An enzyme-linked immunosorbent assay (ELISA) lor the demonstration of the virus of ypring viraemia of carp (SVCV) in liver, kidney and spleen homogenates, and in infected cell cultures is described. The sensitivity of the method is 10"^-10^'' TCID.^,, Olmr' of the examined fluid. The specificity has been confirmed by the ELISA inhibition test and by results of virological examinations. Contamination with bacteria or fungi of samples taken from dead fish had no effect on the results of ELISA. Specific anti-SVCV sera were used successfully for the production of conjugates for the direct immunopcroxidasc and immunofluorescence detection of SVCV in infected cell cultures.

. A double antibody enzyme‐linked immunosorbent assay (ELISA) for the detection of infectious pancreatic necrosis virus (IPNV) is described. The sensitivity of the assay reached 102 TCID50 per 0·1 ml of culture fluid. The specificity of anti‐IPNV sera and of the assay was confirmed by agar‐gel immunodiffusion, by the direct immunoperoxidase technique for the deletion of IPNV in tissue cultures and by the ELISA inhibition test. High values of specific inhibition (over 90% at serum dilutions 1:40–1:2560) and low values of non‐specific inhibition (8·4% at serum dilution 1:160) demonstrated the quality of the rabbit anti‐IPNV serum. The results of ELISA agreed well with those of virological examinations. The potential of ELISA for investigations of a large series of field samples is discussed.

Tomanek J., J. Hampl, M. Sedlacek, J. Willomitzer and E. Chroustova:Labelling of Protein Fractions of Fasciola' hepatica Antigen with U5 I. Acta vet. Bmo, 50,1981: 97-100.Gel filtration of crude Fasciola hepatica antigen on Sephadex G-I00 and G-200 yielded protein fractions that reacted with serum antibodies of F. hepatiCa -infected animals. The fractions were labelled with usI by the oxidation method using chloramine T. The protein-bound radioiodine percentage was 5.4 to 23.6 per cent, depending on the quality of flukes employed for the preparation of crude antigen and on the Na 115 1 employed for iodination. When tested by direct radioimmunodiffusion with positive sera from F. hepatica-infected animals and with control negative sera, the 1251-labelled protein fractions showed the same specificity as the unlabelled ones. The iodinated antigen was stable for 4 weeks, and no more than 5 and 6 per cent of unreacted radioactive iodide were found after 6 and 8 weeks of storage, respectively. Stored at 4 DC, the iodinated antigen could be used for serological reactions for 5 to 8 weeks. Diagnosis, fascioliasis, direct radioimmunodijJusion, protein-bound radioiodine percentage, stability, iodinated antigen.The diagnosis of fascioliasis by serological methods has been described by a number of investigators using differently prepared antigens with varying results. The pertinent literature was reviewed by Koch (1969) and Grelck (1976). The possibility of demonstrating the antibodies by radioimmunoassay (RIA) has not been considered to date. One of the prerequisites for successful RIA is the use of a suitable antigen. Crude antigen obtained from Fasciola hepatica homogenate can be conveniently fractionated by gel filtration on a Sephadex column of appropriate type as was demonstrated by Movsesijan and Borojevic (1973). The relatively specific protein fraction separated in this way can be labelled with an radioactive isotope and used for RIA. For practical purposes it appears most convenient to use 12111 which was employed by Williams et al. (1971) for the labelling of Schistosoma mansoni antigen.Our objective was to separate the functional fraction from crude F. hepatica antigen, to test the conditions of its labelling by the oxidation method with chloramine T and to assess the properties of the iodinated antigen. Materials and MethodsThe antigen was prepared from adult F. hepatica obtained from the liver of infected animals. The flukes were washed in several changes of saline, dried of filter paper and frozen at -18 DC. Mter being thawed, they were ground in a glass homogenizer, macerated in saline for 24 hours at + 4 to + 6 DC and then centrifugated for 20 min. at 12000 r. p. m. The supernatant was aspirated and used for the separation of fractions by gel filtration on a 2.5 x 39 em column of Sephadex G-l00 or an a 2.5 x 85 em column of Sephadex G-200. Elution was carried out with 0.15 molll NaCl, pH 7.0,or 0.2 molll Tris HCl buffer, pH 8.0 Fractions obtained from the individual peaks were concentrated under a ...

The protein-bound radioiodine percentage and the stability and specificity of the protein fraction of Fasciola hepatica antigen labelled with 115 1 by electrolytic iodination were compared with the data obtained for the same batch of the antigenic fraction labelled by the oxidation procedure using chloramine T. There were no significant differences between the results obtained with the two methods.DiagmJ;is of fascioliasis, oxidation method of iodination, protein-bound radioiodine percentage, stability, iodinated antigen.

Insect control is a problem of increasing magnitude in intensive animal production systems where insects are not only a nuisance to animals and animal attendants, but are also involved in the transfer of a number of infectious diseases. This has led to frequent use of insecticides, many of which are injurious to health.Recently effons have been made all over the world to replace toxic inseeticides by natural or synthetic substances that are not injurious to higher warm-blooded organisms including man and have a satisfactory insecticidal efficiency. The rationale behind this approach is concern for the protection of the environment against growing pollution.Experience from honicultural practice (Novak 1978, Rolinkova 1979 has shown that extracts of some plants (e. g. horse-tail, nettle and garlic) have insecticidal effects. Of panicular importance is the recent observation of Schneider and Groth (1976) who found that sodium tetraborate was effective against Musca domestica larvae.The present study was designed to test larvicidal efficiency of some inorganic compounds and plant extracts against Musca domestica larvae under laboratory conditions. Materials and MethodsHouse flies (Musca domestica) were reared in 4 I-bottles by placing of at least 10 imagoes (males and females in approximately equal numbers) into each bottle, the bottom of which was previously filled with 125 g wetted wheat bran and overlaid with 40 g bovine faeces. An ample supply of honey diluted 1 : 10 with water was added as adult food. The necks of the bottles were closed with monofilament nets by means of rubber bands (Fig. 1). The contents of the bottles were wetted daily with water. The temperature of the room where the bottles were kept ranged between 23 and 28°C in summer months and was maintained at 27 to 29 °C in winter months by means of a heat lamp. The development of domestic flies at this temperature and sufficient relative humidity took 4 to 13 days (mean = 6.7 days) from oviposition to emergence of larvae, 4 to days (mean = = 8.8 days) from larval stage to puparium and 4 to 14 days (mean = 7.8 days) from puparium to imago. Thus the development of domestic flies was completed in 12 to 37 days (mean = 21.1 days). The rate of emergence of imagoes from puparia was 41.5 per cent.The compounds tested for larvicidal efficiency were copper sulphate (CuSOJ, iron sulphate (FeSO,), magnesium sulphate (MgSO,) and sodium tetraborate (Na2B.07). These compounds