Due to the changing global epidemiology of Zika virus disease, the US Centers for Disease Control and Prevention (CDC) updated their serologic testing recommendations in November 2019 to no longer endorse routine serological IgM testing for Zika virus.
Cases of locally transmitted Zika in the continental United States or territories have not been reported since May 2018, and limited-to-no Zika virus transmission is currently being reported globally. In 2019, California reported only one confirmed, symptomatic case of Zika virus in an international traveler, and none were reported in Orange County.
In contrast, there are large and ongoing outbreaks of dengue virus in many parts of the world. As of December 1, 2019, 180 dengue cases have been reported in California compared to 107 cases over the same time period in 2018.
Eighteen dengue cases were reported in Orange County in 2019. In comparison, 12 cases were reported in 2018. 10 (53%) of Orange County’s dengue cases in 2019 resulted from exposure in Mexico. Cases were also identified following travel to Asia, Central America, and the Caribbean.