Zika Virus: Information for States and Territories

At a Glance – Zika in the U.S. (updated 3/21/18*) 

U.S. States
Total cases reported: 5,672 (12 cases in 2018)
Travel-associated Zika virus disease cases reported: 5,388
Locally acquired vector-borne cases reported: 229
Sexually transmitted cases: 52
Laboratory acquired cases reported: 2
Pregnant women with any lab evidence of Zika virus infection: 2,418
Liveborn infants with birth defects: 112
Pregnancy losses with birth defects: 9

U.S. Territories
Total cases reported: 37,195 (0 cases in 2018)
Travel-associated cases reported:147
Locally acquired cases reported: 37,048 
Pregnant women with any lab evidence of Zika virus infection: 4,784
Liveborn infants with birth defects: 157
Pregnancy losses with birth defects: 8

*Visit CDC.gov for the most up to date information.This webpage contains cumulative provisional data reported to ArboNET since 1/1/2015.


New from ASTHO: Top Questions on Zika: Simple Answers


Zika virus is a mosquito-borne flavivirus transmitted to humans primarily by the Aedes aegypti mosquitoes, the same mosquitoes that transmit dengue, yellow fever, and chikungunya viruses. CDC estimates that 80 percent of Zika cases are asymptomatic. Symptomatic cases usually result in mild illness and symptoms such as acute onset of fever, rash, joint pain, and conjunctivitis. Some evidence suggests severe outcomes such as Guillian-Barre syndrome and microcephaly in infants via maternal-fetal transmission of Zika virus. There is currently no vaccine to prevent or medicine to treat Zika virus. For more information on Zika virus in the United States see CDC's Zika Virus web page: www.cdc.gov/Zika.

What's New

Update: Noncongenital Zika Virus Disease Cases — 50 U.S. States and the District of Columbia, 2016
This Centers for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report (MMWR) recommends that health care providers continue to test patients with a clinically compatible illness who live in or recently traveled to areas with ongoing Zika virus transmission or had unprotected sex with someone who lives in or traveled to those areas. Although the risk for travel-associated Zika virus disease appears to be decreasing, it is important that persons traveling to areas with a risk for Zika virus transmission continue to take precautions, including using strategies to prevent mosquito bites and sexual transmission.

Maternal Child Health Capacity for Zika Response Report
A newly released study of local jurisdictions developed by the National Association of County and City Health Officials (NACCHO), in partnership with the CDC, and the National Center on Birth Defects and Developmental Disabilities (NCBDDD) discovered that while local health departments have responded diligently to Zika outbreaks in their communities and are heavily engaged in protecting maternal child health, there is room for improvement. Importantly, continued federal funding to support these efforts is vitally needed to safeguard the nation’s health. Congress has proposed eliminating the Prevention and Public Health Fund, which provides funding to local jurisdictions through the CDC. Read NACCHO’s press release for highlights.

Pregnancy Outcomes after ZIKV Infection in French Territories in the Americas
In this article of the New England Journal of Medicine, Hoen et al. report data from a cohort of pregnant women with polymerase-chain-reaction–confirmed symptomatic ZIKV disease in French territories in the Americas. This report provides some of the most compelling data to date that the risk of brain abnormalities, microcephaly, and eye anomalies extends to infections in every trimester of pregnancy. Not surprisingly, the risk of severe microcephaly was limited to infections that occurred during the first or second trimester, but the overall risk of birth defects that have been associated with ZIKV infection was 12.7%, 3.6%, and 5.3% when infection occurred in the first, second, and third trimester, respectively. In addition, the authors report both disproportionate and proportionate microcephaly after infections in any trimester of pregnancy. The finding of proportionate microcephaly suggests that in some cases, ZIKV might affect fetal growth instead of — or in addition to — having a specific destructive effect on the fetal brain. Continue reading the commentary for highlights.


ASTHO staff have compiled the following links to selected resources and background materials that were created by state and territorial health departments and national and international sources for use by state health agency leaders. We'll add to these materials periodically.