Zika

Zika 3-12 days Conjunctivitis, arthralgia, rash, or fever Geography Central/South America Carribean, Puerto Rico Papua New Guinea and American Samoa Timing 3-12 days Signs and Symptoms Conjunctivitis, arthralgia, rash, or fever Mimics dengue, chikungunya Classic Features Conjunctivitis Microcephaly due to congenital infection

Zika Arbovirus, genus Flavivirus Related to dengue, yellow fever, West Nile virus Only 1 in 5 infections are symptomatic Symptoms usually mild, lasting up to a week Before 2015, reported in Africa, SE Asia, Pacific Islands Guillain-Barré reported following Zika infection

Zika 2015 Brazil outbreak associated with increase in babies born with microcephaly Transmission routes now known: From mosquito bite In utero mother to fetus Sexual transmission from male partner Blood transfusion

Zika: Q and A Where is Zika? Guillain-Barré Syndrome Where is Zika in the US? Testing for Congenital Zika What is a positive Zika test? Evaluation of Congenital Zika When do I test for acute Zika? Long term follow-up of Congenital Zika How do I test for acute Zika? Breastfeeding Sexual Transmission Guidance for Travel

Where is Zika? http://www.cdc.gov/zika/geo/index.html, May 26th

What about the US? Active transmission in Puerto Rico, US Virgin Islands, American Samoa 935 cases, 142 pregnant women 591 US travel-associated cases 168 pregnant women 11 sexually transmitted 1 with Guillain-Barré

What is a positive Zika test? Zika virus RNA on reverse transcriptase-PCR Zika virus IgM with neutralizing antibody titers >= 4 times higher than dengue virus neutralizing antibody titers If antibody titers <4x higher, test is considered inconclusive RT-PCR may be negative after in utero infection False positive IgM due to dengue and yellow fever

When to Test for Acute Zika Patients with travel to an affected area within 2 weeks and 2 or more of the following Fever, rash, conjunctivitis, or arthralgia Infants under 2 weeks if mother travelled to an affected area within 2 weeks of delivery and the infant has 2 or more of above symptoms

How to Test for Acute Zika Serum RT-PCR within 7 days of symptoms Urine RT-PCR within 14 days of symptoms IgM serology and neutralizing antibodies >4 days of symptoms CSF can be tested for Zika virus RNA if clinical concern

Figure 6: CDC testing algorithm for Chikungunya, Dengue & Zika virus

Guillain-Barré Syndrome Zika virus infection associated with increased rates of GBS Causal relationship not yet established Risk increases with increasing age

Testing for Congenital Zika Infants with microcephaly or intracranial calcifications and a positive maternal travel history should be tested within 48 hours of birth Infants without those abnormalities should be tested if the mother had positive or inconclusive Zika serum tests Infants without abnormalities do not need to be tested if the mother was negative or had travel but no testing RT-PCR and IgM should both be sent Placenta and umbilical cord tissue can also be tested

Evaluation of Congenital Zika Physical examination Head circumference, length, weight, gestational age Neurologic exam Dysmorphic features Hepatosplenomegaly Rash Cranial ultrasound if not documented as normal in third trimester Ophthalmology exam Newborn hearing screen If abnormalities, consider genetics, neurology & ID

Congenital Neurologic Abnormalities Microcephaly with intracranial calcifications, ventriculomegaly, lissencephaly, pachygyria Fetal Brain Disruption Syndrome Congenital contractures, clubfoot Abnormal eye findings

Zika's ground zero: Generation of babies born with microcephaly face uncertain future

Long-term Follow-Up Infants with positive or inconclusive Zika virus test Additional hearing screen at 6 months Audiology follow-up for abnormal hearing screens Head circumference and developmental milestones through age 1 year Refer for abnormalities (neurology, developmental pediatrics, physical or speech therapy) No known abnormalities from Zika acquired around time of delivery

What about breastfeeding? Zika virus RNA has been found in breastmilk No reported cases of transmission through breastfeeding Benefits outweigh “theoretical” risk of transmission CDC encourages infected mothers and mothers in endemic areas to breastfeed

What about sexual transmission? Zika virus detected in semen up to 62 days after symptom onset Not detected in vaginal swabs In men with clinical illness, transmission occurred before, during, and after symptomatic period Condoms or abstinence x 6 months Men diagnosed with Zika Possibly exposed male partners of pregnant women (travel to affected area)

References Testing: Centers for Disease Control and Prevention. Memorandum, CDC Division of Vector-Borne Diseases: Revised diagnostic testing for Zika, chikungunya, and dengue viruses in US Public Health Laboratories. Available at: http://www.cdc.gov/zika/pdfs/denvchikvzikv-testing-algorithm.pdf. Accessed September 22, 2016.