STH 2017_Day 2_Track 2_Session 1_Zika_Baracco
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Transcript of STH 2017_Day 2_Track 2_Session 1_Zika_Baracco
Emerging Infections: The Wrath of Zika
Gio Baracco MD FACP
Division of Infectious Diseases
University of Miami Miller School of Medicine
Zika is the prototypical emerging infection• Factors affecting its spread:
• Climate• Vectors• Human movement and behavior• Construction
• Long‐term health consequences in vulnerable populations
• Fear• Leads to technological advances• Control is multifaceted
http://www.cnn.com/2016/02/02/health/zika‐forest‐viral‐birthplace/
Zika virus infection and microcephaly
• 35 infants with microcephaly, Brazil, Aug‐Oct 2015• 35/35 mothers lived or visited Zika‐affected areas during pregnancy
• As of Jan 2016, 3530 cases of microcephaly recorded in Brazil (average 146 cases/yr)
• Also, ophthalmologic findings, cerebral calcifications
Pan American Health Organization / World Health Organization. Epidemiological Update: Neurological syndrome, congenital anomalies and Zika virus infection. 17 January, Washington, D.C.: PAHO/WHO; 2016
https://www.cdc.gov/zika/geo/active‐countries.html. Accessed January 12, 2017
https://www.cdc.gov/zika/intheus/maps‐zika‐us.html. Accessed January 12, 2017
Transmission of Zika virus
• Transmitted primarily by mosquitoes of the Aedesgenus (same as Dengue and Chikungunya)
• Ae. aegypti
• Ae. albopictus
• Aggressive daytime biter
• Urban
www.cdc.gov
Global Distribution of Aedesmosquitoes
Ae. aegypti
Ae. albopictus
https://www.cdc.gov/zika/vector/range.html
Aedesmosquitoes
• Breed and mature in water habitats• Primarily artificial containers associated with human dwellings
• Often indoors• Eggs resist desiccation for many months
• Female Aedesmosquitoes spend their lifetime in or around the houses where they emerge as adults
• Flight range ~400 m
http://www.who.int/denguecontrol/mosquito/en/
Science 2005; 310(5747):426‐428 Lancet 2016 Jan 23; 387:335‐336
Zika is spread by human travel
In 2015, 9.9 M travelers departed from airports within 50 km of areas with conditions conducive to year‐round zika transmission. 65% went to the Americas.
Traveler volume was greater to the US, with ~2.8 M travelers
Other routes of transmission
• Intrauterine/intrapartum
• Sexual
• Blood transfusions
• Laboratory exposure
Clinical Manifestations
• Incubation period 2‐7 days
• 80% asymptomatic
• Mild dengue‐like illness
• 2‐5 days
• Fever, body aches, rash,
conjunctivitis
• Complications
• Teratogenic
• Neurologic
Zika virus infection and Guillain‐Barre syndrome
• 2013‐14, French Polynesia• ~32,000 Zika cases (8750 registered)
• 74 patients with neurological/autoimmune conditions after Zika
• 42 with GBS
• Jul 2015, Brazil• 76 pts with neurological syndromes after Zika
• 42 with GBS
• Jan 2016, El Salvador• 46 cases of GBS in 1 month (normal 14)
• Other neurological syndromes: meningitis, meningoencephalitis, myelitis
Pan American Health Organization / World Health Organization. Epidemiological Update: Neurological syndrome, congenital anomalies and Zika virus infection. 17 January, Washington, D.C.: PAHO/WHO; 2016
• 182 women with lab‐confirmed acute Zika infection
• Mild clinical illness
• Outcomes known for 125 affected pregnancies• Fetal death 7%• 42% with grossly abnormal clinical or brain imaging findings or both
• Only 4 infants had microcephaly
• Adverse outcomes were noted regardless of the trimester which the women were infected with Zika
• All infants had abnormalities on brain imaging consistent with intrauterine Zika infection• Subcortical calcifications• Decreased brain volume
• Ventriculomegaly
• All had significant deceleration of head growth
• 60% developed epilepsy
• All developed motor disabilities consistent with mixed cerebral palsy
Diagnosis of Zika
• Clinical/epidemiological
• Trioplex Real‐Time RT‐PCR (rRT‐PCR) for acute illness (<14 days from onset of illness)
• Serum and urine
• A positive test is diagnostic, a negative test does not exclude it
• Zika MAC‐ELISA
• IgM cross‐reacts with Dengue, Yellow Fever, West Nile virus
• Presumed positive, equivocal, or inconclusive tests need confirmation by plaque‐reduction neutralization testing (PRNT)
Zika testing of asymptomatic pregnant women• Women who have traveled to areas with active Zika transmission• rRT‐PCR within 2 weeks of exposure or if positive IgM• IgM testing if 2‐12 weeks after exposure
• MAC‐ELISA screening with PRNT confirmation
• Women who live in areas of active Zika transmission• IgM as part of routine obstetric care in 1st and 2nd
trimester• Reflex PCR for women who are IgM positive
Management
• No specific vaccine or treatment is available
• Supportive care
• Acetaminophen for fever/pain• Avoid NSAIDs
• Self‐limited in about 1 week
• Refer pregnant women with Zika to high‐risk OB care
Counseling
• Main goal: prevent pregnant women (PW) –and others‐ from getting Zika• Avoid travel to areas with active transmission
• Mosquito prevention: remove breeding sites around the house, use repellent, stay in A/C spaces
• Prevention of sexual transmission: condoms or abstinence throughout pregnancy if partner is at risk
• Testing: after exposure for traveler PW; routine 1st and 2nd trimester if PW lives in area with Zika
• Referral to high‐risk OB if test is positive in a PW
https://www.cdc.gov/zika/pregnancy/protect‐yourself.htmlAccessed January 25, 2017
Counseling
https://www.cdc.gov/zika/pregnancy/women‐and‐their‐partners.htmlAccessed January 25, 2017
The Swiss Cheese Model
http://patientsafetyed.duhs.duke.edu/module_e/swiss_cheese.htmlAccessed January 22, 2017
How do we stop the spread?
• Protect those most vulnerable (pregnant women and their babies)• By reducing the burden in the community• By identifying areas with high risk of transmission• By reducing travel to high‐risk areas• By decreasing the concentration of vectors• By preventing mosquito bites• By preventing sexual transmission• By screening blood products
• Develop vaccines• Develop therapeutic agents
“In the end, every outbreak of infectious disease breeds two more outbreaks in panicked succession – the spread of fear, followed by a rush of urgent meetings. To lessen the next panic, health care personnel must meet, plan, and hold local drills now”
R.A. Weinstein. New Eng J Med. 2004; 350(23):2332‐4