Serological Evidence for Schmallenberg Virus Infection in Sheep of Portugal, 2014

Abstract

Between November and December of 2014, a serosurvey was set up to evaluate the presence of Schmallenberg virus (SBV) antibodies in sheep of Portugal. Sera (n = 1068) were tested using an indirect enzyme linked immunosorbent assay (ID Screen(®) Schmallenberg virus indirect, IDvet Innovative Diagnostics, Montpellier, France). The estimated occurrence of immunogobulin G (IgG) antibodies against SBV in sheep of Portugal was 12.8% (95% confidence interval 11.0-15.0%). This is the first study reporting the presence of SBV antibodies in sheep of Portugal.

Serologic evidence for Schmallenberg virus circulation at high altitude, Central Portugal, 2015-2016

“…To define the sample size, a population size of 70,000 (based on the latest Serra da Estrela sheep breed census data) (ANCOSE, ), an expected seroprevalence of 13% (Esteves et al., ), an absolute error of 6%, a 95% confidence level (WINPEPI updated, version 11.35) and an oversampling of 40% to account for possible losses (deaths, sales and exchanges) were considered. As such, blood from 168 sheep was collected in January/February 2015, and in January/February 2016, the same 168 animals were sampled again.…”

“…Reports have shown that SBV has spread across Europe, having reached the farthest western country of continental Europe, Portugal (Esteves et al., ; Stavrou, Daly, Maddison, Gough, & Tarlinton, ). In this country, the first and only serosurvey dates from end 2014 and showed a prevalence of SBV IgG antibodies in 12.8% of sheep across the Portuguese mainland territory (Esteves et al., ).…”

“…Reports have shown that SBV has spread across Europe, having reached the farthest western country of continental Europe, Portugal (Esteves et al., ; Stavrou, Daly, Maddison, Gough, & Tarlinton, ). In this country, the first and only serosurvey dates from end 2014 and showed a prevalence of SBV IgG antibodies in 12.8% of sheep across the Portuguese mainland territory (Esteves et al., ). Recent studies from Europe have shown a decrease in new SBV infections across the continent, potentially associated to a natural substitution of previously exposed animals combined with vaccination, raising concerns for possible SBV re‐emergence if favourable conditions for Culicoides vectors occur (Collins, Barrett, Doherty, McDonnell, & Mee, ; Stavrou et al., ).…”

Epidemiology and Emergence of Schmallenberg Virus Part 1: Origin, Transmission and Differential Diagnosis

“…There are also reports of cases outside Europe [10]. Recently a new study shows the circulation of the virus in Portugal [11] (Figure 3). …”

Schmallenberg virus in Culicoides Latreille (Diptera: Ceratopogonidae) populations in France during 2011-2012 outbreak

“…Altogether, these findings evidence a rapid spread in Europe during the first vector activity period and an extensive circulation of the virus between hosts and vectors populations right after the SBV emergence. The virus has been detected throughout Europe, from Sweden and Poland to Portugal, Turkey and Greece (Azkur et al., ; Chaintoutis et al., ; Chenais et al., ; Esteves et al., ; Kaba, Czopowicz, & Witkowski, ) in both domestic and wild ruminants (Chiari et al., ; Fernandez‐Aguilar et al., ; Laloy et al., ; Larska, Krzysiak, Smreczak, Polak, & Zmudzinski, ; Larska, Polak et al., ; Larska, Krzysiak, Kesik‐Maliszewska, & Rola, ; Linden et al., ; Mouchantat et al., ; Rossi et al., ).…”