Difference in vector competence of two species of sympatric ticks, Amblyomma variegatum and Rhipicephalus appendiculatus, for Dugbe virus (Nairovirus, Bunyaviridae).

Amblyomma variegatum was shown to be a competent vector of Dugbe (DUG) virus whereas Rhipicephalus appendiculatus was not. When DUG virus was taken up orally by A. variegatum nymphs, during capillary feeding, the virus replicated and persisted through moulting to the following adult stage. In contrast, although DUG virus replicated in capillary fed R. appendiculatus nymphs, the virus did not persist trans-stadially into the adult stage. If the oral route of infection was by-passed by direct inoculation into the haemocoel, DUG virus replicated and survived trans-stadially in both tick species, and was subsequently transmitted during feeding. The different responses of R. appendiculatus to oral and intra-coelomic routes suggest that DUG virus is able to infect the gut of this tick species, but that release of the virus from the gut is inhibited.