Get access to all handy features included in the IVIS website
- Get unlimited access to books, proceedings and journals.
- Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
- Bookmark your favorite articles in My Library for future reading.
- Save future meetings and courses in My Calendar and My e-Learning.
- Ask authors questions and read what others have to say.
Wild cervids populations as Schmallenberg virus circulation sensors
Bayrou, C.; Volpe, R.; Lesenfants...
Get access to all handy features included in the IVIS website
- Get unlimited access to books, proceedings and journals.
- Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
- Bookmark your favorite articles in My Library for future reading.
- Save future meetings and courses in My Calendar and My e-Learning.
- Ask authors questions and read what others have to say.
Read
Background: The Schmallenberg virus (SBV) emerged in 2011 in Europe. The epicenter of this spreading was the region which straddled Germany, the Netherlands and Belgium. The dissemination of the virus is based on an arthropod/ruminant cycle. Midges belonging to the Culicoides obsoletus complex have been identified as the main vector population while the majority of tested ruminants supports the infection. After the remarkably fast spreading of the virus across Europe, questions raised about the virus implantation in the conquered lands.
Objectives: The objective of the study was to follow the circulation dynamic of SBV in Wallonia (Belgium) during six years after the emergence (2012-2017). We designed a seroprevalence follow-up of the wild deer populations to answer two main questions: (i) is SBV endemic in Wallonia and, if so, which kind of endemic profile characterizes its implantation? (ii) are wild deer a significant reservoir for the virus?
Material and Methods: The study is based on the annual sampling protocol of the Surveillance Network of Wildlife Diseases (SNWD) of the University of Liège (Belgium). The SNWD takes advantage of the hunting activities in Wallonia to collect, every year, during October, November and December, as many samples as possible to cover the largest number of communities. Blood is collected post-mortem. Sampled deer are classified as adults or juveniles (born the year of sampling) and belong to the two main deer species of Wallonia: roe deer (Capreolus capreolus) and red deer (Cervus elaphus). All samples were analyzed using the commercial ELISA from IDvet: ID Screen Schmallenberg virus Competition Multi-species®. To assess the relative sensitivity (Se) and specificity (Sp) of the ELISA in this context, sero-neutralisation tests (SNT) were carried out on a subset of samples of years 2012, 2013 and 2014.
Results: The study led to the test of 2258 sera: 1140 from roe deer and 1138 from red deer. The geographical distribution of the samples is centered on the Belgian Ardenne. The subset of samples used for the SNT numbered 622 sera. The relative Se of the ELISA in this context was 70% and the relative Sp reached 93%. However, for the 2012 red deer cohort, an unexplained phenomenon dropped the relative Se to 30%. In consequence, the seroprevalence of this group was evaluated by SNT and not included in the statistical analysis.
The profile of the seroprevalence evolution over the six years is similar in the two species. Two years, 2012 and 2016, were characterized by a significantly higher level of circulation (roe deer: 2012 = 44±6% - 2016 = 47±7%; red deer: 2012 = 43±16% SNT-based evaluation – 2016 = 28±7%). Beside these two years, the seroprevalence was low in both species, especially in juveniles for which the seroprevalence did not exceed 6±5%, showing a very limited circulation of the SBV during 2013, 2014, 2015 and 2017. These low circulation years led to a a seroprevalence decrease in the whole population until a floor level close to 10% reached in both species in 2014.
Conclusion: Our study provides evidences that the SBV continues to circulate in Wallonia after 2011. Thus, Wallonia appears as an endemic area characterized by a global hypoendemic state crossed by endemic pulsations. Such an endemic profile is classically explained by the Susceptible-Infectious-Recovered-Susceptible (SIRS) epidemiological model.
The intense 2016 circulation was observed and reported all across Europe. On the contrary, 2012 circulation is more specific to our study and is due to the specific topography of the Belgian Ardenne that locally slowed down the 2011 expansion of the virus.
The fact that floor level seroprevalence was already reached in 2014 for the two populations suggests that wild deer are not the main reservoir of the virus and have limited impact on the global circulation.
Keywords: Schmallenberg, Seroprevalence, Belgium, Deer, Epidemiology.
Get access to all handy features included in the IVIS website
- Get unlimited access to books, proceedings and journals.
- Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
- Bookmark your favorite articles in My Library for future reading.
- Save future meetings and courses in My Calendar and My e-Learning.
- Ask authors questions and read what others have to say.
About
Affiliation of the authors at the time of publication
University of Liège, Liège, Belgium;
University of Namur, Namur, Belgium.
Comments (0)
Ask the author
0 comments