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Oral susceptibility of South African Culicoides species to live-attenuated serotype-specific vaccine strains of African horse sickness virus (AHSV).
Abstract: The oral susceptibility of livestock-associated South African Culicoides midges (Diptera: Ceratopogonidae) to infection with the tissue culture-attenuated vaccine strains of African horse sickness virus (AHSV) currently in use is reported. Field-collected Culicoides were fed on horse blood-virus mixtures each containing one of the seven serotype-specific vaccine strains of AHSV, namely serotypes 1, 2, 3, 4, 6, 7 and 8. The mean titres of virus in the bloodmeals for the seven vaccine strains were between 6.8 and 7.6 log10TCID50/mL. All females (n = 3262) that survived 10 days extrinsic incubation (10 dEI) at 23.5 degrees C were individually assayed in microplate BHK-21 cell cultures. In midges tested immediately after feeding, AHSV was detected in 96.1% individuals; mean virus titre was 2.0 log10TCID50/midge. After 10 dEI virus recovery rates varied in Culicoides (Avaritia) imicola Kieffer from 1% (AHSV-2) to 11% (AHSV-7) and in Culicoides (A.) bolitinos Meiswinkel from 0% (AHSV-3) to 14.6% (AHSV-2). Although our results indicate that two major field vectors C. imicola and C. bolitinos are susceptible to oral infection with vaccine strains of AHSV, the level of viral replication for most of the vaccine strains tested was below the postulated threshold (=2.5 log10TCID50/midge) for fully disseminated orbivirus infection. In this study, for the first time AHSV has been recovered after 10 dEI from six non-Avaritia livestock-associated Old World species: C. engubandei de Meillon (AHSV-4), C. magnus Colaço (AHSV-3, -4), C. zuluensis de Meillon (AHSV-2, -4), C. pycnostictus Ingram & Macfie (AHSV-2), C. bedfordi Ingram & Macfie (AHSV-7), and C. dutoiti de Meillon (AHSV-7). As little is known about the virogenesis of AHSV in the southern African species of Culicoides, the epidemiological significance of our findings in relation to the potential for transmission of current AHSV vaccine strains by Culicoides requires further assessment.
Publication Date: 2003-12-04 PubMed ID: 14651659DOI: 10.1111/j.1365-2915.2003.00467.xGoogle Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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The research article investigates the oral susceptibility of South African midges, specifically Culicoides species, to infection by tissue culture-attenuated vaccine strains of the African horse sickness virus (AHSV). The findings indicate that two major field vectors, C. imicola and C. bolitinos, are susceptible to oral infection by these vaccine strains.
Methodology and Experimental Procedure
- The experiment involved field-collected Culicoides being fed horse blood-virus mixtures, containing one of the seven serotype-specific vaccine strains of AHSV, which include serotypes 1, 2, 3, 4, 6, 7 and 8.
- The average titres of virus in these bloodmeals ranged between 6.8 and 7.6 log10TCID50/mL.
- All surviving females (n = 3262) underwent a 10-day extrinsic incubation period at a temperature of 23.5 degrees C, following which they were individually assayed in microplate BHK-21 cell cultures.
Results and Findings
- In the midges tested immediately after feeding, the presence of AHSV was detected in 96.1% of the individuals. The average virus titre was 2.0 log10TCID50/midge.
- Post the 10-day extrinsic incubation period, the virus recovery rates varied across species: for Culicoides imicola, between 1% (AHSV-2) and 11% (AHSV-7); and for Culicoides bolitinos, between 0% (AHSV-3) and 14.6% (AHSV-2).
- The research found that although C. imicola and C. bolitinos are susceptible to oral infection with the AHSV vaccine strains, the level of viral replication for most strains was below the threshold estimated for fully disseminated orbivirus infection.
- AHSV was recovered after a 10-day incubation period for the first time from six non-Avaritia livestock-associated Old World species: C. engubandei, C. magnus, C. zuluensis, C. pycnostictus, C. bedfordi, and C. dutoiti.
Implications and Further Research
- Since little is known about the virogenesis of AHSV in the southern African species of Culicoides, the epidemiological implications of these findings in relation to the potential for transmission of current AHSV vaccine strains by Culicoides need further examination.
Cite This Article
APA
Paweska JT, Prinsloo S, Venter GJ.
(2003).
Oral susceptibility of South African Culicoides species to live-attenuated serotype-specific vaccine strains of African horse sickness virus (AHSV).
Med Vet Entomol, 17(4), 436-447.
https://doi.org/10.1111/j.1365-2915.2003.00467.x Publication
Researcher Affiliations
- ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa. januszp@nicd.ac.za
MeSH Terms
- Administration, Oral
- African Horse Sickness / prevention & control
- African Horse Sickness / transmission
- African Horse Sickness Virus / classification
- African Horse Sickness Virus / immunology
- Animals
- Ceratopogonidae / virology
- Female
- Horses
- Male
- Serotyping / veterinary
- South Africa
- Vaccines, Attenuated / administration & dosage
- Viral Vaccines / administration & dosage
- Virus Replication
Citations
This article has been cited 8 times.- Blitvich BJ. The Role of Hematophagous Arthropods, Other than Mosquitoes and Ticks, in Arbovirus Transmission. Viruses 2025 Jun 30;17(7).
- Pitchers KG, Boakye OD, Campeotto I, Daly JM. The Potential of Plant-Produced Virus-like Particle Vaccines for African Horse Sickness and Other Equine Orbiviruses. Pathogens 2024 May 28;13(6).
- Kampen H, Werner D. Biting Midges (Diptera: Ceratopogonidae) as Vectors of Viruses. Microorganisms 2023 Nov 4;11(11).
- Federici V, Goffredo M, Mancini G, Quaglia M, Santilli A, Di Nicola F, De Ascentis M, Cabras P, Volpicelli C, De Liberato C, Satta G, Federico G, Leone A, Pisciella M, Portanti O, Pizzurro F, Teodori L, Savini G. Vector Competence of Italian Populations of Culicoides for Some Bluetongue Virus Strains Responsible for Recent Northern African and European Outbreaks. Viruses 2019 Oct 12;11(10).
- Bakhoum MT, Sarr M, Fall AG, Huber K, Fall M, Sembène M, Seck MT, Labuschagne K, Gardès L, Ciss M, Gimonneau G, Bouyer J, Baldet T, Garros C. DNA barcoding and molecular identification of field-collected Culicoides larvae in the Niayes area of Senegal. Parasit Vectors 2018 Dec 3;11(1):615.
- Bakhoum MT, Fall AG, Fall M, Bassene CK, Baldet T, Seck MT, Bouyer J, Garros C, Gimonneau G. Insight on the larval habitat of Afrotropical Culicoides Latreille (Diptera: Ceratopogonidae) in the Niayes area of Senegal, West Africa. Parasit Vectors 2016 Aug 22;9(1):462.
- Gordon SJ, Bolwell C, Rogers C, Musuka G, Kelly P, Labuschagne K, Guthrie AJ, Denison E, Mellor PS, Hamblin C. The occurrence of Culicoides species, the vectors of arboviruses, at selected trap sites in Zimbabwe. Onderstepoort J Vet Res 2015 May 29;82(1):e1-e8.
- Wilson A, Mellor PS, Szmaragd C, Mertens PP. Adaptive strategies of African horse sickness virus to facilitate vector transmission. Vet Res 2009 Mar-Apr;40(2):16.
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