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Zika Virus – An update Dr S Anuradha, Gold Coast Public Health Unit

Zika Virus – An update Dr S Anuradha, Gold Coast Public Health Unit. 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)

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Zika Virus – An update Dr S Anuradha, Gold Coast Public Health Unit

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  1. Zika Virus – An update Dr S Anuradha, Gold Coast Public Health Unit

  2. 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).

  3. 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

  4. Zika - Clinical Context • Incubation Period: May be up to 10 days • Infectious Period: Unknown • No treatment nor vaccine yet • Differential Diagnosis (Zika is milder)

  5. Historical - From 1947 - 2016

  6. 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/publishing.nsf/Content/ohp-zika-countries.htm

  7. 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)

  8. 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”

  9. 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)

  10. 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?

  11. 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

  12. 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

  13. Country of acquisition • All cases notified in Qld were acquired overseas • In 2016, cases were acquired from Samoa (3) and Tonga (3)

  14. Qld Zika notifications • In 2016 one pregnant woman has been notified. • Most reported in SEQ

  15. 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

  16. The specific vector • Elderly ♀Aedesaegypti • 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

  17. Getting ready- Receptive area • Encourage Eliminate Dengue (wolbachia mosquitoes)participation • Vector control at home using interior residual spray (IRS) (90% dengue protectionto occupants) • Zappers, coils, daytime / dusk clothing (legs, feet) and repellents • DEET, pyrethroids, methoprinesafe in pregnancy

  18. Eliminate Breeding Sites

  19. Targeted insecticides

  20. Surveillance • Early detection is key to preventing and managing outbreaks • Labs in Townsville to test for Zika virus from March 2016

  21. 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)

  22. 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

  23. 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

  24. Diagnostic tests

  25. 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

  26. 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

  27. Travel advice • Pregnant, contemplating pregnancy… “Don’t go to the listed countries” • No sexual partners • Safe sex throughout pregnancysemen may be positive for 2 months + • Mosquito avoidance • Insect repellants, clothes, bednet (daytime)

  28. 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)?

  29. 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.au

  30. Thank you

  31. Dengue outbreaks

  32. A. aegypti distribution

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