A comparison of the vector competence of the biting midges, Culicoides (Avaritia) bolitinos and C. (A.) imicola, for the Bryanston serotype of equine encephalosis virus.
Abstract: Equine encephalosis virus (EEV) is widespread and prevalent in southern Africa. In this study, the oral susceptibility of Culicoides (Avaritia) imicola Kieffer (Diptera: Ceratopogonidae) to EEV was confirmed. In addition, C. (A.) bolitinos Meiswinkel, collected in the high-lying eastern Free State, South Africa, was systemically infected with the Bryanston serotype of EEV after feeding through a membrane on artificially infected equine blood containing 4.7 log10 PFU/mL of EEV. The mean infectivity of Bryanston virus in C. bolitinos increased from 1.2 log10 PFU/midge, in midges assayed for virus immediately after feeding on the blood-virus mixture, to 3.1 log10 PFU/midge in midges assayed after 10 days' incubation at 23.5 degrees C. Elevated virus infectivity titres, found in individual infected C. bolitinos, suggested that this Culicoides species is a vector of EEV. This bovine dung-breeding Culicoides species may play an important role in transmitting EEV in the cooler parts of southern Africa, where it can be the most abundant Culicoides species collected near livestock. In the present study the prevalence of infection obtained for C. bolitinos (2.2%) with the Bryanston serotype of EEV was significantly lower than that of C. imicola (18.4%). After incubation, the Bryanston serotype of EEV was also isolated from one of 110 C. onderstepoortensis Fiedler assayed. However, the virus titre in this midge was 1.2 log10 PFU/midge, which is not different from the titre that would be expected immediately after feeding on the blood-virus mixture. Culicoides species that survived the incubation period and that were negative for the presence of Bryanston virus were C. magnus Colaço (96), C. bedfordi Ingram & Macfie (95) and C. pycnostictus Ingram & Macfie (45).
Publication Date: 2003-01-04 PubMed ID: 12510889DOI: 10.1046/j.1365-2915.2002.00385.xGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research examines the involvement of different species of Culicoides midges in the transmission of Equine encephalosis virus (EEV), particularly the Bryanston serotype, in southern Africa. It highlights the lower infection rate of the C. bolitinos species compared to the C. imicola species but considers the former a possible vector due to its abundant presence near livestock in cooler areas.
Research Objective and Method
- This study aimed to confirm the oral susceptibility of the midge Culicoides (Avaritia) imicola Kieffer to the Equine encephalosis virus (EEV) and distinguish the vector competence of Culicoides bolitinos Meiswinkel and C. imicola for Bryanston serotype of EEV.
- The researchers fed C. bolitinos and C. imicola on artificially infected equine blood, then incubated and assayed them to measure the infectivity of the virus within these midges over time.
Findings
- Bryanston virus’s mean infectivity in C. bolitinos increased from 1.2 log10 PFU/midge immediately after feeding to 3.1 log10 PFU/midge after a 10-day incubation at 23.5 degrees Celsius.
- High virus infectivity titres in individual C. bolitinos midges suggest that this species could be a vector of the Bryanston serotype of EEV.
- The infection prevalence rate in C. bolitinos was significantly lower (2.2%) than that in C. imicola (18.4%).
- The Bryanston serotype of EEV was isolated from one in 110 C. onderstepoortensis Fiedler as well, but with a virus titre of 1.2 log10 PFU/midge—consistent with the titre expected immediately after feeding.
- Other Culicoides species like C. magnus Colaço, C. bedfordi Ingram & Macfie, and C. pycnostictus Ingram & Macfie, which survived the incubation period, showed no traces of Bryanston virus.
Conclusion and Implications
- Despite showing a lower infection prevalence rate, C. bolitinos still might play a substantial role in transmitting EEV in cooler southern Africa regions because it often is the most abundant Culicoides species near livestock in such areas.
- The findings contribute to our understanding of the EEV transmission dynamics by identifying the different Culicoides species’ vector competences.
Cite This Article
APA
Venter GJ, Groenewald D, Venter E, Hermanides KG, Howell PG.
(2003).
A comparison of the vector competence of the biting midges, Culicoides (Avaritia) bolitinos and C. (A.) imicola, for the Bryanston serotype of equine encephalosis virus.
Med Vet Entomol, 16(4), 372-377.
https://doi.org/10.1046/j.1365-2915.2002.00385.x Publication
Researcher Affiliations
- Division of Entomology, ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa. GERT@moon.ovi.ac.za
MeSH Terms
- African Horse Sickness / transmission
- African Horse Sickness / virology
- African Horse Sickness Virus / physiology
- Animals
- Ceratopogonidae / classification
- Ceratopogonidae / physiology
- Ceratopogonidae / virology
- Female
- Horses / parasitology
- Horses / virology
- Insect Vectors / physiology
- Insect Vectors / virology
- South Africa
Citations
This article has been cited 3 times.- Tirosh-Levy S, Steinman A. Equine Encephalosis Virus.. Animals (Basel) 2022 Jan 29;12(3).
- More S, Bicout D, Bøtner A, Butterworth A, Calistri P, De Koeijer A, Depner K, Edwards S, Garin-Bastuji B, Good M, Gortazar Schmidt C, Michel V, Miranda MA, Nielsen SS, Raj M, Sihvonen L, Spoolder H, Thulke HH, Velarde A, Willeberg P, Winckler C, Bau A, Beltran-Beck B, Carnesecchi E, Casier P, Czwienczek E, Dhollander S, Georgiadis M, Gogin A, Pasinato L, Richardson J, Riolo F, Rossi G, Watts M, Lima E, Stegeman JA. Vector-borne diseases.. EFSA J 2017 May;15(5):e04793.
- Diarra M, Fall M, Fall AG, Diop A, Seck MT, Garros C, Balenghien T, Allène X, Rakotoarivony I, Lancelot R, Mall I, Bakhoum MT, Dosum AM, Ndao M, Bouyer J, Guis H. Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal.. Parasit Vectors 2014 Mar 31;7:147.
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