Identification of a novel bluetongue virus vector species of Culicoides in Sicily

Abstract

The vectors of bluetongue virus are certain species of Culicoides biting midges, and in the Mediterranean area Culicoides imicola has long been considered to be the only field vector. In Sicily an entomological and serological surveillance programme has been in operation since the autumn of 2000, which has shown that the prevalence and abundance of C. imicola is lower than in many other Italian regions. Moreover, in 2002, there were outbreaks of bluetongue in the absence of C. imicola, and in these regions bluetongue viral RNA was detected by means of a nested reverse-transcriptase PCR in wild-caught, non-blood-engorged, parous Culicoides pulicaris. Furthermore, bluetongue virus serotype 2 was isolated on five occasions from extracts of non-blood-engorged parous C. pulicaris by using embryonated hens eggs and BHK-21 cells as assay systems. These findings suggest that in parts of Italy and possibly in other areas of Europe, where C. imicola is absent or rare, C. pulicaris may act as a fully competent vector of bluetongue virus.

Use of high spatial resolution satellite imagery to characterize landscapes at risk for bluetongue

“…The method presented here is relatively flexible, and new environmental characteristics (such as pedological information [15]) can easily be taken into account if necessary. Before these results can be used to help identify future hotspots outside Corsica which could aid the management of the disease, it is necessary to locally adapt the model to take into consideration prevailing ecological and environmental conditions, especially if different Culicoides species are involved, as in southern [13,43], eastern [35] and recent outbreaks of northern Europe [47]. Such an approach will be adapted to the Var, a French region where C. imicola is present but not the virus, to help focus the trapping sites of the entomological surveillance system in the areas where BT risk is the greatest.…”

Olfaction in vector-host interactions

“…Similarly, C. obsoletus sensu stricto and C. scoticus (which comprise two of the four species in the obsoletus complex), were found to be RT-PCR positive to BTV-8. Culicoides pulicaris Linnaeus s.s. has previously been incriminated in the field transmission of BTV (Caracappa et al 2003), and C. impunctatus (another member of the Pulicaris complex) has been implicated in the laboratory (Carpenter et al 2006, Jennings andMellor 1988). Despite this, the information available suggests that C. obsoletus played a significant role in the European outbreak .…”

The phenology and population dynamics of Culicoides spp. in different ecosystems in The Netherlands

“…Subgenus C. pulicaris. This is a species complex, including the species C. pulicaris and C. punctatus: A known bluetongue virus vector (Caracappa et al, 2003), which also occurs in colder areas like the Netherlands.…”