Zika virus: A primer for clinicians

Article Figures & Data

TABLE 2

Most common causes of congenital microcephaly

Genetic	Acquired
Isolated	Disruptive injuries
Syndromic	Infections (TORCHES—toxoplasmosis,^a rubella, cytomegalovirus,^a herpes simplex virus, syphilis), human immunodeficiency virus
	Teratogens
	Deprivation (malnutrition, placental insufficiency, folate deficiency, maternal hypothyroidism)

↵a Congenital toxoplasmosis is associated with diffuse intracranial calcifications; congenital cytomegalovirus is associated with periventricular calcifications.
Based on information in Ashwal S, Michelson D, Plawner L, Dobyns WB; Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Practice parameter: evaluation of the child with microcephaly (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 2009; 73:887–897.

TABLE 3

Diagnostic tests for Zika virus

Population	Test	When used	Limitations
Healthy adults or children	Zika virus immunoglobulin M (IgM) in serum	2–12 weeks of illness	Possible cross-reactivity with other flaviviruses Limited availability
	Real-time polymerase chain reaction (RT-PCR) in serum	First week of illness	May be negative by day 4 of illness Limited availability
	Plaque reduction neutralization assay	Confirmatory testing for patients with positive IgM	Limited availability Labor-intensive
Pregnant women	Fetal ultrasonography	Pregnant women with a positive Zika virus test Pregnant women exposed to Zika virus who present after 12 weeks of exposure	Needs to be repeated every 3–4 weeks during pregnancy Availability may be limited
Pregnant women	RT-PCR of amniotic fluid	Microcephaly or intracranial calcifications present on ultrasonography	Significance of results has not been conclusive
Newborns suspected of being infected	Histopathology of umbilical cord and placenta	Fetal loss, Zika virus suspected Newborn with microcephaly and intracranial calcifications	Presumptive diagnosis Limited availability
Newborns suspected of being infected	RT-PCR of cord serum, frozen tissue (cord, placenta)	Fetal loss, Zika virus suspected Newborn with microcephaly and intracranial calcifications	Presumptive diagnosis Limited availability