Public Health Image Library. CDC/ Cynthia Goldsmith. Image #

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1 Zika Virus Fredrick M. Abrahamian, D.O., FACEP, FIDSA Clinical Professor of Medicine UCLA School of Medicine Director of Education Department of Emergency Medicine Olive View-UCLA Medical Center Sylmar, California Public Health Image Library. CDC/ Cynthia Goldsmith. Image #

2 Zika Virus Current outbreak in the Americas, Caribbean, & the Pacific World Health Organization: Public Health Emergency of International Concern Arthropod-borne flavivirus Transmitted by mosquitoes Similar to dengue, yellow fever, & West Nile viruses Epidemiology 1947: Zika virus isolated from a monkey 1952: Human cases detected in Africa 2007: Outbreak in Yap Islands of Micronesia ~75% of population infected : Outbreak in French Polynesia ~32,000 infections 2014: Infections in Chile s Easter Island 2015: Infections in Brazil 2

3 Current Zika Transmission (as of 4/13/2017) European Center for Disease Control & Prevention All Countries & Territories with Active Zika Virus Transmission Centers for Disease Control & Prevention 3

4 Zika Cases Reported in the United States (as of 4/12/2017) Centers for Disease Control & Prevention Active Zika Virus Transmission in Florida Centers for Disease Control & Prevention 4

5 Zika Cautionary Area Brownsville, TX Centers for Disease Control & Prevention US Epidemiology (as of 4/12/17) US States: 5,234 cases Travel-associated: 4,935 Locally acquired mosquito-borne: 223 Sexually transmitted: 46 Laboratory acquired: 1 US Territories: 36,526 cases Locally acquired mosquito-borne : 36,383 Travel-associated: 143 5

6 Transmission Infected mosquito bite Aedes aegypti (tropical regions) Aedes albopictus (temperate regions) Maternal-fetal transmission Sexual activity Blood transfusion Organ transplantation Laboratory exposure Estimated Range of Aedes aegypti & Aedes albopictus in the United States, 2016 Centers for Disease Control & Prevention 6

7 Zika Virus RNA Detection Blood: < 1 week (nonpregnant) 10 weeks (pregnant) Urine: 3 months Semen: 6 months (188 days) Sexual transmission: 41 days Higher viral load than blood or urine Saliva: 3 months Other: Female genital tract, CSF, amniotic fluid, & breast milk Public Health Image Library. CDC/ Cynthia Goldsmith. Image # Clinical Manifestations Occur in ~20%-25% of patients Incubation period: 2-14 days Symptoms resolve within a week Severe illness & death is rare Low-grade fever Maculopapular pruritic rash Arthralgia (small joints) Conjunctivitis (non-purulent) 7

8 Public Health Image Library. CDC. Image # Differential Diagnosis Dengue fever Chikungunya Parvovirus infection Rubella Rickettsial infection Group A Streptococcus Measles Leptospirosis Malaria Enterovirus Adenovirus 8

9 Features Zika Dengue Chikungunya Fever Rash Conjunctivitis - - Arthralgia Myalgia Headache Hemorrhage - - Shock - - Centers for Disease Control & Prevention Diagnosis Clinical manifestations plus exposure Case definitions: Suspected Probable: Zika IgM antibody Confirmed: Viral RNA or antigen; or Zika IgM antibody & positive Zika virus plaquereduction neutralization test (PRNT) No role for testing asymptomatic nonpregnant patients 9

10 Diagnosis rrt-pcr for Zika viral RNA (serum or urine) PCR testing for dengue & chikungunya Zika virus serology: Zika virus IgM Zika virus PRNT Beware of cross-reactivity with other flaviviruses or prior history of vaccination for yellow fever or Japanese encephalitis Time to presentation after onset of symptoms Diagnosis 7 days: PCR serum (3-7 days) & urine (2 weeks) 4-7 days with negative PCR: Zika virus IgM; PRNT if not negative 8-14 days: Urine PCR; Zika virus IgM & PRNT 15 days to 12 weeks: Zika virus IgM & PRNT > 12 weeks: No role for serologic testing 10

11 Specimen Type & rrt-pcr Specimen Type Zika rrt-pcr Dengue rrt-pcr Chikungunya rrt-pcr Serum Urine Not Not CSF Amniotic fluid Not Not < 14 days Specimens Collection Time Following Symptom Onset Virus-specific rrt-pcr Testing Virus-specific IgM Testing ± or PRNT Virus-specific IgM Testing Zika ± or Yes Other ± or Pregnancy Zika-specific rrt-pcr Testing 14 days No No PRNT 11

12 <2 weeks Asymptomatic Pregnant Women Zika virus-specific IgM Testing Zika virus-specific rrt-pcr Testing Zika virus-specific IgM Testing in 2-12 weeks ± or PRNT 2-12 weeks Zika ± or Zika-specific rrt-pcr Testing PRNT Complications Congenital microcephaly Guillain-Barré syndrome Mechanism possibly through direct viral neurotoxicity Acute motor axonal neuropathy Median time to neurological Sxs: 6 days Incidence: 2.4 cases/10,000 infections Myelitis Meningoencephalitis 12

13 Management & Prevention Symptomatic treatment Avoid aspirin and NSAIDs Mosquito protection Pregnant women: Avoid travel to areas below 6500 feet (2000 meters) Protected sex Defer blood donation for 6 months Take Home Points Approach to diagnostic testing depends on the timing of presentation after onset of symptoms PCR testing for dengue & chikungunya Zika virus serology: Beware of cross-reactivity with other flaviviruses or prior history of vaccination for yellow fever or Japanese encephalitis No testing asymptomatic nonpregnant patients 13

14 References CDC: N Engl J Med. 2016;374(16): Emerg Infect Dis. 2016;22(7): Ann Intern Med. 2016;165(3): Clin Infect Dis. 2016;63(2): Clin Microbiol Rev. 2016;29(3):