Some reptile ticks are potential vectors of pathogens such as spotted fever group (SFG) rickettsiae. Here, we report for the first time in detail the molecular evidence, DNA sequences and phylogenetic studies, for the presence of Rickettsia spp. in Amblyomma ticks (Amblyomma helvolum and Amblyomma varanense) from snakes in Thailand. A total of 24 tick samples was collected from 4 snake species and identified. A phylogenetic analysis inferred from the partial sequences of the gltA gene indicated that the Rickettsia spp. from 2 Amblyomma helvolum and 1 Amblyomma varanense belong to the same group as the SFG rickettsiae, which are closely related to Rickettsia raoultii strains. In contrast, there was 1 Rickettsia sp. from Amblyomma helvolum grouped into the same clade with other SFG rickettsiae (Rickettsia tamurae, Rickettsia monacensis, and a Rickettsia endosymbiont of Amblyomma dubitatum from Brazil). However, another Rickettsia sp. from Amblyomma varanense was closely related to Rickettsia bellii and Rickettsia sp. strain RDa420 from Thailand. In addition, from phylogenetic results based on the 16S rRNA gene and a concatenated tree of the 3 genes (gltA, ompA, and ompB), we found what may be a novel SFG rickettsia species closely related to Rickettsia raoultii (from both Amblyomma varanense and Amblyomma helvolum). In conclusion, our findings are the first report on the presence of novel SFG rickettsiae in 2 snake tick species, Amblyomma varanense and Amblyomma helvolum in Thailand and in south-eastern Asia.

• MeSH
• arachnida jako vektory klasifikace   mikrobiologie   MeSH
• bakteriální proteiny genetika   MeSH
• DNA bakterií genetika   MeSH
• fylogeneze MeSH
• hadi klasifikace   parazitologie   MeSH
• Ixodidae klasifikace   mikrobiologie   MeSH
• molekulární sekvence - údaje MeSH
• Rickettsia klasifikace   genetika   izolace a purifikace   MeSH
• RNA ribozomální 16S genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Thajsko MeSH

Tick-borne encephalitis (TBE) is one of the leading and most dangerous human viral neuroinfections in Europe and north-eastern Asia. The clinical manifestations include asymptomatic infections, fevers and debilitating encephalitis that might progress into chronic disease or fatal infection. To understand TBE pathology further in host nervous systems, three human neural cell lines, neuroblastoma, medulloblastoma and glioblastoma, were infected with TBE virus (TBEV). The susceptibility and virus-mediated cytopathic effect, including ultrastructural and apoptotic changes of the cells, were examined. All the neural cell lines tested were susceptible to TBEV infection. Interestingly, the neural cells produced about 100- to 10,000-fold higher virus titres than the conventional cell lines of extraneural origin, indicating the highly susceptible nature of neural cells to TBEV infection. The infection of medulloblastoma and glioblastoma cells was associated with a number of major morphological changes, including proliferation of membranes of the rough endoplasmic reticulum and extensive rearrangement of cytoskeletal structures. The TBEV-infected cells exhibited either necrotic or apoptotic morphological features. We observed ultrastructural apoptotic signs (condensation, margination and fragmentation of chromatin) and other alterations, such as vacuolation of the cytoplasm, dilatation of the endoplasmic reticulum cisternae and shrinkage of cells, accompanied by a high density of the cytoplasm. On the other hand, infected neuroblastoma cells did not exhibit proliferation of membranous structures. The virions were present in both the endoplasmic reticulum and the cytoplasm. Cells were dying preferentially by necrotic mechanisms rather than apoptosis. The neuropathological significance of these observations is discussed.

• MeSH
• apoptóza MeSH
• buněčná membrána ultrastruktura   MeSH
• buněčná smrt MeSH
• buněčné linie MeSH
• cytoplazma virologie   MeSH
• cytoskelet metabolismus   ultrastruktura   MeSH
• endoplazmatické retikulum virologie   MeSH
• lidé MeSH
• neuroglie ultrastruktura   virologie   MeSH
• neurony ultrastruktura   virologie   MeSH
• virion ultrastruktura   MeSH
• viry klíšťové encefalitidy fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH