Western Bluetongue virus serotype 3 in Sardinia, diagnosis and characterization

Abstract

Over the last 20 years, Italy has experienced multiple incursions of different serotypes of Bluetongue virus (BTV), a Culicoides‐borne arbovirus, the causative agent of bluetongue (BT), a major disease of ruminants. The majority of these incursions originated from Northern Africa, likely because of wind‐blown dissemination of infected midges. Here, we report the first identification of BTV‐3 in Sardinia, Italy. BTV‐3 circulation was evidenced in sentinel animals located in the province of Sud Sardegna on September 19, 2018. Prototype strain BTV‐3 SAR2018 was isolated on cell culture. BTV‐3 SAR2018 sequence and partial sequences obtained by next‐generation sequencing from nucleic acids purified from the isolate and blood samples, respectively, were demonstrated to be almost identical (99–100% of nucleotide identity) to BTV‐3 TUN2016 identified in Tunisia in 2016 and 2017, a scenario already observed in past incursions of other BTV serotypes originating from Northern Africa.

Bluetongue Serotype 3 in Israel 2013–2018: Clinical Manifestations of the Disease and Molecular Characterization of Israeli Strains

“…BTV-3 circulation has been recently reported in Tunisia, Egypt and Italy. Even though detected either in goats or cattle (7,38,54) in these countries clinical signs associated to BTV-3 infection were observed and described in sheep only (7,38,39). According to the retrospective findings of this study, during 2013-2017 BTV-3 outbreaks were restricted to Negev Desert area, in the southern district, while in 2018 it spread among most coastal and some central areas of Israel (Figure 1, Table 3).…”

“…1st cluster includes strains originated from Africa, Mediterranean Basin and North America (western topotypes, w); 2nd-includes strains originated from Japan, India, and Australia (eastern topotypes, e). The nucleotide (nt) identity between Western and Eastern topotype Seg-2 can be as small as 71.5% (7,(38)(39)(40)(41)(42)(43).…”

“…Between 2016 and 2018, two novel BTV-3 western strains have been identified in two different geographical areas of Tunisiaone in the north-eastern part of the country (Peninsula of Cap Bon, prototype BTV-3 TUN2016) and the other in the South-East near by the border with Libya (prototype strain BTV-3 TUN2016/Zarzis). The BTV-3 TUN2016 spread in 2017 to Italy infecting a single 3-year-old female crossbred sheep belonging to a flock located in the municipality of Trapani, Sicily, which are 150 km distant from Peninsula of Cap Bon (7,39,40) and in 2018 in the Southern area of Sardinia causing numerous outbreaks (38). Clinical signs in infected sheep included depression, fever, nasal discharge, submandibular edema, and crusted discharge around the nostrils.…”

“…Clinical signs in infected sheep included depression, fever, nasal discharge, submandibular edema, and crusted discharge around the nostrils. Four animals died because of the severity of infection (38). In 2016, another BTV-3 strain closely related to TUN2016/Zarzis strain was detected in Egypt (38).…”

“…Four animals died because of the severity of infection (38). In 2016, another BTV-3 strain closely related to TUN2016/Zarzis strain was detected in Egypt (38).…”