scholarly journals Vector competence of Culicoides biting midges from Switzerland for African horse sickness virus and epizootic haemorrhagic disease virus

2022 ◽  
Vol 164 (1) ◽  
pp. 66-70
Author(s):  
L.M. Maurer ◽  
A. Paslaru ◽  
P. R Torgerson ◽  
E. Veronesi ◽  
A. Mathis
Keyword(s):  
Disease Virus ◽  
Vector Competence ◽  
African Horse Sickness ◽  
African Horse Sickness Virus ◽  
Biting Midges ◽  
Haemorrhagic Disease ◽  
Culicoides Biting Midges

scholarly journals Interactions entre les orbivirus et leurs vecteurs Culicoides

2009 ◽  
Vol 62 (2-4) ◽  
pp. 136
Author(s):  
E. Veronesi ◽  
P. P.C. Mertens ◽  
P. Mellor ◽  
K. Darpel ◽  
S. Maan ◽  
...  
Keyword(s):  
Classical Method ◽  
Vector Competence ◽  
African Horse Sickness ◽  
Biting Midges ◽  
Northern European ◽  
Membrane Feeding ◽  
Effects Of Temperature ◽  
Areas Of Interest ◽  
Culicoides Biting Midges ◽  
Surrogate System

Bluetongue, African horse sickness and epizootic haemor­rhagic disease are non-contagious, infectious diseases, caused by orbiviruses transmitted by Culicoides biting midges. Recent incursions of bluetongue virus (BTV) into both Southern and Northern European countries have highlighted our lack of knowledge in the mechanisms involved in the transmission of orbiviruses, which are of importance in understanding their spread. This presentation will discuss preliminary results of vector competence studies and provide an overview of future investigations. An understanding of the rates and temperature limits of virus replication and effects of temperature on vector metabolism can provide simple tools to predict the probability of virus establishment and onwards transmission subsequent to new incursions. Experiments showed that it was possible to use KC cell lines originating from C. sonorensis embryos as a surrogate system to screen rapidly replication rates in prefer­ence to the classical method of infecting and incubating adult insects via membrane feeding on a blood/virus meal. Some of the issues that arose in the development of detection assays are examined. The value of these techniques is then discussed in relation to understanding the effect of laboratory passage history upon orbivirus infectivity and detection, and this is related to an overview of current BTV strains’ distribution. Finally, future areas of interest that may develop from these studies are described.

scholarly journals Culicoides biting midges at the National Zoological Gardens of South Africa : research communication

2007 ◽  
Vol 74 (4) ◽  
Author(s):  
K. Labuschagne ◽  
L.J. Gerber ◽  
I. Espie ◽  
S. Carpenter
Keyword(s):  
South Africa ◽  
Vector Competence ◽  
Far East ◽  
Wild Animals ◽  
Light Traps ◽  
Biting Midges ◽  
Research Communication ◽  
Culicoides Imicola ◽  
Large Numbers ◽  
Culicoides Biting Midges

Culicoides biting midges (Diptera: Ceratopogonidae) are responsible for the transmission of a large number of pathogens to livestock and wild animals. In this study the presence of the genus, using light traps based at four different sites within the National Zoological Gardens of South Africa, was investigated during 2002-2004. In total, 37 species were recorded, including large numbers of Culicoides imicola Kieffer, 1913, which is responsible for the transmission of economically important arboviruses in South Africa, Europe, Middle and Far East. These results are discussed with reference to the wider Culicoides fauna in the Onderstepoort area of South Africa, their vector competence as well as biosecurity at the National Zoological Gardens.

How does the ecology of Culicoides biting midges influence the risk of an epidemic of African Horse Sickness?

2012 ◽  
Vol 32 (10) ◽  
pp. S83-S84
Author(s):  
G. Lo Iacono ◽  
C. Robin ◽  
S. Gubbins ◽  
R. Newton ◽  
J. Wood
Keyword(s):  
African Horse Sickness ◽  
Biting Midges ◽  
Culicoides Biting Midges

scholarly journals An Investigation of Culicoides (Diptera: Ceratopogonidae) as Potential Vectors of Medically and Veterinary Important Arboviruses in South Africa

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1978
Author(s):  
Jumari Snyman ◽  
Gert J. Venter ◽  
Marietjie Venter
Keyword(s):  
South Africa ◽  
Polymerase Chain Reaction ◽  
Disease Outbreaks ◽  
African Horse Sickness ◽  
Chain Reaction ◽  
Biting Midges ◽  
Polymerase Chain ◽  
Culicoides Biting Midges ◽  
Minimum Infection Rate

Culicoides-borne viruses such as bluetongue, African horse sickness, and Schmallenberg virus cause major economic burdens due to animal outbreaks in Africa and their emergence in Europe and Asia. However, little is known about the role of Culicoides as vectors for zoonotic arboviruses. In this study, we identify both veterinary and zoonotic arboviruses in pools of Culicoides biting midges in South Africa, during 2012–2017. Midges were collected at six surveillance sites in three provinces and screened for Alphavirs, Flavivirus, Orthobunyavirus, and Phlebovirus genera; equine encephalosis virus (EEV); and Rhaboviridae, by reverse transcription polymerase chain reaction. In total, 66/331 (minimum infection rate (MIR) = 0.4) pools tested positive for one or more arbovirus. Orthobunyaviruses, including Shuni virus (MIR = 0.1) and EEV (MIR = 0.2) were more readily detected, while only 2/66 (MIR = 0.1) Middelburg virus and 4/66 unknown Rhabdoviridae viruses (MIR = 0.0) were detected. This study suggests Culicoides as potential vectors of both veterinary and zoonotic arboviruses detected in disease outbreaks in Africa, which may contribute to the emergence of these viruses to new regions.

scholarly journals Morphological Keys for the Identification of Tunisian Culicoides Biting Midges (Diptera: Ceratopogonidae)

2021 ◽  
Author(s):  
Darine Slama ◽  
Emna Chaker ◽  
Hamouda Babba
Keyword(s):  
Public Health ◽  
Blood Feeding ◽  
Morphological Characters ◽  
African Horse Sickness ◽  
Culicoides Species ◽  
Microscope Examination ◽  
Biting Midges ◽  
Health Significance ◽  
First Time ◽  
Culicoides Biting Midges

Culicoides biting midges are tiny blood-feeding insects of several diseases with veterinary and public health significance, including Bluetongue in ruminants, African horse sickness in equids and filarial diseases like Onchocercosis and Mansonellosis affecting various species such as humans. Their identification depends basically on the microscope examination of key morphological characters. Consequently, identification keys are important to any non experiment working with these biting midges. The Tunisian fauna of Culicoides biting midges consists of 35 species, whose morphological delineation may be troublesome for non-taxonomists. In response to this situation, and for the first time a key to the adult Culicoides species in Tunisia was prepared.

scholarly journals Identification de virus de la fièvre catarrhale ovine réassortis dans la région Ouest méditerranéenne

2009 ◽  
Vol 62 (2-4) ◽  
pp. 167
Author(s):  
N. S. Maan ◽  
S. Maan ◽  
K. Nomikou ◽  
P. P.C. Mertens
Keyword(s):  
Mediterranean Region ◽  
Western Mediterranean ◽  
Structural Proteins ◽  
Full Genome Sequence ◽  
Biting Midges ◽  
Western Group ◽  
The Family ◽  
Haemorrhagic Disease ◽  
Reassortant Viruses ◽  
Culicoides Biting Midges

Bluetongue virus (BTV) is the species of the genus Orbivirus of the family Reoviridae. BTV can infect most ruminants, caus­ing a severe haemorrhagic disease called bluetongue in sheep. BTV is transmitted among ruminant hosts by certain species of Culicoides (biting midges). The BTV genome is composed of ten linear double-stranded (ds) RNA genome segments, encod­ing seven structural and three non-structural proteins. The seg­mented nature of the genome allows different BTV strains infect­ing the same cell to exchange (reassort) genome segments.  Nine BTV serotypes have been detected in Europe since 1998, including strains belonging to both eastern (BTV-1, 9, 16) and western lineages (BTV-1, 2, 4, 6, 8, 11). Live attenuated mono­valent vaccine strains of BTV-2, 4, 8, 9 (western group) and BTV- 16 (eastern group) have also been used in the Mediterranean region, in attempts to minimise virus circulation. The release of these vaccine strains, some of which have persisted in the field (including BTV-2 and 16), has added further genetic diversity, generating an unprecedented mix of field and vaccine strain viruses. These events have provided unique opportunities for genome segment exchange (reassortment) between different BTV strains and topotypes. Indeed, a strain of BTV-2, derived by reassortment between vaccine strains of BTV-2 and 16 has been previously detected in Italy during 2002.  Full genome sequence analysis of BTV-2 and BTV-4 isolates (1999-2004) from the Western Mediterranean region helped to identify multiple reassortant viruses, involving the exchange of several different genome segments. Reassortant viruses were identified as containing genes derived from different western field strains, from western field and vaccine strains, and from eastern field and western vaccine strains. The detection of these reassortant BTVs in Europe highlights concerns about the use of live BTV vaccines in the region.

scholarly journals Culicoides Biting Midges—Underestimated Vectors for Arboviruses of Public Health and Veterinary Importance

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 376 ◽  
Author(s):  
Franziska Sick ◽  
Martin Beer ◽  
Helge Kampen ◽  
Kerstin Wernike
Keyword(s):  
Public Health ◽  
Vector Competence ◽  
Febrile Illness ◽  
Disease Spread ◽  
Vector Species ◽  
Public Health Importance ◽  
Biting Midges ◽  
Veterinary Importance ◽  
Hematophagous Arthropods ◽  
Culicoides Biting Midges

Culicoides biting midges, small hematophagous dipterans, are the demonstrated or putative vectors of multiple arboviruses of veterinary and public health importance. Despite its relevance in disease spread, the ceratopogonid genus Culicoides is still a largely neglected group of species, predominantly because the major human-affecting arboviruses are considered to be transmitted by mosquitoes. However, when a pathogen is detected in a certain vector species, a thorough search for further vectors often remains undone and, therefore, the relevant vector species may remain unknown. Furthermore, for many hematophagous arthropods, true vector competence is often merely suspected and not experimentally proven. Therefore, we aim to illuminate the general impact of Culicoides biting midges and to summarize the knowledge about biting midge-borne disease agents using the order Bunyavirales, the largest and most diverse group of RNA viruses, as an example. When considering only viruses evidentially transmitted by Culicoides midges, the Simbu serogroup (genus Orthobunyavirus) is presumably the most important group within the virus order. Its members are of great veterinary importance, as a variety of simbuviruses, e.g., the species Akabane orthobunyavirus or Schmallenberg orthobunyavirus, induces severe congenital infections in pregnant animals. The major zoonotic representative of this serogroup occurs in South and Central America and causes the so-called Oropouche fever, an acute febrile illness in humans.

scholarly journals VP2 Exchange and NS3/NS3a Deletion in African Horse Sickness Virus (AHSV) in Development of Disabled Infectious Single Animal Vaccine Candidates for AHSV

2015 ◽  
Vol 89 (17) ◽  
pp. 8764-8772 ◽  
Author(s):  
Sandra G. P. van de Water ◽  
René G. P. van Gennip ◽  
Christiaan A. Potgieter ◽  
Isabel M. Wright ◽  
Piet A. van Rijn
Keyword(s):  
Mammalian Cells ◽  
Reverse Genetics ◽  
African Horse Sickness ◽  
African Horse Sickness Virus ◽  
Vaccine Platform ◽  
Biting Midges ◽  
Content Type ◽  
Vp2 Protein ◽  
Single Animal

ABSTRACTAfrican horse sickness virus (AHSV) is a virus species in the genusOrbivirusof the familyReoviridae. There are nine serotypes of AHSV showing different levels of cross neutralization. AHSV is transmitted by species ofCulicoidesbiting midges and causes African horse sickness (AHS) in equids, with a mortality rate of up to 95% in naive horses. AHS has become a serious threat for countries outside Africa, since endemicCulicoidesspecies in moderate climates appear to be competent vectors for the related bluetongue virus (BTV). To control AHS, live-attenuated vaccines (LAVs) are used in Africa. We used reverse genetics to generate “synthetic” reassortants of AHSV for all nine serotypes by exchange of genome segment 2 (Seg-2). This segment encodes VP2, which is the serotype-determining protein and the dominant target for neutralizing antibodies. Single Seg-2 AHSV reassortants showed similar cytopathogenic effects in mammalian cells but displayed different growth kinetics. Reverse genetics for AHSV was also used to study Seg-10 expressing NS3/NS3a proteins. We demonstrated that NS3/NS3a proteins are not essential for AHSV replicationin vitro. NS3/NS3a of AHSV is, however, involved in the cytopathogenic effect in mammalian cells and is very important for virus release from cultured insect cells in particular. Similar to the concept of the bluetongue disabled infectious single animal (BT DISA) vaccine platform, an AHS DISA vaccine platform lacking NS3/NS3a expression was developed. Using exchange of genome segment 2 encoding VP2 protein (Seg-2[VP2]), we will be able to develop AHS DISA vaccine candidates for all current AHSV serotypes.IMPORTANCEAfrican horse sickness virus is transmitted by species ofCulicoidesbiting midges and causes African horse sickness in equids, with a mortality rate of up to 95% in naive horses. African horse sickness has become a serious threat for countries outside Africa, since endemicCulicoidesspecies in moderate climates are supposed to be competent vectors. By using reverse genetics, viruses of all nine serotypes were constructed by the exchange of Seg-2 expressing the serotype-determining VP2 protein. Furthermore, we demonstrated that the nonstructural protein NS3/NS3a is not essential for virus replicationin vitro. However, the potential spread of the virus by biting midges is supposed to be blocked, since thein vitrorelease of the virus was strongly reduced due to this deletion. VP2 exchange and NS3/NS3a deletion in African horse sickness virus were combined in the concept of a disabled infectious single animal vaccine for all nine serotypes.

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