Validation of an Excretory/Secretory Antigen Based-Elisa for the Diagnosis of Opisthorchis felineus Infection in Humans from Low Trematode Endemic Areas

Abstract

Since opisthorchiasis does not show pathognomonic signs or symptoms, physicians can have serious problems to make a differential diagnosis of this infection in non endemic areas, in particular when there is a simultaneous occurrence with other seasonal infections. Moreover, symptomatic infections due to O. felineus can last a few weeks and then the signs and symptoms disappear, but the worms survive in the bile ducts for years causing hepatobiliary diseases including hepatomegaly, cholangitis, fibrosis of the periportal system, cholecystitis, and gallstones. Consequently, an early diagnosis prevents chronicity and loss of working days. The detection of specific antibodies has been considered as a complementary tool to the fecal examination to establish the definitive diagnosis of this infection and for the follow up. Therefore the aim of this work was the development and validation of an enzyme-linked immunosorbent assay (ELISA) using excretory/secretory antigens (ESA) from O. felineus adult worms to detect anti-Opisthorchis IgG in human sera. A total of 370 human sera were tested: 144 sera from persons with a confirmed diagnosis of opisthorchiasis, 110 sera from healthy Italian people, and 116 sera from people with other parasitic or non-parasitic infections. Results were analyzed by receiver-operator characteristic (ROC) curve analysis. The accuracy of the test, calculated by the area under curve (AUC), yielded a 0.999 value, indicating the high performance of the test. The sensitivity was 100% (95% CI: 97.40% to 100%) and no false-negative sera were detected; the specificity was 99.09% (95% CI: 95.02% to 99.83%). The validated ELISA shows a good performance in terms of sensitivity, repeatability and reproducibility, and it is suitable to detect anti-Opisthorchis IgG in human sera for diagnostic purposes and for the follow up to assess the efficacy of drug treatment.

Efficacy of Dot-ELISA using different antigens in detecting anti-schistosome antibodies among bovines in field conditions

“…The high specificity of ESA in serodiagnosis has been observed by several workers for detecting other trematode infections as well viz, Clonorchis sinensis (Choi et al 2003), Paragonimus sp. (Narain et al 2005), F. hepatica (Awad et al 2009), Opisthorchis felineus (Gomez-Morales et al 2013) and Paramphistomum cervi (Anuracpreeda et al 2013). On perusal of available literature, it is understood that ESA of S. spindale have not yet been utilised for Dot-ELISA.…”

Trematode FlukeProcerovumvariumas Cause of Ocular Inflammation in Children, South India

“…The diagnosis of parasitic diseases is much more difficult when the patient is not a definite host but is instead an intermediate or accidental host; in such cases, fecal egg identification is of no use. Serum samples are also unreliable mainly because of cross-reactive antigens ( 4 , 5 ). Molecular diagnostics can play a vital role in overcoming these obstacles and may lead to a precise diagnosis ( 6 , 7 ).…”

Opisthorchiasis: Diagnostics, Clinical Manifestations, and Management

“…Специфичность ИФА также не очень высока: возможны ложноположительные реакции у больных эхинококкозом, аскаридозом, дифиллоботриозом, трихинеллезом, клонорхозом и фасциолезом, что связано с наличием перекрестнореагирующих антигенов у этих гельминтов и описторхисов [19]. Малоинформативен ИФА и для контроля эффективности терапии, поскольку отмечается возможность длительной циркуляции антител уже после ликвидации инвазии [20].…”

“…Яйца описторхисов имеют характерное строение с т. н. «крышечкой» и определенные размеры -22-32 × 10-19 мкм [20]. При малоинтенсивной инвазии рекомендуют использовать провокационную пробу -исследование дуоденального содержимого и фекалий через 1-2 дня после однократного приема 1 таблетки празиквантела (600 мг): часть взрослых особей паразитов погибает или обездвиживается и может быть найдена в кале или желчи вместе с яйцами [21].…”

“…В основу их положен более высокий удельный вес яиц гельминтов, чем у применяемых растворов. Яйца выпадают в осадок в растворе, концентрируясь в нем, и лучше определяются при исследовании под микроскопом (методы осаждения, или седиментации) [20].…”