Genomic Analysis Illustrated a Single Introduction and Evolution of Israeli Bluetongue Serotype 8 Virus Population 2008–2019

Natalia Golender,Velizar Bumbarov,Avi Eldar,Marcelo Ehrlich,Ily Shlamovitz,Gabriel Kenigswald,Boris Even-Tov,Lior Zamir,Eyal Klement

doi:10.3390/microorganisms9091955

Natalia Golender, Velizar Bumbarov + Show 7 more

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https://doi.org/10.3390/microorganisms9091955

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Abstract

Outbreaks of the European Bluetongue virus (BTV) serotype 8 (BTV-8), which are characterized by activity cycles separated by years of inactivity, may be influenced by genetic changes of the virus or by herd immunity. BTV activity in Israel is characterized by similar dynamics, but differs from European countries in its vector population, environmental conditions, and lack of cattle vaccination against this serotype. Comparison of these two geographical systems and characterization of their epidemiological connection is therefore of high interest in-order to better understand the factors influencing BTV-8 evolution. BTV-8, closely related to the European strain, was introduced to Israel in 2008. It was at the center of BT outbreaks in 2010 and 2015–2016 and thereafter was lastly isolated in Israel in 2019. We performed genetic analyses of twelve BTV-8 Israeli strains isolated between 2008 and 2019 and compared them with published sequences of BTV-8 isolated in other countries. The analysis revealed a single introduction of BTV-8 into Israel and thereafter extensive occurrence of genomic drifts and multiple reassortments with local BTV strains. Comparison of the Israeli and Cypriot BTV-8 from 2015 to 2016 suggests transmission of the virus between the two countries and a separate and parallel development from European or other Israeli BTV-8 strains. The parallel development of other BTV-8 strains was demonstrated by the identification of the Israeli BTV-8 ISR-1194/1/19 strain, which exhibited common origin with reassorted Israeli BTV-8 strains from 2010 and additional reassortment of seven segments. In order to reveal the source of BTV-8 introduction into Israel we performed BEAST analysis which showed that a probable common ancestor for both European and Israeli BTV-8 presumably existed in 2003–2004. In 2019, a possible new introduction occurred in Israel, where a novel BTV-8 strain was detected, sharing ~95% identity by segments 2 and 6 with Nigerian BTV-8NIG1982/07 and European–Middle Eastern strains. The results of the study indicate that Israel and neighboring countries consist a separate environmental and evolutionary system, distinct from European ones.

Highlights

Introduction and Evolution of IsraeliBluetongue Serotype 8 Virus2021, 9, 1955. https://doi.org/10.3390/microorganisms9091955Academic Editor: Roland ZellReceived: 29 July 2021Accepted: 10 September 2021Published: 14 September 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Koret School of Veterinary Medicine, The Robert H
In recent years, the pan-Bluetongue virus (BTV) system described by Wernike et al [29], which is based on detection of Seg-10 fragment has been employed
The scenario we propose for the evolution of BTV-8 in Israel is based on the development of local BTV-8 population through both genomic drift and reassortment; essentially independent from the parallel evolution of European BTV-8 strains

Summary

Introduction

Introduction and Evolution of IsraeliBluetongue Serotype 8 Virus2021, 9, 1955. https://doi.org/10.3390/microorganisms9091955Academic Editor: Roland ZellReceived: 29 July 2021Accepted: 10 September 2021Published: 14 September 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Koret School of Veterinary Medicine, The Robert H. The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 6701101, Israel; Veterinary Servises in the Field, Galil-Golan Veterinary Distinct, Galil-Golan 1231400, Israel; Tel.: +972-3-9688949 (N.G.); +972-8-9489560 (E.K.); Fax: +972-3-9681788 (N.G.); +972-8-9489138 (E.K.) Abstract. Bluetongue (BT) is a non-contagious, vector-borne infectious viral disease of domesticated and wild ruminants caused by bluetongue virus (BTV). It is most commonly observed creativecommons.org/licenses/by/ 4.0/). Microorganisms 2021, 9, 1955 in sheep and in white-tailed deer, causing severe clinical manifestations and death, especially in naïve animals [1]. Based on Seg-2 gene sequences and virus neutralization tests, currently 35 distinct BTV serotypes have been officially recognized [3]

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