Zika virus - NSW Agency for Clinical Innovation · closely related to dengue, yellow fever,...
Transcript of Zika virus - NSW Agency for Clinical Innovation · closely related to dengue, yellow fever,...
Zika virus
Dominic Dwyer Medical Virologist Director, ICPMR and Pathology West Westmead Hospital
Zika virus
Flavivirus • first isolated in 1947 in a rhesus monkey in the
Zika forest, Uganda • enveloped RNA virus ~11 kb • closely related to dengue, yellow fever, Japanese
encephalitis viruses • transmitted by Aedes spp. mosquitoes
Clinical presentation similar to other flaviviruses • fever, rash, myalgia, arthralgia • headache, conjunctivitis • (only) 20% symptomatic
Predicted distribution of Aedes aegypti
Kramer eLife 2015
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Knope et al. 2013; CDI 37: 55-59
Australian travellers and dengue
Zika virus - Australia (24/2/16)
Zika virus - Australia (24/2/16)
Faria NR et al. Science 10.1126/science.aaf5036 (2016)
Travelers to Brazil from countries with recorded ZIKV outbreaks between 2012 and 2015
9.9 million visitors depart Brazilian airports annually 65% to Americas, 27% to Europe and 5% to Asia
Bogoch Lancet 2016
Time series and cartography of reported ZIKV infections and microcephaly cases in Brazil
Faria NR et al. Science 10.1126/science.aaf5036 (2016)
Weekly ZIKV notifications in 5596 municipalities in Brazil (n=2791 cases)
ZIKV cases/100,000 people in each state
Suspected microcephaly cases/100,000 people in each state
Driggers RW et al. N Engl J Med 2016. DOI: 10.1056/NEJMoa1601824
Timeline: Symptoms, Radiographic and Laboratory Studies
Driggers RW et al. N Engl J Med 2016. DOI: 10.1056/NEJMoa1601824
Foetal ultrasound at 19 weeks gestation
Panel A: ZIKV-exposed foetus Thin cerebral cortex with increased extra-axial space (E), dilated third ventricle (T), enlarged frontal horns (F), apparent absence of the cavum septum pellucidum Panel B: Normal foetus at same gestational age Visible cavum septum pellucidum (C)
Serology • Acute and convalescent sera at least 14 days apart • ZIKV IgM and IgG by immunofluorescence (IFA) • EIAs available, but uncertain reliability • Main problem is cross reactivity with other flaviviruses
(and YF vaccine) • Neutralisation is the ‘gold-standard’
Test for dengue, chikungunya (co-circulating) Also consider other viral diseases, malaria, leptospirosis, rickettsial infections etc
Laboratory Testing for Zika virus
Gourinat Emerg Infect Dis 2015, Musso J Clin Virol 2015
RT-PCR • short-lived viraemia (<5 days) • Viruria (<30 days) • saliva, amniotic fluid, semen, breast milk
Test for dengue, chikungunya (co-circulating) Virus isolation
Laboratory Testing for Zika virus
Gourinat Emerg Infect Dis 2015, Musso J Clin Virol 2015
Issues for ED
• Clinical suspicion • Travel history in anyone with a fever or
suspected infection • Pregnancy history and management • Seek advice from ID/microbiology
– differential diagnosis – appropriate specimens and tests – need for testing others (partners, family etc)
• Review NSW and Commonwealth Health Department advice