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Dugbe virus: Comparative study on the vectorial capacity of the different stages of Amblyomma variegatum Fabricius and Hyalomma rufipes Koch after intracoelomic inoculation

Published online by Cambridge University Press:  19 September 2011

Tonye G. Okorie
Tonye G. Okorie
Affiliation:
Department of Zoology, University of Ibadan, Ibadan, Nigeria
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Abstract

Larvae, nymphs and adults of Amblyomma variegatum, and nymphs and adults of Hyalomma rufipes were infected with Dugbe virus by intracoelomic inoculation. Each developmental stage of tick was divided into three groups A, B and C and the three groups were infected respectively with a Dugbe, virus concentration of 4.5 LD50 (log10), 1.5 LD50 (log10) and 0.5 LD50 (log10). The virus multiplied to a high titre in groups A and B and reached a peak which was over 5 (log10) the infective doses of some of the larvae and nymphs.

With the exception of group B adult H. rufipes (with an infection rate of 65%), all other ticks in groups A and B have an infection rate of between 97 to 100%. The infection rate of group C ticks was below 40%.

The 1–5% infection threshold occurred with a dose higher than 0.5 log10 in larvae of A. variegatum and adults of H. rufipes, but with a dose lower than 0.5 (log10) in all other stages of the two tick species. The 50% infection threshold occurred with a dose less than 1.5 (log10) in all the developmental stages of the two tick species.

All the developmental stages of ticks transmitted Dugbe virus to rabbits during feeding.

Résumé

Dévelopmentaire les larves, les nymphs et les adultes de Amblyomma variegatum, et les nymphes et les adultes de Hyalomma rufipes étaient infectés par le virus Dugbe per inoculation intracoelomique. Chaque étape de développement de tatique était divisée en trois groupes A, B, C et ces groupes étaient respectivement infectés par un virus Dugbe aux concentration suivantes: 4,5 LD50 (log10), 1,5 LD50 (log10) et 0,5 LD50 (log10). Le virus s'est beaucoup multiplié dans les groupes A et B avec un maximum de plus de 5 (log10) superieur à la dose infective de quelques uns des groupes de larves et de nymphes.

Le taux d'infection pour tons les étapes développement des tiques en groupe A et groupe B varie de 97 à 100% à l'exception des adultes de H. rufipes en groupe B (avec un taut d'infection de 65%). Toutes les tiques du groupe avaient un taux d'infection inferieur à 40%. Le seuils d'infection 1–5% étaient obtenu avec un dose superieur à 0,5 log10 dans la larvae de A. variegatum comme dans l'adulte de H. rufipes; mais avec un dose inferieur à 0,5 (log10) dans toutes les autre étapes des deut espèces de tique. Le senils d'infection 50% étaient obtenu avec un dose inferieur à 1,5 log10 dans, toutes les étapes de développement des deut espèces de tique.

Toutes les étapes de développement des tiques ont transmit virus Dugbe aux lapins en cours d'alimentation.

Keywords

LarvaenymphsadultsA. variegatumH. rufipesintracoelomic inoculationinfection thresholdinfection ratetransmission rateLes larvesles nymphesles adultsA. variegatumH. rufipesinoculation intracoelomiquele semils d'infectionle taux d'infectionle niveau d'infection (le taux de transmission)
Type
Research Articles
Information
International Journal of Tropical Insect Science , Volume 13 , Issue 3 , June 1992 , pp. 381 - 387
Copyright
Copyright © ICIPE 1992

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References

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