Survey of bluetongue virus infection in free-ranging wild ruminants in Switzerland.

Casaubon, Julien; Chaignat, Valérie; Vogt, Hans-Rudolf; Michel, Adam O; Thür, Barbara; Ryser-Degiorgis, Marie-Pierre (2013). Survey of bluetongue virus infection in free-ranging wild ruminants in Switzerland. BMC veterinary research, 9(166), p. 166. BioMed Central 10.1186/1746-6148-9-166

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BACKGROUND In 2006, bluetongue virus serotype 8 (BTV-8) was detected for the first time in central Europe. Measures to control the infection in livestock were implemented in Switzerland but the question was raised whether free-ranging wildlife could be a maintenance host for BTV-8. Furthermore Toggenburg orbivirus (TOV), considered as a potential 25th BTV serotype, was detected in 2007 in domestic goats in Switzerland and wild ruminants were considered a potential source of infection. To assess prevalences of BTV-8 and TOV infections in wildlife, we conducted a serological and virological survey in red deer, roe deer, Alpine chamois and Alpine ibex between 2009 and 2011. Because samples originating from wildlife carcasses are often of poor quality, we also documented the influence of hemolysis on test results, and evaluated the usefulness of confirmatory tests. RESULTS Ten out of 1,898 animals (0.5%, 95% confidence interval 0.3-1.0%) had detectable antibodies against BTV-8 and BTV-8 RNA was found in two chamois and one roe deer (0.3%, 0.1-0.8%). Seroprevalence was highest among red deer, and the majority of positive wild animals were sampled close to areas where outbreaks had been reported in livestock. Most samples were hemolytic and the range of the optical density percentage values obtained in the screening test increased with increasing hemolysis. Confirmatory tests significantly increased specificity of the testing procedure and proved to be applicable even on poor quality samples. Nearly all samples confirmed as positive had an optical density percentage value greater than 50% in the ELISA screening. CONCLUSIONS Prevalence of BTV-8 infection was low, and none of the tested animals were positive for TOV. Currently, wild ruminants are apparently not a reservoir for these viruses in Switzerland. However, we report for the first time BTV-8 RNA in Alpine chamois. This animal was found at high altitude and far from a domestic outbreak, which suggests that the virus could spread into/through the Alps. Regarding testing procedures, hemolysis did not significantly affect test results but confirmatory tests proved to be necessary to obtain reliable prevalence estimates. The cut-off value recommended by the manufacturer for the screening test was applicable for wildlife samples.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Research Foci > Veterinary Public Health / Herd Health Management
05 Veterinary Medicine > Research Foci > Host-Pathogen Interaction
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Virology and Immunology
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP)
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Center for Fish and Wildlife Health (FIWI)

UniBE Contributor:

Casaubon, Julien; Vogt, Hans-Rudolf; Michel, Adam and Ryser, Marie Pierre

Subjects:

600 Technology > 630 Agriculture

ISSN:

1746-6148

Publisher:

BioMed Central

Language:

English

Submitter:

Susanne Portner

Date Deposited:

16 Jul 2014 16:52

Last Modified:

26 Jun 2016 01:48

Publisher DOI:

10.1186/1746-6148-9-166

PubMed ID:

23941229

BORIS DOI:

10.7892/boris.44265

URI:

https://boris.unibe.ch/id/eprint/44265

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