKV NS5 gene, based on a previously published protocol [6]. All fetal tissue specimens were forwarded to NML and retested using the CDC-designed real-time RT-PCR assay based on the ZIKV strain responsible for the 2007 outbreak in Micronesia, targeting the ZIKV envelope (E) and premembrane (prM) genes [5]. ZIKV RNA was again detected in umbilical cord, placenta, and fetal neural tissue specimens. Transmission electron microscopy was performed at PHOL on placenta, umbilical cord, and neural tissue specimens, however no viral particles were visualized. Fetal tissue karyotyping for aneuploidy was performed as per standard practice, and the result was a normal male chromosomal microarray pattern.

Discussion

Uncertainties remain surrounding the risk of congenital Zika syndrome following maternal infection as well as the spectrum of disease. A recent report found that the proportion of birth defects among 442 pregnancies with laboratory evidence of ZIKV infection [7] was 20-times higher compared to the prevalence from three population-based birth defect surveillance programs during the 2013–2014 pre-Zika years [8]. Brain abnormalities or microcephaly were the most frequently recorded anomalies [8], but a number of case reports and case series have since emerged describing the spectrum of fetal effects of maternal Zika virus infection [9, 10]. We present a case of first trimester maternal infection with significant fetal neurological malformations identified by a 14-week ultrasound following congenital infection at 9-weeks gestation. To our knowledge this is the earliest ultrasound to describe a severely affected fetus following Zika virus infection.

Previous reports have described microcephaly, intracranial calcifications, and other abnormalities in the 2nd and 3rd trimesters (Table 1) [1118]. The greatest risk for microcephaly has been reported to occur with ZIKV infection during the first trimester of pregnancy (Table 1), with estimated risks of possible Zika-associated birth defects in the first, second, and third trimesters of 8%, 5%, and 4%, respectively [19]. However, severely affected fetuses have been described after normal 2nd trimester ultrasounds, with subsequent abnormalities detected in the 3rd trimester (Table 1). Interestingly, there have also been reports of no differences in head circumference among infants born to women with possible ZIKV infection during pregnancy compared to women without infection [20]. The case presented herein describing severe neurological malformation in the early 2nd trimester contributes to our understanding of the spectrum of fetal abnormalities from maternal ZIKV infection.
Table 1

Summary of previously reported Zika congenital syndrome fetal ultrasound abnormalities

Gestation at First Abnormal Ultrasound (weeks)

Study Author, Year

Country of Infection

Gestation at Infection

Ultrasound Findings

Outcome

18

Sarno et al., 2016 [11]

Brazil

NR

Microcephaly, hydranencephaly, intracranial calcifications, destructive lesions of posterior fossa. Hydrothorax, ascites, subcutaneous edema

Fetal demise at 32 weeks

19

Driggers et al., 2016 [12]

Unknown (Guatemala, Mexico or Belize)

11 weeks

Possible intraventricular haemorrhage, corpus callosum agenesis

TA at 21 weeks

19

Pomar et al., 2017 [13]

French Guiana

First trimester

Severe microcephaly, cerebral hypoplasia

Delivery at 32 weeks

19.3

Cortes et al., 2018 [14]

Colombia

NR

Enlarged subarachnoid space, decreased brain volume, ventriculomegaly, malformations in cortical development, simplified gyral pattern, hypoplasic corpus callosum

Unknown

20

Pomar et al., 2017 [13]

French Guiana

First trimester

Cystic dilation of the cisterna magna, cortical hyperechogenicity, vermian hypoplasia, pericallosal echogenicity

Delivery at 38 weeks

21

Besnard et al., 2016 [15]

French Polynesia

First trimester

Microcephaly, parenchymal calcifications, ventriculomegaly, absent corpus callosum, absent cavum septi pellucidi

TA at unknown weeks

22

Pomar et al., 2017 [13]

French Guiana

First trimester

Periventricular hyperechogenicity, irregular ventricular walls, parenchymal and periventricular calcifications

Delivery at 41 weeks

22

Carvalho et al., 2016 [16]

Brazil

9 weeks

Microcephaly, parenchymal and ocular calcifications, Dandy Walker malformation, arthrogryposis

Fetal demise, CS at 37 weeks

22

Besnard et al., 2016 [15]

French Polynesia

First trimester

Microcephaly, parenchymal calcifications, ventriculomegaly, absent corpus callosum, absent of cavum septi pellucidi, enlarged pericerebral space

TA at unknown weeks

24

Carvalho et al., 2016 [16]

Brazil

5 weeks

Dandy Walker malformation, fetal growth restriction, arthrogryposis.

Fetal demise, CS 38.3 weeks

25.3

Cortes et al., 2018 [14]

Colombia

NR

Enlarged subarachnoid space, decreased brain volume, ventriculomegaly, malformations in cortical development, simplified gyral pattern, hypoplasic corpus callosum

NR

26.5

Cortes et al., 2018 [14]

Colombia

NR

Dandy Walker cerebella malformation

NR

27

Carvalho et al., 2016 [16]

Brazil

11 weeks

Microcephaly, ventriculomegaly bilaterally, parenchymal calcifications, increased subarachnoid space

CS delivery of live infant at 38 weeks

27

Cortes et al., 2018 [14]

Colombia

NR

Decreased brain volume, ventriculomegaly, simplified gyral pattern, hypoplastic corpus callosum

NR

28

Pomar et al., 2017 [13]

French Guiana

Second trimester

Severe ventriculomegaly with irregular ventricular walls, thin hypoplastic corpus callosum

TA at 29 weeks

28

Carvalho et al., 2016 [16]

Brazil

8 weeks

Microcephaly, ventriculomegaly, parenchymal calcification, and oligohydraminios

SVD of live infant at 39 weeks

28

Carvalho et al., 2016 [16]

Brazil

8 weeks

Microcephaly, ventriculomegaly, parenchymal calcifications, cortical atrophy and cerebellar hypoplasia.

SVD of live infant at 39 weeks

28

Carvalho et al., 2016 [16]

Brazil

10 weeks

Microcephaly, left ventriculomegaly, increase cisterna magna.

CS delivery of live infant at 40 weeks

28.2

Cortes et al., 2018 [14]

Colombia

NR

Enlarged subarachnoid space, decreased brain volume, ventriculomegaly, malformations in cortical development, simplified gyral pattern, hypoplasic corpus callosum

NR

29

Pomar et al., 2017 [13]

French Guiana

Second trimester

Lentostriatal vasculopathy

Delivery at 39 weeks

29

Carvalho et al., 2016 [16]

Brazil

16 weeks

Microcephaly, periventricular calcifications, megacisterna magna, cerebellar vermis hypoplasia. Thymic and liver calcifications, fetal growth restriction

Stillbirth, labour induced

29

Mlakar et al., 2016 [17]

Brazil

13 weeks

Microcephaly, parenchymal calcifications. Fetal growth restriction, placental calcifications.

TA at 32 weeks

29.2

Besnard et al., 2016 [15]

French Polynesia

NR

Microcephaly, parenchymal calcifications, placental microcalcifications, ventriculomegaly, occipital pseudo-cyst, absent corpus callosum, absent cavum septi pellucidi, enlarged pericerebral space

TA at unknown weeks

29.2

Oliveira Melo et al., 2016 [18]

Brazil

NR

Ventriculomegaly, corpus callosum not visualized, thalami not developed, thin pons and brainstem, non-homogeneous small mass seen at position of basal ganglia, lateral ventricles and fourth ventricle calcifications. Cataracts bilaterally, intraocular calcifications and one eye smaller in size than the other

Unknown

29.3

Besnard et al., 2016 [15]

French Polynesia

First trimester

Microcephaly, ventriculomegaly, occipital pseudo-cyst, enlarged pericerebral space

TA at unknown weeks

30.1

Oliveira Melo et al., 2016 [18]

Brazil

NR

Brain atrophy, calcifications in frontal lobes including caudate, lentostriatal vessels and cerebellum. Corpus callosal and vermian dysgenesis, enlarged cisterna magna.

Unknown

31

Carvalho et al., 2016 [16]

Brazil

8 weeks

Microcephaly, parenchymal and cerebellar calcifications.

SVD of live infant at 40 weeks

31

Carvalho et al., 2016 [16]

Brazil

9 weeks

Microcephaly, parenchymal and cerebellar calcifications, brain atrophy, cerebellar hypoplasia. Right clubfoot, nuchal skin wrinkling, increase cisterna magna, fetal growth restriction.

CS delivery of live infant at 39 weeks

31

Carvalho et al., 2016 [16]

Brazil

NR

Polyhydramnios, parenchymal and cerebellar calcifications. Hepatomegaly, hyperflexion of fingers, and hyperechogenicity of aortic valve, mitral valve and aortic root.

SVD of live infant at 38 weeks

31

Carvalho et al., 2016 [13]

Brazil

NR

Microcephaly, ventriculomegaly, parenchymal calcifications

CS delivery of live infant at 39 weeks

33

Cortes et al., 2018 [14]

Colombia

NR

Enlarged subarachnoid space, decreased brain volume, ventriculomegaly, dysgenetic corpus callosum

NR

34.2

Cortes et al., 2018 [14]

Colombia

NR

Enlarged subarachnoid space, decreased brain volume, ventriculomegaly, malformations in cortical development, simplified gyral pattern, dysgenetic corpus callosum

NR

35

Carvalho et al., 2016 [16]

Brazil

NR

Microcephaly, parenchymal and cerebellar calcifications, ventriculomegaly

CS delivery of live infant at 39 weeks

36

Carvalho et al., 2016 [16]

Brazil

NR

Microcephaly. Right clubfoot, fetal growth restriction

Fetal demise, CS at 38 weeks

36

Carvalho et al., 2016 [16]

Brazil

11 weeks

Microcephaly

CS delivery of live infant at 40 weeks

37

Pomar et al., 2017 [13]

French Guiana

Second trimester

Microcephaly, callosal hypoplasia, gyration anomalies

Delivery at 39 weeks

37

Carvalho et al., 2016 [16]

Brazil

8 weeks

Microcephaly, parenchymal and cerebellar calcifications, left ventriculomegaly

SVD of live infant at 39 weeks

38

Carvalho et al., 2016 [16]

Brazil

10 weeks

Microcephaly, periventricular and parenchymal calcifications, ventriculomegaly. Fetal growth restriction.

CS delivery of live infant at 39 weeks

38

Carvalho et al., 2016 [16]

Brazil

16 weeks

Microcephaly, parenchymal and periventricular calcifications, left ventriculomegaly. Fetal growth restriction, oligohydramnios

CS delivery of live infant at 39 weeks

38

Carvalho et al., 2016 [16]

Brazil

NR

Microcephaly, parenchymal and cerebellar calcifications, ventriculomegaly

SVD of live infant at 39 weeks

39

Carvalho et al., 2016 [16]

Brazil

NR

Microcephaly, parenchymal calcifications.

SVD of live infant at 39 weeks

NR

Pomar et al., 2017 [13]

French Guiana

First trimester

Microcephaly, cerebellar hypoplasia, ventriculomegaly with irregular ventricular walls, periventricular hyperechogenicity, callosal hypoplasia with calcifications, parenchymal califications

NR

NR

Pomar et al., 2017 [13]

French Guiana

Second trimester

Parenchymal hyperechogenicity

Fetal demise at 40 weeks

NR

Pomar et al., 2017 [13]

French Guiana

First trimester

Microcephaly

Fetal demise at 19 weeks

NR not reported, SVD spontaneous vaginal delivery, CS caesarean section, TA therapeutic abortion

We identified persistent viremia at 30-days post symptom onset in the context of prolonged symptomatology and documented fever. For most patients viremia is present for 3–5 days after symptom onset [3]. However, case reports have emerged demonstrating prolonged viremia in pregnant women [21]. One prospective cohort study found that clearance of ZIKV in serum, urine, and semen was seen in 95% of patients by 54 days, 39 days, and 81 days, respectively [22]. Furthermore urine testing in our patient was negative, conflicting with previous reports suggesting urine PCR is positive for longer than serum [23]. Detecting prolonged viremia may prove to be a valuable prognostic indicator for pregnant women. It is likely that viral detection in maternal serum represents high levels of fetal viral replication. Pregnant women may have greater difficulty clearing the virus, which may then lead to fetal infection. Further study investigating this finding is warranted.

The timing of fetal abnormalities ranges from identification at 14-weeks (this report) to post-natal diagnosis. Table 1 summarizes the spectrum of fetal ultrasound abnormalities detected. The spectrum of severity ranges from mild ocular or auditory abnormalities, to microcephaly, to severe brain or musculoskeletal malformations [24]. Additional information on congenital Zika syndrome is needed to better understand the spectrum of illness, however, 5 features have been recognized that are rarely seen with other congenital infections. These include severe microcephaly with a partially collapsed skull, thin cerebral cortices with subcortical calcifications, macular scarring with focal pigmentary retinal mottling, congenital contractures, and early hypertonia with extrapyramidal involvement [25].

Zika virus is currently endemic to most of South and Central America, the Caribbean, and recently areas of southern Florida and Texas in the United States. International guidelines have advised that pregnant women should avoid travel to areas with ongoing transmission of ZIKV [3]. Women unable to avoid travel are advised to use strict personal protective measures including light-coloured long-sleeved clothing, insect repellent containing 20–30% DEET or 20% icaridin, stay in accommodations with screens or air-conditioning, and permethrin treated clothes and bed nets if outdoors [3]. Sexual transmission of ZIKV has also been described, but based on our current understanding of ZIKV epidemiology, likely represents a minor contributor to disease spread. To reduce the possibility of sexual transmission, we recommend that men and women avoid unprotected sexual activity with a male partner who has returned from an endemic area within six months, pending further understanding of the duration of transmission. Recent reports have demonstrated detectable virus in semen up to 6 months from symptom onset [26]. Women are further advised to defer conception for 2 months following travel to an area of ongoing ZIKV transmission, and for 6 months if their male partner accompanied them on travel [3].

Our current approach to diagnosis of pregnant patients exposed to ZIKV is outlined in recent guidelines published by the CDC [27]. Up-to-date testing algorithms can be accessed here: https://www.cdc.gov/zika/hc-providers/testing-for-zikavirus.html. Testing all exposed pregnant women by PCR within two weeks of symptom onset or exposure is recommended. Those negative for ZIKV by PCR should be tested for ZIKV IgM and if positive, confirmed by PRNT. Pregnant women 2–12 weeks from exposure, or symptom onset, should be tested for ZIKV IgM and if positive or equivocal should be tested for ZIKV RT-PCR. As illustrated by our case, however, viremia in women carrying congenitally infected fetuses may be prolonged, and in pregnant women who continue to be symptomatic beyond 2 weeks, ZIKV PCR may be considered.

Recommendations surrounding the management of pregnant women exposed to Zika virus will continue to evolve along with our understanding of the epidemiology and pathogenesis of disease. Expert bodies continue to recommend screening all pregnant women with travel to areas with ongoing transmission of ZIKV. Positive tests should prompt further evaluation with serial ultrasound assessments and possible amniocentesis for ZIKV RT-PCR to facilitate counselling of patients.

Our report has some limitations. We identified higher levels of ZIKV in fetal neurological tissue compared to others, however, due to the dilation and curettage procedure performed, we cannot exclude potential cross-contamination of tissues.

Conclusions

Congenital ZIKV syndrome is a newly recognized complication of this arboviral infection which has spread throughout the Americas. This case report demonstrates that pregnant women can have prolonged viremia and early ultrasounds may detect significant fetal abnormalities. Human vaccine trials are currently underway, however personal protective measures to avoid mosquito bites and deferral of travel to risk areas are currently the cornerstone of prevention, and should be advocated by front line health care providers to all pregnant patients considering travel to ZIKV endemic areas.

Declarations

Acknowledgments

We would like to thank the Viral Zoonosis section at the National Microbiology Laboratory for their efforts performing the microbiologic testing as well as Dr. Katherine W. Fong, MBBS, FRCPC, University of Toront​o, for providing the ultrasound images.

Funding

Not applicable.

Availability of data and materials

All data are presented herein.

Authors’ contributions

KLS and AKB conceived the report. All authors (KLS, NR, KEM, WW, TC, MAD, JG, AKB) contributed equally to literature review, and interpretation of relevant clinical results. KLS, TC, NR, KEM, and AKB drafted the manuscript. All authors provided critical edits and approved the manuscript in its final form.

Ethics approval and consent to participate

Ethics approval for this case report was not sought as there was no human subjects study in which to participate. Patient written consent was obtained for use of her personal and clinical information in this manuscript.

Consent for publication

Patient written consent was obtained for use of her personal and clinical information in this manuscript.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Public Health Ontario, Toronto, Canada
(2)
St. Joseph’s Health Sciences Centre, Toronto, Canada
(3)
Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
(4)
Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Canada
(5)
Department of Family and Community Medicine, University of Toronto, Toronto, Canada
(6)
Department of Obstetrics and Gynecology, University of Toronto, Toronto, Canada
(7)
Sinai Health System, Toronto, Canada
(8)
National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
(9)
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
(10)
Tropical Disease Unit, Toronto General Hospital, Toronto, Canada

References

  1. Riley HD Jr. History of the cytomegalovirus. Southern Med J. 1997;90(2):84–90.View ArticleGoogle Scholar
  2. Goar EL, Potts CR. The relationship of rubella in the mother to congenital cataracts in the child. Trans Am Ophthalmol Soc. 1945;43:135–49.PubMedPubMed CentralGoogle Scholar
  3. Zika Working Group on behalf of the Committee to Advise on Tropical Medicine and Travel (CATMAT). Canadian recommendations on the prevention and treatment of Zika virus: update. Can Comm Dis Rep. 2016;42:101–11.View ArticleGoogle Scholar
  4. Duffy MR, Chen TH, Hancock WT, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. N Engl J Med. 2009;360(24):2536–43.View ArticlePubMedGoogle Scholar
  5. Lanciotti RS, Kosoy OL, Laven JJ, et al. Genetic and serologic properties of Zika virus associated with an epidemic, yap state, Micronesia, 2007. Emerg Infect Dis. 2008;14(8):1232–9.View ArticlePubMedPubMed CentralGoogle Scholar
  6. Balm MN, Lee CK, Lee HK, Chiu L, Koay ES, Tang JWA. Diagnostic polymerase chain reaction assay for Zika virus. J Med Virol. 2012;84(9):1501–5.View ArticlePubMedGoogle Scholar
  7. Honein MA, Dawson AL, Petersen EE, et al. Birth defects among fetuses and infants of US women with evidence of possible Zika virus infection during pregnancy. JAMA. 2017;317:59–68.View ArticlePubMedGoogle Scholar
  8. Cragan JD, Mai CT, Petersen EE, et al. Baseline prevalence of birth defects associated with congenital Zika virus infection – Massachusetts, North Carolina, and Atlanta, Georgia, 2013 – 2014. Morb Mortal Wkly Rep. 2017;66(8):219–22.View ArticleGoogle Scholar
  9. Rasmussen SA, Jamieson DJ, Honein MA, Petersen LR. Zika virus and birth defects--reviewing the evidence for causality. N Engl J Med. 2016;374(20):1981–7.View ArticlePubMedGoogle Scholar
  10. Franca GV, Schuler-Faccini L, Oliveira WK, et al. Congenital Zika virus syndrome in Brazil: a case series of the first 1501 livebirths with complete investigation. Lancet. 2016;388(10047):891–7.View ArticlePubMedGoogle Scholar
  11. Sarno M, Sacramento GA, Khouri R, et al. Zika virus infection and stillbirths: a case of Hydrops Fetalis, Hydranencephaly and fetal demise. PLoS Negl Trop Dis. 2016;10(2):e0004517.View ArticlePubMedPubMed CentralGoogle Scholar
  12. Driggers RW, Ho CY, Korhonen EM, et al. Zika virus infection with prolonged maternal Viremia and fetal brain abnormalities. N Engl J Med. 2016;374(22):2142–51.View ArticlePubMedGoogle Scholar
  13. Pomar L, Malinger G, Benoist G, et al. Association between Zika virus and foetopathy: a prospective cohort study in French Guiana. Preliminary report. Ultrasound Obstet Gynecol. 2017;49(6):729–36.View ArticlePubMedGoogle Scholar
  14. Besnard M, Eyrolle-Guignot D, Guillemette-Artur P, et al. Congenital cerebral malformations and dysfunction in fetuses and newborns following the 2013 to 2014 Zika virus epidemic in French Polynesia. Euro Surveill. 2016;21(13) https://doi.org/10.2807/1560-7917.ES.2016.21.13.30181.
  15. Carvalho FH, Cordeiro KM, Peixoto AB, et al. Associated ultrasonographic findings in fetuses with microcephaly because of suspected Zika virus (ZIKV) infection during pregnancy. Prenatal Diagn. 2016;36(9):882–7.View ArticleGoogle Scholar
  16. Mlakar J, Korva M, Tul N, et al. Zika virus associated with Microcephaly. N Engl J Med. 2016;374(10):951–8.View ArticlePubMedGoogle Scholar
  17. Oliveira Melo AS, Malinger G, Ximenes R, Szejnfeld PO, Alves Sampaio S, Bispo de Filippis AM. Zika virus intrauterine infection causes fetal brain abnormality and microcephaly: tip of the iceberg? Ultrasound Obstet Gynecol. 2016;47(1):6–7.View ArticlePubMedGoogle Scholar
  18. Cortes MS, Rivera AM, Yepez M, et al. Clinical assessment and brain findings in a cohort of mothers, fetuses and infants infected with Zika virus. Am J Obstet Gynecol. 2018; https://doi.org/10.1016/j.ajog.2018.01.012.
  19. Shapiro-Mendoza CK, Rice ME, Galang RR, et al. Pregnancy outcomes of after maternal Zika virus infection during pregnancy – U.S. territories, January 1, 2016-April 25, 2017. Morb Mortal Wkly Rep. 2017;66(23):615–21.View ArticleGoogle Scholar
  20. Adhikari EH, Nelson DB, Johnson KA, et al. Infant outcomes among women with Zika virus infection during pregnancy: results of a large prenatal Zika screening program. Am J Obstet Gynecol. 2017;216(3):292. e1-292.e8View ArticlePubMedGoogle Scholar
  21. Suy A, Sulleiro E, Rodo C, et al. Prolonged Zika virus Viremia during pregnancy. N Engl J Med. 2016;375(26):2611–3.View ArticlePubMedGoogle Scholar
  22. Paz-Bailey G, Rosenberg ES, Doyle K, et al. Persistent of Zika virus in bodily fluids – preliminary report. N Engl J Med. 2017; https://doi.org/10.1056/NEJMoa1613108.
  23. Bingham AM, Cone M, Mock V, et al. Comparison of test results for Zika virus RA in urine, serum, and saliva specimens from persons with travel-associated Zika virus disease - Florida, 2016. MMWR Morbid Mortal Wkly Rep. 2016;65(18):475–8.View ArticleGoogle Scholar
  24. Russell K. Update: interim guidance for the evaluation and management of infants with possible congenital Zika virus infection—United States, 2016. MMWR Morbid Mortal Wkly Rep. 2016;65:870–8.Google Scholar
  25. Moore CA, Staples JE, Dobyns WB, et al. Characterizing the pattern of anomalies in congenital Zika syndrome for pediatric clinicians. JAMA Pediatr. 2016;171(3):288–95.View ArticleGoogle Scholar
  26. Barzon L, Pacenti M, Franchin E, et al. Infection dynamics in a traveller with persistent shedding of Zika virus RNA in semen for six months after returning from Haiti to Italy, January 2016. Euro Surveill. 2016;21(32). https://doi.org/10.2807/1560-7917.ES.2016.21.32.30316.
  27. Oduyebo T, Igbinosa I, Petersen EE, et al. Update: interim guidance for health care providers caring for pregnant women with possible Zika virus exposure - United States, July 2016. MMWR Morbid Mortal Wkly Rep. 2016;65(29):739–44.View ArticleGoogle Scholar

Copyright

© The Author(s). 2018

Advertisement