Research

18 pages, 3849 KiB

Open AccessArticle

Assessing the Risk of Occurrence of Bluetongue in Senegal

by Marie Cicille Ba Gahn, Fallou Niakh, Mamadou Ciss, Ismaila Seck, Modou Moustapha Lo, Assane Gueye Fall, Biram Biteye, Moussa Fall, Mbengué Ndiaye, Aminata Ba, Momar Talla Seck, Baba Sall, Mbargou Lo, Coumba Faye, Cécile Squarzoni-Diaw, Alioune Ka, Yves Amevoin and Andrea Apolloni

Microorganisms 2020, 8(11), 1766; https://doi.org/10.3390/microorganisms8111766 - 11 Nov 2020

Cited by 4 | Viewed by 2317

Abstract

Bluetongue is a non-contagious viral disease affecting small ruminants and cattle that can cause severe economic losses in the livestock sector. The virus is transmitted by certain species of the genus Culicoides and consequently, understanding their distribution is essential to enable the identification [...] Read more.

Bluetongue is a non-contagious viral disease affecting small ruminants and cattle that can cause severe economic losses in the livestock sector. The virus is transmitted by certain species of the genus Culicoides and consequently, understanding their distribution is essential to enable the identification of high-risk transmission areas. In this work we use bioclimatic and environmental variables to predict vector abundance, and estimate spatial variations in the basic reproductive ratio

R_{0}

. The resulting estimates were combined with livestock mobility and serological data to assess the risk of Bluetongue outbreaks in Senegal. The results show an increasing abundance of C. imicola, C. oxystoma, C. enderleini, and C. miombo from north to south.

R_{0}

< 1 for most areas of Senegal, whilst southern (Casamance) and southeastern (Kedougou and part of Tambacounda) agro-pastoral areas have the highest risk of outbreak (

R_{0}

= 2.7 and 2.9, respectively). The next higher risk areas are in the Senegal River Valley (

R_{0}

= 1.07), and the Atlantic coast zones. Seroprevalence rates, shown by cELISA, weren’t positively correlated with outbreak probability. Future works should include follow-up studies of competent vector abundancies and serological surveys based on the results of the risk analysis conducted here to optimize the national epidemiological surveillance system. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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16 pages, 619 KiB

Open AccessArticle

Simultaneous Detection of Bluetongue Virus Serotypes Using xMAP Technology

by Martin Ashby, Paulina Rajko-Nenow, Carrie Batten and John Flannery

Microorganisms 2020, 8(10), 1564; https://doi.org/10.3390/microorganisms8101564 - 11 Oct 2020

Cited by 2 | Viewed by 2470

Abstract

Bluetongue is an economically important disease of ruminants caused by the bluetongue virus (BTV). BTV is serologically diverse, which complicates vaccination strategies. Rapid identification of the causative BTV serotypes is critical, however, real-time PCR (RT-qPCR) can be costly and time consuming to perform [...] Read more.

Bluetongue is an economically important disease of ruminants caused by the bluetongue virus (BTV). BTV is serologically diverse, which complicates vaccination strategies. Rapid identification of the causative BTV serotypes is critical, however, real-time PCR (RT-qPCR) can be costly and time consuming to perform when the circulating serotypes are unknown. The Luminex xMAP technology is a high-throughput platform that uses fluorescent beads to detect multiple targets simultaneously. We utilized existing BTV serotyping RT-qPCR assays for BTV-1 to BTV-24 and adapted them for use with the xMAP platform. The xMAP assay specifically detected all 24 BTV serotypes when testing reference strains. In all BTV-positive samples, the sensitivity of the BTV xMAP was 87.55% whereas the sensitivity of the serotype-specific RT-qPCR was 79.85%. The BTV xMAP assay allowed for the specific detection of BTV serotypes 1–24 at a lower cost than current RT-qPCR assays. Overall, the assay provides a useful novel diagnostic tool, particularly when analyzing large sample sets. The use of the BTV xMAP assay will allow for the rapid assessment of BTV epidemiology and may inform decision-making related to control and prevention measures. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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14 pages, 2422 KiB

Open AccessArticle

Evaluation of Bluetongue Virus (BTV) Antibodies for the Immunohistochemical Detection of BTV and Other Orbiviruses

by Fabian Z. X. Lean, Jean Payne, Jennifer Harper, Joanne Devlin, David T. Williams and John Bingham

Microorganisms 2020, 8(8), 1207; https://doi.org/10.3390/microorganisms8081207 - 07 Aug 2020

Cited by 2 | Viewed by 2811

Abstract

The detection of bluetongue virus (BTV) antigens in formalin-fixed tissues has been challenging; therefore, only a limited number of studies on suitable immunohistochemical approaches have been reported. This study details the successful application of antibodies for the immunohistochemical detection of BTV in BSR [...] Read more.

The detection of bluetongue virus (BTV) antigens in formalin-fixed tissues has been challenging; therefore, only a limited number of studies on suitable immunohistochemical approaches have been reported. This study details the successful application of antibodies for the immunohistochemical detection of BTV in BSR variant baby hamster kidney cells (BHK-BSR) and infected sheep lungs that were formalin-fixed and paraffin-embedded (FFPE). BTV reactive antibodies raised against non-structural (NS) proteins 1, 2, and 3/3a and viral structural protein 7 (VP7) were first evaluated on FFPE BTV-infected cell pellets for their ability to detect BTV serotype 1 (BTV-1). Antibodies that were successful in immunolabelling BTV-1 infected cell pellets were further tested, using similar methods, to determine their broader immunoreactivity against a diverse range of BTV and other orbiviruses. Antibodies specific for NS1, NS2, and NS3/3a were able to detect all BTV isolates tested, and the VP7 antibody cross-reacted with all BTV isolates, except BTV-15. The NS1 antibodies were BTV serogroup-specific, while the NS2, NS3/3a, and VP7 antibodies demonstrated immunologic cross-reactivity to related orbiviruses. These antibodies also detected viral antigens in BTV-3 infected sheep lung. This study demonstrates the utility of FFPE-infected cell pellets for the development and validation of BTV immunohistochemistry. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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16 pages, 1540 KiB

Open AccessArticle

Diversity of Transmission Outcomes Following Co-Infection of Sheep with Strains of Bluetongue Virus Serotype 1 and 8

by Eva Veronesi, Karin Darpel, Simon Gubbins, Carrie Batten, Kyriaki Nomikou, Peter Mertens and Simon Carpenter

Microorganisms 2020, 8(6), 851; https://doi.org/10.3390/microorganisms8060851 - 05 Jun 2020

Cited by 5 | Viewed by 6119

Abstract

Bluetongue virus (BTV) causes an economically important disease, bluetongue (BT), in susceptible ruminants and is transmitted primarily by species of Culicoides biting midges (Diptera: Ceratopogonidae). Since 2006, northern Europe has experienced multiple incursions of BTV through a variety of routes of entry, including [...] Read more.

Bluetongue virus (BTV) causes an economically important disease, bluetongue (BT), in susceptible ruminants and is transmitted primarily by species of Culicoides biting midges (Diptera: Ceratopogonidae). Since 2006, northern Europe has experienced multiple incursions of BTV through a variety of routes of entry, including major outbreaks of strains of BTV serotype 8 (BTV-8) and BTV serotype 1 (BTV-1), which overlapped in distribution within southern Europe. In this paper, we examined the variation in response to coinfection with strains of BTV-1 and BTV-8 using an in vivo transmission model involving Culicoides sonorensis, low passage virus strains, and sheep sourced in the United Kingdom. In the study, four sheep were simultaneously infected using BTV-8 and BTV-1 intrathoracically inoculated C. sonorensis and co-infections of all sheep with both strains were established. However, there were significant variations in both the initiation and peak levels of virus RNA detected throughout the experiment, as well as in the infection rates in the C. sonorensis that were blood-fed on experimentally infected sheep at peak viremia. This is discussed in relation to the potential for reassortment between these strains in the field and the policy implications for detection of BTV strains. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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14 pages, 1484 KiB

Open AccessArticle

Continuous Cell Lines from the European Biting Midge Culicoides nubeculosus (Meigen, 1830)

by Lesley Bell-Sakyi, Fauziah Mohd Jaafar, Baptiste Monsion, Lisa Luu, Eric Denison, Simon Carpenter, Houssam Attoui and Peter P. C. Mertens

Microorganisms 2020, 8(6), 825; https://doi.org/10.3390/microorganisms8060825 - 30 May 2020

Cited by 6 | Viewed by 3150

Abstract

Culicoides biting midges (Diptera: Ceratopogonidae) transmit arboviruses of veterinary or medical importance, including bluetongue virus (BTV) and Schmallenberg virus, as well as causing severe irritation to livestock and humans. Arthropod cell lines are essential laboratory research tools for the isolation and propagation of [...] Read more.

Culicoides biting midges (Diptera: Ceratopogonidae) transmit arboviruses of veterinary or medical importance, including bluetongue virus (BTV) and Schmallenberg virus, as well as causing severe irritation to livestock and humans. Arthropod cell lines are essential laboratory research tools for the isolation and propagation of vector-borne pathogens and the investigation of host-vector-pathogen interactions. Here we report the establishment of two continuous cell lines, CNE/LULS44 and CNE/LULS47, from embryos of Culicoides nubeculosus, a midge distributed throughout the Western Palearctic region. Species origin of the cultured cells was confirmed by polymerase chain reaction (PCR) amplification and sequencing of a fragment of the cytochrome oxidase 1 gene, and the absence of bacterial contamination was confirmed by bacterial 16S rRNA PCR. Both lines have been successfully cryopreserved and resuscitated. The majority of cells examined in both lines had the expected diploid chromosome number of 2n = 6. Transmission electron microscopy of CNE/LULS44 cells revealed the presence of large mitochondria within cells of a diverse population, while arrays of virus-like particles were not seen. CNE/LULS44 cells supported replication of a strain of BTV serotype 1, but not of a strain of serotype 26 which is not known to be insect-transmitted. These new cell lines will expand the scope of research on Culicoides-borne pathogens. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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Review

Jump to: Research, Other

19 pages, 1755 KiB

Open AccessReview

Viral Vector Vaccines against Bluetongue Virus

by Luis Jiménez-Cabello, Sergio Utrilla-Trigo, Eva Calvo-Pinilla, Sandra Moreno, Aitor Nogales, Javier Ortego and Alejandro Marín-López

Microorganisms 2021, 9(1), 42; https://doi.org/10.3390/microorganisms9010042 - 25 Dec 2020

Cited by 13 | Viewed by 4608

Abstract

Bluetongue virus (BTV), the prototype member of the genus Orbivirus (family Reoviridae), is the causative agent of an important livestock disease, bluetongue (BT), which is transmitted via biting midges of the genus Culicoides. To date, up to 29 serotypes of BTV have [...] Read more.

Bluetongue virus (BTV), the prototype member of the genus Orbivirus (family Reoviridae), is the causative agent of an important livestock disease, bluetongue (BT), which is transmitted via biting midges of the genus Culicoides. To date, up to 29 serotypes of BTV have been described, which are classified as classical (BTV 1–24) or atypical (serotypes 25–27), and its distribution has been expanding since 1998, with important outbreaks in the Mediterranean Basin and devastating incursions in Northern and Western Europe. Classical vaccine approaches, such as live-attenuated and inactivated vaccines, have been used as prophylactic measures to control BT through the years. However, these vaccine approaches fail to address important matters like vaccine safety profile, effectiveness, induction of a cross-protective immune response among serotypes, and implementation of a DIVA (differentiation of infected from vaccinated animals) strategy. In this context, a wide range of recombinant vaccine prototypes against BTV, ranging from subunit vaccines to recombinant viral vector vaccines, have been investigated. This article offers a comprehensive outline of the live viral vectors used against BTV. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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10 pages, 1049 KiB

Open AccessReview

Multiple Routes of Bluetongue Virus Egress

by Thomas Labadie, Edward Sullivan and Polly Roy

Microorganisms 2020, 8(7), 965; https://doi.org/10.3390/microorganisms8070965 - 27 Jun 2020

Cited by 15 | Viewed by 3235

Abstract

Bluetongue virus (BTV) is an arthropod-borne virus infecting livestock. Its frequent emergence in Europe and North America had caused significant agricultural and economic loss. BTV is also of scientific interest as a model to understand the mechanisms underlying non-enveloped virus release from mammalian [...] Read more.

Bluetongue virus (BTV) is an arthropod-borne virus infecting livestock. Its frequent emergence in Europe and North America had caused significant agricultural and economic loss. BTV is also of scientific interest as a model to understand the mechanisms underlying non-enveloped virus release from mammalian and insect cells. The BTV particle, which is formed of a complex double-layered capsid, was first considered as a lytic virus that needs to lyse the infected cells for cell to cell transmission. In the last decade, however, a more in-depth focus on the role of the non-structural proteins has led to several examples where BTV particles are also released through different budding mechanisms at the plasma membrane. It is now clear that the non-structural protein NS3 is the main driver of BTV release, via different interactions with both viral and cellular proteins of the cell sorting and exocytosis pathway. In this review, we discuss the most recent advances in the molecular biology of BTV egress and compare the mechanisms that lead to lytic or non-lytic BTV release. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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Other

Jump to: Research, Review

5 pages, 307 KiB

Open AccessBrief Report

BTV-14 Infection in Sheep Elicits Viraemia with Mild Clinical Symptoms

by John Flannery, Lorraine Frost, Petra Fay, Hayley Hicks, Mark Henstock, Marcin Smreczak, Anna Orłowska, Paulina Rajko-Nenow, Karin Darpel and Carrie Batten

Microorganisms 2020, 8(6), 892; https://doi.org/10.3390/microorganisms8060892 - 13 Jun 2020

Cited by 4 | Viewed by 2580

Abstract

In 2011, Bluetongue virus serotype 14 (BTV-14) was detected in Russia during routine surveillance, and was subsequently found in a number of European countries. The strain had high sequence similarity to a BTV-14 vaccine strain. We aimed to determine the risk of this [...] Read more.

In 2011, Bluetongue virus serotype 14 (BTV-14) was detected in Russia during routine surveillance, and was subsequently found in a number of European countries. The strain had high sequence similarity to a BTV-14 vaccine strain. We aimed to determine the risk of this BTV-14 strain causing disease in a UK sheep breed. Four Poll Dorset sheep were infected with a Polish isolate of BTV-14 and infection kinetics were monitored over 28 days. BTV RNA was detected in EDTA blood by 4 days post-infection (dpi) and remained detectable at 28 days post-infection (dpi). Peak viraemia occurred at 6 and 7 dpi with Ct values ranging between 24.6 and 27.3 in all infected animals. BTV antibodies were detected by 10 dpi using a commercial ELISA and neutralising antibodies were detected from 10 dpi. BTV was isolated between 6 and 12 dpi. All infected sheep developed mild clinical signs such as reddening of conjunctiva and mucosal membranes, with one sheep demonstrating more overt clinical signs. Two uninoculated control animals remained clinically healthy and did not have detectable BTV RNA or antibodies. The overall mild clinical symptoms caused by this BTV-14 in this highly susceptible sheep breed were in accordance with the asymptomatic infections observed in the affected countries. Full article

(This article belongs to the Special Issue Bluetongue Virus)

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