Signs and symptoms
Following the bite of an infected mosquito, symptoms may appear after an incubation period of a few days to a week. According to the Center for Disease Control (CDC), only one in five people bitten by an infected mosquito go on to develop symptoms of the illness.14 The most common symptoms include fever, maculopapular rash, joint pain, and conjunctivitis. Additional symptoms include headache (retro-orbital pain), fatigue, malaise, and muscle pain over a few days because the viral incubation time is approximately two to 14 days.3-5
According to the CDC, illness associated with ZKV virus is typically mild—healthy individuals will develop ZIKV antibodies in three to four days and fully recover. Severe cases requiring hospitalization are uncommon, and death associated with ZIKV is rare.14
There are reports of other neurological and autoimmune complications, including Guillain-Barré Syndrome, which have also risen in areas associated with ZIKV outbreaks.15
The health risk and long-term implications are more concerning for pregnant women because ZIKV has been shown to pass through amniotic fluid to the developing fetus and has been associated with congenital anomalies.5,13,16 In a statement released by the CDC, experts agree that a causal relationship between ZIKV infection during pregnancy and microcephaly is strongly suspected, though not yet scientifically proven.14 Presence of the virus was recently found in the brain tissue of a microcephalic fetus of a woman who had symptoms of the virus during her pregnancy while living in Brazil.13
Formulary Watch: 5 things you need to know about Zika
Microcephaly is a congenital condition that results in an abnormally small skull with the potential for incomplete brain development. The accompanying complications surrounding this neurological disorder may result in severe developmental delays and even death. In Brazil alone, there has been a twentyfold increase in cases of microcephaly in 2015 in comparison to the rate observed in previous years.5
Recent studies have also demonstrated ocular complications in infants with presumed congenital ZIKV infection, including but not limited to macular mottling, chorioretinal atrophy, and optic nerve abnormalities (pallor, hypoplasia, and increased cup-to-disc ratio).17,18 The complications of this illness and these vision-threatening conditions could have significant impact on countless families throughout the continent.