April 2018
Update on Zika and West Nile Virus for Orange County
Zika Summary
  • Clinicians should continue to test symptomatic patients who live in or recently traveled to areas with Zika virus transmission or who had unprotected sex with someone who lives in or traveled to these areas.
  • The California Department of Public Health (CDPH), Centers for Disease Control and Prevention (CDC), American College of Obstetrics and Gynecology and the Society for Maternal Fetal Medicine recommend that all pregnant women be evaluated for possible Zika virus exposure during each prenatal care visit.
  • All pregnant women and their partners should take measures to prevent Zika virus infection during pregnancy, including using strategies to prevent mosquito bites and sexual transmission.
New cases of Zika virus infection continue to be identified in California and Orange County, including in pregnant women with potential serious consequences for the babies, such as fetal loss, microcephaly, and other birth defects. Although the incidence of new Zika infections in California has dropped since 2016, 174 infections have been reported in pregnant women, resulting in at least 11 live-born infants with birth defects, as of April 6, 2018. More than half of the infants born in California with Zika-associated birth defects were born to Zika-exposed mothers who were asymptomatic for Zika infection, emphasizing the need for routine assessment of possible Zika exposure at all prenatal care visits.  As of April 28, 2018, 43 Zika cases have been reported in Orange County, with the majority of exposures occurring in Mexico in about 50%, followed by Central America in about 25%, then the Caribbean, and Southeast Asia.  To date, there has been NO locally-acquired vector-borne transmission of Zika in Orange County or California.
Update on Developmental Outcomes of Infants with Congenital Zika Infection
Review of the developmental follow-up of 19 children with congenital Zika infection in Brazil at a median age of 22 months (range 19-24 months) revealed that the majority had severe motor impairment, including cerebral palsy, as well as vision and hearing abnormalities, seizures, feeding challenges and sleeping difficulties, with approximately 75% having at least 3 of these outcomes. The children were noted to have fallen far behind on their age-appropriate developmental milestones and will need long-term follow-up and support, with specialized care from clinicians and caregivers, as they age. See www.cdc.gov/mmwr (12/15/17 issue; Vol. 66, No. 49).
West Nile Virus Season is Starting Soon!
  • West Nile Virus (WNV) is endemic in Orange County and we expect to have cases every year. Orange County has reported between 12 and 280 infections per year over the past 5 years, including 22 deaths.
  • Human cases in Orange County generally have had onset between July and October, but have been reported as early as June and as late as December.
  • Clinicians should consider WNV in patients with encephalitis, aseptic meningitis, acute flaccid paralysis, atypical Guillain-BarrĂ© syndrome, or prolonged fever without other diagnosis, and send serum WNV IgM and IgG, as well as CSF IgM in patients with neuroinvasive disease. 
  • Suspect WNV cases should be reported to Orange County Epidemiology within one (1) working day.

Communicable disease reporting, local human case updates and questions:
OCHCA Epidemiology714-834-8180, www.ochealthinfo.com
Mosquito surveillance, control and prevention:
Orange County Mosquito and Vector Control District 714-971-2421, www.ocvector.org
State and national updates:  

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