Public Health Response to Zika Virus in California James Watt, MD, MPH Chief, Division of Communicable Disease Control Presentation to the California Blood Bank Society May 6, 2017

Disclosure I have no financial relationships with commercial interests to disclose.

Outline Zika epidemiology in California and Mexico Public health activities to control Zika Forecast for 2017

Zika Cases in California, 2015-17 534 travel-associated Zika cases reported as of April 21, 2017 7 sexually-transmitted cases 111 cases pregnant at the time of diagnosis 334 residents of counties with invasive Aedes 368 potentially viremic while in California

Zika Risk in California Essential ingredients of transmission present Viremic persons Vector mosquitoes Risk of sustained transmission very low Environmental and housing conditions limit human/mosquito interaction compared to tropical countries No local transmission of dengue or chikungunya viruses Limited local transmission possible

Travel-Associated Zika Cases in California 2015 - 2017* 18 87 117 33 13 9 3 6 7 27 35 16 4 2 1 41 5 No reported cases 1-10 reported cases 11-20 reported cases 21+ reported cases County with Aedes mosquitoes Updated *as of April 21, 2017

For 2016, 453 Zika cases were reported in California For 2016, 453 Zika cases were reported in California. The epi cure here illustrates 2016 Zika cases by week or onset or specimen collection for asymptomatic cases. The peak onset for Zika cases in 2016 was weeks 27-34, or July 4th through August 22th. This also correlates with peak travel seasons in late June and early August. The average number of cases reported by epi week decreased to 5 cases a week for the month of December compared to 27 a week for July and August.

Exposure Countries for Travel-Associated Zika Cases in California, 2015-2017* Country Number of Cases Mexico 190 Nicaragua 61 Guatemala 49 El Salvador 36 Dominican Republic 26 Costa Rica 25 Puerto Rico Honduras Jamaica 14 Colombia 10 updated *as of April 21, 2017

Zika Virus Disease Cases in Mexico, by Month

Zika Virus Disease Cases Mexico, April 2016

Zika Virus Disease Cases, Mexico, March 2017

Travel to California from Zika-Affected Countries--2015 Air ~4.5 million Final destination airports: Los Angeles 54%, San Francisco 20%, San Diego 6% Highest volume occurred in July and August 66.8% of flights originated in Mexico Sea 1.2 million Arrival ports: Long Beach 65%, Los Angeles 20%, San Diego 8% Land 55 million California county of entry San Diego: ~70%, Imperial ~30% All of the Zika cases reported in California and most of the US are travel related. In 2015 4.5 million travelers flew into California from Zika affected areas, with 67% of those flights originating in Mexico. 1.2 million travelers entered California by ship and 55 million by a land vehicle. This large number of travelers from Zika affected areas increases the risk of local transmission in California and elsewhere in the US.

Public Health Response to Zika in California Is a Collaboration 61 local health departments 77 local vector control agencies CDPH CDC Blood centers Professional partners

National Zika Response Domains Vector Control and Surveillance Maternal and Child Health Surveillance and Response Public Health Surveillance and Epidemiological Investigation Rapid Birth Defects Monitoring and Follow-up Laboratory Testing Travel Health News Prevention of Sexually Transmitted Zika Virus Infections Clinician Outreach and Communication Prevention of Blood Transfusion–transmitted Zika Virus Infections Risk Communication/Community Education Specific activities are tied to the national Zika virus threat stage: Stage 0: no Aedes mosquitoes present (applies to parts of California) Stage 1a: Aedes mosquitoes present, but low season (current situation for Southern California and Central Valley) Stage 1b: Aedes mosquitoes present and active (mosquito activity rises with sustained warm temperatures—late spring/early summer in parts of Inland Empire, late summer in most of Southern California) Stage 2: single household with local transmission Stage 3: multi-person local transmission (3 or more unrelated cases)

Public Health Response Goals Prevent Zika virus infection in pregnant women Prevent travel associated infections Prevent mosquito-borne transmission in California Reduce the impact of Zika virus infection in pregnancy

Prevent Travel Associated Infections in Pregnant Women Vector Control and Surveillance Maternal and Child Health Surveillance and Response Public Health Surveillance and Epidemiological Investigation Rapid Birth Defects Monitoring and Follow-up Laboratory Testing Travel Health News Prevention of Sexually Transmitted Zika Virus Infections Clinician Outreach and Communication Prevention of Blood Transfusion–transmitted Zika Virus Infections Risk Communication/Community Education Challenging due to the complex reasons for international travel. Likely to become more challenging as Zika spreads in the border region. Nevertheless, several prevention opportunities exist: CDPH and other partners are working to inform pregnant women about travel associated risk and prevention strategies Directly through public outreach Through health care providers Prevent secondary infections Inform sexual partners of pregnant women of risk and prevention strategies Prevent transmission through blood transfusion

Prevent Mosquito-borne Transmission in California Vector Control and Surveillance Maternal and Child Health Surveillance and Response Public Health Surveillance and Epidemiological Investigation Rapid Birth Defects Monitoring and Follow-up Laboratory Testing Travel Health News Prevention of Sexually Transmitted Zika Virus Infections Clinician Outreach and Communication Prevention of Blood Transfusion–transmitted Zika Virus Infections Risk Communication/Community Education The opportunities include: Monitoring transmission risk Vector surveillance Human case surveillance Rapid detection of local mosquito-bourne infections through Laboratory testing Human surveillance Response to limit spread from infected persons (travel or local infections) Vector control Epidemiologic investigation Public health response Public education If transmission occurs, rapid investigation to determine scope of transmission

Reduce the Impact of Zika Virus Infection in Pregnancy Vector Control and Surveillance Maternal and Child Health Surveillance and Response Public Health Surveillance and Epidemiological Investigation Rapid Birth Defects Monitoring and Follow-up Laboratory Testing Travel Health News Prevention of Sexually Transmitted Zika Virus Infections Clinician Outreach and Communication Prevention of Blood Transfusion–transmitted Zika Virus Infections Risk Communication/Community Education If infections in pregnancy occur, there are opportunities to support infected women, encourage appropriate fetal and infant evaluation, and monitor infected infants.

What Is the Future for Zika? Slide from CDC

Chikungunya Experience Slide from CDC

The Future of Zika in California? Possibly more cases in 2017 than 2016 If transmission increases in Mexico If virus spreads in Baja California Increasing cases in the summer, but how much? Greatest risk of local transmission in summer Peak of Aedes mosquito activity Highest levels of travel exposure Public health response activities continuing Due to high volume of travel across the land border

Thank You