ZIKA VIRUS – Brief Summary April 6, 2016

Debra Stevens, RN BSN CHEP Worcester County Health Department

Director of Community Health and Emergency Preparedness

Adapted from Maryland Department of Health and Mental Hygiene

Prevention and Health Promotion Administration

The Virus

In the Flaviviridae family: includes Yellow

Fever, West Nile, Dengue

Arbovirus transmitted primary by Aedes

species mosquitoes, most importantly A.

aegypti and A. albopictus

History

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

Outbreak in French Polynesia starting in 10/2013

http://www.nejm.org/doi/full/10.1056/NEJMoa0805715

http://who.int/mediacentre/factsheets/zika/en/

http://ecdc.europa.eu/en/press/news/_layouts/forms/News_DispForm.aspx?List=8db7286c-

fe2d-476c-9133-18ff4cb1b568&ID=954

Areas with Zika Transmission

March 2016

Oceania/Pacific Islands Africa

American Samoa Cape Verde

Marshall Islands

New Caledonia

Samoa

Tonga

Lab-confirmed ZIKV disease cases by state or territory

United States, 2015–2016 (as of March 30, 2016)

MD – 6 travel associated cases

Zika Infection

Incubation period: estimated 3-5 days, up to 14

days

Only about 20% of people infected have

symptoms: Rash, Fever, Conjunctivitis, Arthralgia,

Headache, Myalgia

Viremia (virus in blood) lasts for ≤1 week

Duration of illness: brief, typically ~1 week

Generally illness is mild, but a couple of

important potential complications

Guillain-Barre Syndrome (GBS)

Pregnancy complications, especially microcephaly

Zika & Pregnancy

Increased rates of microcephaly noted in Brazil

in late 2015, 10-20x normal (reported) incidence

Weight of evidence now strongly implicates Zika

virus as a direct cause of microcephaly and

other adverse pregnancy outcomes

CDC currently recommends pregnant women

defer travel to areas with ongoing transmission

Pregnant women who have traveled to affected

areas warrant Zika testing, regardless of

whether they have symptoms

Zika Transmission

Primarily by mosquitoes

Sexual transmission – now documented, new CDC guidance

out for prevention (condom use)

Blood transfusion – at last 1 patient, possibly transmitted prior

to symptom onset

Virus isolated from breast milk, but no known cases

transmitted

Organ or tissue donation – no confirmed cases but

theoretically possible

NOT like Ebola – No special PPE or isolation needed for Zika

patients (just normal Standard Precautions)

Diagnostic Testing

Initially only available at CDC

Testing now available at DHMH public

health laboratory for appropriate

persons

No commercial testing available at this

time

Guidance out on who to test; contact

LHD

Current CDC Guidance on Who to

Test

CDC recommends testing:

Exposed persons with signs or symptoms of Zika virus disease

Exposed pregnant women – even if no symptoms

Infants of mothers exposed during pregnancy (unless mother tested

negative and infant is without signs of microcephaly or other abnormalities)

CDC defines exposure as:

Living in or having traveled to an area with ongoing Zika virus

transmission (underscoring the importance of obtaining travel histories)

Having condomless sex with a male who traveled to an area

with ongoing Zika virus transmission AND who had Zika

symptoms during or within 2 weeks of travel

Treatment for Zika

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

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

Surveillance and epidemiologic investigations Zika infection (reportable) Microcephaly (reportable, including by hospitals) GBS Mosquito

Mosquito control (in concert with MD Dept of Agriculture)

The Vector

Aedes Mosquitoes

Aedes aegypti Aedes albopictus

Aedes in United States

Aedes Mosquitoes

Prefers to live near human habitation

Lays eggs in natural and artificial containers

Primarily aggressive, daytime feeder

Ae. aegypti prefers to bite humans

Ae. albopictus – indiscriminate feeder

Short flight range (<200 yards)

Vectors for Zika, yellow fever, dengue, chikungunya

viruses

Ae. aegypti primary vector – high vectorial capacity

Ae. albopictus competent vector – unknown role in Zika

transmission

Require different methods for surveillance and control than

the mosquitoes that typically transmit West Nile virus

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

Life cycle of Aedes mosquito

The Trouble With Tigers in

Maryland

Aedes albopictus identified in Maryland in 1987

Close association with human habitation – develops in

containers, bamboo shoots, and treeholes

Capable vector of several diseases, including Zika

Incredibly annoying

• Bites mainly during the day, unlike most of our species

• Readily enters homes, cars, etc

• Very persistent and aggressive biter

• Difficult to eliminate unless the egg-laying containers are

eliminated

• Many homeowners will stop using their yards once this

species is established

What the Community Can Do

Regarding Asian Tiger Mosquitoes

Check yard weekly

• Tip or remove all water holding containers

Use Mosquito Dunks or Mosquito

Torpedoes (commercially available)

Talk to neighbors about “tiger”

breeding areas

• Problem cannot be fixed by cleaning only

one yard!

Work with community officials for

community education about “tigers”

and clean up

Asian Tiger Mosquito Larval Habitats

Mosquito Bite Prevention

Reduce/remove mosquito breeding sites

Avoid areas of high mosquito activity

Wear insect repellent. Yes, it is safe! When used as directed insect repellent is

the best way to protect yourself form mosquito bites – even children and pregnant women should protect themselves.

Cover up. When weather permits, wear long sleeved shirts and pants

Keep mosquitoes outside. Use air conditioning or make sure that you repair and use

window/door screens.