Infectious Disease Book













Zika Virus

Aka: Zika Virus
  1. See Also
    1. Congenital Zika Syndrome
  2. Background
    1. First described in Uganda, 1947
    2. First large-scale human outbreak in 2007
  3. Pathophysiology
    1. Genus: Flavivirus
      1. Single-stranded RNA virus
      2. Similar to Dengue, Yellow Fever, West Nile
    2. Regions involved (CDC)
    3. Transmission
      1. Mosquito Bite by infected Aedes albopictus Mosquito (breeds in water containers)
        1. Primates are natural virus reservoir
        2. During epidemics, human to Mosquito to human transmission
      2. Other transmission
        1. In-utero and perinatal transmission
        2. Transfusion (blood, Platelets)
        3. Sexually transmitted
          1. Zika Virus may be transmitted in semen for up to 2-6 months
          2. Peterson (2016) MMWR Morb Mortal Wkly Rep 65(39):1077-81 [PubMed]
  4. Symptoms
    1. Asymptomatic in >80% of cases
    2. Median Incubation Period: 6 days
    3. Duration: Typically mild symptoms for up to 1 week
    4. Common symptomatic presentation (similar in adults and children)
      1. Maculopapular rash (most common)
      2. Fever
      3. Nonpurulent Conjunctivitis
      4. Arthralgia
    5. Associated symptoms
      1. Headache (esp. Retroorbital pain)
      2. Voming
      3. Myalgias
      4. Edema
  5. Differential Diagnosis
    1. Dengue Fever
    2. Leptospirosis
    3. Malaria
    4. Rickettsia
    5. Group A Streptococcus
    6. Rubella
    7. Measles
    8. Parvovirus
    9. Adenovirus
    10. Enterovirus
    11. Alphaviruses (e.g. Chikungunya)
  6. Labs: General
    1. Complete Blood Count
      1. Thrombocytopenia
  7. Labs: Diagnosis (esp. pregnancy)
    1. Preferred testing protocols for pregnant women are evolving and dependent on multiple factors
      1. Timing from symptoms or exposure less than 2 weeks?
      2. Symptomatic?
      3. Endemic region for Zika Virus infection?
    2. CDC Zika Diagnostics
    3. Primary tests
      1. Real-time reverse transcriptase PCR (RNA NAT serum and urine)
        1. Preferred test in first 2 weeks
        2. Sources
          1. Zika RNA is expected in serum from before symptoms to 1 week after (up to 10 weeks rarely)
          2. Zika RNA may be present in urine for up to 2 weeks after symptom onset
          3. Samples may also be obtained from cerebrospinal fluid and amniotic fluid
        3. Positive RNA test confirms Zika, but negative test does not exclude Zika
          1. If negative RNA, obtain Zika Virus IgM and DengueVirus IgM
      2. Serum Zika IgM
        1. Preferred test at 2-12 weeks after symptom onset
        2. False Negatives in first 2 weeks
        3. False Positives with other Flavivirus Infection (esp. previously exposed or vaccinated)
    4. Other testing in unclear cases when primary tests are non-diagnostic
      1. DengueVirus IgM
      2. Serum Plaque Reduction Neutralization Testing (serum PRNT)
        1. Indicated in positive or equivocal Zika Virus IgM
        2. False Positives due to cross reactivity with DengueVirus (avoid in Puerto Rico)
  8. Management
    1. Exclude serious causes in differential (e.g. Dengue Fever)
    2. Supportive Care
    3. Hydration
    4. Analgesics (e.g. NSAIDs, Acetaminophen)
      1. Avoid NSAIDs until Dengue Fever is excluded
      2. Avoid Aspirin (due to Thrombocytopenia risk in Zika, Hemorrhage risk in Dengue Fever)
    5. Reduce transmission to others
      1. Prevent further Mosquito Bites during acute Zika Virus infection
      2. Prevent sexual transmission
  9. Complications
    1. Congenital Zika Syndrome (with severe Microcephaly and associated neurologic complications)
    2. Guillain-Barre Syndrome (also occurs with West Nile Virus)
      1. Risk following Zika Infection: 0.24 per 1000
      2. Median onset of neurologic findings after Zika Infection: 5-6 days
    3. Thrombocytopenia
      1. May be severe, life threatening (rare)
    4. Zika Virus Encephalitis
  10. Prevention
    1. See Prevention of Vector-borne Infection
    2. Pregnant women in Zika active regions
      1. Pregnant women in Zika active regions should use Condoms or abstinence throughout pregnancy
      2. Guidance for pregnant women with Zika Exposure (CDC)
    3. Nonpregnant women in Zika active regions
      1. Strongly consider effective Contraception if not desiring pregnancy
    4. Sexual transmission prevention
      1. Women should use Condoms or abstinence for at least 2 months after infection or exposure
      2. Men should use Condoms to prevent transmission
        1. Use Condoms for 6 months after Zika infection (or when attempting conception after exposure) AND
        2. Use Condoms for 8 weeks after traveling to Zika endemic region
  11. References
    1. CDC Zika Virus
    2. WHO Zika Virus
    3. ACOG Zika Virus
  12. References
    1. Huntington (2016) Am Fam Physician 94(7): 551-7 [PubMed]
    2. Igbinosa (2017) Am Fam Physician 95(8): 507-13 [PubMed]

Zika virus disease (disorder) (C0276289)

Concepts Disease or Syndrome (T047)
SnomedCT 3928002
English zika virus (diagnosis), zika virus, Zika virus disease (disorder), Zika fever, Zika virus disease, Zika; fever, fever; Zika, Mosquito-borne viral fever, Zika
Dutch Zika; koorts, koorts; Zika
Spanish enfermedad por virus Zika (trastorno), enfermedad por virus Zika, fiebre Zika
Derived from the NIH UMLS (Unified Medical Language System)

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