| 1. |
- Cholleti, Harindranath, et al.
(author)
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Characterization of Pipistrellus pygmaeus Bat Virome from Sweden
- 2022
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In: Viruses. - : MDPI AG. - 1999-4915. ; 14
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Journal article (peer-reviewed)abstract
- Increasing amounts of data indicate that bats harbor a higher viral diversity relative to other mammalian orders, and they have been recognized as potential reservoirs for pathogenic viruses, such as the Hendra, Nipah, Marburg, and SARS-CoV viruses. Here, we present the first viral metagenomic analysis of Pipistrellus pygmaeus from Uppsala, Sweden. Total RNA was extracted from the saliva and feces of individual bats and analyzed using Illumina sequencing. The results identified sequences related to 51 different viral families, including vertebrate, invertebrate, and plant viruses. These viral families include Coronaviridae, Picornaviridae, Dicistroviridae, Astroviridae, Hepeviridae, Reoviridae, Botourmiaviridae, Lispviridae, Totiviridae, Botoumiaviridae, Parvoviridae, Retroviridae, Adenoviridae, and Partitiviridae, as well as different unclassified viruses. We further characterized three near full-length genome sequences of bat coronaviruses. A phylogenetic analysis showed that these belonged to alphacoronaviruses with the closest similarity (78–99% at the protein level) to Danish and Finnish bat coronaviruses detected in Pipistrellus and Myotis bats. In addition, the full-length and the near full-length genomes of picornavirus were characterized. These showed the closest similarity (88–94% at the protein level) to bat picornaviruses identified in Chinese bats. Altogether, the results of this study show that Swedish Pipistrellus bats harbor a great diversity of viruses, some of which are closely related to mammalian viruses. This study expands our knowledge on the bat population virome and improves our understanding of the evolution and transmission of viruses among bats and to other species.
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| 2. |
- Cholleti, Harindranath
(author)
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Detection and characterisation of novel vector-borne viruses in Mozambique
- 2018
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Doctoral thesis (other academic/artistic)abstract
- Arthropod vectors carry a wide variety of viruses that can cause vector-borne infectious diseases that affect the health of both humans and animals. The vector-borne viruses present in nature show high diversity and can infect a broad range of hosts. Moreover, some of these viruses may be transmitted to new hosts in the future and possibly become pathogenic and/or zoonotic. This thesis describes the detection and characterisation of novel vector-borne viruses circulating in arthropod vectors from an understudied area, the Zambezi Valley of Mozambique, using a viral metagenomic approach. A combination of sequence-independent amplification, high-throughput sequencing and different bioinformatic tools were used to investigate the viromes of mosquitos and ticks in this area. The results of this study resulted in the identification of a broad range of viruses belonging to several viral families, including Flaviviridae, Rhabdoviridae, Iflaviridae, Picornaviridae, and Dicistroviridae, as well as a number of unclassified RNA viruses that were present in Culex and Mansonia spp. mosquitoes. The full-length genome of a novel flavivirus from Mansonia was characterised, and an analysis of conserved domains showed that it belongs to the insect-specific flaviviruses and is closely related to Nakiwogo virus. Further, a near full-length genome of a highly divergent picorna-like virus from Culex mosquitoes was characterised, and the phylogenetic analysis showed that the novel picorna-like virus clustered with members of iflaviruses, confirming that it belongs to the Iflaviridae viral family in the order Picornavirales. Analysis of the Rhipicephalus tick virome identified a number of reads classified as being in the Orthomyxoviridae family. The assembled contigs showed an amino acid identity (32-52%) towards known viruses in the genus Quaranjavirus. Overall, viral metagenomics was successfully used to detect and characterise the viromes of important vectors (mosquitoes and ticks) from Mozambique. All the viral sequences identified from this study were divergent from previously known viruses and potentially represent novel viruses that are circulating in the Zambezi Valley of Mozambique. These results constitute the basis for further studies on viruses that are circulating in vectors and on the evolution, viral maintenance and transmission of pathogenic arboviruses.
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| 3. |
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| 4. |
- Cholleti, Harindranath, et al.
(author)
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Equine arteritis virus induced cell death is associated with activation of the intrinsic apoptotic signalling pathway
- 2013
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In: Virus Research. - : Elsevier BV. - 0168-1702 .- 1872-7492. ; 171:1, s. 222-226
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Journal article (peer-reviewed)abstract
- Equine arteritis virus (EAV) causes a respiratory and reproductive disease in horses, equine viral arteritis. Though cell death in infection with EAV is considered to occur by apoptosis, the underlying molecular mechanism has not been extensively elucidated. We investigated the expression of mRNA of pro-apoptotic and caspase genes during EAV infection in BHK21 cells, a well-established cell type for EAV replication. Using a SYBR Green real-time PCR, mRNA of p53, Bax, caspase 3 and caspase 9 were found up-regulated in a time dependent manner in EAV infected cells. Western blot analysis for caspase 3 and caspase 9 showed expression of cleaved forms of these proteins during EAV infection. In addition, a luminescence-based cell assay for caspase 3/7 activation as a hallmark in apoptosis confirmed apoptotic cell death. The findings demonstrate that cell death in EAV infected BHK21 cells results from apoptosis mediated through the intrinsic signalling pathway.
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| 5. |
- Cholleti, Harindranath, et al.
(author)
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Genetic characterization of a novel picorna-like virus in Culex spp. Mosquitoes from Mozambique
- 2018
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In: Virology Journal. - : Springer Science and Business Media LLC. - 1743-422X. ; 15
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Journal article (peer-reviewed)abstract
- Background: Mosquitoes are the potential vectors for a variety of viruses that can cause diseases in the human and animal populations. Viruses in the order Picornavirales infect a broad range of hosts, including mosquitoes. In this study, we aimed to characterize a novel picorna-like virus from the Culex spp. of mosquitoes from the Zambezi Valley of Mozambique.& para;& para;Methods: The extracted RNA from mosquito pools was pre-amplified with the sequence independent single primer amplification (SISPA) method and subjected to high-throughput sequencing using the Ion Torrent platform. Reads that are classified as Iflaviridae, Picornaviridae and Dicistroviridae were assembled by CodonCode Aligner and SPAdes. Gaps between the viral contigs were sequenced by PCR. The genomic ends were analyzed by 5' and 3' RACE PCRs. The ORF was predicted with the NCBI ORF finder. The conserved domains were identified with ClustalW multiple sequence alignment, and a phylogenetic tree was built with MEGA. The presence of the virus in individual mosquito pools was detected by RT-PCR assay.& para;& para;Results: A near full-length viral genome (9740 nt) was obtained in Culex mosquitoes that encoded a complete ORF (3112 aa), named Culex picorna-like virus (CuPV-1). The predicted ORF had 38% similarity to the Hubei picorna-like virus 35. The sequence of the conserved domains, Helicase-Protease-RNA-dependent RNA polymerase, were identified by multiple sequence alignment and found to be at the 3' end, similar to iflaviruses. Phylogenetic analysis of the putative RdRP amino acid sequences indicated that the virus clustered with members of the Iflaviridae family. CuPV-1 was detected in both Culex and Mansonia individual pools with low infection rates.& para;& para;Conclusions: The study reported a highly divergent, near full-length picorna-like virus genome from Culex spp. mosquitoes from Mozambique. The discovery and characterization of novel viruses in mosquitoes is an initial step, which will provide insights into mosquito-virus interaction mechanisms, genetic diversity and evolution.
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| 6. |
- Cholleti, Harindranath, et al.
(author)
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House crickets (Othroptera: Gryllidae: Acheta domesticus) reared in small-scale laboratory conditions harbour limited viral flora
- 2022
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In: Journal of insects as food and feed. - 2352-4588. ; 8, s. 1149-1155
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Journal article (peer-reviewed)abstract
- Insects, such as crickets, are being used as a viable food source in many regions of the world, given their nutritional value for human and animal consumption. This study investigated the viral communities present in European house crickets and whether feed influences the composition of the crickets’ virome. The crickets were reared under environmentally controlled conditions and fed fresh red clover (fresh), red clover haylage (haylage), red clover hay (hay) or control feed. The viral metagenomic analysis of six replicates from each feed treatment showed that only a few reads were classified as viruses, mainly assigned to phages and insect-related viruses. A significant difference (P<0.001) was observed between the different treatments in regard to the number of viral reads. The highest number of viral reads was identified in the fresh treatment (2,568 reads), whereas the control treatment had the fewest viral reads (90). Phages were identified in all the treatments; however, they were clearly dominant in the fresh and hay feed treatments. A limited number of insect and plant viral reads from Xinmoviridae, Polydnaviridae, Metaviridae, unclassified and ‘other’ viruses were also found in all the feed treatments. The results from this study may indicate that the feed for the crickets determines the richness of the viral flora of crickets, but overall, very few viral reads were identified, making it hard to draw any conclusion regarding the impact of the feed on viral richness.
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| 7. |
- Cholleti, Harindranath, et al.
(author)
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Investigation of the Virome and Characterization of Issyk-Kul Virus from Swedish Myotis brandtii Bats
- 2023
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In: Pathogens. - : MDPI AG. - 2076-0817. ; 12
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Journal article (peer-reviewed)abstract
- Bats are reservoirs for many different viruses, including some that can be transmitted to and cause disease in humans and/or animals. However, less is known about the bat-borne viruses circulating in Northern European countries such as in Sweden. In this study, saliva from Myotis brandtii bats, collected from south-central Sweden, was analyzed for viruses. The metagenomic analysis identified viral sequences belonging to different viral families, including, e.g., Nairoviridae, Retroviridae, Poxviridae, Herpesviridae and Siphoviridae. Interestingly, through the data analysis, the near-complete genome of Issyk-Kul virus (ISKV), a zoonotic virus within the Nairoviridae family, was obtained, showing 95-99% protein sequence identity to previously described ISKVs. This virus is believed to infect humans via an intermediate tick host or through contact with bat excrete. ISKV has previously been found in bats in Europe, but not previously in the Nordic region. In addition, near full-length genomes of two novel viruses belonging to Picornavirales order and Tymoviridae family were characterized. Taken together, our study has not only identified novel viruses, but also the presence of a zoonotic virus not previously known to circulate in this region. Thus, the results from these types of studies can help us to better understand the diversity of viruses circulating in bat populations, as well as identify viruses with zoonotic potential that could possibly be transmitted to humans.
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| 8. |
- Cholleti, Harindranath, et al.
(author)
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Vector-borne viruses and their detection by viral metagenomics
- 2018
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In: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 8
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Research review (peer-reviewed)abstract
- Arthropods, such as mosquitoes and ticks, are important vectors for different viruses (so called vector-borne viruses), some of which cause a significant number of human and animal deaths every year as well as affect public health worldwide. Dengue virus, yellow fever virus, chikungunya virus, Japanese encephalitis virus, tick-borne encephalitis virus and Zika virus are just a few examples of important vector-borne viruses. The majority of all vector-borne viruses have an RNA genome, which routinely undergo genetic modifications. The changes in the genome, apart from the environmental issues, can also influence the spread of viruses to new habitats and hosts and lead to the emergence of novel viruses, which may become a threat to public health. Therefore, it is important to investigate the viruses circulating in arthropod vectors to understand their diversity, host range and evolutionary history as well as to predict new emerging pathogens. The choice of detection method is important, as most of the methods can only detect viruses that have been previously well described. Viral metagenomics is a useful tool to simultaneously identify all the viruses present in a sample, including novel viruses. This review describes vector-borne viruses, their maintenance and emergence in nature, and detection using viral metagenomics.
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| 9. |
- Cholleti, Harindranath, et al.
(author)
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Viral metagenomics reveals the presence of highly divergent quaranjavirus in Rhipicephalus ticks from Mozambique
- 2018
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In: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 8
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Journal article (peer-reviewed)abstract
- Background: Ticks are primary vectors for many well-known disease-causing agents that affect human and animal populations globally such as tick-borne encephalitis, CrimeanCongo hemorrhagic fever and African swine fever. In this study, viral metagenomics was used to identify what viruses are present in Rhipicephalus spp. ticks collected in the Zambezi Valley of Mozambique. Methods: The RNA was amplified with sequence-independent single primer amplification (SISPA) and high-throughput sequencing was performed on the Ion Torrent platform. The generated sequences were subjected to quality check and classfied by BLAST. CodonCode aligner and SeqMan were used to assemble the sequences. Results: The majority of viral sequences showed closest sequence identity to the Orthomyxoviridae family, although viruses similar to the Parvoviridae and Coronaviridae were also identified. Nearly complete sequences of five orthomyxoviral segments (HA, NP, PB1, PB2, and PA) were obtained and these showed an amino acid identity of 32–52% to known quaranjaviruses. The sequences were most closely related to the Wellfleet Bay virus, detected and isolated from common eider during a mortality event in the USA. Conclusions: In summary, this study has identified a highly divergent virus with in the Orthomyxoviridae family associated with Rhipicephalus ticks from Mozambique. Further genetic and biological studies are needed in order to investigate potential pathogenesis of the identified orthomyxovirus.
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| 10. |
- Hayer, Juliette, et al.
(author)
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Identification and molecular characterization of highly divergent RNA viruses in cattle, Uganda
- 2022
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In: Virus Research. - : Elsevier BV. - 0168-1702 .- 1872-7492. ; 313
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Journal article (peer-reviewed)abstract
- The risk for the emergence of novel viral zoonotic diseases in animals and humans in Uganda is high given its geographical location with high biodiversity. We aimed to identify and characterize viruses in 175 blood samples from cattle selected in Uganda using molecular approaches. We identified 8 viral species belonging to 4 families (Flaviviridae, Peribunyaviridae, Reoviridae and Rhabdoviridae) and 6 genera (Hepacivirus, Pestivirus, Orthobunya-virus, Coltivirus, Dinovernavirus and Ephemerovirus). Four viruses were highly divergent and tetantively named Zikole virus (Family: Flaviviridae), Zeboroti virus (Family: Reoviridae), Zebtine virus (Family: Rhabdoviridae) and Kokolu virus (Family: Rhabdoviridae). In addition, Bovine Hepacivirus, Obodhiang virus, Aedes pseudoscutellaris reovirus and Schmallenberg virus were identified for the first time in Ugandan cattle. We report 8 viral species belonging to 4 viral families including divergent ones in the blood of cattle in Uganda. Hence, cattle may be reservoir hosts for likely emergence of novel viruses with pathogenic potential to cause zoonotic diseases in different species with serious public health implications.
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