Demystifying the Zika Virus [3D Interactive]


active Zika virus map Feb. 2016 -CDCAreas with active Zika virus transmissions. Feb. 1, 2016 - Courtesy of the CDC


Estimated to infect 4 million people by the end of 2016, Zika virus was declared a global health emergency by the World Health Organization (WHO) yesterday afternoon. This declaration, which was used during the 2009 flu pandemic and the 2014 Ebola outbreak, is due to the virus’ suspected association with a birth defect called microcephaly.


Although Zika virus does not pose a serious risk to adults, the WHO declaration will spearhead efforts to find out how the virus is transmitted, how long it stays in the bloodstream, and how it may affect a growing fetus. This declaration will also accelerate the development of treatments (as there are currently none).


While researchers continue their search for answers, click the widgets below to explore what we do know about Zika virus:


Zika Virus Structure:

  • Zika virus is part of the flavivirus family and is closely related to tropical diseases such as dengue virus and West Nile virus.
  • The virus itself contains a signal strand of RNA enclosed within a lipid (fatty) envelope. This envelope is enclosed within a larger cell membrane.
  • Once in the bloodstream of a host, the Zika virus cell membrane undergoes structural changes that enables it to attach to healthy cells.
  • Zika virus uses healthy cells to help it replicate and reproduce.


Zika Virus Transmission:

  • The first human cases of Zika virus appeared in Nigeria in 1954, but the virus did not appear in the Western Hemisphere until May 2015.
  • Zika virus is transmitted by the Aedes mosquito, which live close to people and lay their eggs in or near stagnant water.
  • Zika virus is generally not transmitted by person-to-person contact. However, there have been rare cases where the virus was sexually transmitted, or transmitted from mother to child during birth.


Zika Virus Symptoms:

  • The majority (3 out of 4) people infected with Zika virus have no symptoms.
  • For those who do exhibit symptoms, their symptoms are mild and last between 2-7 days.
  • The most common symptoms of Zika virus include fever, rash, joint pain, and conjunctivitis.
  • Joint pain in Zika virus may be accompanied by muscle pain.
  • The rash associated with Zika virus is maculopapular.  This means that it appears as a relatively smooth rash with small red elevations. The rash usually starts on the face and may spread to broader areas of the body, such as the chest and back.
  • Conjunctivitis is the irritation and reddening of the outermost membrane of the eye. Unlike bacterial “pink eye”, conjunctivitis associated with Zika virus does not produce pus and is not contagious.


Visit the Centers for Disease Control and Prevention website for more information on Zika virus transmission, symptoms, and treatment.