EM1609E "Zika: the Arbovirus du Jour" (IM GR-091616)

The purpose is to review the literature on the ongoing Zika epidemic, much of which has appeared in the past 4 months. Although ZIKV was identified in Africa in 1947 and caused epidemics of a mild illness on South Pacific islands in the 2000s, it was recognized as a significant public health threat only in 2015 with the discovery of an epidemic of microcephaly in offspring of Brazilian women who recalled a mild rash illness months earlier. In the succeeding months it spread to other Latin American countries and to south Florida. Zika is spread almost entirely by the Aedes aegypti mosquito which breeds close to human activity and persists largely through a mosquito-human-mosquito cycle. Zika is spread rarely by sexual transmission, mostly from symptomatic men to women, but asymptomatic and female-to-male spread have been described. ZIKV appears to damage fetal brains by persistently attacking human neural progenitor cells and avoiding immunologic response. Diagnosis of Zika infection is through PCR testing of serum and urine during the acute illness, positive PCR persisting longer in urine, and by serologic testing for anti-Zika IgM with confirmation by PRNT. In the U.S. autochthonous spread is contained by detecting cases and mounting intensive mosquito control in a Zika alert zone around the case. Aerial insecticide spraying is less effective for Zika than for West Nile epidemics. Genetically modified male mosquitoes appear to be a safe, effective strategy for Aedes aegypti eradication in circumscribed epidemic areas, but “perifocal” insecticide treatment and a Zika or polyvalent arboviral vaccine will be needed for continental eradication.

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Target Audience

UT Southwestern faculty, fellows, residents and medical students, community physicians, nurse clinicians, physician assistants and nurses.

Learning Objectives

At the conclusion of this activity, the participant should be able to:

  • Review the epidemiologic evidence for epidemics of Zika illness, microcephaly and Guillain-Barré syndrome.
  • Learn how characteristics of the Aedes aegypti mosquito and its breeding habits close to human activity determine the epidemiology and control of Zika infection.
  • Explore the recent evidence on the pathophysiology of how ZIKV damages fetal brains.
  • Review the evidence for unusual modes of transmission of Zika infection such as sexual transmission, female to male sexual transmission, and asymptomatic transmission.
  • Understand the strategies for diagnosing and managing Zika infection in patients, controlling foci of autochthonous spread, personal protection, and Zika eradication.
Course summary
Available credit: 
  • 1.00 AMA
Course opens: 
Course expires: 

Photo: Robert Haley, M.D.Robert Haley, M.D.
U.S. Armed Forces Veterans Distinguished Chair for Medical Research, Honoring America’s Gulf War Veterans
Professor and Chief, Division of Epidemiology

Available Credit

  • 1.00 AMA


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