Prevalence estimation of Italian ovine cystic echinococcosis in slaughterhouses: A retrospective Bayesian data analysis, 2010–2015

Abstract

Cystic echinococcosis (CE) is a complex zoonosis with domestic and sylvatic life-cycles, involving different intermediate and definitive host species. Many previous studies have highlighted the lack of a surveillance system for CE, its persistence in Italy, and endemicity in several Italian regions. Because of the absence of a uniform surveillance program for both humans and animals, disease occurrence is widely underestimated. This study aimed to estimate the prevalence of ovine CE in Italy. Survey data on the prevalence of Echinococcus granulosus complex infections in Italian sheep farms from 2010 to 2015 were obtained in collaboration with Regional Veterinary Epidemiology Observatories (OEVRs). Bayesian analysis was performed to estimate the true CE farm prevalence. The prior true CE prevalence was estimated using data from Sardinia. Second, Bayesian modelling of the observed prevalence in different regions and the true prevalence estimation from the first step were used to ultimately estimate the prevalence of ovine CE in Italy. We obtained survey data from 10 OEVRs, covering 14 Italian regions. We observed that the risk of CE infection decreased over the years, and it was strictly correlated with the density of susceptible species. Using Sardinia as prior distribution, where the disease farm prevalence was approximately 19% (95% CI, 18.82–20.02), we estimated that the highest endemic CE farm prevalence was in Basilicata with a value of 12% (95% BCI: 7.49–18.9%) and in Piemonte 7.64%(95% BCI: 4.12–13.04%). Our results provide spatially relevant data crucial for guiding CE control in Italy. Precise information on disease occurrence location would aid in the identification of priority areas for disease control implementation by the authorities. The current underestimation of CE occurrence should urge the Italian and European governments to become aware of the public health importance of CE and implement targeted interventions for high-risk areas.

Socio-economic factors as indicators for various animal diseases in Sardinia

“…In this way, the generalisability of the results can be ensured as much as possible. Furthermore, the association between CE and ISTAT territorial indicators for development policies has been successfully studied by Loi et al in 2019 [35], providing interesting results and underling the need of in deep studies. Data on the sex and age of the farmers were collected using the fiscal code downloaded by BDN.…”

“…This hypothesis has subsequently studied in-depth by numerous studies [6] [7] [31] [32]. Furthermore, the spread of CE in association with social factors has also been studied in Sardinia, first by Brundu et al in 2014 [33] and subsequently by Piseddu et al in 2017 [34] and Loi et al in 2019 [35]. Recently, following the succession of numerous seasonal epidemics of bluetongue (BT) in Sardinia, the role of social factors and farm management has been studied extensively, demonstrating the importance of good management practices in disease prevention and relaying information about risk factors to the farmers [36] [37].…”

Spatial Distribution and Epidemiology of Echinococcus Granulosus Infection in Sheep and Goats Slaughtered in a Hyperendemic European Mediterranean Area

“…The data on the prevalence of CE in some Italian regions are scarce. In Basilicata prevalence ranging between 5-28% were reported in sheep from 1996 to 2002 [20] and of 12% from 2010 to 2015 [9]. No previous data were available for goats.…”

“…Deplazes et al [5] showed a heterogeneous geographic distribution in the European Mediterranean area with prevalence values < 0.1% in the coastal regions of France and Spain, reaching values > 50.0% in Italy, with a higher prevalence in the southern (Basilicata and Campania regions) and insular (Sardinia and Sicily) part of the country [8,9,10]. However, the reported prevalence of CE in livestock is widely underestimated, because the surveillance system based on reports recorded at slaughterhouses is still inefficient [9,11]. In addition, the data of surveillance systems are usually obtained for wide geographic areas that assume a homogeneous prevalence [12].…”

Epidemiology and spatial distribution of Echinococcus granulosus in sheep and goats slaughtered in a hyperendemic European Mediterranean area

“…Deplazes et al [ 5 ] showed a heterogeneous geographic distribution in the European Mediterranean area, with prevalence values < 0.1% in the coastal regions of France and Spain, reaching > 50.0% in Italy, with a higher prevalence in the southern (Basilicata and Campania regions) and insular (Sardinia and Sicily) part of the country [ 8 – 10 ]. However, the reported prevalence of CE in livestock is widely underestimated, because the surveillance system based on reports recorded at slaughterhouses is still inefficient [ 9 , 11 ]. In addition, surveillance system data are usually obtained for wide geographic areas without considering that the prevalence of CE can differ widely in different points of the same area [ 12 ].…”