From conventional to next-generation diagnostics in cystic echinococcosis: integrating serology, ultrasonography, and molecular tools: a review.

This review provides the relative roles of serology and ultrasonography in the diagnosis of cystic echinococcosis (CE), emphasizing their performance, limitations, and integration within current and emerging diagnostic strategies. CE is a chronic zoonotic disease caused by Echinococcus granulosus, predominantly affecting the liver and lungs in endemic livestock-raising regions. It is often a silent clinical course, variable clinical presentation, and potential for severe complications that contribute to underdiagnosis and underreporting. Ultrasonography is the first-line tool for hepatic CE, enabling cyst detection and staging according to the WHO-IWGE classification (CE1-CE5) and guiding clinical management. Serological assays (e.g., ELISA, IHA, Western blot) detect antibodies against E. granulosus antigens and perform best for active hepatic cysts (CE1-CE3). Their sensitivity is reduced in inactive or heavily calcified cysts (CE4-CE5), and specificity is limited by cross-reactivity with other helminths and by inter-individual variation in immune responses. Ultrasonography offers high sensitivity and specificity for hepatic cysts, yet is operator-dependent and less effective for small or extrahepatic cysts. Combined use of serology and ultrasonography, as recommended by WHO and CDC algorithms, improves overall diagnostic accuracy and follow-up. Advances in recombinant antigen-based serology, point-of-care tests, portable ultrasound, AI-assisted imaging, and molecular methods (PCR, NGS, and parasite-derived biomarkers) are enabling more sensitive, specific, and accessible CE diagnostics, particularly in resource-limited endemic settings.