Novel putative Bluetongue virus in healthy goats from Sardinia, Italy

Abstract

In recent years, novel Bluetongue virus (BTV) serotypes have been isolated and/or sequenced by researchers within the field. During Bluetongue surveillance activities, we identified a putative novel BTV serotype in healthy goats from Sardinia, Italy. RNAs purified from blood and serum samples were positive for BTV by a generic real time RT-PCR and c-ELISA, respectively, whereas genotyping and serotyping were unsuccessful. By NGS, the whole genome sequence was obtained from two blood samples (BTV-X ITL2015 strains 34200 and 33531). Overall, Seg 2 of BTV-X ITL2015 shows the highest identity (75.3-75.5% nt/77.4-78.1% aa) with recently isolated BTV-27s from Corsica and with the last discovered BTV XJ1407 from China (75.9% nt /78.2% aa), whereas it is less related with BTV-25 from Switzerland (73.0% nt/75.0% aa) and BTV-26 from Kuwait (62.0% nt/60.5% aa). A specific RT-qPCR targeting Seg 2 of BTV-X ITL2015 was assessed in this study. Considering the Seg 2/VP2 identity of BTV-X ITL2015 with BTV-25, 26, 27s and BTV XJ1407 and that serum of BTV-X ITL2015 infected goats failed to neutralize all tested extant serotypes, we propose the existence of a novel BTV serotype circulating in goats in Sardinia. Isolation was so far unsuccessful thus hampering proper antigenic characterization.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): bluetongue

“…In the past decade, new serotypes (BTV‐25, BTV‐26, BTV‐27 and related strains) have been described (Hofmann et al., ; Maan et al., ; Zientara et al., ; Savini et al., ). These differ from the historical 24 serotypes, because they are characterised by causing asymptomatic infections, at least for BTV‐26 (Batten et al., ), they have longer viraemia, suggesting an alternative mechanism of persistence in the host (BTV‐25, Vogtlin et al., ) and use goats and sheep as reservoir hosts (Batten et al., , ).…”

“…There are currently 27 confirmed serotypes of BTV, with additional strains that have been identified that may represent a total of > 30 serotypes (Maan et al., , ,b; Zientara et al., ; Savini et al., ). The global distribution of these serotypes is not uniform, rather different constellations of BTV serotypes are disseminated by different species of Culicoides vector in relatively distinct global ecosystems (Gibbs and Greiner, ; Daniels et al., ; Maclachlan and Osburn, ; Tabachnick, ).…”

Experimental infection of sheep, goats and cattle with a bluetongue virus serotype 4 field strain from Bulgaria, 2014

“…The typical BTV serotypes (BTV‐1 to 24) may cause severe clinical signs particularly in sheep depending on the breed, while goats, cattle and camelids usually remain asymptomatic during BTV infection (Batten et al., ; MacLachlan, Drew, Darpel, & Worwa, ; Schulz, Eschbaumer, Ziller et al., ). Various novel “atypical” BTV serotypes have been discovered during the last decade in goats, sheep and alpaca (Batten et al., ; Bumbarov, Golender, Erster, & Khinich, ; Chaignat et al., ; Savini et al., ; Sun et al., ; Wright, ; Zientara et al., ). The three “atypical” serotypes BTV‐25, 26 and 27 are apathogenic for goats, while mild clinical signs could be observed in some sheep experimentally infected with BTV‐25 or 26.…”

Complete genome sequence of bluetongue virus serotype 4 that emerged on the French island of Corsica in December 2016

“…Bluetongue virus (BTV) is the causative agent of bluetongue (BT), an insect‐transmitted disease of domestic and wild ruminants (Maclachlan, Drew, Darpel, & Worwa, ; Verwoerd & Erasmus, ). Bluetongue virus is the prototype member of the Orbivirus genus in the Reoviridae family (Mertens, Maan, Samuel, & Attoui, ) with 27 serotypes currently described (Zientara et al., ) and at least four putative new serotypes (Maan et al., ; Savini et al., ; Sun et al., ).…”