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ZIKA VIRUS UPDATE April 25, 2016
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Prevention and Health Promotion Administration 2 What is Zika virus? Single-stranded, enveloped RNA virus In the Flaviviridae family Yellow fever West Nile Dengue St. Louis encephalitis A transmission electron micrograph of the Zika virus (CDC)
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Prevention and Health Promotion Administration 3 History of Zika virus First discovered in rhesus monkeys 1947 in Uganda, near the Zika Forest Subsequently described in humans in 1952 in Uganda and United Republic of Tanzania Cases in Africa and Asia during 20th century First outbreak outside of Asia or Africa in 2007 in Yap (Federated States of Micronesia) Outbreak in French Polynesia in October 2013
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Prevention and Health Promotion Administration 4
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Prevention and Health Promotion Administration 5 Recent History of Zika virus
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Prevention and Health Promotion Administration 6 Transmission Primarily through the bite of an infected Aedes sp. mosquito Same mosquitoes that spread dengue, chikungunya, and yellow fever Typically lay eggs in containers and standing water Aggressive daytime biters, can also bite at night Prefer to bite people
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Prevention and Health Promotion Administration 7 Aedes aegypti and Aedes albopictus Aedes aegyptiAedes albopictus (Asian tiger mosquito)
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Prevention and Health Promotion Administration 8 Primary vectors Ae. aegypti Strong preference for human blood Lives around human habitations in urban areas Lays eggs and produces larvae preferentially in artificial containers Primarily daytime feeder; rests indoors High vectorial capacity for Zika (effectiveness of virus transmission in nature) Ae. albopictus Indiscriminate feeder Lives near human habitations in suburban/rural areas Lays eggs and produces larvae in natural or artificial containers Aggressive, daytime feeder in outdoor areas Competent vector of Zika
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Prevention and Health Promotion Administration 9 Life cycle of Aedes mosquito
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Prevention and Health Promotion Administration 10 Updated Aedes Distribution Maps, March 30, 2016
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Prevention and Health Promotion Administration 11 Other modes of transmission From mother to child During pregnancy or delivery from a mother already infected To date, no reports of infants getting Zika virus through breastfeeding Through infected blood or sexual contact Spread of the virus through blood transfusion and sexual contact has been reported Through organ or tissue donation No confirmed cases but theoretically possible
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Prevention and Health Promotion Administration 12 Sexual transmission: what we know Zika virus can be spread by a man to his sex partners In known cases of likely sexual transmission, the men had Zika symptoms Virus can be spread before, during, and after men have symptoms The virus can be present in semen longer than in blood
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Prevention and Health Promotion Administration 13 Suggested timeframes to wait before trying to get pregnant
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Prevention and Health Promotion Administration 14 Incubation Period and Symptoms Incubation period not known Likely few days to 2 weeks Most infections are asymptomatic Most common symptoms Fever Rash – very common, often itchy Joint pain Conjunctivitis (red eyes) Other symptoms include muscle pain and headache
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Prevention and Health Promotion Administration 15 Clinical Presentation ZikaDengueChikungunya Fever+++++ Rash++++++ Conjunctivitis++-- Arthralgia++++++ Myalgia++++ Headache+++ Hemorrhage-++- Shock-+- *Courtesy Dr. Ingrid Rabe, CDC
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Prevention and Health Promotion Administration 16 Zika & pregnancy Increased rates of microcephaly noted in Brazil in late 2015 10-20x normal (reported) incidence Prior associations with neurological and auto-immune complications in French Polynesia outbreak
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April 13, 2016 On the basis of this review, we conclude that a causal relationship exists between prenatal Zika virus infection and microcephaly and other serious brain anomalies.
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Prevention and Health Promotion Administration 18 Diagnostic Testing PCR can detect virus in first week after illness onset Serological testing can detect illness for longer IgM detectable starting ~day #4 after illness onset Potential cross-reactivity with other viruses (WNV, YFV, Dengue) making test interpretation sometimes difficult More complex serological tests can be done to help distinguish Zika from other infections; less helpful if previously infected/vaccinated PCR and IgM ELISA now available at DHMH public health laboratory; CDC conducts confirmatory testing No commercial testing available at this time
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Prevention and Health Promotion Administration 19 Treatment No specific antiviral treatment No vaccine Supportive — rest, fluids, antipyretics, anti-nausea meds Acetaminophen for fever and pain Avoid aspirin and NSAIDS until dengue ruled out to avoid hemorrhagic complications
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Prevention and Health Promotion Administration 20 When providers want to test patients for Zika LHD, DHMH personnel can approve testing at DHMH Labs for: Asymptomatic pregnant women with travel history to Zika-affected area during pregnancy or who become pregnant within 2 weeks of travel Symptomatic travelers (male and female) With 1 or more major symptoms (fever, rash, conjunctivitis, arthralgia), AND Symptom onset within 2 weeks of last day in Zika-affected country Pregnant partners of recent travelers to Zika-affected areas
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Prevention and Health Promotion Administration 21 Countries and territories with active Zika virus transmission
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Prevention and Health Promotion Administration 22 U.S. Zika virus cases, as of April 20, 2016 Lab-confirmed Zika virus disease cases, reported to ArboNet in US States, as of April 20, 2016 Travel-associated Zika virus disease cases reported: 388 Locally acquired vector- borne cases reported: 0 Total: 388 Pregnant: 33 Sexually transmitted: 8 Guillain-Barre syndrome: 1
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Prevention and Health Promotion Administration 23 Maryland confirmed Zika virus infections
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Prevention and Health Promotion Administration 24 Threat to Maryland No locally acquired mosquito-borne Zika virus disease cases have been reported in the continental US but there have been locally acquired cases in Puerto Rico, the US Virgin Islands, and other U.S. territories Many travel-associated Zika cases identified in the U.S. and will continue to increase Many infections will not be diagnosed but could potentially serve as source for transmission Travel-associated cases could result in local spread of the virus in the U.S., including in Maryland
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Prevention and Health Promotion Administration 25 Air travel between U.S. and Zika affected areas ~30 million people fly to the U.S. each year from countries in the Caribbean and Latin America 1 Unlikely Zika would spread as quickly or as widely in the U.S. 2 Better public health infrastructure More air conditioning and screening Earlier disease detection Better mosquito control 1. Sources: Bureau of Transportation Statistics (air travel data) 2. “Anticipating the international spread of Zika virus from Brazil,” The Lancet. Isaac I. Bogoch and Kamran Khan, University of Toronto; Oliver J. Brady and Moritz U.G. Kraemer, University of Oxford
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Prevention and Health Promotion Administration 26 Maryland Public Health Response Providing Zika information to Marylanders via a variety of formats (including website and social media) Providing guidance to MD healthcare providers Working with providers for Zika testing at DHMH (with focus on pregnant women) Coordinating medical management for Zika-infected pregnant women and infants Conducting surveillance and epidemiologic investigations Zika infection (reportable) Microcephaly (reportable, including by hospitals) GBS Mosquito Controlling mosquitoes (in concert with MD Dept of Agriculture)
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Prevention and Health Promotion Administration 27 Current Statewide Zika Activities Zika Awareness Week (April 24-30) Governor proclamations to all LHDs LHDs asked to host/sponsor Zika-related activities Zika Prevention Kits for pregnant women Educational information Repellent Larvicide Condoms
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Prevention and Health Promotion Administration 28 Vector Control for Zika Virus ≠ Vector Control for West Nile Virus Whereas mosquito-based surveillance is the preferred method for monitoring or predicting West Nile virus outbreaks, it is not the preferred method for monitoring or predicting Zika (dengue, chikungunya, or yellow fever) outbreaks For these arboviruses, it is more efficient to detect cases in people
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Prevention and Health Promotion Administration 29 Aedes Surveillance and Control Surveillance Determine presence or absence of Aedes Identify types of containers are producing the most mosquitoes for targeting vector control efforts Understand where mosquito populations occur Monitor the effectiveness of vector control efforts Control Community and property clean up Application of larvicide Application of adulticide Education about personal protection
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Prevention and Health Promotion Administration 30 Principal functions of Zika, dengue and chikungunya mosquito-based surveillance programs Determine presence or absence of Ae. aegypti and Ae. albopictus in a geographic area Identify what types of containers are producing the most mosquitoes for targeting vector control efforts Track larval sites if Ae. aegypti or Ae. albopictus are detected in an area Collect mosquito population data and identify geographic areas of high abundance (high-risk) Monitor the effectiveness of vector control efforts Collect data on mosquito infection rates during outbreaks to: identify primary/secondary mosquito vectors establish thresholds at which humans get infected
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Prevention and Health Promotion Administration 31 Focused vector control activities when any of the following occurs: a) Any detection of Ae. aegypti; b) Threshold levels of Ae. albopictus are reached; OR c) Travel-associated cases of Zika virus infection are detected
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Prevention and Health Promotion Administration 33 Mosquito Bite Prevention
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Aedes albopictus
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