Fast Focus Ultrasound Liver Technique for the Assessment of Cystic Echinococcosis in Sheep

SIMPLE SUMMARY: Cystic 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. ABSTRACT: 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.