| 1. |
- Pettersson, John H-O, 1981-, et al.
(författare)
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Meta-Transcriptomic Comparison of the RNA Viromes of the Mosquito Vectors Culex pipiens and Culex torrentium in Northern Europe
- 2019
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Ingår i: Viruses. - : MDPI. - 1999-4915. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Mosquitoes harbor an extensive diversity of 'insect-specific' RNA viruses in addition to those important to human and animal health. However, because most studies of the mosquito virome have been conducted at lower latitudes, little is known about the diversity and evolutionary history of RNA viruses sampled from mosquitoes in northerly regions. Here, we compared the RNA virome of two common northern mosquito species, Culex pipiens and Culex torrentium, collected in south-central Sweden. Following bulk RNA-sequencing (meta-transcriptomics) of 12 libraries, comprising 120 specimens of Cx. pipiens and 150 specimens of Cx. torrentium, we identified 40 viruses (representing 14 virus families) of which 28 were novel based on phylogenetic analysis of the RNA-dependent RNA polymerase (RdRp) protein. Hence, we documented similar levels of virome diversity as in mosquitoes sampled from the more biodiverse lower latitudes. Many viruses were also related to those sampled on other continents, indicative of a widespread global movement and/or long host-virus co-evolution. Although the two mosquito species investigated have overlapping geographical distributions and share many viruses, several viruses were only found at a specific location at this scale of sampling, such that local habitat and geography may play an important role in shaping viral diversity in Culex mosquitoes.
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| 2. |
- Alfsnes, Kristian, et al.
(författare)
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Retrospective meta-transcriptomic identification of severe dengue in a traveller returning from Africa to Sweden, 1990
- 2021
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Ingår i: One Health. - : Elsevier. - 2352-7714. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Pathogens associated with haemorrhagic fever commonly have zoonotic origins. The first documented imported case of likely viral severe haemorrhagic fever in Sweden occurred in 1990. Despite extensive study, no aetiological agent was identified. Following retrospective investigation with total RNA-sequencing of samples collected between 7 and 36 days from onset of symptoms we identified dengue virus 3 (DENV-3) and a human pegivirus (HPgV). We conclude that the patient likely suffered from haemorrhagic symptoms due to an atypical severe and undiagnosed dengue infection.
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| 3. |
- Asghar, Naveed, et al.
(författare)
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Deep sequencing analysis of tick-borne encephalitis virus from questing ticks at natural foci reveals similarities between quasispecies pools of the virus
- 2017
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Ingår i: Journal of General Virology. - : The Microbiology Society. - 0022-1317 .- 1465-2099. ; 98:3, s. 413-421
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Tidskriftsartikel (refereegranskat)abstract
- Every year, tick-borne encephalitis virus (TBEV) causes severe central nervous system infection in 10 000 to 15 000 people in Europe and Asia. TBEV is maintained in the environment by an enzootic cycle that requires a tick vector and a vertebrate host, and the adaptation of TBEV to vertebrate and invertebrate environments is essential for TBEV persistence in nature. This adaptation is facilitated by the error-prone nature of the virus's RNA-dependent RNA polymerase, which generates genetically distinct virus variants called quasispecies. TBEV shows a focal geographical distribution pattern where each focus represents a TBEV hotspot. Here, we sequenced and characterized two TBEV genomes, JP-296 and JP-554, from questing Ixodes ricinus ticks at a TBEV focus in central Sweden. Phylogenetic analysis showed geographical clustering among the newly sequenced strains and three previously sequenced Scandinavian strains, Toro-2003, Saringe-2009 and Mandal-2009, which originated from the same ancestor. Among these five Scandinavian TBEV strains, only Mandal-2009 showed a large deletion within the 3' non-coding region (NCR), similar to the highly virulent TBEV strain Hypr. Deep sequencing of JP-296, JP-554 and Mandal-2009 revealed significantly high quasispecies diversity for JP-296 and JP-554, with intact 3' NCRs, compared to the low diversity in Mandal-2009, with a truncated 3' NCR. Single-nucleotide polymorphism analysis showed that 40% of the single-nucleotide polymorphisms were common between quasispecies populations of JP-296 and JP-554, indicating a putative mechanism for how TBEV persists and is maintained within its natural foci.
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| 4. |
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| 5. |
- Li, Ruiyun, et al.
(författare)
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Phylogeographic Dynamics of Influenza A(H9N2) Virus Crossing Egypt
- 2020
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Low pathogenic avian influenza (LPAI) virus of subtype H9N2 is the most frequently detected subtype among domestic poultry and is a public health concern because of its zoonotic potential. Due to the multiple and complex routes of LPAIV H9N2 between geographic regions, little is known about the spatial diffusion of H9N2 virus to, within, and from Egypt, where it is endemic among poultry since 2011. Using close to 800 publicly available hemagglutinin (HA) segment nucleotide sequences, associated location and temporal data, we conducted a Bayesian discrete phylogeographic analysis. Here, we reconstructed and traced the origin, spread and principal transmission routes of H9N2 across large geographical regions, in addition to the transmission between Egypt and the rest of the world and between different Egyptian governorates. Our analysis suggests that during the last few decades, H9N2 has been introduced back and forth continuously between the countries where it is endemic. Amongst these regions, Saudi Arabia, United Arab Emirates and Iraq act as main distribution hubs and drive the viral migration worldwide, with bi-directional and long-distance diffusions. It is noteworthy that H9N2 was introduced once to Egypt via Israel in mid 2009, and that the descendants of the Egyptian LAIVs H9N2 were back-transmitted to Israel in 2015. Additionally, governorates in middle Egypt (Giza, Fayoum and Bani Souwaif) are major hubs in the LPAIV H9N2 transmission network in Egypt. This knowledge highlights that H9N2 is both a global and a national concern and can aid in updating the surveillance program and vaccine strain selection.
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| 6. |
- Lu, Meng, et al.
(författare)
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Zoonotic risk assessment among farmed mammals
- 2023
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Ingår i: Cell. - : Elsevier. - 0092-8674 .- 1097-4172. ; 186:9, s. 2040-2040.e1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Farmed mammals may act as hosts for zoonotic viruses that can cause disease outbreaks in humans. This SnapShot shows which farmed mammals, and to what extent, are of particular risk of harboring and spreading viruses from viral families that are commonly associated with zoonotic disease. It also discusses genome surveillance methods and biosafety measures.
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| 7. |
- Pettersson, John H.-O. 1981-, et al.
(författare)
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Circumpolar diversification of the Ixodes uriae tick virome
- 2020
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- Ticks (order: Ixodida) are a highly diverse and ecologically important group of ectoparasitic blood-feeding organisms. One such species, the seabird tick (Ixodes uriae), is widely distributed around the circumpolar regions of the northern and southern hemispheres. It has been suggested thatIx.uriaespread from the southern to the northern circumpolar region millions of years ago and has remained isolated in these regions ever since. Such a profound biographic subdivision provides a unique opportunity to determine whether viruses associated with ticks exhibit the same evolutionary patterns as their hosts. To test this, we collectedIx.uriaespecimens near a Gentoo penguin (Pygoscelis papua) colony at Neko harbour, Antarctica, and from migratory birds-the Razorbill (Alca torda) and the Common murre (Uria aalge)-on Bonden island, northern Sweden. Through meta-transcriptomic next-generation sequencing we identified 16 RNA viruses, seven of which were novel. Notably, we detected the same species, Ronne virus, and two closely related species, Bonden virus and Piguzov virus, in both hemispheres indicating that there have been at least two cross-circumpolar dispersal events. Similarly, we identified viruses discovered previously in other locations several decades ago, including Gadgets Gully virus, Taggert virus and Okhotskiy virus. By identifying the same or closely related viruses in geographically disjunct sampling locations we provide evidence for virus dispersal within and between the circumpolar regions. In marked contrast, our phylogenetic analysis revealed no movement of theIx.uriaetick hosts between the same locations. Combined, these data suggest that migratory birds are responsible for the movement of viruses at both local and global scales. Author summary As host populations diverge, so may those microorganisms, including viruses, that are dependent on those hosts. To examine this key issue in host-microbe evolution we compared the co-phylogenies of the seabird tick,Ixodes uriae, and their RNA viruses sampled from the far northern and southern hemispheres. Despite the huge geographic distance between them, phylogeographic analysis reveals that the same and closely related viruses were found both within and between the northern and southern circumpolar regions, most likely reflecting transfer by virus-infected migratory birds. In contrast, genomic data suggested that theIx.uriaepopulations were phylogenetically distinct between the northern and southern hemispheres. This work emphasises the importance of migratory birds and ticks as vectors and sources of virus dispersal and introduction at both the local and global scales.
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| 8. |
- Pettersson, John H.-O. 1981-, et al.
(författare)
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Re-visiting the evolution, dispersal and epidemiology of Zika virus in Asia
- 2018
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Ingår i: Emerging Microbes & Infections. - : Nature Publishing Group. - 2222-1751. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Based on serological evidence and viral isolation, Zika virus (ZIKV) has circulated for many years relatively benignly in a sylvatic cycle in Africa and an urban cycle in South East Asia (SEA). With the recent availability of limited but novel Indian ZIKV sequences to add to the plethora of SEA sequences, we traced the phylogenetic history and spatio-temporal dispersal pattern of ZIKV in Asia prior to its explosive emergence in the Pacific region and the Americas. These analyses demonstrated that the introduction and dispersal of ZIKV on the Pacific islands were preceded by an extended period of relatively silent transmission in SEA, enabling the virus to expand geographically and evolve adaptively before its unanticipated introduction to immunologically naive populations on the Pacific islands and in the Americas. Our findings reveal new features of the evolution and dispersal of this intriguing virus and may benefit future disease control strategies.
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| 9. |
- Pettersson, John H.-O. 1981-
(författare)
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The Origin of the Genus Flavivirus and the Ecology of Tick-Borne Pathogens
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present thesis examines questions related to the temporal origin of the Flavivirus genus and the ecology of tick-borne pathogens. In the first study, we date the origin and divergence time of the Flavivirus genus. It has been argued that the first flaviviruses originated after the last glacial maximum. This has been contradicted by recent analyses estimating that the tick-borne flaviviruses emerged at least before 16,000 years ago. It has also been argued that the Powassan virus was introduced into North America at the time between the opening and splitting of the Beringian land bridge. Supported by tip date and biogeographical calibration, our results suggest that this genus originated circa 120,000 (156,100–322,700) years ago if the Tamana bat virus is included in the genus, or circa 85,000 (63,700–109,600) years ago excluding the Tamana bat virus. In the second study we estimate the prevalence of tick-borne encephalitis virus (TBEV) in host-seeking Ixodes ricinus from 29 localities in Sweden and compare our data with those of neighbouring countries. Nymphs and adult ticks were screened for TBEV using a real-time PCR assay. The mean TBEV prevalence for all tick stages combined was 0.26% for Sweden and 0.28% for all Scandinavian countries, excluding Iceland. The low prevalence of TBEV in nature may partly be explained by the fact that TBEV occurs in spatially small foci and that the inclusion of ticks from non-infected foci will reduce the prevalence estimate. In the third and fourth study, we conducted the first large-scale investigations to estimate the prevalence and geographical distribution of Anaplasma spp. and Rickettsia spp. in host-seeking larvae, nymphs and adults of I. ricinus ticks in Sweden. Ticks were collected from several localities in central and southern Sweden and were subsequently screened for the presence of Anaplasma spp. and Rickettsia spp. using a real-time PCR assay. For all active tick stages combined, the mean prevalence of Anaplasma spp. and Rickettsia spp. in I. ricinus in Sweden was estimated to 1.1% and 4.8%, respectively. It was also shown that A. phagocytophilum and R. helvetica are the main Anaplasma and Rickettsia species occurring in Sweden.
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| 10. |
- Vikse, Rose, et al.
(författare)
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Geographical distribution and prevalence of tick-borne encephalitis virus in questing Ixodes ricinus ticks and phylogeographic structure of the Ixodes ricinus vector in Norway
- 2020
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Ingår i: Zoonoses and Public Health. - : WILEY. - 1863-1959 .- 1863-2378. ; 67:4, s. 370-381
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Tidskriftsartikel (refereegranskat)abstract
- The tick-borne encephalitis virus (TBEV), a zoonotic flaviviral infection, is endemic in large parts of Norway and Eurasia. Humans are mainly infected with TBEV via bites from infected ticks. In Norway, the main geographical distribution of ticks is along the Norwegian coastline from southeast (similar to 59 degrees N) and up to the southern parts of Nordland County (similar to 65 degrees N). In this study, we collected ticks by flagging along the coast from ostfold County to Nordland County. By whole-genome sequencing of the mitochondrial genome of Ixodes ricinus, the phylogenetic tree suggests that there is limited phylogeographic structure both in Norway and in Europe. The overall TBEV prevalence is 0.3% for nymphs and 4.3% for adults. The highest estimated TBEV prevalence in adult ticks was detected in Rogaland and Vestfold County, while for nymphs it is highest in Vestfold, Vest-Agder and Rogaland. The present work is one of the largest studies on distribution and prevalence of TBEV in ticks in Scandinavia, showing that the virus is wider distributed in Norway than previously anticipated.
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