Bovine Arboviruses inCulicoidesBiting Midges and Sentinel Cattle in Southern Japan from 2003 to 2013

Abstract

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.

Schmallenberg virus detection in Culicoides biting midges in Spain: First laboratory evidence for highly efficient infection of Culicoides of the Obsoletus complex and Culicoides imicola

“…Similarly, Culicoides (most C. imicola ) tested negative at farms reporting SBV abortions in Italy (Balenghien et al., ). A similar scenario is present for Akabane in Japan (Kato et al., ) and Australia where the virus could be usually detected in Culicoides before clinical cases are present in ruminants. In Denmark, however, a longer time frame (5 weeks) for SBV‐positive pools detection was reported (Rasmussen et al., ).…”

The Antiviral RNAi Response in Vector and Non-vector Cells against Orthobunyaviruses

“…SBV, OROV and Sathuperi virus [SATV]) [17–22], ticks (Tete group viruses Bahig and Matruh) [23] or are mosquito/insect-specific [24, 25]. …”

“…More recently, SATV was detected in Japan in 1999 [32]. To date little information is available on its pathogenicity in ruminants [22]. Both SBV and SATV are transmitted by Culicoides sp.…”

Transition of Akabane virus genogroups and its association with changes in the nature of disease in Japan

“…In recent years, bovine encephalomyelitis by post‐natal AKAV infection has often occurred in Japan (Hayama et al., ; Kono et al., ). During the disease appearance, AKAVs were successfully isolated from affected calves, sentinel cattle and Culicoides biting midges (Kato, Shirafuji et al., ; Mitake et al., ; Nakatani, Manabe, Ohtani, Tanaka, & Yamakawa, ; Otani et al., ). Changes in the manifestations of AKAV appear to be associated with a specific genogroup/lineage in recent epizootics.…”