Abstract
Simple SummaryCystic echinococcosis (CE) is a parasitic zoonosis caused by the larval stage of the tapeworm Echinococcus granulosus. The liver ultrasonography can be considered as the gold standard for the in vivo diagnosis detection of CE. Nevertheless, control programs against E. granulosus are considered long-term actions that require an integrated approach and the high expenditure of time and financial resources. This parasitosis still causes severe economic losses both in human healthcare and in the entire livestock breeding system, with loss in milk, meat, and wool production. Considering the impact of this zoonosis in the modern sheep’s breeding system, a reliable hepatic ultrasound could represent an innovative strategy to control and even eradicate the disease in sheep farms. Based on these considerations, the present study aimed to evaluate a fast-focused technique for hepatic CE detection in different sheep breeds and compare the performance of the latter with another fast-scan (previously evaluated in Sarda sheep breed), the complete ultrasound liver examination, and the anatomopathological examination.A complete ultrasound examination (cUS) of the liver was performed on 172 female sheep and compared to the performance of a fast-focused ultrasound technique to diagnose echinococcal cysts. The scanned area was divided in: HYP (right hypocondrium), zone (Z)1 from HYP to the 11th intercostal space (IS), Z2 (10th–8th IS) and Z3 (7th–5th IS). Contiguous scans were also examined (HYP + Z1, Z1 + Z2, Z2 + Z3). Furthermore, during the procedures, the sheep were divided into three groups according to the body weight: Group (G) 1 (lighter), G2 (medium), and G3 (heavier). Finally, diagnostic outcomes were compared with necropsy findings. cUS obtained the highest values of sensitivity (Se) (91%), Specificity (Sp) (80%), and positive-zones (124/138, 90%), as compared to the other scans. cUS was also characterized by high values of Se and Sp and was able to identify a great number of positive-zones, when sheep were divided by body-weight groups. Similar performances were obtained in G1 by HYP (Se: 91%–Sp: 82%; 18/20, 90% of positive-zones) and HYP + Z1 scans (Se: 91%–Sp: 82; 90% of positive-zones, 18/20). Thus, in lighter breeds, the examination of HYP and HYP + Z1 scan windows could be considered reliable techniques for identifying the infected animals, while in heavier sheep the cUS still represents the best option.
Highlights
Cystic echinococcosis (CE), known as hydatid disease or hydatidosis, is a parasitic zoonosis caused by the larval stage of the tapeworm Echinococcus granulosus.The life cycle of the parasite includes dogs and other canids as the definitive hosts, while livestock, as well as humans, are intermediate hosts, harboring the hydatid cysts [1].CE has a worldwide distribution and exhibits the highest prevalence in communities where pastoral activities predominate such as the Mediterranean areas, eastern Europe, the southern tip of South America, several areas of Central Asia, Siberia, and easternChina [2]
There is a lack of guidelines that clearly indicate the ideal type of ultrasound probe and its proper setting to correctly detect the hydatid cysts in the liver of the sheep
The current study represents the first investigation evaluating the use of the US as a potential fast focused technique for CE hepatic lesions detection, in different sheep breeds under field conditions
Summary
This parasite is responsible for severe economic losses both in human healthcare ($763,980,979/year) and in the entire livestock breeding system ($2,51,409,989/year) [3,4]. It has a strong impact on sheep farms’ earnings with loss in milk (7–20%), meat (5–20%), and wool (10–40%) production [5]. The first diagnostic imaging technique for CE detection used in sheep was based on the radiological examination of lungs [11], subsequently, ultrasonography (US) was employed to assess the prevalence of hydatid cysts in the liver of sheep and goats in Turkana, Kenya [12]. There is a lack of guidelines that clearly indicate the ideal type of ultrasound probe and its proper setting to correctly detect the hydatid cysts in the liver of the sheep
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