Zika virus (ZIKV) is a member of the Flaviviridae family, which includes other clinically notable viruses such as the 4 dengue virus serotypes (DENV-1–4). Distinguishing DENVs from ZIKV using the established serologic assays widely used for monitoring DENV transmission is difficult because of antibody cross-reactivity between these closely related flaviviruses. We describe a modified and improved recombinant envelope domain III–based serologic assay for detecting ZIKV type-specific antibodies in regions with endemic DENV transmission. When the assay was used to measure ZIKV seroprevalence in 2017 among children 9–14 years of age living in a region of the Philippines with endemic DENV transmission, we observed a ZIKV seroprevalence of 18%. Investigators should consider using the ZIKV envelope domain III–based assay, which is simple and readily adaptable for use in standard clinical and public health laboratories, to assess ZIKV seroprevalence in areas with endemic DENV transmission.

寨卡病毒 (ZIKV) 是黄病毒科的成员家族，其中包括其他临床上值得注意的病毒，例如 4 种登革热病毒血清型 (DENV-1–4)。由于这些密切相关的黄病毒之间存在抗体交叉反应，因此使用广泛用于监测 DENV 传播的既定血清学检测方法区分 DENV 和 ZIKV 很困难。我们描述了一种改进和改进的基于重组包膜结构域 III 的血清学检测方法，用于检测地方性 DENV 传播地区的 ZIKV 类型特异性抗体。当该测定用于测量 2017 年生活在菲律宾 DENV 流行地区的 9-14 岁儿童的 ZIKV 血清阳性率时，我们观察到 ZIKV 血清阳性率为 18%。调查人员应考虑使用基于 ZIKV 包膜结构域 III 的测定，