ABSTRACT:

Background: Zika virus infection during pregnancy has been recently associated with congenital microcephaly and other
severe neural tube defects. However, the magnitude of confirmed cases and the scope of these anomalies have not been
extensively documented. This review focuses on the magnitude of laboratory-confirmed congenital Zika virus cases among
probable cases and describing the patterns of congenital anomalies allegedly caused by the Zika virus, information which
will inform further research in this area.

Methods: We conducted a literature search for English-language articles about congenital Zika virus infection using online
electronic databases (PubMed/MEDLINE, POPLINE, Embase, Google Scholar, and Web of Knowledge). The search terms
used were, “zika”, “pregnancy”, [year], “microcephaly”, “infants”, “children”, “neonates”, “foetuses”, “neural tube defect”,
and “CNS manifestations” in different combinations. All articles reporting cases or case series between January 2015 and
December 2016 were included. Data were entered into a Microsoft Excel database and analysed to obtain proportions of the
confirmed cases and patterns of anomalies.

Results: A total of 24 articles (11 case series, 9 case reports, and 4 others) were found to be eligible and included in this
review. These articles reported 919 cases, with or without microcephaly, presumed to have congenital Zika virus infection. Of
these cases, 884 (96.2%) had microcephaly. Of the 884 cases of microcephaly, 783 (88.6%) were tested for Zika virus infec-
tion, and 216 (27.6%; 95% confidence interval, 24.5% to 30.8%) were confirmed to be Zika virus-positive. In addition to mi-
crocephaly, other common abnormalities reported – out of 442 cases investigated – were calcifications of brain tissue (n=240,
54.3%), ventriculomegaly (n=93, 20.8%), cerebellar hypoplasia (n=52, 11.7%), and ocular manifestations (n=46, 10.4%).

Conclusion: Based on the available literature, Zika virus infection during pregnancy might lead to a wide array of outcomes
other than microcephaly. There is a need for more epidemiological studies in Zika-endemic areas, particularly in Africa, to
ascertain the role of Zika virus in causing congenital neurological defects.