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Simulation studies of African horse sickness in Spain

  • C. C. Lord
  • M. E. J. Woolhouse
  • P. S. Mellor
Conference paper

Summary

Factors affecting epidemics of African horse sickness in Spain were studied using a mathematical model. The model examined the likelihood of an epidemic after the introduction of the virus, and the effectiveness of vaccination strategies. Two host species (horses and donkeys) and one vector species (the biting midge Culicoides imicola) were included. A stratified random sampling method (Latin hypercube sampling) was used for sensitivity analysis of the likelihood of an epidemic. Systematic variation of vaccination parameters was used to consider alternative control strategies. In general, when an epidemic occurred most potential hosts became infected. The peak prevalence in C. imicola was low, and never exceeded 3%. The most significant factors in the likelihood of an epidemic were vector population size, the recovery rate in horses and the time of year when the virus was introduced. The lag between virus introduction and protection, the proportion of hosts vaccinated, and including donkeys in vaccination programmes where the factors that most strongly affected the success of different vaccination strategies. These factors should be priorities for empirical research, and should be considered in the design of control strategies in areas at risk of virus introduction.

Keywords

Vaccination Strategy Latin Hypercube Sampling Bluetongue Virus Peak Prevalence Entomological Society 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Agresti A (1990) Categorical data analysis. Wiley, New YorkGoogle Scholar
  2. 2.
    Al-busaidy SM, Mellor PS (1991) Epidemiology of bluetongue and related orbiviruses in the Sultanate of Oman. Epidemiol Infect 106: 167–178PubMedCrossRefGoogle Scholar
  3. 3.
    Allingham PG, Standfast HA (1990) An investigation of transovarial transmission of Akabane virus in Culicoides brevitarsis. Aust Vet J 67: 273–274PubMedCrossRefGoogle Scholar
  4. 4.
    Blower SM, Dowlatabadi H (1994) Sensitivity and uncertainty analysis of complex models of disease transmission: an HIV model, as an example. Int Stat Rev 62: 229–243CrossRefGoogle Scholar
  5. 5.
    Blower SM, Hartel D, Dowlatabadi H, Anderson RM, May RM (1991) Drugs, sex and HIV: a mathematical model for New York City. Phil Trans R Soc Lond B 321: 171–187CrossRefGoogle Scholar
  6. 6.
    Blythe SP, Gurney WSC, Maas P, Nisbet RM (1990) User guide for SOLVER, revision 4. 0. APIC, GlasgowGoogle Scholar
  7. 7.
    Borland International (1992) Turbo Pascal user’s guide. Borland International, Scotts Valley, CAGoogle Scholar
  8. 8.
    Braverman Y, Linley JR (1988) Parity and voltinism of several Culicoides spp. ( Diptera: Ceratopogonidae) in Israel, as determined by two trapping methods. J Med Entomol 25: 121–126PubMedGoogle Scholar
  9. 9.
    Braverman Y, Linley JR, Marcus R, Frish K (1985) Seasonal survival and expectation of infective-life of Culicoides spp. (Diptera: Ceratopogonidae) in Israel, with implications for bluetongue virus transmission and a comparison of the parous rate in C. imicola from Israel and Zimbabwe. J Med Entomol 22: 476–484PubMedGoogle Scholar
  10. 10.
    Braverman Y, Boreham PFL, Galun R (1971) The origin of bloodmeals of female Culicoides pallidipennis trapped in a sheepfold in Israel. J Med Entomol 8: 379PubMedGoogle Scholar
  11. 11.
    Capela R, Sousa C, Pena I, Caeiro V (1993) Preliminary note on the distribution and ecology of Culicoides imicola in Portugal. Med Vet Entomol 7: 23–26PubMedCrossRefGoogle Scholar
  12. 12.
    Iman RL, Shortencarrier MJ (1984) A Fortran 77 program & users guide for the generation of Latin Hypercubes & random samples for use with computer models. NUREG/CR-3624, SAND83–365. Sandia National Laboratories, Albuquerque, NMGoogle Scholar
  13. 13.
    Jones RH, Foster NM (1971) Transovarian transmission of bluetongue virus unlikely for Culicoides variipennis. Mosq News 31: 434–437Google Scholar
  14. 14.
    Lord CC, Woolhouse MEJ, Mellor PS (1997) Simulation studies of vaccination strategies in African horse sickness. Vaccine 15: 519–524PubMedCrossRefGoogle Scholar
  15. 15.
    Lord CC, Woolhouse MEJ, Rawlings P, Mellor PS (1996) Simulation studies of African horse sickness and Culicoides imicola ( Diptera, Ceratopogonidae). J Med Entomol 33: 328–338PubMedGoogle Scholar
  16. 16.
    Meiswinkel R, Nevill EM, Venter GJ (1994) Vectors: Culicoides spp. In: Coetzer JAW, Thomson GR, Tustin RC (eds) Infectious diseases of livestock with special reference to southern Africa, vol 1. Oxford University Press, Oxford, pp 68–89Google Scholar
  17. 17.
    Mellor PS (1990) The replication of bluetongue virus in Culicoides vectors. In: Walton TE, Osburn BI (eds) Bluetongue, African horse sickness, and related orbiviruses: Proceedings of the Second Symposium. Curr Top Microbiol Immunol 162: 143–161Google Scholar
  18. 18.
    Mellor PS (1993) African horse sickness: transmission and epidemiology. Vet Res 24: 199–212PubMedGoogle Scholar
  19. 19.
    Nevill E, Anderson D (1972) Host preferences of Culicoides midges: ( Diptera: Ceratopogonidae) in South Africa as determined by precipitin tests and light trap catches. Onderstepoort J Vet Res 39: 147–152PubMedGoogle Scholar
  20. 20.
    Nunamaker RA, Sieburth PJ, Dean VC, Wigington JG, Nunamaker CE, Mecham JO (1990) Absence of transovarial transmission of bluetongue virus in Culicoides variipennis: immunogold labelling of bluetongue virus antigen in developing oocytes from Culicoides variipennis ( Coquillett ). Comp Biochem Physiol 96A: 19–31CrossRefGoogle Scholar
  21. 21.
    Rawlings P, Mellor PS (1994) African horse sickness and the overwintering of Culicoides spp. in the Iberian peninsula. Rev Sci Tech Off Int Epiz 13: 753–761Google Scholar
  22. 22.
    Rodriguez M, Hooghuis H, Castano M (1992) African horse sickness in Spain. Vet Microbiol 33: 129–142PubMedCrossRefGoogle Scholar
  23. 23.
    SAS Institute (1988) SAS user’s guide. SAS Institute, Cary, NCGoogle Scholar
  24. 24.
    Sellers RF, Pedgley DE, Tucker MR (1977) Possible spread of African horse sickness on the wind. J Hyg (Camb) 79: 279–298CrossRefGoogle Scholar
  25. 25.
    Venter GJ, Hill E, Pajor ITP, Nevill EM (1991) The use of a membrane feeding technique to determine the infection rate of Culicoides imicola (Diptera, Ceratopogonidae) for 2 bluetongue virus serotypes in South Africa. Onderstepoort J Vet Res 58: 5–10PubMedGoogle Scholar
  26. 26.
    Venter GJ, Sweatman GK (1989) Seasonal abundance and parity of Culicoides biting midges associated with livestock at Roma, Lesotho ( Diptera: Ceratopogonidae). Onderstepoort J Vet Res 56: 173–177PubMedGoogle Scholar
  27. 27.
    Venter GJ, Williams R, Nevill EM (1992) The value of donkeys as sentinels for African horse sickness. In: Walton TE, Osburn BI (eds) Bluetongue, African horse sickness and related orbiviruses: proceedings of the second symposium, Paris 1991. CRC Press, Boca Raton, pp 825–831Google Scholar
  28. 28.
    Walker AR, Boreham PFL (1976) Blood feeding of Culicoides ( Diptera: Ceratopogonidae) in Kenya in relation to the epidemiology of bluetongue and ephemeral fever. Bull Entomol Res 66: 181–188CrossRefGoogle Scholar
  29. 29.
    Walker AR, Davies FG (1971) A preliminary survey of the epidemiology of bluetongue in Kenya. J Hyg (Camb) 69: 47–60CrossRefGoogle Scholar

Copyright information

© Springer-Verlag/Wien 1998

Authors and Affiliations

  • C. C. Lord
    • 1
  • M. E. J. Woolhouse
    • 1
  • P. S. Mellor
    • 2
  1. 1.Department of ZoologyUniversity of OxfordOxfordUK
  2. 2.Pirbright LaboratoryInstitute for Animal HealthPirbrightUK

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