Sero-epidemiological study of Taenia saginata cysticercosis in Belgian cattle.

A sero-epidemiological survey of Taenia saginata cysticercosis was carried out to determine the prevalence of the infection in cattle presented for slaughter in Belgium. Between November 1997 and June 1998, a total of 1164 serum samples were collected in 20 export abattoirs. Meat inspection was routinely carried out by veterinary inspectors. Serum samples were examined for circulating parasite antigen using a monoclonal antibody-based sandwich enzyme-linked-immunosorbent assay (Ag-ELISA). Thirty six serum samples (3.09%) were found positive in the Ag-ELISA, while by meat inspection on the same animals cysticerci were detected in only three carcasses (0.26%). Sero-prevalence was positively correlated with the age of the animals. The sero-prevalence found in this study was more than 10 times higher than the annual prevalence (0.26%) reported by the Institute for Veterinary Inspection. This study clearly indicates that the classical meat inspection techniques detect only a minor fraction of the carcasses infected with cysticerci.

A sensitive and specific 30-min Dot-ELISA for the detection of anti-leishmania antibodies in the dog.

A very rapid, sensitive and specific Dot-ELISA was developed for diagnosing visceral leishmaniosis in dogs infected with Leishmania infantum. Sera from 26 healthy dogs and 127 dogs with different infectious disease including 40 dogs with leishmaniosis, and 87 dogs with other suspected or confirmed infectious diseases, was evaluated in an alkaline phosphatase ELISA on a nitrocellulose membrane, sensitized with soluble promastigote antigen. The test procedure lasted only 30 min. Distinction between leishmania positive and leishmania negative sera was complete at a dilution of 1/320, hence there was no cross-reactivity, not even with sera from dogs with trypanosomal or babesial infections. Therefore, it is concluded that this test has a very high sensitivity and specificity for the detection of anti-leishmania antibodies in the dog. The Dot-ELISA was significantly positive correlated with the direct agglutination test (DAT), the indirect immunofluorescence test (IFAT), and the Slide-ELISA. A significant concordance of the four tests was also demonstrated.

Improved detection of circulating antigen in cattle infected with Taenia saginata metacestodes.

In order to improve the sensitivity and the specificity of an existing IgM monoclonal antibody-based ELISA (Brandt et al., 1992) for the detection of circulating antigen in the sera of cattle infected with T. saginata metacestodes, a modified sandwich ELISA was developed. Monoclonal antibodies (MAbs) of the IgG isotype were produced against the excretory-secretory (ES)-products of T. saginata metacestodes. Since it was shown that the affinity of these IgG MAbs for ES antigen was higher than that of the IgM MAbs, the latter were replaced by two IgG1 MAbs (158C11 and 60H8). Furthermore, heat treatment of the sera significantly increased the OD-values of ES-spiked serum samples as compared to nontreated samples. It also decreased the number of false positive reactions. When the original IgM MAb-based ELISA was compared with the IgG MAb-based ELISA using heat treated sera from animals harbouring more than 50 living metacestodes of T. saginata, the sensitivity increased from 56% with the former to 92% with the latter assay. Only a small percentage of animals carrying less than 50 cysts were detected both with the ELISA using IgG or IgM MAbs. The specificity of the IgM- and IgG MAb-based ELISAs was 93.4% and 98.7% respectively.