Effect of fasciolicides on the antigenaemia in sheep naturally infected with Fasciola hepatica

Abstract

A study was developed to evaluate the influence of triclabendazole (Fasinex) and netobimin (Hapasil) the antigenaemia in sheep naturally infected with Fasciola hepatica during 16 weeks. A sandwich-ELISA (enzyme-linked immunosorbent assay) using a rabbit polyclonal IgG antibody to F. hepatica antigens was employed and the data obtained were compared to those from coprological and indirect-ELISA techniques. Triclabendazole reduced the values of circulating antigens at weeks 2-4 post-treatment and faecal output at weeks 2-8 post-treatment, but antibodies showed positive values until the end of the study. Netobimin did not reduce circulating antigens of the trematode nor egg-excretion; and IgG antibodies did not decrease throughout the study.

A recombinant-based ELISA evaluating the efficacy of netobimin and albendazole in ruminants with naturally acquired fascioliasis

“…The fact that antibody levels in the treated groups did not fall to the levels found in uninfected animals and increased 4 weeks after treatment, could suggest that chemoprophylaxis was unsuccessful. However, given that the animals were maintained under field conditions throughout the experiment, treated animals were likely to have been exposed to further parasitic challenge (Sánchez-Andrade et al, 2001), which may explain the increased IgG response 4 weeks after challenge. Such a scenario might also explain why antibody levels did not fall to those found in uninfected control animals.…”

“…Such a scenario might also explain why antibody levels did not fall to those found in uninfected control animals. In experimentally infected sheep, triclabendazole treatment did not result in a drop in IgG values to those of control animals in the 14 weeks after treatment (Paz-Silva et al, 2005) and in naturally infected sheep a 50–60% reduction in antibody levels against F. hepatica -excretory/secretory antigens was achieved following triclabendazole administration (Sánchez-Andrade et al, 2001). In our study, IgG levels were reduced by 50% in the treated animals and a significant reduction in the IgG response, rather than the given level of antibody, appears to reflect the efficacy of treatment.…”

“…The efficacy of albendazole and netobimin treatments was determined by calculating the reduction in serum IgG and in faecal epg. These parameters were termed the efficacy indices (EI) 1 and 2, respectively, and were calculated according to the following formulae (Sánchez-Andrade et al, 2001):…”

Fasciola hepatica saposin-like protein-2–based ELISA for the serodiagnosis of chronic human fascioliasis

“…This is because 100% of persons with acute or chronic infection develop high and sustainable levels of IgG antibody against the parasite, while the IgM isotype is only detectable in patients with acute infection, and the IgE and IgA antibodies are detected in a limited number of infected patients (Demirci et al, 2009). However, even the presence of IgG antibodies does not correlate with the existence of an active infection; it indicates an exposure to the parasite (Sanchez-Andrade et al, 2001). In that sense, antigen-capture detection assays could undoubtedly be a better alternative to the antibody detection in serum (Espino et al, 1990, Mezo et al, 2004).…”

Fasciola Species Introgression: Just a Fluke or Something More?

“…The maintenance of positive antibody titres post-treatment, however, limits the application of the antibody ELISA to the detection of Fasciola spp. exposure [ 60 , 61 ]. A coprological antigen ELISA (coproELISA) enables the diagnosis of current infections via the detection of F. hepatica and F. gigantica antigens as early as 6 and 9 WPI, respectively, with antigen levels declining rapidly post-treatment [ 62 ].…”