A Multicenter Retrospective Study of Cystic and Alveolar Echinococcosis Patients in the United States (1997–2024)

Echinococcoses are neglected zoonotic diseases caused by larval cestodes of the genus Echinococcus. Regions of the United States rarely experience locally acquired infections, and most contemporary cases are presumed to be imported, predominantly from hyperendemic regions such as Central and East Asia, the Middle East, and North Africa. However, significant knowledge gaps remain regarding the current disease burden within the US healthcare system. The epidemiology, baseline clinical features, and outcomes are summarized for patients diagnosed with cystic echinococcosis (CE) or alveolar echinococcosis (AE) in the present study using retrospective, deidentified data from the TriNetX research network, a federated database that encompasses 89 healthcare organizations and more than 126 million patients (1997-2024). Individuals with Echinococcus infection were identified using International Classification of Diseases, 10th Revision, code B67, and demographic characteristics, geographic distribution, medical and surgical interventions, and mortality were assessed from 2003 to 2023. More than 36,000 patients with any B67 diagnosis were identified, of whom 728 had codes specific to CE, and 75 had codes specific to AE. There were more CE cases in the Southern United States, whereas most AE were reported in the Northeastern United States. Many patients were asymptomatic, with limited use of diagnostic imaging or serologic testing. Antiparasitic medication or surgical procedures were recorded most commonly in AE patients (18%), with mortality rates between 28% and 38% at 20 years post-index. Although locally acquired AE and CE appear to be emerging in the Northeastern United States, the overall prevalence remains low nationwide. The authors advocate for heightened awareness of echinococcoses among US-based clinicians and recommend prospective surveillance studies to improve clinical outcomes and understanding of local transmission risks.