Microcephaly Caused by Lymphocytic Choriomeningitis Virus

Maia Delaine; Anne-Sophie Weingertner; Antoine Nougairede; Quentin Lepiller; Samira Fafi-Kremer; Romain Favre; Rémi Charrel

Disclosures

Emerging Infectious Diseases. 2017;23(9):1548-1550. 

In This Article

The Study

The patient was a 29-year-old G1P0 pregnant woman hospitalized at 23 weeks' gestation after routine ultrasonography because of fetal ascites and minor ventriculomegaly. Her medical history was unremarkable. The woman and her husband were farmers. Written informed consent was obtained from the patient for participation in this study.

Ultrasonography of the fetus showed symmetric ventriculomegaly and hyperechogenicity of the cerebral parenchyma (Figure). It also detected ascites, a minor pericardial effusion, and cardiomegaly with a hyperechogenic myocardium. The medium cerebral artery peak systolic velocity was 1.98 multiples of median, which indicated fetal anemia. Subsequent ultrasonography showed a rapid increase in ventriculomegaly, cortical atrophy, growth of ascites, and episodes of bradyarrhythmia.

Figure.

Ultrasonography of congenital microencephaly caused by infection with lymphocytic choriomeningitis virus diagnosed in the fetus of a 29-year-old pregnant women at 23 weeks' gestation. A) Fetal brain at 23 weeks' gestation showing symetric ventriculomegaly (14 mm). Yellow symbols indicate axis at which size of cerebral ventricle was measured. B) Fetal brain at 26 weeks' gestation showing symetric ventriculomegaly (20 mm) and thinning of the cortical mantle. Yellow symbols indicate axis at which size of cerebral ventricle was measured. C) Fetal heart at 24 weeks' gestation showing pericardial effusion (*) and cardiomyopathy with hyperechogenic muscle. D) Sagittal section of fetal abdomen at 26 weeks' gestation showing ascites (*).

An initial diagnosis of congenital infection with parvovirus B19 was rejected because maternal serologic results were negative for this virus. Serologic test results were also negative for cytomegalovirus, rubella virus, Toxoplasma gondii, and Treponema pallidum. The patient had been vaccinated against varicella virus.

We performed amniocentesis at 24 weeks' gestation: results showed a standard karyotype (46, XX). Results of PCR screening of amniotic fluid were negative for TORCH agents (toxoplasmosis/Toxoplasma gondii, other infections, rubella virus, cytomegalovirus, herpes simplex virus-2 or neonatal herpes simplex virus), as well as enterovirus, Listeria monocytogenes, Mycoplasma spp., and Ureaplasma spp. The biochemical profile of ascites indicated an infection. A fetal blood sample showed moderate anemia. Because of these negative results for virus infections, an ascitic fluid sample was tested by PCR for LCMV.

We extracted virus RNA from an ascite sample by using a Z1-XL Biorobot and a Virus Mini Kit (QIAGEN, Hilden, Germany). A 253-nt region in the small RNA segment was amplified by using sense primer CML-F0 (5′-ARCAARGGIATYTGTAGYTGTGG-3′) and reverse primer CML-R3 (5′-CTYATGGAYTGCATCATYTTTGA-3′) in a QuantiTect SYBR Green Real-Time PCR Device (QIAGEN), a CFX96 thermal cycler (Bio-Rad Laboratories, Hercules, CA, USA), and the cycling protocol reported for flaviviruses.[5]

To better characterize this strain, a 686-bp product was amplified by using primers for the virus polymerase gene[6] and directly sequenced. We used this sequence for alignment with homologous virus sequences in GenBank and performed phylogenetic analysis by using the maximum-likelihood method based on the Kimura 2-parameter model implemented in MEGA 6.06 software.[7]

We tested 5 samples for virus small gene segment by using a specific Sybr Green Real Time PCR. Amniotic fluid was positive for LCMV. Fetal brain and placenta biopsy specimens and a serum sample from the mother were negative for LCMV. The matching sequence was compared with 42 other LCMV sequences by using BLAST (https://blast.ncbi.nlm.nih.gov/Blast.cgi). Genetic identities ranged from 77.2% to 90.8% at the nucleotide level.

For confirmation and better genetic characterization, we tested samples by using a reverse transcription PCR specific for virus large gene segment. Again, only amniotic fluid was positive. The 686-nt sequence matched 31 other sequences in GenBank (identity range 78.2%–88%). All specimens were inoculated onto Vero cells, but virus was not isolated.

The patient reported an influenza-like illness during the 16th week of pregnancy, which had resolved spontaneously in a few days. She also reported that there were mice on the farm.

On the basis of echographic findings, the couple decided to terminate the pregnancy at 28 weeks' gestation. A fetal blood sample showed increased anemia and thrombocythemia.

Fetopathologic examination showed hepatosplenomegaly, thymic hypertrophy, ascites, and pericardial and pleural effusion. Examination of the brain showed severe microcephaly with polymicrogyria, a thin cortex, and diffuse periventricular calcifications. We also detected bilateral chorioretinitis. The placenta was unremarkable, and results of genetic analysis were within reference ranges.

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