Figure 4. Prevalence of Zika-virus–associated birth defects (no. cases/100,000 live births), by province, Costa Rica, March 2016–March 2018. Cases are distributed by place of residence of the mother, not by place of birth. The 2 provinces in which prevalence of Zika virus–associated birth defects was highest (Puntarenas and Limón) are on the coast and have a humid tropical climate.