# Ultrasound screening for cystic echinococcosis of school-age children in endemic areas of Chile: A pilot cross-sectional study towards integration in the Regional Program for the Elimination of Cystic Echinococcosis 2020–2029

## TL;DR

A pilot ultrasound screening in school-age children in Chile found low cystic echinococcosis prevalence, suggesting it may not support monitoring but could aid early detection.

## Contribution

This study evaluates the feasibility of ultrasound screening for cystic echinococcosis in Chilean school-age children to support regional elimination efforts.

## Key findings

- Ultrasound screening of school-age children in Chile is technically feasible.
- CE prevalence in school-age children was low (0.3%) across three municipalities.
- Early case detection via screening could support targeted control measures.

## Abstract

Cystic echinococcosis (CE) is a public health problem in livestock-breeding areas, including Chile, which adhered to the Pan American Health Organization Regional Program for the Elimination of CE 2020–2029. Abdominal ultrasound (US) screening of school-aged children (SAC) in high-risk areas is envisaged by the Action Plan for Control, Monitoring and Prevention of CE of the Ministry of Health (MoH) of Chile. We implemented pilot US screening and estimated CE prevalence in SAC in three municipalities prioritized by the MoH, to inform about the feasibility of targeting this age group within the activities of the Action Plan.

A cross-sectional US screening was carried out in SAC (6–14 years) in Río Hurtado (Coquimbo region), Paillaco (Los Ríos), and Chile Chico (Aysén) municipalities. CE was diagnosed according to the WHO-IWGE recommendations. A total of 873 SAC were screened over 10 working days, with excellent participation (81–93%). Three children had hepatic CE cysts (3/873; 0.3%); the highest prevalence was found in Chile Chico (0.6%, 95% CI 0.2%-2.2%).

US screening in SAC is technically feasible in Chile. While prevalence of CE in SAC might be too low to allow school-based monitoring and evaluation of a structured control program, US screening in SAC could allow early case-finding and support the implementation of control measures around new diagnoses.

Cystic echinococcosis (CE) is a zoonosis transmitted between dogs and ungulates; in humans, CE is a public health problem where livestock breeding is practiced, including Chile, which adhered to the Pan American Health Organization Regional Program for the Elimination of Cystic Echinococcosis 2020–2029. Abdominal ultrasound (US) screening of school-aged children (SAC) in high-risk areas is envisaged by the Action Plan for Control, Monitoring and Prevention of CE of the Ministry of Health (MoH) of Chile. US screening in SAC is carried out in the Control Program of CE in Río Negro provice, Argentina; furthermore, targeting SAC in control programs for other neglected tropical diseases is common, due to the possibility for an early treatment and the easy accessibility of SAC. We implemented an US screening and estimated CE prevalence in SAC in three municipalities identified by the MoH of Chile as at high risk. Our results showed that US screening in SAC is feasible in Chile; however, prevalence of CE in this age group might be too low to allow school-based monitoring and evaluation of a control program. On the contrary, US screening in SAC could allow early case-finding and support the implementation of control measures around new diagnoses.