Cardinium bacteria, members of the phylum Cytophaga-Flavobacterium-Bacteroides (CFB), are intracellular bacteria in arthropods that are capable of inducing reproductive abnormalities in their hosts, which include parasitic wasps, mites, and spiders. A high frequency of Cardinium infection was detected in planthoppers (27 out of 57 species were infected). A high frequency of Cardinium infection was also found in spider mites (9 out of 22 species were infected). Frequencies of double infection by Cardinium and Wolbachia bacteria (Alphaproteobacteria capable of manipulating reproduction of their hosts) were disproportionately high in planthoppers but not in spider mites. A new group of bacteria, phylogenetically closely related to but distinct from previously described Cardinium bacteria (based on 16S rRNA and gyrB genes) was found in 4 out of 25 species of Culicoides biting midges. These bacteria possessed a microfilament-like structure that is a morphological feature previously found in Cardinium and Paenicardinium. The bacteria close to the genus Cardinium consist of at least three groups, A, B, and C. Group A is present in various species of arthropods and was previously referred to as "Candidatus Cardinium hertigii," group B is present in plant parasitic nematodes and was previously referred to as "Candidatus Paenicardinium endonii," and group C is present in Culicoides biting midges. On the basis of morphological and molecular data, we propose that the nomenclature of these three groups be integrated into a single species, "Candidatus Cardinium hertigii."Compared to the Wolbachia bacteria, which belong to the alpha subdivision of the phylum Proteobacteria and are known as master manipulators of arthropod reproduction (48), the Cardinium bacteria, which belong to the phylum CytophagaFlavobacterium-Bacteroides (CFB), are relatively new to biological study. The phylum CFB includes many other bacteria associated with arthropods, such as symbionts in cockroaches (3) and termites (4) and the male-killing agents of ladybird beetles (21). Cardinium was first observed in tick cell cultures as an unknown intracellular prokaryote that was rod shaped and had an array of tubes extending from the cytoplasmic membrane (22). In 2001, related symbiotic bacteria were reported as manipulators of arthropod reproduction because they caused feminization, by which genetic males were converted into phenotypic females, in the false spider mite Brevipalpas obovatus (45) and parthenogenesis, in which haploid eggs were converted into viable diploid females, in the parasitoid wasp Encarsia pergandiella (50). Since the 16S rRNA gene sequences of these bacteria exhibited 96% to 98% similarity to the tick microorganism, they were classified in the phylum CFB. Subsequently, bacteria in this group were found to induce cytoplasmic incompatibility (CI), in which uninfected female hosts produce few offspring when mated with infected males in parasitic wasps of the genus Encarsia (20) and in two spider mites, Eotetranychus suginamensis and Bryobi...

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.

Background: Akabane virus is a member of the genus Orthobunyavirus in the family Bunyaviridae. It is transmitted by hematophagous arthropod vectors such as Culicoides biting midges and is widely distributed in temperate to tropical regions of the world. The virus is well known as a teratogenic pathogen which causes abortions, stillbirths, premature births and congenital abnormalities with arthrogryposishydranencephaly syndrome in cattle, sheep and goats. On the other hand, it is reported that the virus rarely induces encephalomyelitis in cattle by postnatal infection. A first large-scale epidemic of Akabane viral encephalomyelitis in cattle occurred in the southern part of Japan from summer to autumn in 2006. The aim of this study is to define the epidemiological, pathological and virological properties of the disease.

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Two viruses were isolated from bovine blood in the southernmost part of Japan in 1994 and 2001, respectively. Genetic analyses showed that the viruses were Batai virus of the genus Orthobunyavirus of the family Bunyaviridae. The sequencing of three genomic RNA segments of the Japanese and Malaysian Batai virus strains revealed that the M RNA segment of Batai virus had high sequence identity with that of Ngari virus. Our results indicate that Ngari virus is a genetic reassortant with S and L RNA segments from Bunyamwera virus and an M RNA segment from Batai virus.

Epizootic congenital abnormalities, encephalomyelitis and febrile illnesses in cattle caused by arthropod-borne viruses (arboviruses) are prevalent in Japan. Causative viruses including orthobunyaviruses, orbiviruses and rhabdovirus are thought to be transmitted by Culicoides biting midges. Recently, the incursions of several arboviruses, potentially Culicoides-borne, were newly confirmed in Japan. However, their spread pattern and exact vector species are currently uncertain. Attempts to isolate arboviruses from Culicoides biting midges and sentinel cattle were conducted in Kagoshima, located at the southernmost end of the main islands of Japan, a potentially high-risk area for incursion of arboviral diseases and outbreak of endemic ones. Seventy-eight isolates comprising Akabane, Peaton and Sathuperi viruses of the genus Orthobunyavirus of the family Bunyaviridae, bluetongue virus serotype 16, D'Aguilar virus, Bunyip Creek virus and epizootic haemorrhagic disease virus serotype 1 of the genus Orbivirus of the family Reoviridae, a potentially novel rhabdovirus of the genus Ephemerovirus and unidentified orbivirus-like viruses were obtained from Culicoides biting midges and sentinel cattle between 2003 and 2013. Akabane, Sathuperi, D'Aguilar and Bunyip Creek viruses were selectively isolated from Culicoides oxystoma, suggesting this vector's responsibility for these arbovirus outbreaks. The results of virus isolation also implied that C. tainanus, C. jacobsoni and C. punctatus are competent for the transmission of bluetongue virus serotype 16, Peaton virus and epizootic haemorrhagic disease virus serotype 1, respectively. Our monitoring in Culicoides biting midges and sentinel cattle detected the circulation of Akabane virus just prior to the accumulations of bovine congenital abnormalities and encephalomyelitis by it around study sites in 2003, 2006, 2008 and 2013. Silent circulations of the other arboviruses, including potentially new viruses, were also detected during the study period.

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The monophyly of the Imicola complex, a natural species complex within subgenus C. subgen. Avaritia Fox of the biting midge genus Culicoides Latreille, is supported using morphological and molecular analyses. A diagnosis for the group along with comparative redescriptions of the male and female of the species represented in Australasia, C. brevitarsis Kieffer and C. nudipalpis Delfinado and a description of C. asiatica Bellis sp. nov., are presented together with keys for their specific determination and molecular support for their status.