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Bulletin de La Societe de Pathologie... Aug 2016Sandflies are vectors of protozoa, viruses, and bacteria. To investigate the transmission of phleboviruses, a total of 8753 sandflies were collected in four foci of...
Sandflies are vectors of protozoa, viruses, and bacteria. To investigate the transmission of phleboviruses, a total of 8753 sandflies were collected in four foci of leishmania. A total of 16 distinct species were morphologically identified. Nested-PCR and cell culture screening for phleboviruses, using an assay targeting the polymerase gene, showed positive results for 19 pools of sandflies. Sequencing of the corresponding products confirmed the results and allowed identification of Toscana virus exclusively. Corresponding sandfly species originated from four different foci, and were different from those commonly reported in the literature. Sequence analysis shows that the Moroccan Toscana viruses belong to genotype B and appear close to the Toscana viruses isolated in France and Spain. This study reported the existence of the virus in the north, center and south of the country. The abundance and diversity of sandflies in Morocco, Mediterranean climate, would support the continuous circulation of Toscana virus in our country, posing a potential risk of emergence of these arboviruses.
Topics: Animals; Bunyaviridae Infections; Chlorocebus aethiops; DNA, Viral; Disease Reservoirs; Genotype; Humans; Insect Vectors; Molecular Epidemiology; Morocco; Phlebotomus; Phlebovirus; Phylogeny; Polymerase Chain Reaction; Vero Cells
PubMed: 27193286
DOI: 10.1007/s13149-016-0498-x -
MSphere Jun 2018The recent emergence of novel tick-borne RNA viruses has complicated the epidemiological landscape of tick-borne infectious diseases, posing a significant challenge to...
The recent emergence of novel tick-borne RNA viruses has complicated the epidemiological landscape of tick-borne infectious diseases, posing a significant challenge to public health systems that seek to counteract tick-borne diseases. The identification of two novel tick-borne phleboviruses (TBPVs), severe fever with thrombocytopenia syndrome virus (SFTSV) and Heartland virus (HRTV), as causative agents of severe illness in humans has accelerated the investigation and discoveries of novel TBPVs. In the present study, we isolated a novel TBPV designated Mukawa virus (MKWV) from host-questing females captured in Japan. Genetic characterization revealed that MKWV is a member of the genus in the family Interestingly, MKWV is genetically distinct from other known TBPVs and shares a most recent common ancestor with mosquito/sandfly-borne (insect-borne) phleboviruses. Despite its genetic similarity to insect-borne phleboviruses, the molecular footprints of its viral proteins and its biological characteristics define MKWV as a tick-borne virus that can be transmitted to mammals. A phylogenetic ancestral-state reconstruction for arthropod vectors of phleboviruses including MKWV based on viral L segment sequences indicated that ticks likely harbored ancestral phleboviruses that evolved into both the tick-borne and MKWV/insect-borne phlebovirus lineages. Overall, our findings suggest that most of the phlebovirus evolution has occurred in hard ticks to generate divergent viruses, which may provide a seminal foundation for understanding the mechanisms underlying the evolution and emergence of pathogenic phleboviruses, such as Rift Valley fever virus and SFTSV/HRTV. The emergence of novel tick-borne RNA viruses causing severe illness in humans has complicated the epidemiological landscape of tick-borne diseases, requiring further investigation to safeguard public health. In the present study, we discovered a novel tick-borne phlebovirus from ticks in Japan. While its viral RNA genome sequences were similar to those of mosquito/sandfly-borne viruses, molecular and biological footprints confirmed that this is a tick-borne virus. The unique evolutionary position of the virus allowed us to estimate the ancestral phlebovirus vector, which was likely a hard tick. Our findings may provide a better understanding of the evolution and emergence of phleboviruses associated with emerging infectious diseases, such as severe fever with thrombocytopenia syndrome (SFTS) and Heartland virus disease.
Topics: Animals; Evolution, Molecular; Female; Ixodes; Japan; Phlebovirus; Phylogeny
PubMed: 29898985
DOI: 10.1128/mSphere.00239-18 -
Ticks and Tick-borne Diseases Jul 2018Following the identification of severe fever with thrombocytopenia syndrome and Heartland viruses, the interest on tick-borne phleboviruses has increased rapidly....
Following the identification of severe fever with thrombocytopenia syndrome and Heartland viruses, the interest on tick-borne phleboviruses has increased rapidly. Uukuniemi virus has been proposed as a model for tick-borne phleboviruses. However, the number of available sequences is limited. In the current study we performed whole-genome sequencing on two Uukuniemi viral strains isolated in 2000 and 2004 from Ixodes ricinus ticks in the Czech Republic. Both strains cluster together with Potepli63 strain isolated in the country in 1963. Although the Czech strains were isolated many years apart, a high identity was seen at the nucleotide and amino acid levels, suggesting that UUKV has a relatively stable genome.
Topics: Animals; Bunyaviridae Infections; Czech Republic; Genome, Viral; Ixodes; Tick-Borne Diseases; Uukuniemi virus; Whole Genome Sequencing
PubMed: 29699908
DOI: 10.1016/j.ttbdis.2018.04.011 -
Transboundary and Emerging Diseases May 2022Rift Valley fever phlebovirus (RVFV) is an arthropod-borne virus that can cause severe disease in ruminants and humans. Epidemics occur mainly after heavy rainfall,...
Black rats (Rattus rattus) as potential reservoir hosts for Rift Valley fever phlebovirus: Experimental infection results in viral replication and shedding without clinical manifestation.
Rift Valley fever phlebovirus (RVFV) is an arthropod-borne virus that can cause severe disease in ruminants and humans. Epidemics occur mainly after heavy rainfall, which leads to a significant increase in the occurrence of RVFV-transmitting mosquitoes. During inter-epidemic periods, the virus is assumed to be maintained between mosquitoes, susceptible livestock and yet unknown wildlife. The widespread rodent Rattus rattus (black rat) has been suspected to be involved in RVFV maintenance. In order to elucidate its susceptibility and thus its possible role in the transmission cycle of the virus, an experimental infection study was performed. Black rats were subcutaneously infected with highly virulent RVFV strain 35/74 and euthanized on days 3, 14 and 28 post-infection. Additional black rats served as non-infected contact animals. The infected black rats showed high susceptibility to RVFV infection. Generation of RVFV-neutralizing antibodies was found, and the rats developed viraemias lasting up to 17 days. Viral RNA was found in tissues until the last day of the experiment. However, neither a clinical manifestation nor virus-induced histopathological lesions were observed in any rat. These findings indicate the persistence of RVFV in black rats without affecting the animals. In contact animals, no evidence of horizontal RVFV transmission was found, although the co-housed infected rats showed oral, rectal and conjunctival RVFV shedding. Results of this study point to an involvement of black rats in the RVFV transmission cycle, and further studies are needed to investigate their potential role in the maintenance of the virus.
Topics: Animals; Culicidae; Phlebovirus; Rats; Rift Valley Fever; Rift Valley fever virus; Virus Replication
PubMed: 33794070
DOI: 10.1111/tbed.14093 -
Viruses Apr 2021Severe fever with thrombocytopenia syndrome (SFTS), which is caused by SFTS virus (SFTSV), is a tick-borne emerging zoonosis with a high case-fatality rate. At present,... (Review)
Review
Severe fever with thrombocytopenia syndrome (SFTS), which is caused by SFTS virus (SFTSV), is a tick-borne emerging zoonosis with a high case-fatality rate. At present, there is no approved SFTS vaccine, although the development of a vaccine would be one of the best strategies for preventing SFTS. This article focused on studies aimed at establishing small animal models of SFTS that are indispensable for evaluating vaccine candidates, developing these vaccine candidates, and establishing more practical animal models for evaluation. Innate immune-deficient mouse models, a hamster model, an immunocompetent ferret model and a cat model have been developed for SFTS. Several vaccine candidates for SFTS have been developed, and their efficacy has been confirmed using these animal models. The candidates consist of live-attenuated virus-based, viral vector-based, or DNA-based vaccines. SFTS vaccines are expected to be used for humans and companion dogs and cats. Hence for practical use, the vaccine candidates should be evaluated for efficacy using not only nonhuman primates but also dogs and cats. There is no practical nonhuman primate model of SFTS; however, the cat model is available to evaluate the efficacy of these candidate SFTS vaccines on domesticated animals.
Topics: Animals; Cat Diseases; Cats; Cricetinae; Disease Models, Animal; Dog Diseases; Dogs; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Phlebovirus; Primates; Severe Fever with Thrombocytopenia Syndrome; Viral Vaccines
PubMed: 33917632
DOI: 10.3390/v13040627 -
Virologica Sinica Feb 2017Severe fever with thrombocytopenia syndrome virus (SFTSV) is a globe-shaped virus covered by a dense icosahedral array of glycoproteins Gn/Gc that mediate the attachment... (Review)
Review
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a globe-shaped virus covered by a dense icosahedral array of glycoproteins Gn/Gc that mediate the attachment of the virus to host cells and the fusion of viral and cellular membranes. Several membrane factors are involved in virus entry, including C-type lectins and nonmuscle myosin heavy chain IIA. The post-fusion crystal structure of the Gc protein suggests that it is a class II membrane fusion protein, similar to the E/E1 protein of flaviviruses and alphaviruses. The virus particles are internalized into host cell endosomes through the clathrin-dependent pathway, where the low pH activates the fusion of the virus with the cell membrane. With information from studies on other bunyaviruses, herein we will review our knowledge of the entry process of SFTSV.
Topics: Animals; Host-Pathogen Interactions; Humans; Phlebovirus; Virus Internalization
PubMed: 27995422
DOI: 10.1007/s12250-016-3858-6 -
The American Journal of Tropical... Feb 2020The genus is a diverse group of globally occurring viruses, including tick-, mosquito-, and sand fly-borne pathogens. Phleboviruses have historically been classified by...
The genus is a diverse group of globally occurring viruses, including tick-, mosquito-, and sand fly-borne pathogens. Phleboviruses have historically been classified by serological methods. However, molecular methods alone have been used to identify emergent novel and related strains in recent years. This makes reconciling the classification of historically and newly characterized viruses challenging. To address this in part, we describe the characterization of the genomes of the Frijoles and Chilibre species complex phleboviruses, and three unclassified phleboviruses isolated in the Americas: Caimito, Itaporanga, and Rio Grande viruses that had previously only been described at the serological level. With the exception of , the phleboviruses sequenced in this study are phylogenetically related to the current species , , or the Chagres antigenic complex. Unexpectedly, molecular and phylogenetic analysis suggests Chilibre and Caimito viruses are taxonomically related to the family . These viruses have a genomic architecture similar to peribunyaviruses and form monophyletic groups within the genus . Our data highlight the importance of reconciling serological and molecular taxonomic classification. In addition, we suggest the taxonomy of Chilibre and Caimito viruses should be revised.
Topics: Americas; Animals; Genome, Viral; Humans; Phlebovirus; Phylogeny
PubMed: 31802735
DOI: 10.4269/ajtmh.19-0717 -
Annals of Emergency Medicine Sep 2014
Topics: Animals; Bunyaviridae Infections; Humans; Ixodidae; Male; Phlebovirus
PubMed: 25149964
DOI: 10.1016/j.annemergmed.2014.06.012 -
Traffic (Copenhagen, Denmark) Jun 2016Bunyaviruses represent a growing threat to humans and livestock globally. The receptors, cellular factors and endocytic pathways used by these emerging pathogens to...
Bunyaviruses represent a growing threat to humans and livestock globally. The receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely unidentified and poorly characterized. DC-SIGN is a C-type lectin highly expressed on dermal dendritic cells that has been found to act as an authentic entry receptor for many phleboviruses (Bunyaviridae), including Rift Valley fever virus (RVFV), Toscana virus (TOSV) and Uukuniemi virus (UUKV). We found that these phleboviruses can exploit another C-type lectin, L-SIGN, for infection. L-SIGN shares 77% sequence homology with DC-SIGN and is expressed on liver sinusoidal endothelial cells. L-SIGN is required for UUKV binding but not for virus internalization. An endocytosis-defective mutant of L-SIGN was still able to mediate virus uptake and infection, indicating that L-SIGN acts as an attachment receptor for phleboviruses rather than an endocytic receptor. Our results point out a fundamental difference in the use of the C-type lectins L-SIGN and DC-SIGN by UUKV to enter cells, although both proteins are closely related in terms of molecular structure and biological function. This study sheds new light on the molecular mechanisms by which phleboviruses target the liver and also highlights the added complexity in virus-receptor interactions beyond attachment.
Topics: Cell Adhesion Molecules; Endocytosis; Endothelial Cells; HeLa Cells; Humans; Lectins, C-Type; Liver; Phlebovirus; Protein Binding; Receptors, Cell Surface; Virus Internalization
PubMed: 26990254
DOI: 10.1111/tra.12393 -
The Journal of General Virology Apr 2023Sand flies (Diptera: Phlebotominae) are proven vectors of various pathogens of medical and veterinary importance. Although mostly known for their pivotal role in the... (Review)
Review
Sand flies (Diptera: Phlebotominae) are proven vectors of various pathogens of medical and veterinary importance. Although mostly known for their pivotal role in the transmission of parasitic protists of the genus that cause leishmaniases, they are also proven or suspected vectors of many arboviruses, some of which threaten human and animal health, causing disorders such as human encephalitis (Chandipura virus) or serious diseases of domestic animals (vesicular stomatitis viruses). We reviewed the literature to summarize the current published information on viruses detected in or isolated from phlebotomine sand flies, excluding the family with the genus , as these have been well investigated and up-to-date reviews are available. Sand fly-borne viruses from four other families (, , and ) and one unclassified group () are reviewed for the first time regarding their distribution in nature, host and vector specificity, and potential natural transmission cycles.
Topics: Animals; Humans; Psychodidae; Phlebovirus; Animals, Domestic; Arboviruses; Rhabdoviridae
PubMed: 37018120
DOI: 10.1099/jgv.0.001837