Snapshot A 30-year-old G1P0 woman delivers a baby with microcephaly at 38 weeks via normal spontaneous vaginal delivery. During her first trimester, she went on a trip to Puerto Rico in December of 2015 and had multiple mosquito bites there. A week after this trip, she had a low-grade fever, itchy maculopapular rash, and conjunctivitis that resolved within 10 days. She had not gone consistently to her prenatal appointments. On physical exam, the baby has congenital microcephaly. A serum sample from the baby is collected. Introduction Classification Zika virus an enveloped positive-sense, single-stranded RNA flavivirus transmission Aedes mosquitoes can be vertically and sexually transmitted Epidemiology incidence more common in tropical and subtropical climates Central and South America the Caribbean risk factors mosquito exposure travel to endemic areas sexual exposure to others who have traveled to endemic areas Pathogenesis the Zika virus replicates in skin cells (e.g., keratinocytes and fibroblasts), which undergo cell death the virus spreads via blood and induces an innate immune response may potentially penetrate through the placental barrier, leading to teratogenicity Associated conditions microcephaly Guillain-Barré syndrome Prognosis most infections are asymptomatic if symptomatic, the disease will occur 3-12 days after exposure typically, the disease is self-limited if vertically transmitted and depending on time of infection, fetuses may have microcephaly, intracranial calcifications, and cerebral malformation Presentation Symptoms Zika virus infection may have a pruritic rash miscarriage arthralgia headache hematospermia (in males) Physical exam Zika virus infection conjunctival injection low-grade fever macular or papular rash vertically transmitted to fetus congenital microcephaly intracranial calcifications ocular lesions Studies Labs serum or urine Zika virus immunoglobulin M (IgM) often the initial test screen in pregnant women with risk factors during the first and second trimester serum or urine reverse-transcriptase polymerase chain reaction (RT-PCR) confirmatory testing if IgM is positive Making the diagnosis based on clinical presentation and laboratory studies Differential Dengue fever distinguishing factor often presents with signs of hemorrhage and without conjunctivitis Treatment Conservative supportive care indication all patients modalities hydration pain control anti-pyretic medications Complications Permanent neurologic damage Guillain-Barré syndrome