Concepts in Immunology and Diagnosis of Hydatid Disease

Abstract

Echinococcosis is a cosmopolitan zoonosis caused by adult or larval stages of cestodes belonging to the genus Echinococcus (family Taeniidae). The two major species of medical and public health importance are Echinococcus granulosus and E. multilocularis, which cause cystic echinococcosis (CE) and alveolar echinococcosis (AE), respectively. Both CE and AE are both serious diseases, the latter especially so, with a high fatality rate and poor prognosis if managed inappropriately. This review discusses new concepts and approaches in the immunology and diagnosis of CE, but comparative reference has also been made to AE infection and to earlier pivotal studies of both diseases. The review considers immunity to infection in the intermediate and definitive hosts, innate resistance, evasion of the immune system, and vaccination of intermediate and definitive hosts, and it particularly emphasizes procedures for diagnosis of CE and AE, including the value of immunodiagnostic approaches. There is also discussion of the new advances in recombinant and related DNA technologies, especially application of PCR, that are providing powerful tools in the fields of vaccinology and molecular diagnosis of echinococcosis

Differential Diagnosis and Management of a Recurrent Hepatic Cyst: A Case Report and Review of Literature

“…16 The lipoproteins antigen B (AgB) and antigen 5 (Ag5) are the major components of hydatid cyst fluid and are the most widely used antigens in current assays for immunodiagnosis of cystic echinococcosis. 21 To identify these antigens, multiple serologic tests are used: complement fixation test, immunoelectrophoresis, indirect hemagglutination, latex agglutination, indirect fluorescence test, and enzyme immunoassays such as ELISA test. There are multiple studies in the published literature that reflect large variability in the sensitivity and specificity of these tests and additional variability between laboratories, producing false results.…”

Shared and non-shared antigens from three different extracts of the metacestode of Echinococcus granulosus

“…Thus, HCF is mainly used for the immunodiagnosis of human cystic echinococcosis, based on the detection of antigen 5 and antigen B. The subunit of 8/12 kDa from antigen B is considered the most specific component of HCF in the genus Echinococcus (Verastegui et al 1992, Zhang et al 2003. S-Ag from protoscoleces have been used for the serodiagnosis of dog echinococcosis, as protoscoleces are the infective stage of the parasite in the definitive host.…”

“…The intermediate larval stage (metacestode) can grow in a wide range of mammal species including humans, that acquire infection through accidental ingestion of eggs. Currently, diagnosis of hydatidosis/echinococcosis is based on a combination of imaging techniques (ultrasonography, computerized axial tomography, X-rays) and immunodiagnostic methods such as ELISA and immunoblotting (Zhang et al 2003).…”

Dot-Elisa for evaluation of hydatid cyst wall, protoscoleces and hydatid cyst fluid antigens in the serodiagnosis of cystic echinococcosis

“…Thus, serodiagnosis plays the most important role in the diagnosis of CE because of their low cost and ease of performance. Serodiagnosis based on the detection of antiEchinococcus antibodies in the serum, remains the mainstay in the laboratory diagnosis of CE 3,25 .…”