La Crosse Research Articles

DESEMPENHO DA IRRIGAÇÃO E FERTIRRIGAÇÃO AVALIADAS POR CONTROLE ESTATÍSTICO DE QUALIDADE - DOI: 10.13083/1414-3984/reveng.v23n6p541-551

A avaliação de um sistema de irrigação pode ser feita com uso da uniformidade de distribuição de água, sendo o Coeficiente de Uniformidade de Christiansen (CUC) o mais utilizado, pois além de ser uma fonte de avaliação de seu bom funcionamento, também é uma forma de verificar sua viabilidade de implantação e operação. Com este trabalho objetivou-se utilizar o Controle Estatístico de Qualidade (CEP), por meio do índice de capacidade do processo, para avaliar a uniformidade de distribuição de água de um sistema de irrigação por aspersão convencional operando com água e realizando a fertirrigação. Os ensaios foram conduzidos no Núcleo Experimental de Engenharia Agrícola – NEEA – pertencente a Universidade Estadual do Oeste do Paraná – UNIOESTE – Campus Cascavel – Paraná, com o uso de 2 aspersores modelo Super10, marca NAANDAN, espaçados 9 m entre si e 18 coletores com espaçamento de 3 m. Os fatores climáticos foram monitorados e coletados em intervalos de 10 min por uma estação climatológica sem fio, marca La Crosse ao longo de 25 ensaios de 1 h para irrigação e fertirrigação. Para os ensaios de irrigação, foi encontrado um CUC médio de 79,72% sendo que o valor médio de velocidade do vento foi de 1,85 m s-1 e com fertirrigação o CUC encontrado foi de 77,14% com velocidade média do vento de 1,50 m s-1. Foram calculados os limites inferior e superior de controle para elaboração do gráfico de controle de qualidade bem como o índice de capacidade do processo para os coeficientes de uniformidade.Os resultados obtidos permitiram concluir que o controle estatístico de qualidade é uma ferramenta de grande auxílio para classificarsistemas de irrigação na busca da otimização do uso da água.

Evaluating Surveillance Methods for Arboviral Vectors of La Crosse Virus and West Nile Virus of Southern Appalachia.

To monitor mosquito-borne diseases, public health departments conduct mosquito and pathogen surveillance. Our objective was to evaluate mosquito monitoring methods for collecting La Crosse virus (LACV) and West Nile virus (WNV) vectors (Aedes and Culex mosquitoes, respectively) in southern Appalachia. Centers for Disease Control and Prevention (CDC) light traps baited with carbon dioxide (CO(2)), CDC light traps baited with CO(2) and BG lure, BG-Sentinel traps baited with CO(2), gravid traps baited with oak (Quercus)-water infusion, and resting traps were compared in eastern Tennessee in 2013. Traps operated at 8 different urban sites throughout Knox County were randomly assigned to and rotated among 6 plots within each site. Results were specific for each vector; the BG-Sentinel trap was the best method for Aedes triseriatus, the CDC trap baited with CO(2) and BG lure was the best method for Ae. albopictus, and the gravid trap was the best method for Ae. japonicus. Culex erraticus collections varied by week and trapping method, indicating no single method was best, but the questing traps collected more mosquitoes. There was no significant trapping difference for Cx. pipiens complex in this region using the methods tested. The results suggest using a combination of trapping methods when sampling for LACV and/or WNV mosquito vectors in southern Appalachia. Effective trapping methods are necessary to enable accurate surveillance, improve control methods, enhance understanding of dispersal, and use for early detection of vectors and pathogens.

Serological Survey for Antibodies to Mosquito-Borne Bunyaviruses Among US National Park Service and US Forest Service Employees

Serum samples from 295 employees of Great Smoky Mountains National Park (GRSM), Rocky Mountain National Park (ROMO), and Grand Teton National Park with adjacent Bridger-Teton National Forest (GRTE-BTNF) were subjected to serological analysis for mosquito-borne bunyaviruses. The sera were analyzed for neutralizing antibodies against six orthobunyaviruses: La Crosse virus (LACV), Jamestown Canyon virus (JCV), snowshoe hare virus (SSHV), California encephalitis virus, and Trivittatus virus (TVTV) belonging to the California serogroup and Cache Valley virus (CVV) belonging to the Bunyamwera serogroup. Sera were also tested for immunoglobulin (Ig) G antibodies against LACV and JCV by enzyme-linked immunosorbent assay (ELISA). The proportion of employees with neutralizing antibodies to any California serogroup bunyavirus was similar in all three sites, with the prevalence ranging from 28% to 36%. The study demonstrated a seroprevalence of 3% to CVV across the three parks. However, proportions of persons with antibodies to specific viruses differed between parks. Participants residing in the eastern regions had a higher seroprevalence to LACV, with 24% (18/75) GRSM employees being seropositive. In contrast, SSHV seroprevalence was limited to employees from the western sites, with 1.7% (1/60) ROMO and 3.8% (6/160) GRTE-BTNF employees being positive. Seroprevalence to JCV was noted in employees from all sites at rates of 6.7% in GRSM, 21.7% in ROMO, and 15.6% in GRTE-BTNF. One employee each from ROMO (1.7%) and GRTE-BTNF (1.9%) were positive for TVTV. This study also has illustrated the greater sensitivity and specificity of plaque reduction neutralization test compared to IgG ELISA in conducting serosurveys for LACV and JCV.

The Yin and Yang of Antiviral Innate Immunity in Central Nervous System.

The innate immune system provides protection against invading neurotropic viruses. It acts as the first line of defense against invading viruses and plays an elementary role in their pathogenesis. The list of viruses capable of infecting human central nervous system (CNS) is quite long, most important of them are Japanese Encephalitis virus (JEV), rabies virus, West Nile virus (WNV), herpes simplex virus (HSV), St. Louis encephalitis virus (SLEV), La Crosse virus, tick borne encephalitis virus (TEBE) and polio virus. Germ line pattern recognition receptors (PRRs) such as Toll like receptors (TLRs), nucleotide binding oligomerization domain (NOD) - like receptors (NLRs), retinoic acid-inducible gene I (RIG-I) -like helicases or RIG-I-like receptors (RLRs) and cytosolic DNA sensors recognize the pathogen associated molecular patterns (PAMPs) and initiate an immune response against invading pathogen. Although PRRs were originally characterized in peripheral immune cells but accumulating evidence also suggest their crucial roles in CNS to combat against neurotropic viruses. In this review, we will highlight the recent developments in our understating of the mechanisms by which PRRs in resident brain cells provide protection against invading neurotropic viruses.

Bulles de France: les stéréotypes et l’interculturel en BD par Géraldine Jeffroy

the book is centered on the métropole; there is no mention of la francophonie, which is a serious deficiency in any modern French textbook.However,as experienced instructors know, no textbook is perfect, and Voilà does serve as a good resource for adult beginning French students and their instructors. Learners enjoy the diversity of activities and the authentic sources as well as the useful chapter topics. Voilà is thus an effective textbook for teaching material relevant to adult students’ contexts. University of Wisconsin, Madison Sage Goellner Jeffroy, Géraldine, et Unter. Bulles de France: les stéréotypes et l’interculturel en BD. Grenoble: PUG, 2013. ISBN 978-2-7061-2201-9. Pp. 144. 19 a. Desperately looking for a change of pace in the classroom? This text adopts a nonconventional approach to the discovery of contemporary French society as it proposes humoristic comic strips as a point of departure to the discussion of social issues. The book is organized around eight main themes such as sports, public health, or working life. While the themes are typical of those found in mainstream textbooks’ cultural inserts, each explores more specific topics such as the transformation of urban life with the development of the Vélib’, or the debate around GMO and organic foods. Each main category includes five or six related topics with the following structure. The first two sections, Pour commencer and Comprendre, respectively, propose prereading activities and comprehension activities related to the study of the comic strip. A third section, Imaginer/S’exprimer, makes the transition between the text analysis and cultural discussion questions as it encourages students to personally relate to the topics at hand. A fourth section, Pour aller plus loin, provides students historical and background explanations on the cultural content and invites them to further reflect on the given topic,often by comparing their findings with their own cultural experience. Finally, a lexical insert concludes each section to give students the necessary tools to understand the comic strip and express an opinion about its content. The text’s pedagogical approach lies within the recommendations of the CERCL (Cadre européen commun de référence pour les langues) by mainly focusing on the development of students’ sociocultural competence.As such, Bulles de France is not a college language method that includes grammatical explanations or activities pertaining to the mechanics of language learning. Nevertheless, this text provides the premises for a course rich in discussions as it includes visual literacy, as well as analysis of non-verbal communication and onomatopoeia via the study of comic strips. The ideal target audience has an intermediate level, although given its structure and content, each section could be easily adapted to a level as low as novice-mid on the ACTFL proficiency scale. In fact, the accompanying website suggests pedagogical approaches for lower levels, as well as cultural references for further activities (songs, websites, etc.). Instructors of upper level courses will also easily complement the manual with other media, debate 190 FRENCH REVIEW 89.3 Reviews 191 questions, or writing activities. Given its flexibility in approach, content, and structure, Bulles de France could be used as a complementary resource in any language class. It could also act as the main text for a course focusing on contemporary civilization or current events, as it would bring a less dramatic perspective to consider more delicate topics such as secularism, freedom of speech, or parity in politics.As students become more and more familiar with the comics’ main character Geoffroy, not only will they get a better insight into contemporary French issues, but also on the French themselves. And this, through the study of stereotypes, whether they appear in gestures, comportments , attitudes, or beliefs within each of the comics. University of Wisconsin, La Crosse Virginie Cassidy Laliberté, Robert, et Aleksandra Grzybowska, éd. Le Québec, connais-tu? Québec: PU du Québec, 2014. ISBN 978-2-7605-3923-5. Pp. 923. $100 Can. Cet excellent programme, unique en son genre et seulement disponible en format numérique (pdf), se compose de sept ouvrages qui peuvent être achetés séparément ou en série complète. Il s’adresse aux professeurs...

A Comprehensive Review of IVC Filters in a Community Tertiary Center

Introduction Retrievable inferior vena cava (IVC) filters are frequently used to prevent pulmonary embolus (PE). Indwelling filters can be associated with complications; timely removal is recommended. In our institution, activated trauma (AT) patients are enrolled in a prospective protocol and tracked by the trauma team, who refer for retrieval as soon as feasible. Interventional radiology maintains a database for traumatic injury (TI) and medical (M) patients and calls them for retrieval at 90 days. To this end, the primary goal of this study was to assess different retrieval patterns between Level 1 and 2 trauma patients, traumatic injury patients not triggering trauma response, and those with medical indications for IVC filters. An additional analysis to examine rates of recurrent thrombosis stratified for filter retention and anticoagulation status was performed.MethodsA retrospective chart review was performed for all patients who had an IVC filter placed between January 2005 and March 2015 at Gundersen Medical Center in La Crosse, WI. Data were collected regarding patients' demographics, risk factors for thrombosis, indications for and details of filter type and placement, post-placement anticoagulation, filter retrieval, and complications arising from filter placement, retention, and retrieval. Patients were divided into AT, TI, and M groups. AT consisted of Level 1 or 2 traumas triggering management by trauma service, TI patients had lesser trauma not triggering trauma team referral, and M patients had filters for medical indications. Those who were lost to follow up or died within 30 days were excluded from all analysis except demographics. Those with permanent filters were omitted from retrieval analysis.ResultsOf the 633 charts reviewed, 4 were excluded for lack of data, 41 were lost to follow-up and 68 died within 30 days. Table 1 summarizes patient category characteristics. Activated trauma patients were younger and had their filter retrieved more often (p<0.0001) than medical or TI patients. The medical population were older, had more risk factors for recurrent thrombosis (median 2 risk factors, range 0-8) and more likely to remain on chronic anticoagulation (27.9%). Those receiving anticoagulation after filter placement had greater rates of recurrent thrombosis (p<0.0001), but more risk factors (p<0.0001)for thrombosis compared to those receiving no anticoagulation. No significant differences were observed in thrombosis-free survival with regard to filter retention. However, rates of DVT after filter placement were 8% higher if the filter was retained rather than removed across all 3 groups(p=0.0011, McNemar's Chi-square).DiscussionHigher rates of DVT in patients with a filter in place are in line with current research associating IVC filters with DVT formation. We observed that patients on lifelong anticoagulation had a higher rate of recurrent thrombosis but increased risk factors for thrombosis, thus identifying a higher risk group for thrombotic events.AT patients in a protocol setting had higher IVC filter retrieval rates compared to the M and IT patients with routine efforts at retrieval. The large gap between M/TI and AT filter retrieval is associated with but not fully explained by the increased risk factors and age of the M and IT groups. Protocolized retrieval of IVC filters increases retrieval rates. Further research is warranted in assessing the impact of protocolized retrieval in the medical and traumatic injury populations.Table 1Patient Category CharacteristicsPatient CategoryN (%)Age (median, range)Retrieval Rate (%)Activated trauma (AT)195 (31%)41 (15-92)78%Traumatic injury (TI)74 (11.8%)44 (16-93)43%Medical (M)360 (57.2%)68 (17-101)38% DisclosuresParsons:Celgene: Speakers Bureau.

The TAM receptor Mertk protects against neuroinvasive viral infection by maintaining blood-brain barrier integrity.

The TAM receptors Tyro3, Axl, and Mertk are receptor tyrosine kinases that dampen host innate immune responses following engagement with their ligands, Gas6 and Protein S, which recognize phosphatidylserine on apoptotic cells. In a form of apoptotic mimicry, many enveloped viruses display phosphatidylserine on the outer leaflet of their membranes, enabling TAM receptor activation and down-regulation of antiviral responses. Accordingly, we hypothesized that a deficiency of TAM receptors would enhance antiviral responses and protect against viral infection. Unexpectedly, mice lacking Mertk and/or Axl but not Tyro3 exhibited greater vulnerability to infection with neuroinvasive West Nile and La Crosse viruses. This phenotype was associated with increased blood-brain barrier permeability, which enhanced virus entry into and infection of the brain. Activation of Mertk synergized with IFN-β to tighten cell junctions and prevent virus transit across brain microvascular endothelial cells. Because TAM receptors restrict pathogenesis of neuroinvasive viruses, these findings have implications for TAM antagonists that are currently in clinical development.

Preparing for the Next Epidemic with Basic Virology.

Preparing for the Next Epidemic with Basic Virology.

How do Nutritional Stress and La Crosse Virus Infection Interact? Tests for Effects on Willingness to Blood Feed and Fecundity in Aedes albopictus (Diptera: Culicidae).

Evolutionary theory predicts that vector-borne pathogens should have low virulence for their vector because of selection against pathogens that harm the vector sufficiently to reduce transmission. Environmental factors such as nutritional stress can alter vector-pathogen associations by making the vectors more susceptible to pathogens (condition-dependent competence) and vulnerable to the harm caused by pathogen replication (condition-dependent virulence). We tested the hypotheses of condition-dependent competence and condition-dependent virulence by examining the interactive effects of short-term sugar deprivation and exposure to La Crosse virus (LACV) in female Aedes albopictus (Skuse). We predicted that infection status interacts with sugar deprivation to alter willingness to blood feed and fecundity in the second gonotrophic cycle (condition-dependent virulence). Sugar deprivation had no effect on body infection or disseminated infection rates. Infection status, sugar treatment, and their interaction had no effect on fecundity. Mosquitoes that had intermittent access to sugar were significantly more willing to take a second bloodmeal compared with those that had continuous access to sugar. Infection status and the interaction with sugar treatment had no effect on blood-feeding behavior. Thus, we found no evidence of short-term sugar deprivation leading to condition-dependent competence for, or condition-dependent virulence of, LACV in Ae. albopictus.

Interferon-Regulatory Factor 5-Dependent Signaling Restricts Orthobunyavirus Dissemination to the Central Nervous System.

Interferon (IFN)-regulatory factor 5 (IRF-5) is a transcription factor that induces inflammatory responses after engagement and signaling by pattern recognition receptors. To define the role of IRF-5 during bunyavirus infection, we evaluated Oropouche virus (OROV) and La Crosse virus (LACV) pathogenesis and immune responses in primary cells and in mice with gene deletions in Irf3, Irf5, and Irf7 or in Irf5 alone. Deletion of Irf3, Irf5, and Irf7 together resulted in uncontrolled viral replication in the liver and spleen, hypercytokinemia, extensive liver injury, and an early-death phenotype. Remarkably, deletion of Irf5 alone resulted in meningoencephalitis and death on a more protracted timeline, 1 to 2 weeks after initial OROV or LACV infection. The clinical signs in OROV-infected Irf5(-/-) mice were associated with abundant viral antigen and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells in several regions of the brain. Circulating dendritic cell (DC) subsets in Irf5(-/-) mice had higher levels of OROV RNA in vivo yet produced lower levels of type I IFN than wild-type (WT) cells. This result was supported by data obtained in vitro, since a deficiency of IRF-5 resulted in enhanced OROV infection and diminished type I IFN production in bone marrow-derived DCs. Collectively, these results indicate a key role for IRF-5 in modulating the host antiviral response in peripheral organs that controls bunyavirus neuroinvasion in mice. Oropouche virus (OROV) and La Crosse virus (LACV) are orthobunyaviruses that are transmitted by insects and cause meningitis and encephalitis in subsets of individuals in the Americas. Recently, we demonstrated that components of the type I interferon (IFN) induction pathway, particularly the regulatory transcription factors IRF-3 and IRF-7, have key protective roles during OROV infection. However, the lethality in Irf3(-/-) Irf7(-/-) (DKO) mice infected with OROV was not as rapid or complete as observed in Ifnar(-/-) mice, indicating that other transcriptional factors associated with an IFN response contribute to antiviral immunity against OROV. Here, we evaluated bunyavirus replication, tissue tropism, and cytokine production in primary cells and mice lacking IRF-5. We demonstrate an important role for IRF-5 in preventing neuroinvasion and the ensuing encephalitis caused by OROV and LACV.

Patient and provider perceptions about exercise in cancer care, excluding breast: Are we on the same page?

238 Background: Cancer organizations recommend physical activity as part of therapy to aid in symptom management, reduce recurrence and improve overall quality of life. What the optimal exercise program should look like and what stakeholder barriers exist are unclear. Methods: We convened three focus groups, one with metastatic patients, one with non-metastatic patients, one with the providers in the Cancer Center and conducted individual interviews at Gundersen Health System in La Crosse, Wisconsin. The constant comparative method was used to identify themes about exercise as part of cancer treatment. Results: No statistical differences in demographic characteristics exist between metastatic (N = 9) and non-metastatic (N = 11) patients. Impacts of exercise on cancer, who should instruct patients about exercise and how/where the exercise should take place emerged as the main themes. Discordance between patients and providers (N = 10) was identified in these areas. Patients felt that exercise during treatment provided intrinsic value (“Exercise mentally is important”) whereas providers connect exercise to positive disease outcome (“There are decreased recurrence rates for multiple different malignancies that have been proven in large studies”). Patients resoundingly expressed a desire to receive instructions for exercise from their oncologist (“I rely a lot on my oncologist...they are tuned into you”). Providers expressed a desire for a referral process to a cancer trained physical therapist or trainer who would guide patients through an exercise program (“to have assistance from someone who is trained… would be really beneficial”). Conclusions: Providers recognize the importance of exercise as part of a cancer treatment plan, yet they agree that time constraints associated with a busy practice impacts the priority of exercise instructions. Bridging the gap we identified between patient and providers’ perceptions has potential for cancer care across the nation. We plan to further study the discord after designing standard exercise recommendations at varied levels of intensity through collaboration with oncology providers, physical therapy and Livestrong personnel utilizing venues in our region.

Oropuche virus: A virus present but ignored

ResumenBunyaviruses are RNA viruses that affect animals and plants; they have five genera and four of them affect humans: Orthobunyavirus, Nairovirus, Phlebovirus and Hantavirus. All of them are Arbovirus, except Hantavirus. The Orthobunyaviruses comprise Oropouche, Tahyna, La Crosse virus, California encephalitis virus and Heartland virus recently discovered (1). Except for Heartland virus which is transmitted by ticks of the genus Amblyoma, these Phleboviruses have as vectors mosquitoes, which bite small mammals which are able to be as reservoirs amplifiers.

West Nile Virus and Other Nationally Notifiable Arboviral Diseases - United States, 2014.

Arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. West Nile virus (WNV) is the leading cause of domestically acquired arboviral disease in the United States (1). However, several other arboviruses also cause sporadic cases and seasonal outbreaks. This report summarizes surveillance data reported to CDC in 2014 for WNV and other nationally notifiable arboviruses, excluding dengue. Forty-two states and the District of Columbia (DC) reported 2,205 cases of WNV disease. Of these, 1,347 (61%) were classified as WNV neuroinvasive disease (e.g., meningitis, encephalitis, or acute flaccid paralysis), for a national incidence of 0.42 cases per 100,000 population. After WNV, the next most commonly reported cause of arboviral disease was La Crosse virus (80 cases), followed by Jamestown Canyon virus (11), St. Louis encephalitis virus (10), Powassan virus (8), and Eastern equine encephalitis virus (8). WNV and other arboviruses cause serious illness in substantial numbers of persons each year. Maintaining surveillance programs is important to help direct prevention activities.

La Crosse Encephalitis Virus Infection in Field-Collected Aedes albopictus, Aedes japonicus, and Aedes triseriatus in Tennessee.

La Crosse virus (LACV) is a mosquito-borne virus and a major cause of pediatric encephalitis in the USA. La Crosse virus emerged in Tennessee and other states in the Appalachian region in 1997. We investigated LACV infection rates and seasonal abundances of the native mosquito vector, Aedes triseriatus, and 2 recently introduced mosquito species, Ae. albopictus and Ae. japonicus, in an emerging disease focus in Tennessee. Mosquitoes were collected using multiple trapping methods specific for Aedes mosquitoes at recent human case sites. Mosquito pools were tested via reverse transcriptase-polymerase chain reaction (RT-PCR) of the S segment to detect multiple Bunyamwera and California serogroup viruses, including LACV, as well as real-time RT-PCR of the M segment. A total of 54 mosquito pools were positive, including wild-caught adult females and laboratory-reared adults, demonstrating transovarial transmission in all 3 species. Maximum likelihood estimates (per 1,000 mosquitoes) were 2.72 for Ae. triseriatus, 3.01 for Ae. albopictus, and 0.63 for Ae. japonicus. We conclude that Ae. triseriatus and Ae. albopictus are important LACV vectors and that Ae. japonicus also may be involved in virus maintenance and transmission.

Severe La Crosse meningoencephalitis in children: report of two cases

La Crosse virus is an arbovirus of the California Serogroup (Family Bunyaviridae), transmitted by the “tree-hole mosquito,” Aedes triseriatus . La Crosse encephalitis cases occur annually from July to October. The majority of cases are asymptomatic, only a minority (

La Crosse Virus Field Detection and Vector Competence of Culex Mosquitoes.

La Crosse virus (LACV), a leading cause of arboviral pediatric encephalitis in the United States, is emerging in Appalachia. Here, we report field and laboratory evidence that suggest LACV may be using Culex mosquitoes as additional vectors in this region. This bunyavirus was detected by reverse-transcriptase polymerase chain reaction in two pools of Culex mosquitoes in southwestern Virginia and in six pools in West Virginia. To assess vector competence, we offered LACV blood meals to field-collected Culex restuans Theobald, Cx. pipiens L., and Aedes triseriatus (Say). Both Culex species were susceptible to infection. LACV-positive salivary expectorate, indicative of the ability to transmit, was detected in a small proportion of Cx. restuans (9%) and Cx. pipiens (4%) compared with Ae. triseriatus (40%). In a companion study of Cx. restuans only, we found that adults derived from nutritionally stressed larvae were significantly more likely to disseminate and transmit LACV. Our results indicate a potential role of Culex spp. in LACV dynamics that should be explored further in endemic areas.

Human and Murine IFIT1 Proteins Do Not Restrict Infection of Negative-Sense RNA Viruses of the Orthomyxoviridae, Bunyaviridae, and Filoviridae Families.

Interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) is a host protein with reported cell-intrinsic antiviral activity against several RNA viruses. The proposed basis for the activity against negative-sense RNA viruses is the binding to exposed 5'-triphosphates (5'-ppp) on the genome of viral RNA. However, recent studies reported relatively low binding affinities of IFIT1 for 5'-ppp RNA, suggesting that IFIT1 may not interact efficiently with this moiety under physiological conditions. To evaluate the ability of IFIT1 to have an impact on negative-sense RNA viruses, we infected Ifit1(-/-) and wild-type control mice and primary cells with four negative-sense RNA viruses (influenza A virus [IAV], La Crosse virus [LACV], Oropouche virus [OROV], and Ebola virus) corresponding to three distinct families. Unexpectedly, a lack of Ifit1 gene expression did not result in increased infection by any of these viruses in cell culture. Analogously, morbidity, mortality, and viral burdens in tissues were identical between Ifit1(-/-) and control mice after infection with IAV, LACV, or OROV. Finally, deletion of the human IFIT1 protein in A549 cells did not affect IAV replication or infection, and reciprocally, ectopic expression of IFIT1 in HEK293T cells did not inhibit IAV infection. To explain the lack of antiviral activity against IAV, we measured the binding affinity of IFIT1 for RNA oligonucleotides resembling the 5' ends of IAV gene segments. The affinity for 5'-ppp RNA was approximately 10-fold lower than that for non-2'-O-methylated (cap 0) RNA oligonucleotides. Based on this analysis, we conclude that IFIT1 is not a dominant restriction factor against negative-sense RNA viruses. Negative-sense RNA viruses, including influenza virus and Ebola virus, have been responsible for some of the most deadly outbreaks in recent history. The host interferon response and induction of antiviral genes contribute to the control of infections by these viruses. IFIT1 is highly induced after virus infection and reportedly has antiviral activity against several RNA and DNA viruses. However, its role in restricting infection by negative-sense RNA viruses remains unclear. In this study, we evaluated the ability of IFIT1 to inhibit negative-sense RNA virus replication and pathogenesis both in vitro and in vivo. Detailed cell culture and animal studies demonstrated that IFIT1 is not a dominant restriction factor against three different families of negative-sense RNA viruses.

Negative-Strand RNA Virus L Proteins: One Machine, Many Activities

Structures of L proteins from La Crosse orthobunyavirus and vesicular stomatitis virus reveal insights into RNA synthesis and distinctive mRNA capping mechanisms of segmented and non-segmented negative-sense single-strand RNA viruses.

Structural biology. Copying the bunyavirus genome.

The structure of the La Crosse orthobunyavirus L protein suggests a new model for the replication of segmented negative-strand viral genomes.

Structural Insights into Bunyavirus Replication and Its Regulation by the vRNA Promoter

SummarySegmented negative-strand RNA virus (sNSV) polymerases transcribe and replicate the viral RNA (vRNA) within a ribonucleoprotein particle (RNP). We present cryo-EM and X-ray structures of, respectively, apo- and vRNA bound La Crosse orthobunyavirus (LACV) polymerase that give atomic-resolution insight into how such RNPs perform RNA synthesis. The complementary 3′ and 5′ vRNA extremities are sequence specifically bound in separate sites on the polymerase. The 5′ end binds as a stem-loop, allosterically structuring functionally important polymerase active site loops. Identification of distinct template and product exit tunnels allows proposal of a detailed model for template-directed replication with minimal disruption to the circularised RNP. The similar overall architecture and vRNA binding of monomeric LACV to heterotrimeric influenza polymerase, despite high sequence divergence, suggests that all sNSV polymerases have a common evolutionary origin and mechanism of RNA synthesis. These results will aid development of replication inhibitors of diverse, serious human pathogenic viruses.