Parechoviruses cause a spectrum of clinical presentations ranging from self-limited to severe encephalitis. In July 2022, state health departments across the USA received an increase in reports of PeV infections among infants. A retrospective cohort study describing the clinical characteristics and outcomes of PeV encephalitis in infants aged < 90 days. Rates of PeV encephalitis were determined based on the number of PeV encephalitis cases out of all meningoencephalitis multiplex polymerase chain reaction panel (MEP) obtained among infants aged < 90 days per year. Out of 2115 infants evaluated for meningoencephalitis, 32 (1.5%) cases of PeV encephalitis were identified. All cases had an absence of pleocytosis and normal protein and glucose levels on CSF analysis. Half of the cases presented with a symptomatic triad (fever, rash, and fussiness). More than one-third of cases (39%) presented with a sepsis-like syndrome, 13% presented with seizures, and 25% were admitted to the pediatric intensive care unit (PICU). MRI of the brain was obtained in four of the cases presented with seizure, all of which demonstrated characteristic radiological findings of the periventricular white matter with frontoparietal predominance and involving the corpus callosum, thalami, and internal and external capsules. Rates of PeV encephalitis varied from year to year, with the highest rates in 2018 and 2022. PeV was the second most detected pathogen in MEP in both 2018 and 2022, and the fifth most detected pathogen in all positive MEP during the study period 2017–2022.

Conclusion: PeV can cause encephalitis and sepsis-like syndrome in infants, and it should be considered even with normal CSF parameters. Prospective studies are needed to better understand PeV epidemiology and to monitor outbreaks.

副孤病毒可引起一系列临床表现，从自限性到严重脑炎。2022 年 7 月，美国各州卫生部门收到的婴儿 PeV 感染报告有所增加。一项描述 90 天以下婴儿 PeV 脑炎临床特征和结果的回顾性队列研究。PeV 脑炎的发生率是根据每年年龄 < 90 天的婴儿中获得的所有脑膜脑炎多重聚合酶链反应检测 (MEP) 中的 PeV 脑炎病例数来确定的。在接受脑膜脑炎评估的 2115 名婴儿中，发现了 32 例（1.5%）PeV 脑炎病例。脑脊液分析显示，所有病例均未出现细胞增多，蛋白质和葡萄糖水平正常。一半病例出现三联症症状（发烧、皮疹和烦躁）。超过三分之一的病例 (39%) 出现脓毒症样综合征，13% 出现癫痫发作，25% 被送入儿科重症监护室 (PICU)。对 4 例癫痫发作病例进行了脑部 MRI 检查，所有病例均显示脑室周围白质的特征性放射学发现，以额顶叶为主，累及胼胝体、丘脑以及内外囊。PeV 脑炎的发病率每年都有所不同，其中 2018 年和 2022 年的发病率最高。PeV 是 2018 年和 2022 年 MEP 中检测到的第二大病原体，也是 2017 年研究期间所有阳性 MEP 中检测到的第五大病原体 – 2022 年。

结论：PeV 可引起婴儿脑炎和败血症样综合征，即使脑脊液参数正常也应予以考虑。需要进行前瞻性研究以更好地了解 PeV 流行病学并监测疫情。