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Zika Virus – An update Dr S Anuradha, Gold Coast Public Health Unit
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What is Zika Virus? Zika is a RNA virus of the Flavivirus family Spreads to people primarily through the bite of an infected Aedes species mosquito (vector) Vectors are the same as for dengue virus, Aedes aegypti (N & C Qld and some SW Qld) and Aedes albopictus (Torres Strait).
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Zika – Clinical Context Short, mild illness; 80% asymptomatic Low grade Fever Arthralgia (small joints) ~swelling Headaches (retro-orbital), muscle pains Conjunctivitis, maculo-papular rash Tiredness, weakness
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Zika - Clinical Context Incubation Period: May be up to 10 days Infectious Period: Unknown No treatment nor vaccine yet Differential Diagnosis (Zika is milder)
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Historical - From 1947 - 2016
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Global Update Between 1 Jan 2007 and 17 Feb 2016, 48 countries and territories have reported local transmission of Zika virus DoH website for list of countries: http://www.health.gov.au/internet/main/publi shing.nsf/Content/ohp-zika-countries.htm
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Association with birth defects and neurological disorders Increase in the cases of microcephaly (Brazil & French Polynesia) Increase in cases of Guillain-Barré syndrome (GBS) (atleast 5 countries)
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Public Health Emergency WHO declared a Public Health Emergency of International Concern (PHEIC) on 1 February 2016 WHO declared that “Surveillance for microcephaly and GBS should be standardized and enhanced, particularly in areas of known Zika virus transmission and areas at risk of such transmission ”
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Birth defects: the defence Microcephaly is a measurement, not a syndrome Reports mainly from NE Brazil, not elsewhere Poverty, pesticides, other factors? Birth cohort showing high rate before Zika (but steep rise in severe cases after)
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What’s the risk of microcephaly? Background rate ~5 per 100,000 births Brazil, 2015 ~4700 (max) cases in 2.9M births That would be 162 per 100,000 If ~1.5M infections in population 200M At same attack rate~ 21,000 affected pregnancies Risk (pregnancy with Zika) could be 3% – 15% Uncertainties: Can silent infections damage fetus? Stage of pregnancy? Cofactors? What about breast-feeding?
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Association with birth defects and neurological disorders Circumstantial relationship?? Clinical and Epidemiological information is emerging fast Case-control study using 100 cases of microcephaly currently underway
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Australia Update In Australia there have been 27 cases notified, with the first in 2012 The first case of Zika notified in Queensland was in 2014 As at 15 Feb 2016, Qld’s total is 18 cases 7 in 2014 4 in 2015 7 in 2016
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Country of acquisition All cases notified in Qld were acquired overseas In 2016, cases were acquired from Samoa (3) and Tonga (3) Country of acquisition Number of notifications in Qld Cook Islands7 Samoa3 Tonga3 Vanuatu2 El Salvador1 Solomon Islands1
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Qld Zika notifications In 2016 one pregnant woman has been notified. Most reported in SEQ Hospital and Health Service Number of Notifications Gold Coast4 Metro South4 Townsville3 West Moreton3 Metro North2 Mackay1
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Minister’s Round Table 03 February 2016 - Qld. Health Minister met with health experts and other stakeholders Recognition that greatest risk for local transmission is in north Queensland Ministerial priorities: Research Laboratory testing capability Community engagement Local government engagement with mosquito surveillance and control
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The specific vector Elderly ♀ Aedes aegypti Day biting, shy, fussy, travels ≤ 200m Hides indoors, under furniture, dark surfaces Extrinsic Incubation period: 8 - 12 days Infective for life Not a bush mozzie
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Getting ready- Receptive area Encourage Eliminate Dengue (wolbachia mosquitoes) participation Vector control at home using interior residual spray (IRS) (90% dengue protection to occupants) Zappers, coils, daytime / dusk clothing (legs, feet) and repellents DEET, pyrethroids, methoprine safe in pregnancy
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Eliminate Breeding Sites
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Targeted insecticides
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Surveillance Early detection is key to preventing and managing outbreaks Labs in Townsville to test for Zika virus from March 2016
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Testing for Zika Returned from Zika country + sick Returned from Zika country + Pregnant, (sick or not) Test early for the virus (PCR: 0 - 7 days) Pregnant: urine PCR can be positive up to 2 weeks Semen? Serology (testing for antibodies IgG & IgM)
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Testing for Zika in Pregnancy Symptomatic Pregnant Women H/o place of travel and date of symptom onset Test for Zika + others relevant travel- related illness Recommended specialist ID advice to discuss DD
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Testing for Zika in Pregnancy Asymptomatic Pregnant Women H/o dates/duration/place of travel H/o mozzy bites Blood collected at initial presentation irrespective of time of exposure If presents < 2 weeks of exposure, blood collected held at lab for future testing
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Diagnostic tests
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Sexual Transmission Zika virus has been found in saliva or urine for more than one week after blood clears Two cases of probable sexual transmission reported so far – both from men Seminal fluid positive for virus for 9 weeks after onset of symptoms – so duration of infectivity currently unknown No evidence that an infected woman can transmit Zika virus through sex
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Sexual Transmission Recommendations for men who have recently travelled to areas with ongoing Zika virus transmission Pregnant partner - Use condoms consistently or abstain from sexual activity for the duration of pregnancy Confirmed Zika infection and non pregnant partner - Use condoms consistently or abstain from sexual activity for 3 months
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Travel advice Pregnant, contemplating pregnancy… “Don’t go to the listed countries” No sexual partners Safe sex throughout pregnancy semen may be positive for 2 months + Mosquito avoidance Insect repellants, clothes, bednet (daytime)
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Unknowns?? Real link to microcephaly, adult GBS? Sensitivity and Specificity of tests? Asymptomatic transmission? Rate, duration of sexual transmission? Low level circulation (Dengue endemic countries)?
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Updates Qld Health website https://www.health.qld.gov.au/news- alerts/health-alerts/zika/ Communicable disease control guidance The Australian Government Department of Health Contact Public Health Unit on 5687 9000 or email gcphucdc@health.qld.gov.augcphucdc@health.qld.gov.au
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Thank you
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Dengue outbreaks
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A. aegypti distribution
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