Zika Virus



  • Zika Virus is Named After the Ugandan Forest Where it was First Isolated from a Rhesus Monkey
    • Virus was First Isolated in 1947
    • First Human Cases of Zika Virus Infection were in 1952 in Uganda and Tanzania
    • Zika Virus Subsequently Spread Across Africa

Modern Geographic Foci of Zika Virus Infection

  • Outbreak in the Yap Islands of Micronesia in 2007
  • Outbreak in French Polynesia in 2013-2014
    • Affected Approximately 66% of the Population: 32k infections
  • Chilean Easter Island Cases Reported in 2014: Zika virus was first found in the Western hemisphere
  • Brazilian Cases Reported in May, 2015
  • Florida and Texas Cases/Traveler-Associated Cases in 2015-2016
    • First US Case of Zika Virus-Associated Microcephaly was Reported in Hawaii in 2016: mother had resided in Brazil during her pregnancy
    • First US Case of Sexually-Transmitted Zika Virus Infection in Texas in 2016


  • Zika Virus is an Arbovirus (Arthropod-Borne Virus) (see Arboviruses)
    • Family Flaviviridae
    • Genus Flavivirus: “flavus” means yellow in Latin (originated from Yellow Fever Virus, so named because of its propensity to cause jaundice)
  • Routes of Transmission
    • Bite from an Infected Mosquito (see Mosquito Bite): primary mode of transmission
      • Aedes Aegypti Mosquito: in most cases
      • Aedes Albopictus Mosquito (Asian Tiger Mosquito): also known to harbor Zika virus
    • Blood Product Transfusion
    • Human to Human Transmission (Apart from Sexual Transmission): has also been reported (although mechanism of transmission is unclear)
    • Laboratory Exposure
    • Maternal-Fetal Transmission
    • Organ Transplant
    • Sex (Vaginal, Anal, and Oral)


Real-Time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) for Zika Virus

  • Diagnostic
    • Testing for Dengue Virus and Chikungunya Virus Should Also Be Simultaneously Performed (see Dengue Virus and Chikungunya Fever): a single PCR test for all 3 infections is available from the CDC and other laboratories
  • Samples
    • Serum: primary specimen
    • Urine: primary specimen
    • Whole Blood: sometimes used

Zika Virus Serology

  • May Be Diagnostic

Clinical Manifestations

General Comments

  • Incubation Period: 2-14 days
  • Disease Course
    • Clinical Manifestations Occurs in 20-25% of Patients Who Become Infected (MMWR Morb Mortal Wkly Rep, 2016) [MEDLINE]
    • Illness is Usually Mild and Self-Limited: resolving within 2-7 days after onset
  • Distinction Between the Clinical Presentations of Zika Virus, Dengue Virus, and Chikungunya Virus (see Dengue Virus and Chikungunya Fever) (Centers for Disease Control and Prevention, “Zika Virus-What Clinicians Need to Know?” Clinician Outreach and Communication Activity Call 1/26/16) [LINK]

Cardiovascular Manifestations

  • Myocarditis (see Myocarditis)
    • Epidemiology: rare case reports

Dermatologic Manifestations

  • Pruritic Maculopapular Rash (see Papules)
    • Epidemiology: common
    • Clinical: usually begins on the face and spreads to trunk, extremities, palms, and soles

Gastrointestinal Manifestations

Hematologic Manifestations

  • Thrombocytopenia (see Thrombocytopenia)
    • Epidemiology
      • Rare Case Reports
      • Case Series Zika Virus Infections in Patients with Renal/Liver Transplants (Am J Transplant., 2017) [MEDLINE]: these cases presented with thrombocytopenia, bacterial superinfection, and graft dysfunction (but without rash, conjunctivitis, or neurologic symptoms)

Neurologic Manifestations

  • Asthenia (see xxxx)
    • Epidemiology: may occur
  • Congenital Microcephaly
    • Epidemiology
      • Congenital Microcephaly Has Been Reported in Neonates Born to Women Who Were Infected with Zika Virus
  • Dysesthesia (see Dysesthesia)
    • Epidemiology: may occur
  • Guillain-Barre Syndrome (see Guillain-Barre Syndrome)
    • Epidemiology
      • Case Reports (Lancet, 2016) [MEDLINE]
      • Latency: ranging from 6 days to 5-9 wks after the acute episode
  • Headache (see Headache)
    • Epidemiology: may occur
  • Meningioencephalitis (see Meningitis and Encephalitis)
    • Epidemiology: has been reported
  • Myelitis (see Transverse Myelitis)
    • Epidemiology: has been reported
  • Neuropsychiatric/Cognitive Symptoms
    • Epidemiology: has been reported

Ophthalmologic Manifestations

  • Nonpurulent Conjunctivitis (see Conjunctivitis)
  • Retro-Orbital Pain (see xxxx)
    • Epidemiology: may occur
  • Uveitis (see Uveitis)
    • Epidemiology: rare case reports

Otolaryngologic Manifestations

  • Transient Hearing Loss (see Hearing Loss)
    • Epidemiology: rare case reports

Rheumatologic Manifestations

  • Arthralgias (see Arthralgias)
    • Clinical: mostly involving the small joints of the hands and feet
  • Myalgias (see Myalgias)
    • Epidemiology: may occur

Other Manifestations

  • Fever (see Fever): usually low-grade (up to 38.5 degrees C)


Protection from Mosquito Bites

  • Clothing
  • Insect Repellant
  • Mosquito Netting
  • Staying Indoors

Mosquito Control

  • Eliminate Standing Water Sources

Prevention of Sexual Transmission

  • Avoid Unprotected Sexual Contact
  • Barrier Protection

Blood/Organ/Tissue Donor Screening

  • Blood Donor Screening
  • US FDA Recommendations for Hematopoietic Stem Cells, Tissues, and Donor Gametes


Supportive Care

  • Hydration
  • Acetaminophen (Tylenol) (see Acetaminophen): as required for pain


  • Guillain-Barre syndrome outbreak associated with Zika virus infection in French Polynesia: a case-control study.  Lancet.  2016;387(10027):1531–1539 [MEDLINE]
  • Zika virus-associated Guillain-Barre syndrome: a warning for critical care physicians.  Intensive Care Med.  2016 Sep;42(9):1485–1486. doi: 10.1007/s00134-016-4364-x [MEDLINE]
  • Travel-Associated Zika Virus Disease Cases Among U.S. Residents–United States, January 2015-February 2016. MMWR Morb Mortal Wkly Rep. 2016;65(11):286 [MEDLINE]
  • Zika Virus Infection Among U.S. Pregnant Travelers – August 2015-February 2016. MMWR Morb Mortal Wkly Rep. 2016;65(8):211-4 [MEDLINE]
  • Patterns in Zika Virus Testing and Infection, by Report of Symptoms and Pregnancy Status – United States, January 3-March 5, 2016. MMWR Morb Mortal Wkly Rep. 2016;65(15):395 [MEDLINE]
  • Centers for Disease Control and Prevention, “Zika Virus-What Clinicians Need to Know?” Clinician Outreach and Communication Activity (COCA) Call 1/26/16 (Accessed 7/17) [LINK]
  • Travel-Associated Zika Virus Disease Acquired in the Americas Through February 2016: A GeoSentinel Analysis. Ann Intern Med. 2017;166(2):99 [MEDLINE]
  • Zika Virus Infection and Solid Organ Transplantation: A New Challenge. Am J Transplant. 2017;17(3):791 [MEDLINE]