scholarly journals Vector Competence of Italian Populations of Culicoides for Some Bluetongue Virus Strains Responsible for Recent Northern African and European Outbreaks

Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 941 ◽  
Author(s):  
Valentina Federici ◽  
Maria Goffredo ◽  
Giuseppe Mancini ◽  
Michela Quaglia ◽  
Adriana Santilli ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence ◽  
Oral Infection ◽  
Balearic Islands ◽  
Rt Pcr ◽  
Vector Species ◽  
Vaccination Programs ◽  
Culicoides Obsoletus ◽  
Culicoides Imicola ◽  
Virus Strains

The distribution of Bluetongue virus (BTV) in Europe can be represented by two distinct and interconnected epidemiological systems (episystems), each characterized by different ecological characteristics and vector species. This study investigated the vector competence of Italian populations of Culicoides imicola and Culicoides obsoletus/scoticus to some representative BTV strains after artificial oral infection. The BTV strains were selected according to their ability to spread to one or both episystems and included BTV-4 ITA, responsible of the recent Italian and French BTV-4 outbreaks; the BTV-2 strain which caused the first BTV incursion in Italy, Corsica, and Balearic Islands; BTV-4 MOR, responsible for the epidemic in Morocco; and BTV-8, the strain which spread through Europe between 2006 and 2008. Blood-soaked cotton pledgets and Hemotek membrane feeder using Parafilm® membrane were used to artificially feed midges. For each population/strain, recovery rates (positive/tested heads) were evaluated using serogroup- and serotype-specific RT-PCR. The trial demonstrated that, except for the Abruzzo population of C. obsoletus/C. scoticus, which was refractory to BTV-4 MOR infection, all the investigated Culicoides populations are susceptible to the selected BTV strains and that, if prompt vaccination programs and restriction measures had not been implemented, BTV-2 and BTV-4 MOR could have spread all over Europe.

Bluetongue virus detection in new Culicoides species in Sardinia, Italy

2019 ◽  
Vol 184 (20) ◽  
pp. 621-621 ◽  
Author(s):  
Cipriano Foxi ◽  
Giorgio Meloni ◽  
Giantonella Puggioni ◽  
Daniela Manunta ◽  
Angelamaria Rocchigiani ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence ◽  
Virus Detection ◽  
Culicoides Species ◽  
Rt Pcr ◽  
Biting Midges ◽  
Body Regions ◽  
Culicoides Imicola ◽  
Obsoletus Complex ◽  
The Mediterranean Basin

Bluetongue is an infectious disease transmitted by Culicoides biting midges. Culicoides imicola is considered the main vector in the Mediterranean basin but other species have been implicated in the Bluetongue virus (BTV) transmission. During 2017, BTV serotype 4 re-occurred in Sardinia causing outbreaks in sheep farms. A survey was carried out on affected farms with the aim to detect the virus in field-collected Culicoides. Biting midges were morphologically identified, pooled and then assayed with a real time RT-PCR. To evaluate BTV dissemination, some Culicoides were dissected and head, thorax and abdomen were tested singly by PCR. A total of 173,738 Culicoides adults were collected. Viral RNA was detected in 68 out of 77 pools and all species analysed resulted positive. Detection of BTV in parous female body regions (head, thorax and abdomen) confirmed the full dissemination of BTV in all species analysed. During this study, the vector competence of C imicola, C newsteadi s.l. and Obsoletus complex was confirmed. The authors found two new Culicoides species BTV positive, C paolae never associated with BTV transmission and C circumscriptus only recently found BTV positive in Turkey, which could be considered potential vectors.

scholarly journals Isolation and identification of arboviruses from the Sultanate of Oman

1991 ◽  
Vol 106 (2) ◽  
pp. 403-413 ◽  
Author(s):  
S. M. Al-Busaidy ◽  
P. S. Mellor
Keyword(s):  
Surveillance System ◽  
Virus Isolate ◽  
Vector Competence ◽  
Oral Infection ◽  
High Titre ◽  
Akabane Virus ◽  
Sultanate Of Oman ◽  
Vector Surveillance ◽  
Isolation And Identification ◽  
Culicoides Imicola

SUMMARYSentinel herds and a vector surveillance system were used to identify the presence of arboviruses in Oman. Two strains of bluetongue virus (BTV) serotype 4 and two strains of Akabane virus, were isolated and identified. Both BTV isolates and one Akabane virus isolate came from goats while the second Akabane isolate came from Culicoides imicola. This is the first isolation of an Akabane virus from Culicoides in Arabia. Vector competence studies with the Oman viruses in laboratory reared C. variipennis showed that after oral infection both viruses replicated in Culicoides and were maintained at high titre for at least 10 days post infection.

Sensitivity of Culicoides obsoletus (Meigen) (Diptera: Ceratopogonidae) to deltamethrin determined by an adapted WHO standard susceptibility test

Parasitology ◽  
2013 ◽  
Vol 141 (4) ◽  
pp. 542-546 ◽  
Author(s):  
R. DEL RÍO ◽  
R. VENAIL ◽  
C. CALVETE ◽  
C. BARCELÓ ◽  
T. BALDET ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
World Health Organization ◽  
Bluetongue Virus ◽  
Susceptibility Test ◽  
World Health ◽  
Biting Midges ◽  
Culicoides Obsoletus ◽  
Culicoides Imicola ◽  
Health Organization ◽  
Who Susceptibility Test

SUMMARYBluetongue is a disease of major economic concern in Europe. Its causative agent, bluetongue virus (BTV), is transmitted by several Culicoides species (mainly Culicoides imicola and Culicoides obsoletus in Europe). The application of insecticides on animals may reduce transmission of BTV, however, no formulation is currently licensed specifically against Culicoides midges. The present study assesses the susceptibility of C. obsoletus to deltamethrin using an adapted World Health Organization (WHO) susceptibility test. Midges were exposed to different dosages of deltamethrin for 1 h, and mortality after 1 h and 24 h was recorded. Results indicated that deltamethrin is highly toxic to C. obsoletus since a dose of 1·33×10−4% was enough to kill 50% of the population (LD50) in 24 h. The deltamethrin concentration needed to kill 90% of the population (LD90) was 5·55×10−4%. The results obtained in the present work could help to create a system that can be used to assess insecticide resistance and susceptibility of Culicoides biting midges.

scholarly journals Detection of Insect-Specific Flaviviruses in Mosquitoes (Diptera: Culicidae) in Northeastern Regions of South Africa

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2148
Author(s):  
Milehna M. Guarido ◽  
Kamini Govender ◽  
Megan A. Riddin ◽  
Maarten Schrama ◽  
Erin E. Gorsich ◽  
...  
Keyword(s):  
South Africa ◽  
Carbon Dioxide ◽  
Vector Competence ◽  
Mosquito Species ◽  
Rt Pcr ◽  
Vector Species ◽  
Entomological Surveillance ◽  
Culex Flavivirus ◽  
Pathogenic Viruses ◽  
Anopheline Mosquitoes

Mosquitoes in the Aedes and Culex genera are considered the main vectors of pathogenic flaviviruses worldwide. Entomological surveillance using universal flavivirus sets of primers in mosquitoes can detect not only pathogenic viruses but also insect-specific ones. It is hypothesized that insect-specific flaviviruses, which naturally infect these mosquitoes, may influence their vector competence for zoonotic arboviruses. Here, entomological surveillance was performed between January 2014 and May 2018 in five different provinces in the northeastern parts of South Africa, with the aim of identifying circulating flaviviruses. Mosquitoes were sampled using different carbon dioxide trap types. Overall, 64,603 adult mosquitoes were collected, which were screened by RT-PCR and sequencing. In total, 17 pools were found positive for insect-specific Flaviviruses in the mosquito genera Aedes (12/17, 70.59%) and Anopheles (5/17, 29.41%). No insect-specific viruses were detected in Culex species. Cell-fusing agent viruses were detected in Aedes aegypti and Aedes caballus. A range of anopheline mosquitoes, including Anopheles coustani, An. squamosus and An. maculipalpis, were positive for Culex flavivirus-like and Anopheles flaviviruses. These results confirm the presence of insect-specific flaviviruses in mosquito populations in South Africa, expands their geographical range and indicates potential mosquito species as vector species.

Expansion of Culicoides imicola, the main bluetongue virus vector in Europe, into Catalonia, Spain

2005 ◽  
Vol 156 (13) ◽  
pp. 415-417 ◽  
Author(s):  
V. Sarto i Monteys ◽  
D. Ventura ◽  
N. Pages ◽  
C. Aranda ◽  
R. Escosa
Keyword(s):  
Bluetongue Virus ◽  
Virus Vector ◽  
Culicoides Imicola

scholarly journals Detection of multiple enteric virus strains within a foodborne outbreak of gastroenteritis: an indication of the source of contamination

2004 ◽  
Vol 133 (1) ◽  
pp. 41-47 ◽  
Author(s):  
C. I. GALLIMORE ◽  
C. PIPKIN ◽  
H. SHRIMPTON ◽  
A. D. GREEN ◽  
Y. PICKFORD ◽  
...  
Keyword(s):  
Arabian Gulf ◽  
Enteric Virus ◽  
Multiple Infections ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Epidemiological Analysis ◽  
Viral Aetiology ◽  
Polymerase Chain ◽  
Most Probable Explanation ◽  
Virus Strains

An outbreak of acute gastroenteritis of suspected viral aetiology occurred in April 2003 in the British Royal Fleet Auxillary ship (RFA) Argus deployed in the Northern Arabian Gulf. There were 37 cases amongst a crew of 400 personnel. Of 13 samples examined from cases amongst the crew, six enteric viruses were detected by reverse transcriptase polymerase chain reaction (RT–PCR). Five different viruses were identified including, three norovirus genotypes, a sapovirus and a rotavirus. No multiple infections were detected. A common food source was implicated in the outbreak and epidemiological analysis showed a statistically significant association with salad as the source of the outbreak, with a relative risk of 3·41 (95% confidence interval of 1·7–6·81) of eating salad on a particular date prior to the onset of symptoms. Faecal contamination of the salad at source was the most probable explanation for the diversity of viruses detected and characterized.

scholarly journals Identification and Differentiation of the Twenty Six Bluetongue Virus Serotypes by RT–PCR Amplification of the Serotype-Specific Genome Segment 2

PLoS ONE ◽  
2012 ◽  
Vol 7 (2) ◽  
pp. e32601 ◽  
Author(s):  
Narender S. Maan ◽  
Sushila Maan ◽  
Manjunatha N. Belaganahalli ◽  
Eileen N. Ostlund ◽  
Donna J. Johnson ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Pcr Amplification ◽  
Genome Segment ◽  
Rt Pcr

scholarly journals Wolbachia prevalence in the vector species Culex pipiens and Culex torrentium in a Sindbis virus-endemic region of Sweden

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alexander Bergman ◽  
Jenny C. Hesson
Keyword(s):  
Culex Pipiens ◽  
Sindbis Virus ◽  
Vector Competence ◽  
Horizontal Transmission ◽  
Vector Species ◽  
Endemic Region ◽  
Species Determination ◽  
Terrestrial Arthropods ◽  
Endosymbiotic Bacteria ◽  
Vector Borne

Abstract Background Wolbachia pipientis are endosymbiotic bacteria present in a large proportion of terrestrial arthropods. The species is known to sometimes affect the ability of its host to transmit vector-borne pathogens. Central Sweden is endemic for Sindbis virus (SINV), where it is mainly transmitted by the vector species Culex pipiens and Culex torrentium, with the latter established as the main vector. In this study we investigated the Wolbachia prevalence in these two vector species in a region highly endemic for SINV. Methods Culex mosquitoes were collected using CDC light traps baited with carbon dioxide over 9 years at 50 collection sites across the River Dalälven floodplains in central Sweden. Mosquito genus was determined morphologically, while a molecular method was used for reliable species determination. The presence of Wolbachia was determined through PCR using general primers targeting the wsp gene and sequencing of selected samples. Results In total, 676 Cx. pipiens and 293 Cx. torrentium were tested for Wolbachia. The prevalence of Wolbachia in Cx. pipiens was 97% (95% CI 94.8–97.6%), while only 0.7% (95% CI 0.19–2.45%) in Cx. torrentium. The two Cx. torrentium mosquitoes that were infected with Wolbachia carried different types of the bacteria. Conclusions The main vector of SINV in the investigated endemic region, Cx. torrentium, was seldom infected with Wolbachia, while it was highly prevalent in the secondary vector, Cx. pipiens. The presence of Wolbachia could potentially have an impact on the vector competence of these two species. Furthermore, the detection of Wolbachia in Cx. torrentium could indicate horizontal transmission of the endosymbiont between arthropods of different species. Graphical abstract

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