UMEM Educational Pearls

Category: International EM

Title: What is Zika?

Keywords: Zika, flavivirus, travel, infectious diseases (PubMed Search)

Posted: 1/20/2016 by Jon Mark Hirshon, MD, MPH, PhD
Click here to contact Jon Mark Hirshon, MD, MPH, PhD

Zika virus is a mosquito-borne flavivirus. 

  • The flavivirus genus includes multiple other human viral infections, including yellow fever, West Nile, dengue and tick-borne encephalitis.
  • The primary vector for Zika virus is Aedes aegypti, though Aedes albopictus can also transmit it.


While outbreaks have been previously reported in Africa, Asia and the islands of the Pacific, it was first reported in the Western Hemisphere in May 2015. 

  • Per the CDC, as of January 15, 2016, local transmission had been identified in at least 14 countries or territories in the Americas. 
  • There has been no local transmission (yet) in the Continental US.


Clinical Disease:

  • One in five infected become symptomatic
  • Clinical illness is usually mild and lasts for several days or a week
    • Severe disease is uncommon, though Guillain-Barre syndrome has been reported in patients following suspected Zika infection
    • Fatalities are rare
    • Of note: congenital malformations have been seen in pregnant women infected with Zika
  • Characteristic clinical findings can include:
    • acute onset of fever,
    • maculopapular rash,
    • arthralgia,
    • conjunctivitis


Diagnosis and Treatment

  • Consider the diagnosis in symptomatic travels returning from affected areas
  • RT-PCR can be used on serum specimens from the first week of illness
  • There is no current commercial test available
  • Treatment is symptomatic and supportive
    • No specific antiviral therapy



  • Avoid mosquito bites
    • Wear long sleeves and pants
    • Use insect repellents when outdoors (such as DEET)
    • Delay travel to known affected areas if you are pregnant