Epidemiological distribution of Echinococcus granulosus s.l. infection in human and domestic animal hosts in European Mediterranean and Balkan countries: A systematic review.

Francesca Tamarozzi,Michele Drigo,Rudi Cassini,Andrea Fittipaldo,Matteo Legnardi,Paul Robert Torgerson

doi:10.1371/journal.pntd.0008519

Francesca Tamarozzi, Michele Drigo + Show 4 more

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https://doi.org/10.1371/journal.pntd.0008519

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Abstract

Cystic echinococcosis (CE) is a neglected zoonosis caused by infection with the cestode Echinococcus granulosus sensu lato. We carried out a systematic literature review on E. granulosus s.l. human and animal (cattle, sheep, dog) infection in European Mediterranean and Balkan countries in 2000-2019, to provide a picture of its recent epidemiology in this endemic area. MEDLINE, EMBASE, Scopus, Google Scholar and Open Grey databases were searched. Included cases were: i) for humans, data from hospital records and imaging studies; ii) for dogs, data from necropsy and coprological studies; iii) for ruminants, cases based on slaughter inspection. The NUTS (Nomenclature of Territorial Units for Statistics) classification was used to categorize extracted data in epidemiological units, defined as data referred to one NUTS2 (basic region) in one year time. Data were then aggregated to NUTS1 level (major regions), calculating the average incidence value of included epidemiological units. For prevalence studies covering different epidemiological units, the pooled prevalence was estimated. Data were extracted from 79 publications, 25 on human infection (covering 437 epidemiological units), and 54 on animal infection (52 epidemiological units for cattle, 35 for sheep and 25 for dogs). At NUTS1 level, average annual incidence rates of human CE ranged from 0.10-7.74/100,000; pooled prevalence values ranged from 0.003-64.09% in cattle, 0.004-68.73% in sheep, and 0-31.86% in dogs. Southern and insular Italy, central Spain, Romania and Bulgaria reported the highest values. Bovine data showed a more similar pattern to human data compared to sheep and dogs. Limitation of evidence included the paucity of human prevalence studies, data heterogeneity, and the patchy geographical coverage, with lack of data especially for the Balkans. Our results confirm Italy, Spain, and Eastern Europe being the most affected areas, but data are extremely heterogeneous, geographical coverage very patchy, and human prevalence studies extremely scant. Results also highlight the notorious problem of underreporting of E. granulosus s.l. infection in both humans and animals.

Highlights

Cystic echinococcosis (CE) is a neglected parasitic zoonosis caused by infection with the cestode Echinococcus granulosus sensu lato species complex
Cystic echinococcosis (CE) is a neglected zoonosis caused by infection with the parasite Echinococcus granulosus sensu lato, naturally transmitted between canids and livestock; CE in humans can be a serious condition
CE is responsible for significant health and economic losses, but its real burden is difficult to estimate

Summary

Introduction

Cystic echinococcosis (CE) is a neglected parasitic zoonosis caused by infection with the cestode Echinococcus granulosus sensu lato species complex. The parasite is endemic worldwide, especially prevalent in areas where livestock breeding is practiced [1]. It is naturally transmitted between canids, definitive hosts harbouring the adult cestodes in the intestine and shedding parasite eggs with the faeces, and livestock, intermediate hosts getting infected upon ingestion of parasite eggs, where the larval stage (metacestode) develops in the form of fluidfilled cysts in liver, lungs and other organs. In Spain, Benner and colleagues [5] estimated, for the year 2005, and overall economic loss due to human and livestock CE of about € 150 million, of which about 130 million were human-associated and about 16 million animal-associated

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