The recent outbreak of malformations in ruminants in Northern Europe caused by Schmallenberg virus induced us to analyze the genetic properties of the related orthobunyaviruses and clarify their relationship. The sequencing of three genomic RNA segments of Sathuperi, Shamonda and Douglas viruses (SATV, SHAV and DOUV) revealed that the M RNA segment of SATV and DOUV had a high degree of sequence identity with that of Schmallenberg virus, but the S and L RNA segments closely matched those of SHAV. Phylogenetic analysis of the three genomic RNA segments indicated that Schmallenberg virus is a reassortant, with the M RNA segment from SATV and the S and L RNA segments from SHAV.

No abstract

No abstract

No abstract

Although Culicoides biting midges act as a vector of important human and domestic animal diseases, their ecology is poorly understood. The lack of proper identification systems of Culicoides larvae is one of the main obstacles to progress in research. Based on mitochondrial sequences of 19 Japanese Culicoides species, we designed a universal primer set to amplify the partial sequence of the mitochondrial cytochrome c oxidase I (cox 1). The polymerase chain reaction product amplified from extracted DNA of Culicoides larvae using the primer set was directly sequenced, and species identification based on the variation at cox1 was conducted. Using the molecular identification system, we sorted 243 specimens of field-collected larvae from the southern part of Japan into 10 species including Culicoides arakawae (Arakawa), Culicoides oxystoma Kieffer, and Culicoides brevitarsis Kieffer, which are regarded as vectors of important livestock animal diseases. Eight species of Culicoides larvae, including C. arakawae and C. oxystoma, were recovered from active paddy fields and an abandoned paddy field. The result suggests that paddy fields contribute to breeding a variety of Culicoides species and maintenance and spread of Culicoides-borne pathogens. In contrast, larvae of C. brevitarsis were collected from cattle dung in pastures. The molecular identification system described herein using nucleotide sequences successfully achieved larval identification and will be useful for a better understanding of larval habitats of Culicoides biting midges.