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Francisco Gonzalez-scarano - One of the best experts on this subject based on the ideXlab platform.
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La Crosse Virus (LaCV) Gc Fusion Peptide Mutants have Impaired Growth and Fusion Phenotypes, but Remain Neurotoxic
Virology, 2010Co-Authors: Samantha S. Soldan, Bradley S. Hollidge, Valentina Wagner, Friedemann Weber, Francisco Gonzalez-scaranoAbstract:La Crosse Virus is a leading cause of pediatric encephalitis in the Midwestern United States and an emerging pathogen in the American South. The LaCV glycoprotein Gc pLays a critical role in entry as the Virus attachment protein. A 22 amino acid hydrophobic region within Gc (1066-1087) was recently identified as the LaCV fusion peptide. To further define the role of Gc (1066-1087) in Virus entry, fusion, and neuropathogenesis, a panel of recombinant LaCV (rLaCV) fusion peptide mutant Viruses was generated. Replication of mutant rLaCVs was significantly reduced. In addition, the fusion peptide mutants demonstrated decreased fusion phenotypes reLative to LaCV-WT. Interestingly, these Viruses maintained their ability to cause neuronal loss in culture, suggesting that the fusion peptide of LaCV Gc is a determinant of properties associated with neuroinvasion (growth to high titer in muscle cells and a robust fusion phenotype), but not necessarily of neurovirulence.
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Mutagenesis of the La Crosse Virus glycoprotein supports a role for Gc (1066-1087) as the fusion peptide.
Virology, 2006Co-Authors: Matthew L. Plassmeyer, Samantha S. Soldan, Karen M. Stachelek, Susan M. Roth, Julio Martín-garcía, Francisco Gonzalez-scaranoAbstract:Abstract The La Crosse Virus (LaCV) M segment encodes two glycoproteins (Gn and Gc), and pLays a critical role in the neuropathogenesis of LaCV infection as the primary determinant of neuroinvasion. A recent study from our group demonstrated that the region comprising the membrane proximal two-thirds of Gc, amino acids 860–1442, is critical in mediating LaCV fusion and entry. Furthermore, computational analysis identified structural simiLarities between a portion of this region, amino acids 970–1350, and the E1 fusion protein of two alphaViruses: Sindbis Virus and Semliki Forrest Virus (SFV). Within the region 970–1350, a 22-amino-acid hydrophobic segment (1066–1087) is predicted to correLate structurally with the fusion peptides of cLass II fusion proteins. We performed site-directed mutagenesis of key amino acids in this 22-amino acid segment and determined the functional consequences of these mutations on fusion and entry. Several mutations within this hydrophobic domain affected glycoprotein expression to some extent, but all mutations either shifted the pH threshold of fusion below that of the wild-type protein, reduced fusion efficiency, or abrogated cell-to-cell fusion and pseudotype entry altogether. These results, coupled with the aforementioned computational modeling, suggest that the LaCV Gc functions as a cLass II fusion protein and support a role for the region Gc 1066–1087 as a fusion peptide.
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La Crosse Virus Nonstructural Protein NSs Counteracts the Effects of Short Interfering RNA
Journal of virology, 2005Co-Authors: Samantha S. Soldan, Matthew L. Plassmeyer, Meghan K. Matukonis, Francisco Gonzalez-scaranoAbstract:Through a process known as RNA interference (RNAi), double-stranded short interfering RNAs (siRNAs) silence gene expression in a sequence-specific manner. Recently, several viral proteins, including the nonstructural protein NSs of tomato spotted wilt Virus (a pLant-infecting bunyaVirus), the interferon antagonist protein NS1 of influenza Virus, and the E3L protein of vaccinia Virus, have been shown to function as suppressors of RNAi, presumably as a counterdefense against celluLar mechanisms that decrease viral production. La Crosse Virus (LaCV), a member of the California serogroup of orthobunyaViruses, has a trisegmented negative-stranded genome comprised of Large (L), medium (M), and small (S) segments. To develop a strategy for segment-specific inhibition of transcription, we designed 13 synthetic siRNAs targeting specific RNA segments of the LaCV genome that decreased LaCV replication and antigen expression in mammalian (293T) and insect (C6/36) cells. Furthermore, NSs, a LaCV nonstructural protein, markedly inhibited RNAi directed both against an LaCV M segment construct and against a host gene (glyeraldehyde-3-phosphate dehydrogenase), suggesting a possible role for this viral protein in the suppression of RNA silencing. Segment-specific siRNAs will be useful as a tool to analyze LaCV transcription and replication and to obtain recombinant Viruses. Additionally, NSs will help us to identify molecuLar pathways involved in RNAi and further define its role in the innate immune system.
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Pseudotype formation with La Crosse Virus glycoproteins.
Journal of General Virology, 1998Co-Authors: Keith Bupp, Francisco Gonzalez-scaranoAbstract:Pseudotype formation is a powerful tool for analysing mechanisms of Virus neutralization and entry, since it allows for analysis of glycoprotein properties without the necessity for preparing recombinant genomes. Using recombinant vaccinia Viruses, we prepared pseudotypes of La Crosse Virus with recombinant glycoproteins cloned from the monoclonal antibody (MAb)-resistant variant V31. The resulting pseudotypes became partially resistant to MAb 807-31. Furthermore, when the V31 glycoproteins were incorporated into a second MAb-resistant variant (V33), the pseudotyped Virus became sensitive to neutralization by the MAb (807-33) originally used in its selection. These results suggest a simple technique for the incorporation of glycoprotein mutations into bunyaViruses, allowing analysis of mechanisms of neutralization and other Virus entry functions.
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The ExtracelluLar Domain of La Crosse Virus G1 Forms Oligomers and Undergoes pH-Dependent Conformational Changes
Virology, 1996Co-Authors: Andrew Pekosz, Francisco Gonzalez-scaranoAbstract:Abstract The La Crosse Virus G1 glycoprotein pLays a critical role in Virus binding to susceptible cells and in the subsequent fusion of viral and celluLar membranes. A soluble form of the G1 glycoprotein (sG1) prepared in a recombinant baculoVirus system mimics the cell-binding pattern of La Crosse Virus and inhibits La Crosse Virus infection (A. Pekosz et al., Virology 214, 339–348, 1995), presumably by competing for a celluLar receptor, a finding that implies that sG1 can perform some functions absent G2, the smaller of the two bunyaVirus glycoproteins. We have performed experiments to determine whether sG1 is present as an oligomer and whether it undergoes the conformational changes associated with fusion (F. Gonzalez-Scarano, Virology 140, 209–216, 1985). Our results indicate that both sG1 and native G1 undergo simiLar changes in conformation after exposure to an acidic environment, as detected by reactivity with monoclonal antibodies. Furthermore, using chemical cross-linking, both proteins were detected as oligomers (most likely dimers). Sucrose density gradient analysis of sG1 verified that it was present in monomeric and oligomeric forms. These results demonstrate that the isoLated G1 glycoprotein can undergo a pH-dependent change in conformation in the absence of its transmembrane and cytopLasmic tail domains and that the extracelluLar portion of the glycoprotein can oligomerize.
Barry J. Beaty - One of the best experts on this subject based on the ideXlab platform.
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Aedes triseriatus Females Transovarially Infected with La Crosse Virus Mate More Efficiently Than Uninfected Mosquitoes
Journal of medical entomology, 2009Co-Authors: Sara M. Reese, Carol D. Blair, E. S. Gabitzsch, Meaghan K. Beaty, Barry J. BeatyAbstract:The mating efficiencies (the percentage of females inseminated by males) of field-collected and Laboratory-colonized Aedes triseriatus (Say) (Diptera: Culicidae) female mosquitoes transovarially infected or uninfected with La Crosse Virus (LaCV) were compared. The females were pLaced in cages with age-matched males, and the insemination rates (number of inseminated females of the total number of females examined) were determined daily by detection of sperm in the spermathecae. LaCV-infected mosquitoes typically mated earlier than uninfected mosquitoes, i.e., insemination occurred earlier after the mixing of males and females. LaCV load was not correLated with increased insemination.
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Patterns of Variation in the Inhibitor of Apoptosis 1 Gene of Aedes triseriatus, a Transovarial Vector of La Crosse Virus
Journal of Molecular Evolution, 2009Co-Authors: Eric T. Beck, Carol D. Blair, Barry J. Beaty, Saul Lozano Fuentes, David A. Geske, William C. BlackAbstract:Aedes triseriatus mosquitoes transovarially transmit (TOT) La Crosse Virus (LaCV) to their offspring with minimal damage to infected ovaries. Ae. triseriatus inhibitor of apoptosis 1 ( AtIAP1 ) is a candidate gene conditioning the ability to vertically transmit LaCV. AtIAP1 was amplified and sequenced in adult mosquitoes reared from field-collected eggs. Sequence analysis showed that AtIAP1 has much higher levels of genetic diversity than genes found in other mosquitoes. Despite this Large amount of diversity, strong purifying selection of polymorphisms located in the BaculoVirus inhibitor of apoptosis repeat (BIR) domains and, to a lesser extent, in the 5′ untransLated region seems to indicate that these portions of AtIAP1 are the most important. These results indicate that the 5′UTR pLays an important role in transcription and transLation and that the BIR domains are important functional domains in the protein. Single nucleotide polymorphisms (SNPs) were compared between LaCV-positive and -negative mosquitoes to test for associations between segregating sites and the ability to be transovarially infected with LaCV. Initial results indicated that five SNPs were associated with TOT of LaCV; however, these results were not replicable with Larger sample sizes.
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Potential for La Crosse Virus segment reassortment in nature.
Virology journal, 2008Co-Authors: Sara M. Reese, Bradley J. Blitvich, Carol D. Blair, Barry J. Beaty, Dave Geske, William C. BlackAbstract:The evolutionary success of La Crosse Virus (LaCV, family Bunyaviridae) is due to its ability to adapt to changing conditions through intramolecuLar genetic changes and segment reassortment. Vertical transmission of LaCV in mosquitoes increases the potential for segment reassortment. Studies were conducted to determine if segment reassortment was occurring in naturally infected Aedes triseriatus from Wisconsin and Minnesota in 2000, 2004, 2006 and 2007. Mosquito eggs were collected from various sites in Wisconsin and Minnesota. They were reared in the Laboratory and adults were tested for LaCV antigen by immunofluorescence assay. RNA was isoLated from the abdomen of infected mosquitoes and portions of the small (S), medium (M) and Large (L) viral genome segments were amplified by RT-PCR and sequenced. Overall, the viral sequences from 40 infected mosquitoes and 5 Virus isoLates were analyzed. Phylogenetic and linkage disequilibrium analyses revealed that approximately 25% of infected mosquitoes and Viruses contained reassorted genome segments, suggesting that LaCV segment reassortment is frequent in nature.
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Effect of La Crosse Virus Infection on Insemination Rates in Female Aedes triseriatus (Diptera: Culicidae)
Journal of medical entomology, 2006Co-Authors: E. S. Gabitzsch, Carol D. Blair, Barry J. BeatyAbstract:Aedes triseriatus (Say) (Diptera: Culicidae) females orally infected with La Crosse Virus after ingesting an infectious bloodmeal were compared for mating efficiency with females that ingested a noninfectious bloodmeal. After 14-d extrinsic incubation to allow for dissemination of the infection, all females were offered a second noninfectious bloodmeal and were pLaced in cages with age-matched males for 5 d. After 6 d, insemination rates were determined by detection of sperm in the spermathecae. Insemination rates of the La Crosse Virus-infected females were significantly greater than in uninfected females.
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quantitative trait loci conditioning transovarial transmission of La Crosse Virus in the eastern treehole mosquito ochlerotatus triseriatus
Insect Molecular Biology, 2003Co-Authors: Douglas H Graham, Barry J. Beaty, Jennifer L Holmes, William C. BlackAbstract:: Quantitative trait loci (QTL) affecting the ability of the Eastern treehole mosquito, Ochlerotatus triseriatus, to transovarially transmit (TOT) La Crosse Virus (LaC) were mapped in an F1 intercross. The Holmen strain of O. triseriatus, previously selected for TOT refractoriness, was Crossed to the AIDL strain that had been selected for TOT permissiveness. In P1 and F1 parents and 49 F2 individuals, regions of 10 cDNA loci were analysed with single strand conformation polymorphism (SSCP) analysis to identify and orientate linkage groups. Genotypes were also scored at fifty-six random amplified polymorphic DNA (RAPD)-SSCP loci. Twenty-eight F2 offspring were individually analysed for TOT. Three QTL for TOT were detected with standard interval mapping on chromosomes II and III. Alleles at the three loci contributed additively towards determining the overall TOT rate and cumuLatively accounted for approximately 53% of the phenotypic variance in TOT.
William C. Black - One of the best experts on this subject based on the ideXlab platform.
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Patterns of Variation in the Inhibitor of Apoptosis 1 Gene of Aedes triseriatus, a Transovarial Vector of La Crosse Virus
Journal of Molecular Evolution, 2009Co-Authors: Eric T. Beck, Carol D. Blair, Barry J. Beaty, Saul Lozano Fuentes, David A. Geske, William C. BlackAbstract:Aedes triseriatus mosquitoes transovarially transmit (TOT) La Crosse Virus (LaCV) to their offspring with minimal damage to infected ovaries. Ae. triseriatus inhibitor of apoptosis 1 ( AtIAP1 ) is a candidate gene conditioning the ability to vertically transmit LaCV. AtIAP1 was amplified and sequenced in adult mosquitoes reared from field-collected eggs. Sequence analysis showed that AtIAP1 has much higher levels of genetic diversity than genes found in other mosquitoes. Despite this Large amount of diversity, strong purifying selection of polymorphisms located in the BaculoVirus inhibitor of apoptosis repeat (BIR) domains and, to a lesser extent, in the 5′ untransLated region seems to indicate that these portions of AtIAP1 are the most important. These results indicate that the 5′UTR pLays an important role in transcription and transLation and that the BIR domains are important functional domains in the protein. Single nucleotide polymorphisms (SNPs) were compared between LaCV-positive and -negative mosquitoes to test for associations between segregating sites and the ability to be transovarially infected with LaCV. Initial results indicated that five SNPs were associated with TOT of LaCV; however, these results were not replicable with Larger sample sizes.
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Potential for La Crosse Virus segment reassortment in nature.
Virology journal, 2008Co-Authors: Sara M. Reese, Bradley J. Blitvich, Carol D. Blair, Barry J. Beaty, Dave Geske, William C. BlackAbstract:The evolutionary success of La Crosse Virus (LaCV, family Bunyaviridae) is due to its ability to adapt to changing conditions through intramolecuLar genetic changes and segment reassortment. Vertical transmission of LaCV in mosquitoes increases the potential for segment reassortment. Studies were conducted to determine if segment reassortment was occurring in naturally infected Aedes triseriatus from Wisconsin and Minnesota in 2000, 2004, 2006 and 2007. Mosquito eggs were collected from various sites in Wisconsin and Minnesota. They were reared in the Laboratory and adults were tested for LaCV antigen by immunofluorescence assay. RNA was isoLated from the abdomen of infected mosquitoes and portions of the small (S), medium (M) and Large (L) viral genome segments were amplified by RT-PCR and sequenced. Overall, the viral sequences from 40 infected mosquitoes and 5 Virus isoLates were analyzed. Phylogenetic and linkage disequilibrium analyses revealed that approximately 25% of infected mosquitoes and Viruses contained reassorted genome segments, suggesting that LaCV segment reassortment is frequent in nature.
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quantitative trait loci conditioning transovarial transmission of La Crosse Virus in the eastern treehole mosquito ochlerotatus triseriatus
Insect Molecular Biology, 2003Co-Authors: Douglas H Graham, Barry J. Beaty, Jennifer L Holmes, William C. BlackAbstract:: Quantitative trait loci (QTL) affecting the ability of the Eastern treehole mosquito, Ochlerotatus triseriatus, to transovarially transmit (TOT) La Crosse Virus (LaC) were mapped in an F1 intercross. The Holmen strain of O. triseriatus, previously selected for TOT refractoriness, was Crossed to the AIDL strain that had been selected for TOT permissiveness. In P1 and F1 parents and 49 F2 individuals, regions of 10 cDNA loci were analysed with single strand conformation polymorphism (SSCP) analysis to identify and orientate linkage groups. Genotypes were also scored at fifty-six random amplified polymorphic DNA (RAPD)-SSCP loci. Twenty-eight F2 offspring were individually analysed for TOT. Three QTL for TOT were detected with standard interval mapping on chromosomes II and III. Alleles at the three loci contributed additively towards determining the overall TOT rate and cumuLatively accounted for approximately 53% of the phenotypic variance in TOT.
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Selection of Refractory and Permissive Strains of Aedes triseriatus (Diptera: Culicidae) for Transovarial Transmission of La Crosse Virus
Journal of medical entomology, 1999Co-Authors: D. H. Graham, Barry J. Beaty, J. L. Holmes, S. Higgs, William C. BlackAbstract:The genetic basis of transovarial transmission of La Crosse Virus in Aedes triseriatus (Say) was investigated through selection experiments on 2 mosquito strains. One strain was subject to selection for transovarial transmission refractoriness, the other for permissiveness to transovarial transmission. Response to selection for a low filial infection rate was rapid, decreasing from 18 to 3% in 3 generations. However, no response to selection for permissiveness was observed in the other strain; the average filial infection rates through 4 generations fluctuated between 25 and 40%. By contrast, the transovarial transmission rate in both strains showed a consistent response to selection in both directions. These patterns are consistent with a model in which transovarial transmission is controlled by a single genetic locus and permissiveness is conditioned by dominant alleles; whereas the filial infection rate is nongenetic and influenced by stochastic factors in the mosquito and Virus.
Carol D. Blair - One of the best experts on this subject based on the ideXlab platform.
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La Crosse Virus in Aedes albopictus mosquitoes, Texas, USA, 2009.
Emerging infectious diseases, 2010Co-Authors: Amy J. Lambert, Carol D. Blair, Mary D’anton, Winnann Ewing, Michelle Harborth, Robyn Seiferth, Jeannie Xiang, Robert S. LanciottiAbstract:We report the arthropod-borne pediatric encephalitic agent La Crosse Virus in Aedes albopictus mosquitoes collected in DalLas County, Texas, USA, in August 2009. The presence of this Virus in an invasive vector species within a region that lies outside the Virus’s historically recognized geographic range is of public health concern.
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Aedes triseriatus Females Transovarially Infected with La Crosse Virus Mate More Efficiently Than Uninfected Mosquitoes
Journal of medical entomology, 2009Co-Authors: Sara M. Reese, Carol D. Blair, E. S. Gabitzsch, Meaghan K. Beaty, Barry J. BeatyAbstract:The mating efficiencies (the percentage of females inseminated by males) of field-collected and Laboratory-colonized Aedes triseriatus (Say) (Diptera: Culicidae) female mosquitoes transovarially infected or uninfected with La Crosse Virus (LaCV) were compared. The females were pLaced in cages with age-matched males, and the insemination rates (number of inseminated females of the total number of females examined) were determined daily by detection of sperm in the spermathecae. LaCV-infected mosquitoes typically mated earlier than uninfected mosquitoes, i.e., insemination occurred earlier after the mixing of males and females. LaCV load was not correLated with increased insemination.
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Patterns of Variation in the Inhibitor of Apoptosis 1 Gene of Aedes triseriatus, a Transovarial Vector of La Crosse Virus
Journal of Molecular Evolution, 2009Co-Authors: Eric T. Beck, Carol D. Blair, Barry J. Beaty, Saul Lozano Fuentes, David A. Geske, William C. BlackAbstract:Aedes triseriatus mosquitoes transovarially transmit (TOT) La Crosse Virus (LaCV) to their offspring with minimal damage to infected ovaries. Ae. triseriatus inhibitor of apoptosis 1 ( AtIAP1 ) is a candidate gene conditioning the ability to vertically transmit LaCV. AtIAP1 was amplified and sequenced in adult mosquitoes reared from field-collected eggs. Sequence analysis showed that AtIAP1 has much higher levels of genetic diversity than genes found in other mosquitoes. Despite this Large amount of diversity, strong purifying selection of polymorphisms located in the BaculoVirus inhibitor of apoptosis repeat (BIR) domains and, to a lesser extent, in the 5′ untransLated region seems to indicate that these portions of AtIAP1 are the most important. These results indicate that the 5′UTR pLays an important role in transcription and transLation and that the BIR domains are important functional domains in the protein. Single nucleotide polymorphisms (SNPs) were compared between LaCV-positive and -negative mosquitoes to test for associations between segregating sites and the ability to be transovarially infected with LaCV. Initial results indicated that five SNPs were associated with TOT of LaCV; however, these results were not replicable with Larger sample sizes.
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Potential for La Crosse Virus segment reassortment in nature.
Virology journal, 2008Co-Authors: Sara M. Reese, Bradley J. Blitvich, Carol D. Blair, Barry J. Beaty, Dave Geske, William C. BlackAbstract:The evolutionary success of La Crosse Virus (LaCV, family Bunyaviridae) is due to its ability to adapt to changing conditions through intramolecuLar genetic changes and segment reassortment. Vertical transmission of LaCV in mosquitoes increases the potential for segment reassortment. Studies were conducted to determine if segment reassortment was occurring in naturally infected Aedes triseriatus from Wisconsin and Minnesota in 2000, 2004, 2006 and 2007. Mosquito eggs were collected from various sites in Wisconsin and Minnesota. They were reared in the Laboratory and adults were tested for LaCV antigen by immunofluorescence assay. RNA was isoLated from the abdomen of infected mosquitoes and portions of the small (S), medium (M) and Large (L) viral genome segments were amplified by RT-PCR and sequenced. Overall, the viral sequences from 40 infected mosquitoes and 5 Virus isoLates were analyzed. Phylogenetic and linkage disequilibrium analyses revealed that approximately 25% of infected mosquitoes and Viruses contained reassorted genome segments, suggesting that LaCV segment reassortment is frequent in nature.
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Effect of La Crosse Virus Infection on Insemination Rates in Female Aedes triseriatus (Diptera: Culicidae)
Journal of medical entomology, 2006Co-Authors: E. S. Gabitzsch, Carol D. Blair, Barry J. BeatyAbstract:Aedes triseriatus (Say) (Diptera: Culicidae) females orally infected with La Crosse Virus after ingesting an infectious bloodmeal were compared for mating efficiency with females that ingested a noninfectious bloodmeal. After 14-d extrinsic incubation to allow for dissemination of the infection, all females were offered a second noninfectious bloodmeal and were pLaced in cages with age-matched males for 5 d. After 6 d, insemination rates were determined by detection of sperm in the spermathecae. Insemination rates of the La Crosse Virus-infected females were significantly greater than in uninfected females.
Ephantus J Muturi - One of the best experts on this subject based on the ideXlab platform.
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comparative susceptibility of ochlerotatus japonicus ochlerotatus triseriatus aedes albopictus and aedes aegypti diptera culicidae to La Crosse Virus
Journal of Medical Entomology, 2016Co-Authors: Ephantus J Muturi, Allison T Parker, Jennifer J BaraAbstract:Invasive mosquito species can increase the transmission risk of native mosquito-borne diseases by acting as novel vectors. In this study, we examined the susceptibility of three exotic invasive mosquito species Aedes aegypti (L.), Ae. albopictus (Skuse), and Ochlerotatus japonicus (Theobald) to La Crosse Virus (LaCV) reLative to the native primary vector Ochlerotatus triseriatus (Say). Adult females of the four mosquito species were orally challenged with LaCV; incubated for 3, 5, 7, 9, or 11 d; and their midgut infection rates, dissemination rates, and effective vector competence were determined. Overall, Oc. japonicus (2.92) had the highest effective vector competence values, followed by Ae. albopictus (1.55), Ae. aegypti (0.88), and Oc. triseriatus (0.64) . In addition, we assessed the reLationship between mosquito size and LaCV susceptibility for field-collected Oc. triseriatus and Oc. japonicus . We hypothesized that smaller adults would be more susceptible to LaCV; however, our results did not support this hypothesis. Infected Oc. triseriatus tended to be Larger than exposed but uninfected females, while infected and uninfected Oc. japonicus were simiLarly sized. These findings suggest that Oc. japonicus , Ae. albopictus , and Ae. aegypti have significant potential to transmit LaCV and more research is needed to uncover their potential role in LaCV epidemiology.
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Epidemiology of La Crosse Virus Emergence, AppaLachia Region, United States.
Emerging infectious diseases, 2016Co-Authors: Sharon Bewick, Ephantus J Muturi, Folashade B. Agusto, Justin M. Calabrese, William F. FaganAbstract:La Crosse encephalitis is a viral disease that has emerged in new locations across the AppaLachian region of the United States. Conventional wisdom suggests that ongoing emergence of La Crosse Virus (LaCV) could stem from the invasive Asian tiger (Aedes albopictus) mosquito. Efforts to prove this, however, are complicated by the numerous transmission routes and species interactions involved in LaCV dynamics. To analyze LaCV transmission by Asian tiger mosquitoes, we constructed epidemiologic models. These models accurately predict empirical infection rates. They do not, however, support the hypothesis that Asian tiger mosquitoes are responsible for the recent emergence of LaCV at new foci. Consequently, we conclude that other factors, including different invasive mosquitoes, changes in climate variables, or changes in wildlife densities, should be considered as alternative expLanations for recent increases in La Crosse encephalitis.
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effect of oral infection of La Crosse Virus on survival and fecundity of native ochlerotatus triseriatus and invasive stegomyia albopicta
Medical and Veterinary Entomology, 2014Co-Authors: Katie S Costanzo, Ephantus J Muturi, Allison V Montgomery, Barry W. AltoAbstract:ArboViruses can have benign, deleterious, or beneficial effects on the vector. We tested the hypothesis that oral infection with La Crosse Virus (LaCV) will have little to no effect on mosquito longevity and fecundity, a prediction of low virulence selected in a system with frequent vertical transmission. We tested the effects of infection in native Ochlerotatus triseriatus Say and invasive Stegomyia albopicta Skuse (Diptera: Culicidae). We artificially fed adult female mosquitoes of each species with either LaCV-infected or uninfected bovine blood and determined adult longevity and fecundity. For females fed LaCV-infected blood, bodies and legs, respectively, were separately homogenized and assayed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) to determine the LaCV infection and dissemination rates. Ochlerotatus triseriatus had a higher infection and dissemination rate than St. albopicta. For both species, female size had no effect on infection status. Infection status also had no effect on longevity or fecundity for both species. We suggest that the high frequency of vertical transmission may have selected for strains of the Virus with low virulence in two vectors, in spite of their different evolutionary histories with the Virus.
