Harmonizing methods for wildlife abundance estimation and pathogen detection in Europe-a questionnaire survey on three selected host-pathogen combinations

__Background:__ The 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 t

Genetic diversity and phenotypic associations of feline caliciviruses from cats in Switzerland

Feline calicivirus (FCV) is a common viral pathogen in domestic cats worldwide. The variable regions of the capsid (VP1) gene of FCV have one of the highest recorded rates of molecular evolution. Understanding the genetic diversity and phylogeny of FCV is a prerequisite to exploring the epidemiology and pathogenesis of this virus and to the development of efficacious vaccine strategies. In this study, we undertook a nationwide molecular characterization of FCV using for the first time nearly complete capsid (VP1) gene sequences. Sequences from 66 FCV samples were used to investigate the correlation between viral phylogeny and several traits, including geographic origin, signalment, husbandry, FCV vaccination, and co-infections. Codon-based nucleotide alignment showed that individual nucleotides and their corresponding amino acid sites were either invariant or highly variable. Using a threshold of 20% genetic distance in variable region E, FCV samples were grouped into 52 strains, 10 of which comprised 2 to 3 samples. Significant associations between FCV phylogeny and host characteristics were found, specifically the pedigree status of the cats, and two well-supported lineages were identified in which the current FCV strain definition was confounded. No correlation between viral genetic distances and geographic distances was evident. The greater resolution of the FCV phylogeny in this study compared to previous studies can be attributed to our use of more conserved regions of the capsid (VP1) gene; nonetheless, our results were still hampered by sequence saturation. The study highlights the need for whole genome sequences for FCV phylogeny studies

Long-term infection of goats with bluetongue virus serotype 25

Toggenburg Orbivirus (TOV) is the prototype of bluetongue virus serotype 25 (BTV-25). It was first detected in goats in Switzerland in 2008. The virus does not induce clinical signs in infected goats. In field samples viral RNA could be detected only in goats and never in other ruminants. BTV-25 RNA was repeatedly detected for more than one year in the blood of goats from a single flock in Principality of Liechtenstein. Since viral persistence over such a long period has never been reported for bluetongue, blood samples from 110 goats and 2 sheep of that flock were collected during a period of up to two years and analyzed for the presence of BTV-25 RNA and antibodies. Most of the animals which tested positive for BTV-25 RNA, remained positive during the whole investigation period. Moreover, five of these goats were BTV-25 RNA positive over a period of 19-25 months. A weak antibody response against BTV VP7 was commonly observed. As BTV-25 cannot be propagated in any culture system, the presence of virus could only be demonstrated in samples by viral RNA detection using RT-qPCR. To address the question of infectivity of the virus in blood from long-term positive animals, goats were experimentally infected with this blood. Viral replication was demonstrated by increasing RNA amounts. Thus, our findings provide evidence that BTV-25 can persist much longer in an infected host than known so far for other BTV serotypes. Hence, persistence of infectious BTV represents an additional important factor in BTV epidemiology