Hidden burden of surgical cystic echinococcosis in Arequipa, Peru: An unrecognized population at risk

Peru is endemic for Echinococcus granulosus sensu lato (s.l.), a cestode that causes cystic echinococcosis (CE) in humans. Epidemiological and clinical research has focused extensively on the central and southern highlands, where the parasite is hyperendemic. However, the region of Arequipa, with active transmission of the parasite, has received much less attention. In 2011, a state clinical-surgical program for CE patients was launched in the city of Arequipa. Over less than two years, before program funds were reallocated, surgeons treated 177 patients. This volume underscores the urgent need to prioritize and include Arequipa in CE control programs in Peru. This study characterizes patients who underwent surgical treatment during the programs duration and investigates evidence of active E. granulosus s.l. transmission in Arequipa. We extracted socio-demographic, epidemiological, and clinical data from 129 records of CE patients treated between December 2011 and November 2013. We compared frequencies across variables, including the patients age, sex, residence, education level, and occupation. We also mapped patient origins, with 40.3% being autochthonous to the Arequipa region. Patients median age was 26 (IQR: 16-45), 55% were men, and 69% were students, farmers, or housemakers. In contrast to other reports, where hepatic cases are predominant, 70% of the cases were pulmonary. The southern highlands of Peru, including Arequipa, suffer from endemic transmission of E. granulosus s.l. Limited access to healthcare hinders timely diagnosis and treatment, exacerbating the public health burden. While implementing or reinstating clinical-surgical units in Arequipa and other endemic areas would improve care and case monitoring, these measures alone are not sufficient. Effective control requires integrated One Health approaches and intersectoral collaboration across human, animal, and environmental health sectors. Author summaryCystic echinococcosis (CE) is a neglected parasitic disease caused by Echinococcus granulosus sensu lato (s.l.), which significantly impacts human and animal health in endemic regions, including southern Peru. This study analyzed medical records of patients diagnosed with CE at a major hospital in Arequipa, Peru, aiming to describe its epidemiology and clinical characteristics, and to highlight Arequipa as a historically overlooked region in CE research and control efforts. The findings reveal that CE disproportionately affects younger populations and rural communities, with men, students, farmers, and housemakers being at higher risk. Pulmonary involvement was notably more frequent than hepatic involvement, diverging from trends reported in other studies. The results underscore the importance of strengthening clinical- surgical units in the southern highlands and the necessity of including Arequipa in national control programs. Moreover, limited access to healthcare in rural and migrant populations underscores the importance of equitable resource allocation and sustained efforts to address health disparities. We emphasize the urgency of implementing integrated control strategies that combine human, animal, and environmental health approaches within a One Health framework. These findings provide valuable insights to inform policy and guide the development of cost-effective, interdisciplinary interventions focused on reducing the burden of CE in vulnerable populations.