Browsing by Author "Kimura, S."
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Item Entomological Assessment of the Status and Risk of Mosquito-borne Arboviral Transmission in Ghana(viruses, 2020-01-27) Amoa-Bosompem, M.; Kobayashi, D.; Murota, K.; Faizah, A.N.; Itokawa, K.; Fujita, R.; Osei, J.H.N.; Agbosu, E.; Pratt, D.; Kimura, S.; Kwofie, K.D.; Ohashi, M.; Bonney, J.H.K.; Dadzie, S.; Sasaki, T.; Ohta, N.; Isawa, H.; Sawabe, K.; Iwanaga, S.Entomological surveillance is one of the tools used in monitoring and controlling vector-borne diseases. However, the use of entomological surveillance for arboviral infection vector control is often dependent on finding infected individuals. Although this method may su ce in highly endemic areas, it is not as e ective in controlling the spread of diseases in low endemic and non-endemic areas. In this study, we examined the e ciency of using entomological markers to assess the status and risk of arbovirus infection in Ghana, which is considered a non-endemic country, by combining mosquito surveillance with virus isolation and detection. This study reports the presence of cryptic species of mosquitoes in Ghana, demonstrating the need to combine morphological identification and molecular techniques in mosquito surveillance. Furthermore, although no medically important viruses were detected, the importance of insect-specific viruses in understanding virus evolution and arbovirus transmission is discussed. This study reports the first mutualistic relationship between dengue virus and the double-stranded RNA Aedes aegypti totivirus. Finally, this study discusses the complexity of the virome of Aedes and Culex mosquitoes and its implication for arbovirus transmission.Item Screening for tick‑borne and tick‑associated viruses in ticks collected in Ghana(Springer, 2021) Amoa‑Bosompem, M.; Kobayashi, D.; Faizah, A.N.; Kimura, S.; Antw, A.; Agbosu, E.; Pratt, D.; Ohashi, M.; Bonney, J.H.K.; Dadzie, S.; Ejiri, H.; Ohta, N.; Sawabe, K.; Iwanaga, S.; Isawa, H.Ticks are blood-sucking arthropods that transmit many pathogens, including arboviruses. Arboviruses transmitted by ticks are generally referred to as tick-borne viruses (TBVs). TBVs are known to cause diseases in humans, pets, and livestock. There is, however, very limited information on the occurrence and distribution of TBVs in sub-Saharan Africa. This study was designed to determine the presence and distribution of ticks infesting dogs and cattle in Ghana, as well as to identify the tick-borne or tick-associated viruses they harbour. A more diverse population of ticks was found to infest cattle (three genera) relative to those infesting dogs (one genus). Six phleboviruses and an orthonairovirus were detected in tick pools screened by RT-PCR. Subsequent sequence analysis revealed two distinct phleboviruses and the previously reported Odaw virus in ticks collected from dogs and a virus (16GH-T27) most closely related to four unclassifed phleboviruses in ticks collected from cattle. The virus 16GH-T27 was considered a strain of Balambala tick virus (BTV) and named BTV strain 16GH-T27. Next-generation sequencing analysis of the BTV-positive tick pool detected only the L and S segments. Phylogenetic analysis revealed that BTV clustered with viruses previously defined as M-segment-deficient phleboviruses. The orthonairovirus detected in ticks collected from cattle was confirmed to be the medically important Dugbe virus. Furthermore, we discuss the importance of understanding the presence and distribution of ticks and TBVs in disease prevention and mitigation and the implications for public health. Our findings contribute to the knowledge pool on TBVs and tick-associated viruses.