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In this study, an indirect Newcastle disease virus enzyme-linked immunosorbent assay (ELISA) for waterfowl was evaluated concerning its efficiency and its suitability to monitor the antibody response in Muscovy ducks (Cairina moschata) and domestic geese (Anser anser var. domestica) following vaccination with a commercial inactivated NDV vaccine for chickens. Three weeks after vaccination seroconversion was already evident in the ELISA. Comparison of the ELISA results with those of the haemagglutination inhibition (HI) test provided a positive linear correlation between both tests (Pearson's product-moment correlation; r00.652; PB0.001). However, a discrepancy of test results was evident in weeks 7 and 10, with 10 sera of vaccinated birds evaluated negative by HI test but positive by ELISA. Eight of these sera were confirmed to yield avian paramyxovirus specific reactivity by western blot analysis. Relative diagnostic sensitivity and specificity were determined to be 100.0% and 91.7% for the ELISA, compared with 91.1% and 97.2% for the HI test. Thus, the established ELISA represents a suitable alternative to the HI test in the monitoring of the immune response of waterfowl after vaccination, particularly for the analysis of high sample numbers. Further on, the results emphasize the immunogenicity of the inactivated Newcastle disease virus vaccine in domestic geese and Muscovy ducks.

Classical swine fever (CSF) is one of the most important viral diseases of domestic pigs ( Sus scrofa domesticus) and wild boar ( Sus scrofa ). For at least 4 decades, several European Union member states were confronted with outbreaks among wild boar and, as it had been shown that infected wild boar populations can be a major cause of primary outbreaks in domestic pigs, strict control measures for both species were implemented. To guarantee early detection and to demonstrate freedom from disease, intensive surveillance is carried out based on a hunting bag sample. In this context, virologic investigations play a major role in the early detection of new introductions and in regions immunized with a conventional vaccine. The required financial resources and personnel for reliable testing are often large, and sufficient sample sizes to detect low virus prevalences are difficult to obtain. We conducted a simulation to model the possible impact of changes in sample size and sampling intervals on the probability of CSF virus detection based on a study area of 65 German hunting grounds. A 5-yr period with 4,652 virologic investigations was considered. Results suggest that low prevalences could not be detected with a justifiable effort. The simulation of increased sample sizes per sampling interval showed only a slightly better performance but would be unrealistic in practice, especially outside the main hunting season. Further studies on other approaches such as targeted or risk-based sampling for virus detection in connection with (marker) antibody surveillance are needed.

BackgroundThe need for wildlife health surveillance as part of disease control in wildlife, domestic animals and humans on the global level is widely recognized. However, the objectives, methods and intensity of existing wildlife health surveillance programs vary greatly among European countries, resulting in a patchwork of data that are difficult to merge and compare. This survey aimed at evaluating the need and potential for data harmonization in wildlife health in Europe. The specific objective was to collect information on methods currently used to estimate host abundance and pathogen prevalence. Questionnaires were designed to gather detailed information for three host-pathogen combinations: (1) wild boar and Aujeszky’s disease virus, (2) red fox and Echinococcus multilocularis, and (3) common vole and Francisella tularensis.ResultsWe received a total of 70 responses from 19 European countries. Regarding host abundance, hunting bags are currently the most widely accessible data source for widely distributed mid-sized and larger mammals such as red fox and wild boar, but we observed large differences in hunting strategies among countries as well as among different regions within countries. For small rodents, trapping is the method of choice, but practical applications vary among study sites. Laboratory procedures are already largely harmonized but information on the sampled animals is not systematically collected.ConclusionsThe answers revealed that a large amount of information is available for the selected host-pathogen pairs and that in theory methods are already largely harmonized. However, the comparability of the data remains strongly compromised by local differences in the way, the methods are applied in practice. While these issues may easily be overcome for prevalence estimation, there is an urgent need to develop tools for the routine collection of host abundance data in a harmonized way. Wildlife health experts are encouraged to apply the harmonized APHAEA protocols in epidemiological studies in wildlife and to increase cooperation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0935-x) contains supplementary material, which is available to authorized users.