zika virus and microcephaly
TRANSCRIPT
Zika virus and microcephalyKrisztian Magori, Ph.D.
Assistant Professor of BiostatisticsDepartment of Biology
Eastern Washington University
1. What is Zika virus disease? How is it connected to microcephaly?
2. How much risk there is in WA state?
3. What can you tell to your concerned patients?
What is Zika virus disease?
Zika Fever: mostly asymptomaticresolves in <1 week
Guillain-Barre Syndrome:paralysis
Congenital microcephaly
How do we define microcephaly?
HC<2 SD less than mean
HC<3 SD less than mean
Calcifications, ventriculomegaly
What is Zika virus?
• +-sense double-stranded RNA virus• Flaviviridae family• Discovered in the Ziika Forest in Uganda in 1947
Case studies
Mlakar et al., NEMJ 201625 yr old European women who got pregnant in Natal, Brazil in February 2015symptoms of Zika infection in 13th week of gestation
Zika virus causes fetal brain damage following infection of pregnant macaque
Waldorf et al., Nature Medicine 2016
Association between Zika virus infection and brain abnormalities in case-control study
• 8 public hospitals in Recife, Brazil• Cases are newborns with microcephaly• 2 controls for each case
De Araujo, Lancet Inf Dis 2016
What percentage of infected mothers’ children have brain abnormalities?
French Polynesia (1%) Brazil (20%)
Brasil et al., NEJM 2016Cauchemez et al., Lancet 2016
Potential role of prior dengue virus infection
Anti-body dependent enhancement (dengue viruses)
Lots of dengue transmission in Brazil but not in French Polynesia
Zika virus and dengue viruses closely related
Hypothesis: prior dengue infection of the mother leads to more severe Zika infection through antibody-dependent enhancement
What is the prognosis for babies born with Zika virus disease?
48 infants born in Brazil with probable congenital Zika virus syndrome
Da Silva et al., Emerg. Inf. Dis. 2016
What is the prognosis?
6 infants born without microcephaly developed microcephaly subsequently
Cost of raising child w microcephaly could be up to $4 M
Da Silva et al., Emerg. Inf. Dis. 2016
Similarities to other neuroteratogenicdiseases
In Humans:TORCH: Toxoplasma, Other, Rubella, Cytomegalovirus, Herpes SimplexOther: VEEV, JEV
In Animals:JEV, Schmallenberg, Akabane, Cache Valley, Aino, Bluetongue, Bovine viral diarrhea, Border disease, Classical Swine Fever
1. What is Zika virus disease? How is it connected to microcephaly?
2. How much risk there is in WA state?
3. What can you tell to your concerned patients?
Local transmission in Miami-Dade county, FL180 local cases reported
potentially 10 times as many
endemic
potential recursion in the Spring
Imported cases in the US4016 cases in US States
899 pregnancies
27,402 cases inUS territories
1,927 pregnancies in US territories
28 microcephaly
What is the situation in WA state?
• 48 reported cases
• All imported
• No local transmission
• WA does not have the right mosquito species
What can you tell to your patients concerned about Zika virus disease?
1. Avoid travel to areas with active ZIKV transmission
2. Practice safe sex with partner who visited areas with active ZIKV transmission in the last 6 month
3. If cannot avoid travel, practice extreme personal protection
4. If already visited or had unprotected sex with partner who visited, get tested
Practice safe sex
Both men and women should practice safe sex or abstinence for 6 month following travel to areas with active transmission or 6 month after onset of symptoms
If already visited, get tested for ZIKV All pregnant patients should be assessed for possible Zikavirus exposure at each prenatal visit
Those who meet the criteria should be tested
RT-PCR, IgM, cross-reactivity, PRNT
http://www.doh.wa.gov/YouandYourFamily/IllnessandDisease/ZikaVirus/healthcareprovidersClinicallabs
Resources if you have a patient with confirmed Zika virus infection
1. US Zika Pregnancy Registryhttp://www.cdc.gov/zika/hc-providers/registry.html
2. Jackson Memorial Hospital, University of Miami Zikaresponse unithttp://pediatrics.med.miami.edu/zika-response-team
Take-home messages
1. Zika virus causes a terrible disease, including microcephaly and other adverse outcomes
2. Zika virus is actively transmitted by mosquitoes in many parts of the world, but not WA
3. Pregnant women should not visit areas with active transmission, and should practice safe sex with partners who did travel to those areas
4. While the risk is real, it is very low, unless you visit areas with active transmission