Trends and correlates of cystic echinococcosis in Chile: 2001–2012

Echinococcosis is a neglected zoonotic disease affecting over 1 million people worldwide at any given time.It is the leading cause of hospital admissions for parasitic diseases in Chile.We conducted a retrospective investigation of hospitalized cases to describe the epidemiological trends of echinococcosis in Chile.We also examined the potential environmental risk factors for echinococcosis hospitalization rates.Through nation-wide hospital discharge data, a total of 11,516 hospitalized patients with cystic echinococcosis were identified between January 2001 and December 2012.The mean age of hospitalization was 40 years, with notable gender difference in pediatric patients.The hospitalization rate was found to be overall steadily decreasing from 2001 (7.02 per 100,000) to 2012 (4.53 per 100,000) with a 5% decrease per year (rate ratio = 0.95 [95% CI: 0.94, 0.96]).The hospitalization rate was higher in the south of Chile compared to the north.Goat density and intermediate precipitation were found to be significantly positively associated with the hospitalization rate while annual average temperature was found to be significantly negatively associated with the hospitalization rate.Findings of this study indicate that echinococcosis is still an important public health burden in Chile related to interaction with livestock and climate.Efforts should be placed on targeted prevention measures for farmers and raising awareness of echinococcosis among health care workers. Author summaryHumans are infected by many types of parasites that originate from animals.Cystic echinococcosis (CE) is a tapeworm infection that affects over 1 million people over the world at any given time, with symptoms such as abdominal pain, chest pain, vomiting, and allergic reactions.The lifecycle of this parasite is maintained between dogs and livestock, and humans are 'accidentally' infected through ingesting parasite eggs.This makes the control of CE difficult for public health practitioners.Attempts have been made to better understand which animals or environmental factors increase or decrease the number of human CE infections, but mainly with data from only one point in time.