NEJM Case Report On MMWR Patient B Zika Termination

[niman]

Zika Virus Infection with Prolonged Maternal Viremia and Fetal Brain Abnormalities

Rita W. Driggers, M.D., Cheng-Ying Ho, M.D., Ph.D., Essi M. Korhonen, M.Sc., Suvi Kuivanen, M.Sc., Anne J. Jääskeläinen, Ph.D., Teemu Smura, Ph.D., Avi Rosenberg, M.D., Ph.D., D. Ashley Hill, M.D., Roberta L. DeBiasi, M.D., Gilbert Vezina, M.D., Julia Timofeev, M.D., Fausto J. Rodriguez, M.D., Lev Levanov, Ph.D., Jennifer Razak, M.G.C., C.G.C, Preetha Iyengar, M.D., Andrew Hennenfent, D.V.M., M.P.H., Richard Kennedy, M.D., Robert Lanciotti, Ph.D., Adre du Plessis, M.B., Ch.B., M.P.H., and Olli Vapalahti, M.D., Ph.D.

March 30, 2016DOI: 10.1056/NEJMoa1601824

 

SOURCE INFORMATION

From the Department of Gynecology and Obstetrics, Division of Maternal Fetal Medicine (R.W.D., J.T.), and the Department of Pathology (F.J.R.), Johns Hopkins University School of Medicine, Baltimore; the Division of Maternal Fetal Medicine, Sibley Memorial Hospital (R.W.D., J.T., J.R.), the Division of Pathology and Center for Genetic Medicine Research (C.-Y.H., A.R., D.A.H.), Division of Pediatric Infectious Diseases (R.L.D.), Department of Diagnostic Radiology and Imaging (G.V.), and the Fetal Medicine Institute, Division of Fetal and Transitional Medicine (A.P.), Children’s National Health System, the Departments of Integrative Systems Biology (C.-Y.H., D.A.H.), Pediatrics and Microbiology, Immunology and Tropical Medicine (R.L.D.B.), and Radiology and Pediatrics (G.V.), George Washington University School of Medicine and Health Sciences, the Center for Policy, Planning and Evaluation (P.I.) and Centers for Disease Control and Prevention (CDC)–Council of State and Territorial Epidemiologists (CSTE) Applied Epidemiology Fellowship (A.H.), District of Columbia Department of Health, and One Medical Group (R.K.) — all in Washington, DC; the Departments of Virology (E.M.K., S.K., T.S., L.L., O.V.) and Veterinary Biosciences (E.M.K., O.V.), University of Helsinki, and the Department of Virology and Immunology, University of Helsinki and Helsinki University Hospital (A.J.J., O.V.), Helsinki; and the Arboviral Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging Zoonotic Infectious Diseases, CDC, Atlanta (R.L.).

Address reprint requests to Dr. Driggers at [email protected], to Dr. du Plessis at [email protected], or to Dr. Vapalahti at [email protected].

http://www.nejm.org/doi/full/10.1056/NEJMoa1601824#t=article

Edited March 30, 2016 by niman

[niman]

The current outbreak of Zika virus (ZIKV) infection has been associated with an apparent increased risk of congenital microcephaly. We describe a case of a pregnant woman and her fetus infected with ZIKV during the 11th gestational week. The fetal head circumference decreased from the 47th percentile to the 24th percentile between 16 and 20 weeks of gestation. ZIKV RNA was identified in maternal serum at 16 and 21 weeks of gestation. At 19 and 20 weeks of gestation, substantial brain abnormalities were detected on ultrasonography and magnetic resonance imaging (MRI) without the presence of microcephaly or intracranial calcifications. On postmortem analysis of the fetal brain, diffuse cerebral cortical thinning, high ZIKV RNA loads, and viral particles were detected, and ZIKV was subsequently isolated.

[niman]

Zika virus (ZIKV), a mosquito-borne flavivirus and member of the Flaviviridae family, was originally isolated from a sentinel primate in Uganda in 1947.1 ZIKV was associated with mild febrile disease and maculopapular rash in tropical Africa and some areas of Southeast Asia. Since 2007, ZIKV has caused several outbreaks outside its former distribution area in islands of the Pacific: in 2007 on Yap island in Micronesia, in 2013 and 2014 in French Polynesia, and in 2015 in South America, where ZIKV had not been identified previously.2-5 There are separate African and Asian lineages of the virus,6 and the latter strains have caused the outbreaks in the Pacific and the Americas.7 As in the transmission of dengue and chikungunya viruses, the main transmission cycle of ZIKV occurs between urban aedes mosquitoes and humans.

One striking feature of the current ZIKV outbreak is the apparent increased risk of intrauterine or perinatal transmission of the virus as well as the marked increase in the number of newborns with microcephaly reported in Brazil.8-17 A recent prospective study showed fetal ultrasonographic abnormalities in 12 of 42 women (29%) with ZIKV infection during pregnancy; 7 of the 42 fetuses (17%) that were studied had microcephaly, cerebral atrophy, or brain calcifications.11 Because of the association between ZIKV infection and microcephaly and other neurologic disorders, the World Health Organization has declared the ZIKV epidemic a public health emergency of international concern.13

Early in this particular outbreak, investigations into the viral pathogenesis, vertical transmission rates, potential viral cofactors, and sensitivity and specificity of diagnostic testing have presented more questions than answers. Nevertheless, the Centers for Disease Control and Prevention (CDC) has issued a travel advisory for pregnant women,15 as well as guidelines for health providers caring for all travelers from affected regions.16,17 The CDC recommends that pregnant women with a history of travel to an area in which ZIKV is endemic should undergo ZIKV serologic testing and fetal ultrasonography to screen for microcephaly or intracranial calcifications.16 For a diagnosis of fetal ZIKV infection, RNA detection in amniotic fluid may be considered in pregnant women with positive results on ZIKV serologic testing.16 Here we present a report of a case of congenital ZIKV infection and subsequent findings in a pregnancy that was terminated at 21 weeks of gestation.

[niman]

CASE REPORT

A 33-year-old Finnish woman who was in the 11th week of gestation was on holiday in Mexico, Guatemala, and Belize with her husband in late November 2015. (Details are provided in Section 1.0 of the Supplementary Appendix, available with the full text of this article at NEJM.org.) During their travels, she and her husband recalled being bitten by mosquitoes, particularly in Guatemala. One day after her arrival at her current residence in Washington, D.C., she became ill with ocular pain, myalgia, and mild fever (maximum, 37.5°C), which lasted for 5 days. On the second day of fever, a rash developed (Figure 1FIGURE 1Timeline of Symptoms and Radiographic and Laboratory Studies., and Fig. S5 in the Supplementary Appendix). Her husband was concomitantly reporting similar symptoms. Serologic analysis that was performed 4 weeks after the onset of illness while she was on a trip to her native Finland was positive for IgG antibodies and negative for IgM antibodies against dengue virus. Subsequent serologic analysis was positive for both IgG and IgM antibodies against ZIKV, findings that were compatible with acute or recent ZIKV infection. Serologic analysis for the presence of chikungunya virus was negative. The patient had been vaccinated against tick-borne encephalitis and yellow fever more than 10 years earlier.

Fetal ultrasonography that was performed at 13, 16, and 17 weeks of gestation (1, 4, and 5 weeks after the resolution of symptoms) showed no evidence of microcephaly or intracranial calcifications. However, there was a decrease in the fetal head circumference from the 47th percentile at 16 weeks to the 24th percentile at 20 weeks.

At 16 weeks of gestation, the presence of flavivirus in serum was detected on nested reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assay, and sequencing showed identity to Central American epidemic strains of ZIKV. The finding was confirmed with a specific ZIKV quantitative RT-PCR assay (Table S2 in the Supplementary Appendix). The Division of Vector-Borne Diseases Arbovirus Diagnostic Laboratory at the CDC reported serologic evidence of infection at 17 weeks of gestation, with serum positivity for ZIKV IgM and a titer of more than 1:2560 on a plaque-reduction neutralization test. On the basis of these results, the patient sought more thorough assessment of the fetus.

Fetal ultrasonography at 19 weeks of gestation showed abnormal intracranial anatomy (Figure 2FIGURE 2Fetal Ultrasonography at 19 Weeks of Gestation., and Fig. S1 in the Supplementary Appendix). The cerebral mantle appeared to be thin with increased extra-axial spaces. Both frontal horns were enlarged with heterogeneous, predominantly echogenic material present in the frontal horn and body of the left lateral ventricle, a finding that raised concern about intraventricular hemorrhage. Dilation and upward displacement of the third ventricle, dilation of the frontal horns of the lateral ventricles, concave medial borders of the lateral ventricles, and the absence of the cavum septum pellucidum suggested agenesis of the corpus callosum. No parenchymal calcifications were seen. The head circumference measured in the 24th percentile for gestational age. The remainder of the fetal anatomy was normal.

Fetal MRI at 20 weeks of gestation showed diffuse atrophy of the cerebral mantle, which was most severe in the frontal and parietal lobes, with the anterior temporal lobes least affected (Figure 3FIGURE 3Magnetic Resonance Imaging of the Fetal Brain at 19 Weeks of Gestation.). The normal lamination pattern of the cerebral mantle was absent, and the subplate zone was largely undetectable. The corpus callosum was significantly shorter than expected for gestational age, with an anterior–posterior length of 14 mm (expected range, 18 to 22).18,19 The cavum septum pellucidum was very small. The lateral ventricles were mildly enlarged, as was the third ventricle, with a transverse diameter measuring 2.5 mm (average measurement at gestational age, 1.75 mm [range, 1.1 to 2.3]).18 The fourth ventricle was normal. The volume of the choroid plexus was unusually prominent, without evidence of hemorrhage. No focal destructive lesions were identified within the cerebral cortex or white matter. The cerebellum was normal in appearance and size. Given the grave prognosis, the patient elected to terminate the pregnancy at 21 weeks of gestation.

[niman]

METHODS

We tested samples obtained from the patient, her spouse, and the fetus and from viral isolation trials for ZIKV RNA using nested pan-flavivirus RT-PCR and quantitative RT-PCR for ZIKV. Levels of ZIKV IgM, IgG, and neutralizing-antibody titers were determined by means of standard methods. We performed immunohistochemical and electron microscopic analyses to study fetal brain tissue. Viral isolation trials using the patient’s serum and fetal tissues were performed with the use of SK-N-SH human neuroblastoma cells, Vero E6 green monkey kidney cells, and C6/36 Aedes albopictus mosquito cells. We used next-generation sequencing and Bayesian analysis to study the genetics of the ZIKV strain isolate. Additional details about the analyses are provided in the Methods section of the Supplementary Appendix.

[niman]

RESULTS

Fetal Neurologic Abnormalities

A postmortem examination was performed with materials collected for additional study. Gross examination showed normal fetal anatomy and severe autolysis. The brain weighed 30 g (reference weight, 49±1520) and showed no apparent gross abnormalities. Microscopic analysis revealed abundant apoptosis primarily affecting the intermediately differentiated postmigratory neurons in the neocortex (Figure 4FIGURE 4Neuropathological Features of Fetal ZIKV Infection., and Fig. S2 in the Supplementary Appendix). Early mineralization was seen in association with apoptotic neurons focally. In contrast, the well-differentiated neurons of the basal ganglia and limbic regions as well as primitive cells in the germinal matrix appeared to be unaffected.

In addition to the cortical neuronal abnormalities, the subventricular zone and white matter showed severe volume loss with extensive axonal rarefaction and macrophage infiltrates (Figure 4). This pattern correlates with the atrophy of the subplate seen on prenatal imaging. There was diffuse infiltration of macrophages in the cerebral cortex, subventricular zone, white matter, and leptomeninges but not in the germinal matrix of the ganglionic eminence. Scattered loose microglial aggregates were observed in the deep gray matter and brain stem, but there was no evidence of well-formed microglial nodules or other classic histologic features of viral encephalitis, such as perivascular inflammatory infiltrates, viral inclusions, or ventriculitis. Ultrastructural examination of fixed cortical tissue showed a rare aggregate of intracellular electron-dense, viral-like particles that measured 39 to 41 nm in diameter (mean, 40.26). Our ability to specifically localize the cellular compartment housing the particles was limited by poor tissue preservation, but the morphologic features and size of this structure were similar to those reported by Mlakar et al.10 and the CDC.21 The choroid plexus was focally enlarged and edematous, with scant hemosiderin deposits, which may appear to be similar to intraventricular hemorrhage on prenatal imaging. Histologic examination of the eyes, spinal cord gray matter, dorsal-root ganglia, and spinal nerves did not reveal overt microscopic abnormalities. Spinal white-matter tracts were not well visualized. A detailed pathological description of the brain and other organs is provided in the Methods section of the Supplementary Appendix.

Fetal and Maternal ZIKV Viral Loads

The highest ZIKV viral loads were found in fetal brain, with substantial viral loads in the placenta, fetal membranes, and umbilical cord, as studied on quantitative RT-PCR (Table S2 in theSupplementary Appendix). Lower amounts of ZIKV RNA were found in fetal muscle, liver, lung, and spleen. Amniotic fluid that was obtained at the time of termination was positive for ZIKV RNA with low viral counts. On PCR assays to detect DNA, the amniotic fluid was negative for parvovirus B19, herpes simplex virus types 1 and 2, cytomegalovirus (CMV), and Toxoplasma gondii, and the fetal brain tissue was negative for herpes simplex virus types 1 and 2 and varicella–zoster virus.

Maternal serum that was obtained on the day before termination was also positive for ZIKV RNA with a low viral count (2.1×103 copies per milliliter). No ZIKV RNA was detected in the serum, peripheral-blood mononuclear cells, saliva, or urine in samples obtained 11 days and 13 days after termination. On IgM analysis, the mother had no evidence of serum antibodies indicating acute infection with CMV, parvovirus B19, T. gondii, or rubella virus. Samples obtained from her spouse were all negative for ZIKV RNA, including urine (obtained 11 weeks after travel), serum (obtained 5 and 11 weeks after travel), and semen (obtained 10 and 12 weeks after travel), although results of testing for ZIKV IgG (titer 320) and IgM (titer 20) were positive.

Virus Isolation

ZIKV replication was detected as an increase in ZIKV RNA on quantitative RT-PCR assay of SK-N-SH and Vero E6 cells inoculated with the fetal brain sample. The quantities of ZIKV RNA increased rapidly in the SK-N-SH cells after the first day of inoculation, whereas in the Vero E6 cells, viral RNA loads started to increase on day 4 after inoculation. Viral replication was not detected in cells inoculated with other samples. The tissue-inoculated SK-N-SH and Vero E6 cells were further shown to express ZIKV antigens by reactivity with human convalescent anti-ZIKV serum (obtained from the father of the fetus) on immunofluorescence staining and to produce flavivirus-like particles, as seen on electron microscopy (Figure 5FIGURE 5Isolation of ZIKV from Fetal Brain Tissue, ZIKV Growth in Fetal Tissues, Electron Microscopy of a Flavivirus-like Particle, and Amino Acid Differences in the Newly Isolated Strain.).

A complete ZIKV genome was sequenced from supernatant of SK-N-SH cells on day 5 after inoculation. Phylogenetic analysis indicated that the viral strain (designated ZIKV_FB-GWUH-2016; GenBank number, KU870645) was a member of the Asian genotype and closely related to two ZIKV sequences obtained from Guatemalan patients who presented with mild illness (Figure 6FIGURE 6Phylogenetic Tree Showing Newly Isolated ZIKV Strain., and Fig. S6 in the Supplementary Appendix).7 The FB-GWUH-2016 strain had 23 to 51 nucleotide differences and 8 to 14 amino acid differences as compared with the ZIKV strains detected previously in the Americas (99.6 to 99.8% identities) (Figure 5D). Five of the eight differences in amino acids between FB-GWUH-2016 and the Guatemalan strains were specific for the FB-GWUH-2016 strain (i.e., differences that were not detected in other ZIKV strains sequenced so far). One amino acid substitution was a reversion toward the African ZIKV genotype. Three amino acid substitutions were common for FB-GWUH-2016 and the Guatemalan strains but distinct from all other reported ZIKV strains

[niman]

DISCUSSION

The current recommendations for ZIKV diagnostic practices are based on the understanding that ZIKV viremia lasts for less than a week after the onset of infection.15 During the week of symptomatic infection, RNA detection in serum or blood is considered to be the diagnostic method of choice. ZIKV RNA can be detected in urine for some days longer.22,23 ZIKV is also present in semen for an unknown length of time, and scattered reports of sexual transmission of ZIKV have emerged.24-28 ZIKV RNA testing is not recommended for pregnant women after the first week after the onset of clinical disease. The diagnosis is usually based on a ZIKV-specific antibody response with higher IgM and neutralizing-antibody responses to ZIKV than to other flaviviruses.13 However, we have detected ZIKV RNA in the serum of a pregnant woman at 4 weeks and 10 weeks after the clinical onset of ZIKV infection but not after delivery. We suspect that the persistent ZIKV viremia in the patient described here was a consequence of viral replication in the fetus or placenta, which had high viral loads. Therefore, in addition to current ZIKV diagnostics, the use of quantitative RT-PCR methods may be a potential diagnostic approach for ongoing placental or fetal infections in pregnant women. Notably, in this patient, the ZIKV RNA levels were slightly higher in the maternal serum than in the amniotic fluid. The dynamics of ZIKV RNA in the serum of infected pregnant women are not well understood and will need to be assessed in larger studies.

It is estimated that 80% of ZIKV infections are asymptomatic.29 Although the evidence of the association between the presence of ZIKV in pregnant women and fetal brain abnormalities continues to grow, the timing of infection during fetal development and other factors that may have an effect on viral pathogenesis and their effects on the appearance of brain abnormalities on imaging are poorly understood. Oliveira Melo et al.9 described two cases of ZIKV intrauterine infection associated with microcephaly and brain calcifications that were diagnosed by means of ultrasonography during the third trimester. Similar to the fetus in our report, the two fetuses in that study showed abnormal development of the corpus callosum and decreased brain parenchymal volume. In the case described by Mlakar et al.,10 the results of ultrasonography that was performed at 14 weeks and 20 weeks of gestation were normal, but microcephaly, ventriculomegaly, and calcifications were seen on ultrasonography at 29 weeks of gestation.10 In the larger Brazilian cohort, cerebellar atrophy was seen in a fetus at 20 weeks of gestation, but microcephaly was not diagnosed until 27 to 35 weeks in their cohort.11 In our study, a review of three sequential ultrasonographic images between 16 and 20 weeks showed a decrease in the fetal head circumferences from the 47th percentile to the 24th percentile, which suggests a reduction in the rate of brain growth during that period (Fig. S3 in the Supplementary Appendix). We suspect these reductions in brain growth would have eventually met the criteria for microcephaly. As this case shows, the latency period between ZIKV infection of the fetal brain and the detection of microcephaly and intracranial calcifications on ultrasonography is likely to be prolonged. Negative ultrasonographic studies during this period would be falsely reassuring and might delay critical time-sensitive decision making. Serial ultrasonographic measurements of head circumference may provide useful predictive information. The superior soft-tissue resolution of fetal brain MRI might be more sensitive to developmental and encephaloclastic changes, thereby expediting the detection of evolving fetal brain anomalies.

This case is an early foray into the histopathological findings associated with ZIKV in the midgestational fetal brain. The overwhelming findings were of loss of intermediately differentiated postmigratory neurons through an apoptotic mechanism. There appeared to be preservation of more differentiated neurons in basal ganglia, limbic region, and dorsal spinal cord. The germinal matrix cells also appeared to be spared. Of note, the germinal matrix consists predominantly of glioblasts at midgestation with the majority of the neuroblasts having already migrated out of the zone. Although we could not evaluate neuronal precursor subtypes other than calretinin-expressing interneuron lineage cells, selective neuronal vulnerability to ZIKV injury requires further investigation.

The successful isolation of infectious ZIKV from human fetal brain fulfills Koch’s second postulate regarding the isolation of pathogens from a diseased organism and strengthens the association between congenital ZIKV infection and fetal brain damage. Although ZIKV RNA was found in several fetal organs and the placenta, the virus could be isolated only from brain tissue. The rapid isolation in a human neuroblastoma cell line suggests a predilection of the ZIKV strain for human neural lineage cells. This hypothesis is in line with the histopathological findings and the results of a recent study showing a high rate of ZIKV infection in cortical neural progenitor cells but not in embryonic or pluripotent stem cells.30 The close genetic relationship between the isolate in our report and Guatemalan ZIKV strains was consistent with the anamnestic knowledge on the likely geographical origin of the infection. We found a relatively high frequency of nonsynonymous mutations between the FB-GWUH-2016 genome and the Guatemalan ZIKV genome (Fig. S4 in theSupplementary Appendix), a finding that could indicate viral adaptation to growth in the fetal brain. However, no amino acid changes were identical to previously reported alterations in the ZIKV genome sequenced from fetal brain tissue.10

In conclusion, our study highlights the possible importance of ZIKV RNA testing of serum obtained from pregnant women beyond the first week after symptom onset, as well as a more detailed evaluation of the fetal intracranial anatomy by means of serial fetal ultrasonography or fetal brain MRI. The isolation of ZIKV from fetal brain provides additional evidence for the association between congenital ZIKV infection and fetal brain damage and provides tools for further studies of the pathogenesis of ZIKV-induced microcephaly. Future studies at various gestational ages will offer better insight into the role of ZIKV infection in abnormal brain development and provide markers for its detection.

 

 

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

Drs. Driggers and Ho, Ms. Korhonen, and Ms. Kuivanen and Drs. du Plessis and Vapalahti contributed equally to this article.

This article was published on March 30, 2016, at NEJM.org.

We thank the patient and her husband for their support of our study; Irina Suomalainen, Inkeri Luoto, and Sanna Mäki of the University of Helsinki for their technical assistance; Tamas Baszinka and Kirsi Aaltonen for their help in preparing samples; Dr. Eili Huhtamo for guidance in setting up the nested RT-PCR assay; the Finnish IT Center for Science for the allocation of computational resources; and Yvette Veloso, Mandy Field, and Laurie King for their technical support.

[niman]

REFERENCES

1. 1

   Dick GW, Kitchen SF, Haddow AJ. Zika virus. I. Isolations and serological specificity.Trans R Soc Trop Med Hyg 1952;46:509-520
   CrossRef | Web of Science | Medline

2. 2

   Cao-Lormeau VM, Roche C, Teissier A, et al. Zika virus, French Polynesia, South Pacific, 2013. Emerg Infect Dis 2014;20:1085-1086
   Web of Science | Medline

3. 3

   Duffy MR, Chen T-H, Hancock WT, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. N Engl J Med 2009;360:2536-2543
   Free Full Text | Web of Science | Medline

4. 4

   Musso D, Nilles EJ, Cao-Lormeau VM. Rapid spread of emerging Zika virus in the Pacific area. Clin Microbiol Infect 2014;20:O595-6
   CrossRef | Web of Science | Medline

5. 5

   Zika virus outbreaks in the Americas. Wkly Epidemiol Rec 2015;90:609-610
   Medline

6. 6

   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;14:1232-1239
   CrossRef | Web of Science | Medline

7. 7

   Lanciotti RS, Lambert AJ, Holodniy M, Saavedra S, del Carmen Castillo SL. Phylogeny of Zika virus in western hemisphere, 2015. Emerg Infect Dis (in press).

8. 8

   Besnard M, Lastere S, Teissier A, Cao-Lormeau V, Musso D. Evidence of perinatal transmission of Zika virus, French Polynesia, December 2013 and February 2014. Euro Surveill 2014;19
   CrossRef | Medline

9. 9

   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;47:6-7
   CrossRef | Web of Science | Medline

10. 10

    Mlakar J, Korva M, Tul N, et al. Zika virus associated with microcephaly. N Engl J Med2016;374:951-958
    Free Full Text | Web of Science | Medline

11. 11

    Brasil P, Pereira JP Jr, Raja Gabaglia C, et al. Zika virus infection in pregnant women in Rio de Janeiro — preliminary report. N Engl J Med. DOI: 10.1056/NEJMoa1602412.
    Medline

12. 12

    Interim guidelines for pregnant women during a Zika virus outbreak — United States, 2016.MMWR Morb Mortal Wkly Rep 2016;65:30-33
    CrossRef | Web of Science | Medline

13. 13

    Zika virus infection: global update on epidemiology and potentially associated clinical manifestations. Wkly Epidemiol Rec 2016;91:73-81
    Medline

14. 14

    Rapid risk assessment: Zika virus epidemic in the Americas: potential association with microcephaly and Guillain-Barre syndrome. Stockholm: European Center for Disease Prevention and Control, 2015.

15. 15

    Zika travel information. Atlanta: Centers for Disease Control and Prevention, January 2016 (http://wwwnc.cdc.gov/travel/page/zika-travel-information).

16. 16

    Update: interim guidance for health care providers caring for women of reproductive age with possible Zika virus exposure — United States, 2016. MMWR Morb Mortal Wkly Rep2016 March 25 (http://www.cdc.gov/mmwr/volumes/65/wr/mm6512e2er.htm?s_cid=mm6512e2er).
    Web of Science

17. 17

    CDC health advisory: recognizing, managing, and reporting Zika virus infections in travelers returning from Central America, South America, the Caribbean and Mexico. Atlanta: Centers for Disease Control and Prevention, 2016 (http://emergency.cdc.gov/han/han00385.asp).

18. 18

    Table 24. In: Kline-Fath B, Bahado-Singh R, Bulas DI. Fundamental and advanced fetal imaging: ultrasound and MRI. Philadelphia: Wolters Kluwer Health, 2015:860-863.

19. 19

    Harreld JH, Bhore R, Chason DP, Twickler DM. Corpus callosum length by gestational age as evaluated by fetal MR imaging. AJNR Am J Neuroradiol 2011;32:490-494
    CrossRef | Web of Science | Medline

20. 20

    Means and standard deviations of organ weights and measurements of live-born infants. In: Gilbert-Barness E, Debich-Spicer DE. Handbook of pediatric autopsy pathology. . New York: Humana Press, 2005:54.

21. 21

    About Zika virus disease. Atlanta: Centers for Disease Control and Prevention, 2016 (http://www.cdc.gov/zika/about/index.html).

22. 22

    Gourinat AC, O’Connor O, Calvez E, Goarant C, Dupont-Rouzeyrol M. Detection of Zika virus in urine. Emerg Infect Dis 2015;21:84-86
    CrossRef | Web of Science | Medline

23. 23

    Korhonen EM, Huhtamo E, Smura T, Kallio-Kokko H, Raassina M, Vapalahti O. Zika virus infection in a traveller returning from the Maldives, June 2015. Euro Surveill 2016;21
    CrossRef | Medline

24. 24

    Musso D, Roche C, Robin E, Nhan T, Teissier A, Cao-Lormeau VM. Potential sexual transmission of Zika virus. Emerg Infect Dis 2015;21:359-361
    CrossRef | Web of Science | Medline

25. 25

    Foy BD, Kobylinski KC, Chilson Foy JL, et al. Probable non-vector-borne transmission of Zika virus, Colorado, USA. Emerg Infect Dis 2011;17:880-882
    CrossRef | Web of Science | Medline

26. 26

    McCarthy M. Zika virus was transmitted by sexual contact in Texas, health officials report.BMJ 2016;352:i720-i720
    CrossRef | Web of Science | Medline

27. 27

    Venturi G, Zammarchi L, Fortuna C, et al. An autochthonous case of Zika due to possible sexual transmission, Florence, Italy, 2014. Euro Surveill 2016;21

28. 28

    Transmission of Zika virus through sexual contact with travelers to areas of ongoing transmission — continental United States, 2016. MMWR Morb Mortal Wkly Rep2016;65:215-216
    CrossRef | Web of Science | Medline

29. 29

    Zika virus: clinical evaluation and disease. Atlanta: Centers for Disease Control and Prevention (http://www.cdc.gov/zika/hc-providers/clinicalevaluation.html).

30. 30

    Tang H, Hammack C, Ogden SC, et al. Zika virus infects human cortical neural progenitors and attenuates their growth. Cell Stem Cell2016 March 3 (Epub ahead of print)

[niman]

[niman]

Pregnant Women May Be Able To Get Answers About Zika Earlier

• Facebook
• Twitter
• Google+
• Email

March 30, 20165:00 PM ET

MICHAELEEN DOUCLEFF

Twitter

i

A pregnant woman gets an ultrasound in Guatemala City on Feb. 2, monitoring for the birth defect microcephaly.

Johan Ordonez/AFP/Getty Images

Last November, a couple from Washington, D.C., took a weeklong vacation. They visited Mexico, Guatemala and Belize. And got bitten by plenty of mosquitoes.

Two days after they returned home, the woman — who was pregnant — fell ill. She had muscle pain, a fever and a rash.

"At first she didn't think much about it," says OB-GYN Rita Driggers, who saw the woman at Johns Hopkins University School of Medicine. "But then all the news started coming out about Zika, so the woman went and got tested."

The test came back positive. And then the big question became: Was her baby going to be OK?

At first, everything looked good on a standard ultrasound, Driggers says. Even during the 20th week of the pregnancy, the fetus didn't have microcephaly or calcifications in the brain — two telltale signs of a Zika infection.

But when doctors ran MRI on the fetus, the good news quickly faded.

"There were severe abnormalities within the brain," Driggers says. "The width of the brain was very, very thin. ... Some structures were completely missing."

The woman decided to terminate the pregnancy. And she allowed Driggers and her colleagues to study the baby. The case — published Wednesday in The New England Journal of Medicine — offers insights into how Zika infects a fetus and suggests ways women may be able to find out earlier whether babies will have birth defects.

First, the virus lingered in the patient's blood for months after she got sick. Usually a person's immune system clears out Zika in a week or so. But in this case, Driggers thinks the virus was hiding out inside the fetus — and repeatedly infecting the mother.

"So if you're seeing the virus in the mom's blood more than a week after symptoms," Driggers says, "then perhaps what's going on is that the baby is infected with Zika."

GOATS AND SODA

The Poignant Cry Of Babies With Birth Defects Linked to Zika

Second, looking only for microcephaly isn't enough. Right now the Centers for Disease Control and Prevention recommends doctors measure the size of the fetus's head with an ultrasound near the 20th week of the pregnancy to check for Zika-related problems.

But with this new case, doctors could see brain abnormalities by MRI before there were signs of microcephaly.

"This is very alarming," says Dr. Carla Janzen, a maternal-fetal medicine specialist at UCLA, who wasn't involved in the study. "If we see more cases like this, the [CDC's] guidelines will probably have to change" to include MRI screening or more intensive ultrasound tests.

http://www.npr.org/sections/goatsandsoda/2016/03/30/472307332/one-woman-s-case-may-change-zika-screening-for-expectant-mothers?utm_source=twitter.com&utm_campaign=health&utm_medium=social&utm_term=nprnews

 

[niman]

· 

Posted just now · Report post

The evidence that Zika causes fetal brain damage is now 'awfully strong'

 

A report describes an abnormal pregrancy following a Zika infection

• By Arielle Duhaime-Ross
•  
• on March 30, 2016 05:00 pm
•  
• Email 
• @ArielleDRoss 
•  

 Share on Facebook (31) Tweet  Share (2) Pin (2)

A fetus that was aborted weeks after the mother was infected with Zika provides striking evidence that the virus causes fetal brain abnormalities, researchers say. The report, published today in the New England Journal of Medicine, isn't the first to document a case of a mother passing on the virus to a fetus, but it does provide the most detailed look yet at changes that occurred in the fetus' brain following a mother's Zika infection.

In the study, researchers describe the case of a 33-year-old Finnish woman who was almost three months pregnant when she became infected with Zika during a trip to Guatemala. Fetal ultrasounds later showed that her fetus' head wasn't growing at a normal rate; its brain also began to display abnormal anatomy, researchers say. After the pregnancy was terminated, scientists found Zika virus in the fetus' brain, as well as in the umbilical cord and placenta. Because researchers were able to follow the pregnancy every step of the way, scientists think this case lends strong support to the idea that Zika virus causes fetal brain damage.

 

 "THAT’S PRETTY MUCH A SMOKING GUN."

"What makes this study so convincing is that this one case was so thoroughly studied from the time of infection to the ultrasound studies," says Lee Norman, an intelligence officer in disaster medicine planning in the United States Army National Guard, who didn’t work on the study. Because the woman was so closely followed by doctors, researchers were able to eliminate other factors that could have played a role in the fetal brain abnormalities and focus in on the Zika virus. "Finding the virus in the brain of the fetus in the NEJM study — that’s pretty much a smoking gun," he says.

In most cases, the Zika virus isn't dangerous. About 80 percent of people infected with the virus never develop symptoms, which resemble the flu and last no more than a week. But an outbreak of the virus in Brazil has caused concern among health officials who suspect Zika might be responsible for stillbirths, problems with the placenta that may harm a developing fetus, and a birth defect that can affect the brain size of newborns, microcephaly. There's no cure or treatment for the virus. And even though Zika is mostly transmitted through mosquito bites, it is possible to become infected through sexual contact. Because of this, the US government recommends that women with Zika should wait eight weeks before trying to conceive, and men should wait at least six months after their symptoms first appear to have unprotected sex. Both recommendations were made despite the fact that scientists have yet to demonstrate a definitive link between Zika and fetal brain abnormalities. Now, scientists are working to document the effects of the virus in expecting mothers.

THE ANATOMY OF THE FETUS' BRAIN WAS ABNORMAL

The woman's pregnancy was normal prior to her Zika infection. But three months in, during a trip to Guatemala, she began to show Zika-like symptoms. Four weeks after she had recovered, the woman tested positive for antibodies that fight off Zika; another batch of tests eliminated other possible culprits, like dengue. Then, between her 16th and 19th week of pregnancy, the fetus' head stopped growing at a normal rate; its head went from being in the 47th percentile to the 24th percentile, meaning that only 24 percent of fetuses have a head that size or smaller at that stage. A fetal ultrasound also showed that the anatomy of the fetus' brain was abnormal. "Given the grave prognosis," the mother decided to have an abortion, the researchers wrote in the study; she was five months pregnant by then.

 

 "I THINK THAT THE EVIDENCE IS NOW AWFULLY STRONG."

The report provides "very striking evidence" that Zika virus infection causes severe abnormalities, says Sara Cherry, a microbiologist at the University of Pennsylvania who didn't work on the study. But a single case isn't enough to prove Zika's role in fetal brain abnormalities, she says. What matters is the picture that data from this study and others paint. Emerging and aggregate data "really do show that Zika virus infection can lead to developmental defects in the fetus," she says. Harvard University immunologist Eric Rubin put things more bluntly. The study "doesn't prove the link between Zika and microcephaly," he told The Verge. "However, particularly given the other recently published study, that shows that women who develop Zika during pregnancy are at high risk for fetal abnormalities, I think that the evidence is now awfully strong."

Earlier this month, another study showed that women who are infected with Zika during the first trimester of pregnancy face a 1 in 100 chance that their fetus will develop microcephaly. According to Hongjun Song, a neuroscientist at Johns Hopkins University, the only way scientists will be able to definitely prove that Zika causes fetal brain abnormalities is by conducting a large, controlled study. Norman, for his part, says scientists need to test the effects of Zika on animals.

http://www.theverge.com/2016/3/30/11332044/zika-fetus-brain-damage-evidence-abnormalities

[niman]

Biomedicine

Zika Attacked a Baby’s Brain as Doctors Watched

U.S. and Finnish doctors caught the brain-shrinking virus in action, and say tests are possible.

• by Antonio Regalado
•  
• March 30, 2016

Doctors used MRIs and blood tests to watch, in nearly real-time, as the Zika virus destroyed the brain of a fetus whose mother had been infected during a vacation in Latin America.

The nine-week ordeal of a Finnish woman who was bitten by mosquitoes during a trip to Mexico, Guatemala, and Belize is described in the New England Journal of Medicine.

The Zika virus began spreading quickly in the Americas last year and, by last fall, doctors in northeast Brazil were linking the infection to microcephaly, a devastating, life-altering birth defect in which babies are born with shrunken heads and brains.

That link is now a fact. “What we do know for sure is if the fetal brain is infected, that this appears to be a very bad situation,” said Adre du Plessis, director of the Fetal Medicine Institute at the Children’s National Health System in Washington, D.C.

The woman, who lives in Washington, D.C., was 33 and three months pregnant at the time she got infected with Zika. She suffered a mild fever and rash, but became concerned after reading news reports of Zika’s link to microcephaly. Over Christmas she had her blood tested in Finland during a trip to her home country.

The test, which looks for the virus’s genetic material, came back positive. But at first, ultrasound exams didn’t show any abnormality, leading Du Plessis to caution that such widely used tests may not be picking up problems.

The woman later underwent a series of MRIs, which offered a detailed and frightening picture of the baby’s brain “turning to liquid,” says Olli Vapalahti, who runs an arbovirus research center at the University of Helsinki and is the senior author of the case report.

People infected with Zika usually clear the virus in seven days, sometimes a little longer. In this case, the woman kept testing positive for the virus for just over two months. Vapalahti believes the tests were picking up the virus replicating inside the fetus’s brain tissue.

“We tracked it in real time in a way,” he says. “Our study brings hope that maybe we can screen pregnant mothers with a viral test, and then do MRI studies.” Given the guarantee of severe disability, the woman chose to have an abortion at week 20.

The bigger problem is how to counsel women in less affluent parts of Latin America who won’t have access to repeated MRIs or multiple tests. In many Latin countries, access to abortion is restricted. Infection during pregnancy doesn’t always cause a birth defect; the factors that determine when microcephaly results from a Zika infection still aren’t known.

The threat of Zika seems almost existential. Yet eventually the virus may become less of a danger due to a phenomenon called “herd immunity.” That is because it’s believed that once infected, people become immune to it. That means girls and women infected now probably won’t be at risk if they get pregnant later. Also, as fewer and fewer people are susceptible and able to spread Zika, the virus may retreat back to the forest.

https://www.technologyreview.com/s/601153/zika-attacked-a-babys-brain-as-doctors-watched/#/set/id/601150/

Edited March 31, 2016 by niman

[niman]

SCIENTIFIC METHOD / SCIENCE & EXPLORATION

CDC braces for Zika’s US invasion as scientists watch virus melt fetal brain

Experts prepare for pockets of transmission on US mainland as mosquito season begins.

by Beth Mole - Apr 1, 2016 4:28pm EDT

• Share
• Tweet
• Email

 1

A female Aedes aegypti mosquito takes flight after a blood meal.

CDC

The Centers for Disease Control and Prevention gathered more than 300 local, state, and federal authorities and experts at its Atlanta headquarters Friday to prepare for clusters of mosquito-transmitted Zika infections on the US mainland.

“The mosquitoes that carry Zika virus are already active in US territories, hundreds of travelers with Zika have already returned to the continental US, and we could well see clusters of Zika virus in the continental US in the coming months,” CDC Director Tom Frieden said in a statement prior to today’s meeting. “Urgent action is needed, especially to minimize the risk of exposure during pregnancy.”

Zika, a virus that has been tearing across Central and South America since last year, is mostly transmitted by mosquito, but it can also be spread through sexual contact. Generally the virus only causes mild illness, with symptoms including fever, rash, pink eye, and aches. But in the recent outbreaks, Zika has been linked to rare cases of paralyzing auto-immune disease, called Guillain-Barré syndrome. Of most concern, it's also linked to devastating birth defects, including microcephaly, in which babies are born with small, malformed heads and brains.

Enlarge

CDC

While researchers are still studying the link between Zika and microcephaly, health experts fear that microcephaly is just one of the potential problems for the unborn. “Perhaps one of the most important unknowns is what is the range of fetal abnormalities in addition to microcephaly,” Frieden said in a press conference during the summit. Microcephaly may just be the extreme, he and others noted. Babies exposed to the virus in utero may also suffer from less obvious developmental and cognitive problems, he speculated.

 

The fear is bolstered by recent data that has only strengthened the tie between the virus and the birth defect, with some studies finding the virus killing off developing brain cells. In a study released this week in the New England Journal of Medicine, researchers report tracking the development of a fetus whose mother was infected with the virus during a trip to Central America while she was three months pregnant.

With blood tests and magnetic resonance images (MRI), researchers watched as the baby’s brain essentially turned to liquid in the course of nine weeks. The woman aborted the fetus at week 21.

Friday’s one-day summit covered such breaking scientific data on the virus and provided training to authorities on how to prevent, treat, and talk with the public (particularly pregnant women) about Zika and its health effects. Experts also focused on coordinating efforts to stamp down mosquito populations.

Enlarge / Estimated range of Aedes aegypti and Aedes albopictus in the United States, 2016.

CDC

There’s a hodge-podge of practices in various communities for tackling mosquito control, and many of them are very effective, according to Amy Pope, a White House deputy homeland security advisor and deputy assistant to the president who spoke at the press conference. “The goal of today’s summit is to bring all of those practices together in one place, give folks sort of the menu of options, so that they can develop a comprehensive plan well in advance of when we see mosquitoes biting around the continental United States,” she said.

Though health experts don’t foresee extensive mosquito-borne outbreaks of Zika in the US, there’s reason to expect small clusters of transmission. Zika is transmitted by Aedes mosquitoes, particularlyAedes aegypti and to a lesser extent Aedes albopictus. These mosquitoes, which are present in some areas of the US, can also transmit yellow fever, dengue, and chikungunya viruses. Small outbreaks of chikungunya and dengue pop up in certain areas each year, particularly in Texas and Florida. Health experts suspect that Zika may behave similarly.

Enlarge / A representation of the surface of the Zika virus with protruding envelope glycoproteins (red) shown.

Courtesy of Kuhn and Rossmann research groups, Purdue University.

Frieden stressed the difficulty of knocking backAedes populations, which are day-biters that can breed in very small amounts of standing water. Coordinated, sustained, and well-funded efforts are needed to control these populations, he said.

So far, there is no vaccine or specific treatment for Zika. However, in another scientific report in the journal Science this week, researchers report getting the first detailed, 3D image of the virus using cryo-electron microscopy. While the viral close-up looks unsurprisingly similar to that of dengue—a related virus—there are minor differences. Those findings could provide clues to how researchers might defeat the virus with a vaccine.

New England Journal of Medicine, 2015. DOI:10.1056/NEJMoa1601824  (About DOIs).

Science, 2015. DOI: 10.1126/science.aaf5316

http://arstechnica.com/science/2016/04/cdc-braces-for-zikas-us-invasion-as-scientists-watch-virus-melt-fetal-brain/

[niman]

Anthony Fauci notes that a non-human primate model replicates the persistence of Zika in pregnant females.

[niman]

Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), said research and vaccine activities are going full blast with transferred funds, but the efforts won't accomplish their goals without full emergency funding. "When the president asked for $1.9 billion, we needed $1.9 billion."

He added that scientists are learning more about Zika virus every day, with progress being made to understand the damage at the fetal brain cell molecular level and on animal models for studying the disease. Fauci said preliminary work with monkey models suggest that virus levels in pregnant females persist much longer than in those who aren't pregnant.

http://www.cidrap.umn.edu/news-perspective/2016/04/studies-show-zika-brain-damage-feds-express-deep-concern

[niman]

Microcephaly and other fetal malformations potentially associated with Zika virus infection or suggestive of congenital infection have been reported in six countries (Brazil, Cabo Verde, Colombia, French Polynesia, Martinique and Panama). Two cases, each linked to a stay in Brazil, were detected in Slovenia and the United States of America. A further case, linked to a brief stay in Mexico, Guatemala and Belize, was detected in a pregnant woman in the United States of America.

http://www.who.int/emergencies/zika-virus/situation-report/21-april-2016/en/