101
|
Jansen MD, Jensen BB, Brun E. Clinical manifestations of pancreas disease outbreaks in Norwegian marine salmon farming - variations due to salmonid alphavirus subtype. JOURNAL OF FISH DISEASES 2015; 38:343-53. [PMID: 24661057 DOI: 10.1111/jfd.12238] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/20/2014] [Accepted: 01/23/2014] [Indexed: 05/13/2023]
Abstract
Pancreas disease (PD) in Norwegian salmonid aquaculture has traditionally been caused by salmonid alphavirus (SAV) subtype 3. Following the isolation of a novel SAV subtype in 2010, marine SAV2, two separate endemic areas have developed. It has been debated whether disease outbreaks due to marine SAV2 result in milder clinical manifestations compared to outbreaks caused by SAV3. The aim of this study was to descriptively investigate site-level differences in the clinical manifestations of marine SAV2 and SAV3 at Norwegian seawater sites diagnosed with PD in 2012. The findings suggest that Norwegian PD outbreaks caused by marine SAV2 result in lower mortality and milder clinical signs compared to outbreaks caused by SAV3. For sites without reported PD-related mortality, there was no difference in the mortality levels between sites infected by marine SAV2 and SAV3. The results also indicate that there are no differences in grading quality at slaughter between the SAV subtypes.
Collapse
|
102
|
Cano I, Joiner C, Bayley A, Rimmer G, Bateman K, Feist SW, Stone D, Paley R. An experimental means of transmitting pancreas disease in Atlantic salmon Salmo salar L. fry in freshwater. JOURNAL OF FISH DISEASES 2015; 38:271-281. [PMID: 25297529 DOI: 10.1111/jfd.12310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/05/2014] [Accepted: 08/06/2014] [Indexed: 06/04/2023]
Abstract
A challenge model for pancreas disease in Atlantic salmon, Salmo salar L. fry, was developed comparing two salmonid alphavirus (SAV) subtypes: SAV1 and SAV5. Viral doses of 3 × 10(5) TCID50 mL(-1) for SAV1 and 3 × 10(4) for SAV5 were tested in triplicate tanks, each containing 450 salmon fry. Cumulative mortalities of 1.2% were recorded. Titres of virus recovered from the mortalities ranged from 10(2) to 10(7) TCID50 mL(-1) . Fry were sampled at 3, 5 and 7.5 weeks post-challenge. Sampling after 3 weeks revealed a high prevalence of infection in the absence of clinical signs, and infectious virus was recovered from 80% and 43% of sampled fry infected with SAV1 and SAV5, respectively. After 5 weeks pancreas, heart and red skeletal muscle lesions were generally observed, whilst degeneration in white skeletal muscle was observed only in fish infected with SAV1. In situ hybridisation confirmed the presence of viral genome in infected pancreas, heart and muscle. After 7.5 weeks, infectious virus (both isolates) was recovered from 13.3% of the fish sampled, with a viral titre of 10(2) TCID50 mL(-1) . Clearly, salmon fry are susceptible to SAV infection and pancreas disease.
Collapse
|
103
|
Heidari Z, Tinsley J, Bickerdike R, McLoughlin MF, Zou J, Martin SAM. Antiviral and metabolic gene expression responses to viral infection in Atlantic salmon (Salmo salar). FISH & SHELLFISH IMMUNOLOGY 2015; 42:297-305. [PMID: 25462555 DOI: 10.1016/j.fsi.2014.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 06/04/2023]
Abstract
Salmonid alphavirus (SAV), the aetiological agent of pancreas disease, is recognized as a serious pathogen of farmed Atlantic salmon. This disease results in loss of weight followed by poor growth of surviving fish, as such it is viewed as a wasting disease. SAV and other chronic disease causing viruses affect the heart and skeletal muscle tissues, at present the mechanisms by which pathology occurs is unknown. The relationship between antiviral activity and other physiological parameters especially in skeletal muscle are currently not examined in depth in fish. An experimental SAV (isotype 3) infection was carried out using a cohabitation approach, from which samples were collected at 0, 4, 8 & 12 week post challenge. Maximum viral load in the muscle tissue was 4 weeks post infection which was reduced at 8 weeks and undetectable by 12 weeks. Histopathology score peaked at 4 weeks post infection in pancreas and heart whereas there was maximum damage in skeletal muscle at 8 weeks. The peak expression of antiviral immune genes coincided with the viral load. Several genes involved in protein degradation were increased following infection including atrogin-1 and cathepsin D, at 4 weeks post challenge suggesting reallocation of amino acid reserves. Taken together, these observations increase our understanding of salmon poor growth during viral infection, and will serve as a basis to develop strategies to manage this viral wasting disease.
Collapse
|
104
|
Alegría R, Arriagada G, Urcelay S, Hamilton-West C. Cross-sectional study to investigate the presence of salmon pancreas disease virus in wild and feral fish populations in 10 lakes, Los Lagos Region, Chile. JOURNAL OF FISH DISEASES 2015; 38:113-119. [PMID: 24382013 DOI: 10.1111/jfd.12217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/15/2013] [Accepted: 11/16/2013] [Indexed: 06/03/2023]
|
105
|
Nasar F, Haddow AD, Tesh RB, Weaver SC. Eilat virus displays a narrow mosquito vector range. Parasit Vectors 2014; 7:595. [PMID: 25515341 PMCID: PMC4297418 DOI: 10.1186/s13071-014-0595-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 12/06/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Most alphaviruses are arthropod-borne and utilize mosquitoes as vectors for transmission to susceptible vertebrate hosts. This ability to infect both mosquitoes and vertebrates is essential for maintenance of most alphaviruses in nature. A recently characterized alphavirus, Eilat virus (EILV), isolated from a pool of Anopheles coustani s.I. is unable to replicate in vertebrate cell lines. The EILV host range restriction occurs at both attachment/entry as well as genomic RNA replication levels. Here we investigated the mosquito vector range of EILV in species encompassing three genera that are responsible for maintenance of other alphaviruses in nature. METHODS Susceptibility studies were performed in four mosquito species: Aedes albopictus, A. aegypti, Anopheles gambiae, and Culex quinquefasciatus via intrathoracic and oral routes utilizing EILV and EILV expressing red fluorescent protein (-eRFP) clones. EILV-eRFP was injected at 10(7) PFU/mL to visualize replication in various mosquito organs at 7 days post-infection. Mosquitoes were also injected with EILV at 10(4)-10(1) PFU/mosquito and virus replication was measured via plaque assays at day 7 post-infection. Lastly, mosquitoes were provided bloodmeals containing EILV-eRFP at doses of 10(9), 10(7), 10(5) PFU/mL, and infection and dissemination rates were determined at 14 days post-infection. RESULTS All four species were susceptible via the intrathoracic route; however, replication was 10-100 fold less than typical for most alphaviruses, and infection was limited to midgut-associated muscle tissue and salivary glands. A. albopictus was refractory to oral infection, while A. gambiae and C. quinquefasciatus were susceptible only at 10(9) PFU/mL dose. In contrast, A. aegypti was susceptible at both 10(9) and 10(7) PFU/mL doses, with body infection rates of 78% and 63%, and dissemination rates of 26% and 8%, respectively. CONCLUSIONS The exclusion of vertebrates in its maintenance cycle may have facilitated the adaptation of EILV to a single mosquito host. As a consequence, EILV displays a narrow vector range in mosquito species responsible for the maintenance of other alphaviruses in nature.
Collapse
|
106
|
Blakely PK, Delekta PC, Miller DJ, Irani DN. Manipulation of host factors optimizes the pathogenesis of western equine encephalitis virus infections in mice for antiviral drug development. J Neurovirol 2014; 21:43-55. [PMID: 25361697 DOI: 10.1007/s13365-014-0297-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/18/2014] [Accepted: 09/24/2014] [Indexed: 11/25/2022]
Abstract
While alphaviruses spread naturally via mosquito vectors, some can also be transmitted as aerosols making them potential bioterrorism agents. One such pathogen, western equine encephalitis virus (WEEV), causes fatal human encephalitis via multiple routes of infection and thus presumably via multiple mechanisms. Although WEEV also produces acute encephalitis in non-human primates, a small animal model that recapitulates features of human disease would be useful for both pathogenesis studies and to evaluate candidate antiviral therapies. We have optimized conditions to infect mice with a low passage isolate of WEEV, thereby allowing detailed investigation of virus tropism, replication, neuroinvasion, and neurovirulence. We find that host factors strongly influence disease outcome, and in particular, that age, gender, and genetic background all have significant effects on disease susceptibility independent of virus tropism or replication within the central nervous system. Our data show that experimental variables can be adjusted in mice to recapitulate disease features known to occur in both non-human primates and humans, thus aiding further study of WEEV pathogenesis and providing a realistic therapeutic window for antiviral drug delivery.
Collapse
MESH Headings
- Administration, Intranasal
- Alphavirus Infections/pathology
- Alphavirus Infections/virology
- Animals
- Behavior, Animal
- Cognition
- Disease Models, Animal
- Encephalitis Virus, Western Equine/pathogenicity
- Encephalitis Virus, Western Equine/physiology
- Host Specificity
- Injections, Intraperitoneal
- Injections, Subcutaneous
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred DBA
- RNA, Viral/blood
- Seizures/pathology
- Seizures/virology
- Species Specificity
- Viral Load
- Virus Replication
Collapse
|
107
|
Schmidt-Posthaus H, Diserens N, Jankowska Hjortaas M, Knüsel R, Hirschi R, Taksdal T. First outbreak of sleeping disease in Switzerland: disease signs and virus characterization. DISEASES OF AQUATIC ORGANISMS 2014; 111:165-171. [PMID: 25266904 DOI: 10.3354/dao02766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Sleeping disease is a contagious disease mainly of freshwater farmed rainbow trout, caused by salmonid alphavirus (SAV) Subtype 2. Here we describe the first case in Switzerland. Pathological changes ranged from acute pancreas necrosis to more chronic lesions with complete loss of exocrine pancreas and simultaneous degenerative, inflammatory and regenerative heart and muscle lesions. The partial sequencing of SAV E2 and nsp3 genes placed the Swiss SAV variant within the Subtype 2 clustering together with freshwater isolates from UK and continental Europe. Although mortality stayed low, growth rates were significantly reduced, making the disease economically relevant.
Collapse
|
108
|
Graham DA, Rowley HR, Frost P. Cross-neutralization studies with salmonid alphavirus subtype 1-6 strains: results with sera from experimental studies and natural infections. JOURNAL OF FISH DISEASES 2014; 37:683-91. [PMID: 23957811 DOI: 10.1111/jfd.12167] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/15/2013] [Accepted: 07/16/2013] [Indexed: 05/13/2023]
Abstract
The serological reactivity between strains of each of the six currently genetically defined subtypes of salmonid alphavirus (SAV) was examined by comparison of homologous and heterologous virus neutralization titres on sera from experimentally infected fish. With the exception of the level of SAV subtype 6 neutralization by heterologous sera, good cross-neutralization was detected between all subtypes, albeit with variation in geometric mean titres when each subtype-specific serum set was tested against the panel of virus subtypes. A similar pattern was evident with field sera, except that heterologous neutralization of the SAV6 strain was more evident. In only 23% of available pairwise comparisons was the homologous titre recorded with an experimentally derived serum fourfold or greater than the heterologous titre, and in only two instances was this difference demonstrated in both directions. No virus strains consistently met the old serology-based criteria (Sub-committee on Inter-relationships Among Catalogued Alphaviruses) to be considered separate subtypes within an alphavirus species. Only when testing with an SAV subtype-2-specific monoclonal antibody was a major difference between homologous and heterologous neutralization capacity evident. These results provide new direct or indirect information in terms of SAV classification, vaccine efficacy and the selection and validation of reagents for serological and immunological diagnostic purposes.
Collapse
|
109
|
AHLM C, ELIASSON M, VAPALAHTI O, EVANDER M. Seroprevalence of Sindbis virus and associated risk factors in northern Sweden. Epidemiol Infect 2014; 142:1559-65. [PMID: 24029159 PMCID: PMC9167656 DOI: 10.1017/s0950268813002239] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/18/2013] [Accepted: 08/16/2013] [Indexed: 12/31/2022] Open
Abstract
Mosquito-borne Sindbis virus (SINV) cause disease characterized by rash, fever and arthritis which often leads to long-lasting arthralgia. To determine the seroprevalence of SINV and associated risk factors in northern Sweden, a randomly selected population aged between 25 and 74 years were invited to join the MONICA study. Serum from 1611 samples were analysed for specific IgG antibodies. Overall, 2·9% had IgG against SINV. More men (3·7%) than women (2·0%) were SINV seropositive (P = 0·047) and it was more common in subjects with a lower educational level (P = 0·013) and living in small, rural communities (P < 0·001). Seropositivity was associated with higher waist circumference (P = 0·1), elevated diastolic blood pressure (P = 0·037), and history of a previous stroke (P = 0·011). In a multiple logistic regression analysis, adjusting for known risk factors for stroke, seropositivity for SINV was an independent predictor of having had a stroke (odds ratio 4·3, 95% confidence interval 1·4-13·0, P = 0·011).
Collapse
|
110
|
Yu W, Mengersen K, Dale P, Mackenzie JS, Toloo G(S, Wang X, Tong S. Epidemiologic patterns of Ross River virus disease in Queensland, Australia, 2001-2011. Am J Trop Med Hyg 2014; 91:109-118. [PMID: 24799374 PMCID: PMC4080548 DOI: 10.4269/ajtmh.13-0455] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 01/08/2014] [Indexed: 11/07/2022] Open
Abstract
Ross River virus (RRV) infection is a debilitating disease that has a significant impact on population health, economic productivity, and tourism in Australia. This study examined epidemiologic patterns of RRV disease in Queensland, Australia, during January 2001-December 2011 at a statistical local area level. Spatio-temporal analyses were used to identify the patterns of the disease distribution over time stratified by age, sex, and space. The results show that the mean annual incidence was 54 per 100,000 persons, with a male:female ratio of 1:1.1. Two space-time clusters were identified: the areas adjacent to Townsville, on the eastern coast of Queensland, and the southeast areas. Thus, although public health intervention should be considered across all areas in which RRV occurs, it should specifically focus on high-risk regions, particularly during summer and autumn to reduce the social and economic impacts of RRV infection.
Collapse
|
111
|
Kading RC, Biggerstaff BJ, Young G, Komar N. Mosquitoes used to draw blood for arbovirus viremia determinations in small vertebrates. PLoS One 2014; 9:e99342. [PMID: 24901448 PMCID: PMC4047049 DOI: 10.1371/journal.pone.0099342] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 05/14/2014] [Indexed: 11/19/2022] Open
Abstract
Serial samples from the same individuals may be required for certain virological studies, however, some small animals cannot easily be blood-sampled. Therefore, we evaluated the use of Culex quinquefasciatus Say and Aedes albopictus Skuse mosquitoes as “biological syringes” to draw blood for virus titer determinations in small vertebrates. Groups of chicks (Gallus gallus), hamsters (Mesocricetus auratus), and house sparrows (Passer domesticus) were experimentally infected with West Nile virus (WNV) or Highlands J virus (HJV). In general, good correlation was seen between mosquito- and syringe-derived blood samples at titers ≥5.0 log10 pfu/mL serum as compared with titers <5.0 log10 pfu/mL serum for chicks, hamsters, and sparrows. Ninety-two percent (24/26) of sparrows with virus titers >105 pfu/mL serum had mosquito- and syringe-derived titers within one log of each other. Sparrow viremia profiles generated from single mosquito blood meals and syringe were not significantly different (p>0.05). This technique is valuable for assessing the roles of small vertebrates in the ecologies of arboviruses, and could be used in applications beyond virology and infectious diseases, when <10 µL of whole blood is required.
Collapse
|
112
|
Ip HS, Wiley MR, Long R, Palacios G, Shearn-Bochsler V, Whitehouse CA. Identification and characterization of Highlands J virus from a Mississippi sandhill crane using unbiased next-generation sequencing. J Virol Methods 2014; 206:42-5. [PMID: 24880070 DOI: 10.1016/j.jviromet.2014.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 11/17/2022]
Abstract
Advances in massively parallel DNA sequencing platforms, commonly termed next-generation sequencing (NGS) technologies, have greatly reduced time, labor, and cost associated with DNA sequencing. Thus, NGS has become a routine tool for new viral pathogen discovery and will likely become the standard for routine laboratory diagnostics of infectious diseases in the near future. This study demonstrated the application of NGS for the rapid identification and characterization of a virus isolated from the brain of an endangered Mississippi sandhill crane. This bird was part of a population restoration effort and was found in an emaciated state several days after Hurricane Isaac passed over the refuge in Mississippi in 2012. Post-mortem examination had identified trichostrongyliasis as the possible cause of death, but because a virus with morphology consistent with a togavirus was isolated from the brain of the bird, an arboviral etiology was strongly suspected. Because individual molecular assays for several known arboviruses were negative, unbiased NGS by Illumina MiSeq was used to definitively identify and characterize the causative viral agent. Whole genome sequencing and phylogenetic analysis revealed the viral isolate to be the Highlands J virus, a known avian pathogen. This study demonstrates the use of unbiased NGS for the rapid detection and characterization of an unidentified viral pathogen and the application of this technology to wildlife disease diagnostics and conservation medicine.
Collapse
|
113
|
Jardine A, Neville PJ, Dent C, Webster C, Lindsay MDA. Ross River virus risk associated with dispersal of Aedes (Ochlerotatus) camptorhynchus (Thomson) from breeding habitat into surrounding residential areas: muddy lakes, Western Australia. Am J Trop Med Hyg 2014; 91:101-108. [PMID: 24799370 PMCID: PMC4080547 DOI: 10.4269/ajtmh.13-0399] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Rapid population growth in Western Australia has resulted in increased development of land for residential housing, and new developments are often proposed close to water because of intrinsic aesthetic values. However, this placement may place future residents at risk of mosquito-borne disease, of which Ross River virus (RRV) disease is the most common in Australia. Mosquito dispersal data were combined with a spatial analysis of human RRV cases to show that mosquitoes dispersed readily from larval habitat into surrounding low- and high-density residential areas and that residents living within 2 km of mosquito breeding habitat had a significantly higher rate of RRV disease. This finding highlights the importance of planning authorities in state and local governments to consider the implications of mosquito-borne disease risks when assessing residential development applications.
Collapse
|
114
|
Shchelkanov MI, L'vov DK, Kolobukhina LV, Al'khovskiĭ SV, Shchetinin AM, Saĭfullin MA, Kruzhkova IS, Aristova VA, Morozova TV, Samokhvalov EI, Gushchina EA, Klimenko SM, Arsen'eva TV, Ambrosi OE, Bazarova MV, Malyshev NA. [Isolation of the Chikungunya virus in Moscow from the Indonesian visitor (September, 2013)]. Vopr Virusol 2014; 59:28-34. [PMID: 25335416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The results of the virological identification of the Chikungunya fever case in Moscow (September, 2013) in an Indonesian visitor are presented. The clinic, electron microscopy, and molecular genetic data are discussed. The Ghikungunya virus (CHIKV) strain CHIKVILEIV-Moscow/1/2013 belonging to the Asian genotype (ID GenBank KF872195) was deposited into the Russian State Collection of viruses (GKV 1239; 18.11.2013).
Collapse
|
115
|
Olagnier D, Scholte FEM, Chiang C, Albulescu IC, Nichols C, He Z, Lin R, Snijder EJ, van Hemert MJ, Hiscott J. Inhibition of dengue and chikungunya virus infections by RIG-I-mediated type I interferon-independent stimulation of the innate antiviral response. J Virol 2014; 88:4180-94. [PMID: 24478443 PMCID: PMC3993760 DOI: 10.1128/jvi.03114-13] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/20/2014] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED RIG-I is a cytosolic sensor critically involved in the activation of the innate immune response to RNA virus infection. In the present study, we evaluated the inhibitory effect of a RIG-I agonist on the replication of two emerging arthropod-borne viral pathogens, dengue virus (DENV) and chikungunya virus (CHIKV), for which no therapeutic options currently exist. We demonstrate that when a low, noncytotoxic dose of an optimized 5'triphosphorylated RNA (5'pppRNA) molecule was administered, RIG-I stimulation generated a robust antiviral response against these two viruses. Strikingly, 5'pppRNA treatment before or after challenge with DENV or CHIKV provided protection against infection. In primary human monocytes and monocyte-derived dendritic cells, the RIG-I agonist blocked both primary infection and antibody-dependent enhancement of DENV infection. The protective response against DENV and CHIKV induced by 5'pppRNA was dependent on an intact RIG-I/MAVS/TBK1/IRF3 axis and was largely independent of the type I IFN response. Altogether, this in vitro analysis of the antiviral efficacy of 5'pppRNA highlights the therapeutic potential of RIG-I agonists against emerging viruses such as DENV and CHIKV. IMPORTANCE DENV and CHIKV are two reemerging mosquito-borne viruses for which no therapeutic options currently exist. Both viruses overlap geographically in tropical regions of the world, produce similar fever-like symptoms, and are difficult to diagnose. This study investigated the inhibitory effect of a RIG-I agonist on the replication of these two viruses. RIG-I stimulation using 5'pppRNA before or after DENV or CHIKV infection generated a protective antiviral response against both pathogens in immune and nonimmune cells; interestingly, the protective response against the viruses was largely independent of the classical type I interferon response. The antiviral efficacy of 5'pppRNA highlights the therapeutic potential of RIG-I agonists against emerging viruses such as DENV and CHIKV.
Collapse
|
116
|
Butt AM, Nasrullah I, Tong Y. Genome-wide analysis of codon usage and influencing factors in chikungunya viruses. PLoS One 2014; 9:e90905. [PMID: 24595095 PMCID: PMC3942501 DOI: 10.1371/journal.pone.0090905] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 02/06/2014] [Indexed: 02/03/2023] Open
Abstract
Chikungunya virus (CHIKV) is an arthropod-borne virus of the family Togaviridae that is transmitted to humans by Aedes spp. mosquitoes. Its genome comprises a 12 kb single-strand positive-sense RNA. In the present study, we report the patterns of synonymous codon usage in 141 CHIKV genomes by calculating several codon usage indices and applying multivariate statistical methods. Relative synonymous codon usage (RSCU) analysis showed that the preferred synonymous codons were G/C and A-ended. A comparative analysis of RSCU between CHIKV and its hosts showed that codon usage patterns of CHIKV are a mixture of coincidence and antagonism. Similarity index analysis showed that the overall codon usage patterns of CHIKV have been strongly influenced by Pan troglodytes and Aedes albopictus during evolution. The overall codon usage bias was low in CHIKV genomes, as inferred from the analysis of effective number of codons (ENC) and codon adaptation index (CAI). Our data suggested that although mutation pressure dominates codon usage in CHIKV, patterns of codon usage in CHIKV are also under the influence of natural selection from its hosts and geography. To the best of our knowledge, this is first report describing codon usage analysis in CHIKV genomes. The findings from this study are expected to increase our understanding of factors involved in viral evolution, and fitness towards hosts and the environment.
Collapse
|
117
|
Sheela PJ, Sumathy K. Serological correlates of immune protection conferred by Chikungunya virus infection. Acta Virol 2014; 57:471-3. [PMID: 24294963 DOI: 10.4149/av_2013_04_471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chikungunya virus (CHIKV), an Alphavirus of the family Togaviridae is a positive strand RNA virus that is transmitted commonly by the Aedes mosquitoes. The characteristic clinical symptom of the virus infection is incapacitating arthralgia that could persist for few weeks to several months in the affected individuals (1, 2). High morbidity with severe polyarthralgia, rashes and ocular, hemorrhagic and sensorineural complications are reported in the re-emerging infection (3-5). The acquisition of an A226V mutation in the envelope protein E1 has increased the transmissibility of the virus in the widely prevalent Ae. Albopictus mosquitoes (6). CHIKV infection has become more widespread in the recent years as the mosquito vectors have expanded into new areas. Imported cases of CHIKV have been reported in nearly 40 countries until now (7).
Collapse
|
118
|
Al'khovskiĭ SV, L'vov DK, Shchelkanov MI, Shchetinin AM, Deriabin PG, Gitel'man AK, Botikov AG, Samokhvalov EI. [Complete genome characterization of the Kyzylagach virus (KYZV) (Togaviridae, Alphavirus, Sindbis serogroup) isolated from mosquitoes Culex modestus Ficalbi, 1889 (Culicinae) collected in a colony of herons (Ardeidae Leach, 1820) in Azerbaijan]. Vopr Virusol 2014; 59:27-31. [PMID: 25895208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Complete genome sequencing of the Kyzylagach virus (KYZV) LEIV-65A strain isolated from the Culex modestus Ficalbi, 1889 (Culicinae), which was collected in the colony of the Ardeidae Leach, 1820 birds on the coast of Caspian sea, Kyzyl-Agach bay, in the southern part of Azerbaijan, was carried out. KYZV has high homology (about 99%) with the Chinese XJ-160 strain of the Sindbis virus (SINV) isolated from Anopheles sp. in Xinjiang Uyghur autonomic region (north-eastern China). Homologies of KYZV and XJ-160 with European SINV strains are 82% and 93% for the nucleotide and amino acid sequences, respectively (GenBank ID: KF981618). The difference between the nucleotide sequences of KYZV and Australian SINV/SW6562 strain is 19%; amino acid sequences, 12%. Since XJ-160 strain is extremely similar to KYZV, the first could be considered as the KYZV strain. The geography of the KYZV and XJ-160 isolation points and their genetic distance from the European viruses allow the KYZV to be suggested as a SINV (genotype IV) topotypic variant typical of Transcaucasia and Central Asia.
Collapse
|
119
|
Ooi YS, Stiles KM, Liu CY, Taylor GM, Kielian M. Genome-wide RNAi screen identifies novel host proteins required for alphavirus entry. PLoS Pathog 2013; 9:e1003835. [PMID: 24367265 PMCID: PMC3868536 DOI: 10.1371/journal.ppat.1003835] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/31/2013] [Indexed: 12/21/2022] Open
Abstract
The enveloped alphaviruses include important and emerging human pathogens such as Chikungunya virus and Eastern equine encephalitis virus. Alphaviruses enter cells by clathrin-mediated endocytosis, and exit by budding from the plasma membrane. While there has been considerable progress in defining the structure and function of the viral proteins, relatively little is known about the host factors involved in alphavirus infection. We used a genome-wide siRNA screen to identify host factors that promote or inhibit alphavirus infection in human cells. Fuzzy homologue (FUZ), a protein with reported roles in planar cell polarity and cilia biogenesis, was required for the clathrin-dependent internalization of both alphaviruses and the classical endocytic ligand transferrin. The tetraspanin membrane protein TSPAN9 was critical for the efficient fusion of low pH-triggered virus with the endosome membrane. FUZ and TSPAN9 were broadly required for infection by the alphaviruses Sindbis virus, Semliki Forest virus, and Chikungunya virus, but were not required by the structurally-related flavivirus Dengue virus. Our results highlight the unanticipated functions of FUZ and TSPAN9 in distinct steps of alphavirus entry and suggest novel host proteins that may serve as targets for antiviral therapy. Alphaviruses are a group of small enveloped viruses that include important human pathogens for which there are no antiviral therapies or vaccines. Alphaviruses enter host cells by receptor-mediated endocytosis and low pH-triggered membrane fusion, and exit by budding from the host cell plasma membrane. The roles of host cell proteins in these events are not well understood in spite of extensive studies. Here we performed a screen using small interfering RNAs to identify host factors involved in alphavirus infection of human cells. We defined the mechanism of two novel host proteins that promote alphavirus entry. Fuzzy homologue (FUZ), a protein with roles in cilia biogenesis, promoted endocytosis of both alphaviruses and a well-studied endocytic cargo, transferrin. The tetraspanin membrane protein, TSPAN9, did not significantly affect endocytic uptake or acidification, but was critical for the efficient fusion of the virus in the endosome. These two proteins were required for infection by several different alphaviruses, suggesting that they may be useful targets for drugs to prevent alphavirus infection.
Collapse
|
120
|
Kramer RM, Zeng Y, Sahni N, Kueltzo LA, Schwartz RM, Srivastava IK, Crane L, Joshi SB, Volkin DB, Middaugh CR. Development of a stable virus-like particle vaccine formulation against Chikungunya virus and investigation of the effects of polyanions. J Pharm Sci 2013; 102:4305-14. [PMID: 24129946 PMCID: PMC3869236 DOI: 10.1002/jps.23749] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/06/2013] [Accepted: 09/24/2013] [Indexed: 11/07/2022]
Abstract
Chikungunya virus (CHIKV) is an alphavirus that infects millions of people every year, especially in the developing world. The selective expression of recombinant CHIKV capsid and envelope proteins results in the formation of self-assembled virus-like particles (VLPs) that have been shown to protect nonhuman primates against infection from multiple strains of CHIKV. This study describes the characterization, excipient screening, and optimization of CHIKV VLP solution conditions toward the development of a stable parenteral formulation. The CHIKV VLPs were found to be poorly soluble at pH 6 and below. Circular dichroism, intrinsic fluorescence, and static and dynamic light scattering measurements were therefore performed at neutral pH, and results consistent with the formation of molten globule structures were observed at elevated temperatures. A library of generally recognized as safe excipients was screened for their ability to physically stabilize CHIKV VLPs using a high-throughput turbidity-based assay. Sugars, sugar alcohols, and polyanions were identified as potential stabilizers and the concentrations and combinations of select excipients were optimized. The effects of polyanions were further studied, and while all polyanions tested stabilized CHIKV VLPs against aggregation, the effects of polyanions on conformational stability varied.
Collapse
|
121
|
Sparks JT, Vinyard BT, Dickens JC. Gustatory receptor expression in the labella and tarsi of Aedes aegypti. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:1161-1171. [PMID: 24157615 DOI: 10.1016/j.ibmb.2013.10.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/25/2013] [Accepted: 10/10/2013] [Indexed: 06/02/2023]
Abstract
The yellow-fever mosquito, Aedes aegypti, infects a growing number of people every year with dengue, yellow fever and chikungunya viruses. Contact chemoreception in mosquitoes influences a number of behaviors including host-selection, oviposition and feeding. While these behaviors are in many instances well documented, the molecular mechanisms mediating them are not well understood. Here we report the results of sequencing total messenger RNA in the labella and tarsi of both male and female Ae. aegypti to reveal Gustatory Receptor (GR) gene expression profiles in these major gustatory appendages. Gene expression levels in each tissue were verified by RT-qPCR. We discuss potential functions for the GRs revealed here by considering homologous GRs in other insects. Specific GRs provide molecular targets for modification of gustatory-mediated behaviors in this important disease vector.
Collapse
|
122
|
Cruz DJM, Bonotto RM, Gomes RGB, da Silva CT, Taniguchi JB, No JH, Lombardot B, Schwartz O, Hansen MAE, Freitas-Junior LH. Identification of novel compounds inhibiting chikungunya virus-induced cell death by high throughput screening of a kinase inhibitor library. PLoS Negl Trop Dis 2013; 7:e2471. [PMID: 24205414 PMCID: PMC3814572 DOI: 10.1371/journal.pntd.0002471] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 08/27/2013] [Indexed: 12/16/2022] Open
Abstract
Chikungunya virus (CHIKV) is a mosquito-borne arthrogenic alphavirus that causes acute febrile illness in humans accompanied by joint pains and in many cases, persistent arthralgia lasting weeks to years. The re-emergence of CHIKV has resulted in numerous outbreaks in the eastern hemisphere, and threatens to expand in the foreseeable future. Unfortunately, no effective treatment is currently available. The present study reports the use of resazurin in a cell-based high-throughput assay, and an image-based high-content assay to identify and characterize inhibitors of CHIKV-infection in vitro. CHIKV is a highly cytopathic virus that rapidly kills infected cells. Thus, cell viability of HuH-7 cells infected with CHIKV in the presence of compounds was determined by measuring metabolic reduction of resazurin to identify inhibitors of CHIKV-associated cell death. A kinase inhibitor library of 4,000 compounds was screened against CHIKV infection of HuH-7 cells using the resazurin reduction assay, and the cell toxicity was also measured in non-infected cells. Seventy-two compounds showing ≥50% inhibition property against CHIKV at 10 µM were selected as primary hits. Four compounds having a benzofuran core scaffold (CND0335, CND0364, CND0366 and CND0415), one pyrrolopyridine (CND0545) and one thiazol-carboxamide (CND3514) inhibited CHIKV-associated cell death in a dose-dependent manner, with EC50 values between 2.2 µM and 7.1 µM. Based on image analysis, these 6 hit compounds did not inhibit CHIKV replication in the host cell. However, CHIKV-infected cells manifested less prominent apoptotic blebs typical of CHIKV cytopathic effect compared with the control infection. Moreover, treatment with these compounds reduced viral titers in the medium of CHIKV-infected cells by up to 100-fold. In conclusion, this cell-based high-throughput screening assay using resazurin, combined with the image-based high content assay approach identified compounds against CHIKV having a novel antiviral activity - inhibition of virus-induced CPE - likely by targeting kinases involved in apoptosis. Recent outbreaks and expanding global distribution of Chikungunya virus (CHIKV) in different regions of Asia, Africa and Europe necessitates the development of effective therapeutic interventions. At present, only two antiviral compounds (chloroquine and ribavirin) that inhibit viral infection in vitro have been used in clinical cases of chikungunya infections. However, neither of these compounds have shown strong efficacy in vivo. Recent attempts to identify new antiviral candidates for CHIKV using cell-based phenotypic approach have been reported. In this study, we developed a simple cell-based high-throughput assay using resazurin to identify potential anti-CHIKV compounds. This high-throughput assay is based on the metabolic reduction of resazurin to the highly fluorescent resorufin by viable cells as an indicator of activity against CHIKV-induced CPE. We screened 4,000 small molecules belonging to the BioFocus kinase inhibitor chemical library and found a cluster of related molecules with antiviral activity against CHIKV. Finally, we characterized the putative mode of action of these active compounds using an image-based high content assay and conventional virological methods (i.e., virus yield reduction assay, microneutralization assay).
Collapse
|
123
|
Lee EY, Schultz KLW, Griffin DE. Mice deficient in interferon-gamma or interferon-gamma receptor 1 have distinct inflammatory responses to acute viral encephalomyelitis. PLoS One 2013; 8:e76412. [PMID: 24204622 PMCID: PMC3811984 DOI: 10.1371/journal.pone.0076412] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 08/23/2013] [Indexed: 11/25/2022] Open
Abstract
Interferon (IFN)-gamma is an important component of the immune response to viral infections that can have a role both in controlling virus replication and inducing inflammatory damage. To determine the role of IFN-gamma in fatal alphavirus encephalitis, we have compared the responses of wild type C57BL/6 (WTB6) mice with mice deficient in either IFN-gamma (GKO) or the alpha-chain of the IFN-gamma receptor (GRKO) after intranasal infection with a neuroadapted strain of sindbis virus. Mortalities of GKO and GRKO mice were similar to WTB6 mice. Both GKO and GRKO mice had delayed virus clearance from the brain and spinal cord, more infiltrating perforin(+) cells and lower levels of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 mRNAs than WTB6 mice. However, inflammation was more intense in GRKO mice than WTB6 or GKO mice with more infiltrating CD3(+) T cells, greater expression of major histocompatibility complex-II and higher levels of interleukin-17A mRNA. Fibroblasts from GRKO embryos did not develop an antiviral response after treatment with IFN-gamma, but showed increases in TNF-alpha, IL-6, CXCL9 and CXCL10 mRNAs although these increases developed more slowly and were less intense than those of WTB6 fibroblasts. These data indicate that both GKO and GRKO mice fail to develop an IFN-gamma-mediated antiviral response, but differ in regulation of the inflammatory response to infection. Therefore, GKO and GRKO cannot be considered equivalent when assessing the role of IFN-gamma in CNS viral infections.
Collapse
|
124
|
Zheng Y, Kielian M. Imaging of the alphavirus capsid protein during virus replication. J Virol 2013; 87:9579-89. [PMID: 23785213 PMCID: PMC3754095 DOI: 10.1128/jvi.01299-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/14/2013] [Indexed: 01/02/2023] Open
Abstract
Alphaviruses are enveloped viruses with highly organized structures. The nucleocapsid (NC) core contains a capsid protein lattice enclosing the plus-sense RNA genome, and it is surrounded by a lipid bilayer containing a lattice of the E1 and E2 envelope glycoproteins. Capsid protein is synthesized in the cytoplasm and particle budding occurs at the plasma membrane (PM), but the traffic and assembly of viral components and the exit of virions from host cells are not well understood. To visualize the dynamics of capsid protein during infection, we developed a Sindbis virus infectious clone tagged with a tetracysteine motif. Tagged capsid protein could be fluorescently labeled with biarsenical dyes in living cells without effects on virus growth, morphology, or protein distribution. Live cell imaging and colocalization experiments defined distinct groups of capsid foci in infected cells. We observed highly motile internal puncta that colocalized with E2 protein, which may represent the transport machinery that capsid protein uses to reach the PM. Capsid was also found in larger nonmotile internal structures that colocalized with cellular G3BP and viral nsP3. Thus, capsid may play an unforeseen role in these previously observed G3BP-positive foci, such as regulation of cellular stress granules. Capsid puncta were also observed at the PM. These puncta colocalized with E2 and recruited newly synthesized capsid protein; thus, they may be sites of virus assembly and egress. Together, our studies provide the first dynamic views of the alphavirus capsid protein in living cells and a system to define detailed mechanisms during alphavirus infection.
Collapse
|
125
|
Chen R, Wang E, Tsetsarkin KA, Weaver SC. Chikungunya virus 3' untranslated region: adaptation to mosquitoes and a population bottleneck as major evolutionary forces. PLoS Pathog 2013; 9:e1003591. [PMID: 24009512 PMCID: PMC3757053 DOI: 10.1371/journal.ppat.1003591] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/19/2013] [Indexed: 12/11/2022] Open
Abstract
The 3' untranslated genome region (UTR) of arthropod-borne viruses is characterized by enriched direct repeats (DRs) and stem-loop structures. Despite many years of theoretical and experimental study, on-going positive selection on the 3'UTR had never been observed in 'real-time,' and the role of the arbovirus 3'UTR remains poorly understood. We observed a lineage-specific 3'UTR sequence pattern in all available Asian lineage of the mosquito-borne alphavirus, chikungunya virus (CHIKV) (1958-2009), including complicated mutation and duplication patterns of the long DRs. Given that a longer genome is usually associated with less efficient replication, we hypothesized that the fixation of these genetic changes in the Asian lineage 3'UTR was due to their beneficial effects on adaptation to vectors or hosts. Using reverse genetic methods, we examined the functional importance of each direct repeat. Our results suggest that adaptation to mosquitoes, rather than to mammalian hosts, is a major evolutionary force on the CHIKV 3'UTR. Surprisingly, the Asian 3'UTR appeared to be inferior to its predicted ancestral sequence for replication in both mammals and mosquitoes, suggesting that its fixation in Asia was not a result of directional selection. Rather, it may have resulted from a population bottleneck during its introduction from Africa to Asia. We propose that this introduction of a 3'UTR with deletions led to genetic drift and compensatory mutations associated with the loss of structural/functional constraints, followed by two independent beneficial duplications and fixation due to positive selection. Our results provide further evidence that the limited epidemic potential of the Asian CHIKV strains resulted from founder effects that reduced its fitness for efficient transmission by mosquitoes there.
Collapse
|