The Diagnosis of Human Fascioliasis by Enzyme-Linked Immunosorbent Assay (ELISA) Using Recombinant Cathepsin L Protease

Abstract

BackgroundFascioliasis is a worldwide parasitic disease of domestic animals caused by helminths of the genus Fasciola. In many parts of the world, particularly in poor rural areas where animal disease is endemic, the parasite also infects humans. Adult parasites reside in the bile ducts of the host and therefore diagnosis of human fascioliasis is usually achieved by coprological examinations that search for parasite eggs that are carried into the intestine with the bile juices. However, these methods are insensitive due to the fact that eggs are released sporadically and may be missed in low-level infections, and fasciola eggs may be misclassified as other parasites, leading to problems with specificity. Furthermore, acute clinical symptoms as a result of parasites migrating to the bile ducts appear before the parasite matures and begins egg laying. A human immune response to Fasciola antigens occurs early in infection. Therefore, an immunological method such as ELISA may be a more reliable, easy and cheap means to diagnose human fascioliasis than coprological analysis.Methodology/Principal findingsUsing a panel of serum from Fasciola hepatica-infected patients and from uninfected controls we have optimized an enzyme-linked immunosorbent assay (ELISA) which employs a recombinant form of the major F. hepatica cathepsin L1 as the antigen for the diagnosis of human fascioliasis. We examined the ability of the ELISA test to discern fascioliasis from various other helminth and non-helminth parasitic diseases.Conclusions/SignificanceA sensitive and specific fascioliasis ELISA test has been developed. This test is rapid and easy to use and can discriminate fasciola-infected individuals from patients harbouring other parasites with at least 99.9% sensitivity and 99.9% specificity. This test will be a useful standardized method not only for testing individual samples but also in mass screening programs to assess the extent of human fascioliasis in regions where this zoonosis is suspected.

Evaluation of a set of refolded recombinant antigens for serodiagnosis of human fascioliasis

“…Gold standard for the diagnosis of fasciolosis is the conventional coprological method. Nevertheless this approach is not reliable inthe acute phase of the disease and has poor sensitivity during the chronic phase [ 5 ]; therefore antibody detection is one of the most convenient tests, allowing diagnosis in the early stage of human fascioliasis compared to the coprological test [ 6 ]. Diagnosis of IgG antibodies in human serum by ELISA is considered as a sensitive diagnostic tool to identify acute and chronic phase [ 29 ].…”

“…Additionally, eggs may not exist in the stool samples of infected patients with mature flukes since eggs are often released intermittently; also in the low parasitic burden of chronic cases, the eggs often be undetected [ 5 ]. Since anti- Fasciola antibodies can be detected after 2–7 weeks post-infection, serological tests such as Enzyme-linked immunosorbent assay (ELISA) can play a key role in the diagnosis of acute human fascioliasis when the eggs are not yet obvious in the stools [ 6 – 9 ]. Most of the available commercial serological kits, as well as in-house ELISAs, are based on excretory/secretory (E/S) products as antigen.…”

Human fascioliasis endemic areas in Argentina: multigene characterisation of the lymnaeid vectors and climatic-environmental assessment of the transmission pattern

“…In Uruguay and Brazil, human reports only concern sporadic and isolated cases. In the Caribbean region, human fascioliasis mainly poses problems in Cuba, where patients are continuously diagnosed [ 42 , 43 ] even in high numbers [ 44 ], and Haiti [ 45 ]. Puerto Rico may still be considered an area of risk for human infections considering the epidemiological situation in the past [ 46 ].…”

Comparative transcriptome profiling approach to glean virulence and immunomodulation-related genes of Fasciola hepatica

“…Fasciola hepatica , the liver fluke, is a digenetic trematode helminth, causing highly damaging hepatobiliary disease (fasciolosis) in mammalians including economically important ruminants (such as cattle and sheep) and humans [ 1 ]. Fasciolosis results in a significant economic loss in livestock industry worldwide and more cases have been reported in humans in different countries [ 1 - 4 ].…”

“…Fasciola hepatica , the liver fluke, is a digenetic trematode helminth, causing highly damaging hepatobiliary disease (fasciolosis) in mammalians including economically important ruminants (such as cattle and sheep) and humans [ 1 ]. Fasciolosis results in a significant economic loss in livestock industry worldwide and more cases have been reported in humans in different countries [ 1 - 4 ]. The disease is currently treated with anti-helminthics (such as triclabendazole), but the observed anti-helminthic drug resistance [ 5 ] necessitates more effective strategies for the treatment and/or the prevention of fasciolosis.…”