Publications by authors named "Patricia V Aguilar"

53 Publications

Closing the Rift: Discovery of a novel virus receptor.

Cell 2021 Sep 23;184(20):5084-5086. Epub 2021 Sep 23.

Department of Pathology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA; Institute for Human Infection and Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA; Center for Tropical Diseases, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA. Electronic address:

In this issue of Cell, Ganaie et al. reports the identification of LRP1 as a receptor of the highly pathogenic Rift Valley fever virus. By using genome-wide CRISPR-Cas9 screening and functional studies, Ganaie et al. identified LRP1 and several co-factors as essential elements for virus infection.
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http://dx.doi.org/10.1016/j.cell.2021.09.004DOI Listing
September 2021

Antiviral activity of oleandrin and a defined extract of Nerium oleander against SARS-CoV-2.

Biomed Pharmacother 2021 Jun 3;138:111457. Epub 2021 Mar 3.

Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Phoenix Biotechnology, Inc., San Antonio, TX 78217, USA. Electronic address:

With continued expansion of the coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome 2 (SARS-CoV-2), both antiviral drugs as well as effective vaccines are desperately needed to treat patients at high risk of life-threatening disease. Here, we present in vitro evidence for significant inhibition of SARS-CoV-2 by oleandrin and a defined extract of N. oleander (designated as PBI-06150). Using Vero cells, we found that prophylactic (pre-infection) oleandrin (as either the pure compound or as the active principal ingredient in PBI-06150) administration at concentrations as low as 0.05 µg/ml exhibited potent antiviral activity against SARS-CoV-2, with an 800-fold reduction in virus production, and a 0.1 µg/ml concentration resulted in a greater than 3000-fold reduction in infectious virus production. The half maximal effective concentration (EC) values were 11.98 ng/ml when virus output was measured at 24 h post-infection, and 7.07 ng/ml measured at 48 h post-infection. Therapeutic (post-infection) treatment up to 24 h after SARS-CoV-2 infection of Vero cells also reduced viral titers, with 0.1 µg/ml and 0.05 µg/ml concentrations causing greater than 100-fold reduction as measured at 48 h, and the 0.05 µg/ml concentration resulting in a 78-fold reduction. Concentrations of oleandrin up to 10 µg/ml were well tolerated in Vero cells. We also present in vivo evidence of the safety and efficacy of defined N. oleander extract (PBI-06150), which was administered to golden Syrian hamsters in a preparation containing as high as 130 µg/ml of oleandrin. In comparison to administration of control vehicle, PBI-06150 provided a statistically significant reduction of the viral titer in the nasal turbinates (nasal conchae). The potent prophylactic and therapeutic antiviral activities demonstrated here, together with initial evidence of its safety and efficacy in a relevant hamster model of COVID-19, support the further development of oleandrin and/or defined extracts containing this molecule for the treatment of SARS-CoV-2 and associated COVID-19 disease and potentially also for reduction of virus spread by persons diagnosed early after infection.
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http://dx.doi.org/10.1016/j.biopha.2021.111457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927596PMC
June 2021

A trans-complementation system for SARS-CoV-2 recapitulates authentic viral replication without virulence.

Cell 2021 04 23;184(8):2229-2238.e13. Epub 2021 Feb 23.

Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA. Electronic address:

The biosafety level 3 (BSL-3) requirement to culture severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a bottleneck for research. Here, we report a trans-complementation system that produces single-round infectious SARS-CoV-2 that recapitulates authentic viral replication. We demonstrate that the single-round infectious SARS-CoV-2 can be used at BSL-2 laboratories for high-throughput neutralization and antiviral testing. The trans-complementation system consists of two components: a genomic viral RNA containing ORF3 and envelope gene deletions, as well as mutated transcriptional regulator sequences, and a producer cell line expressing the two deleted genes. Trans-complementation of the two components generates virions that can infect naive cells for only one round but does not produce wild-type SARS-CoV-2. Hamsters and K18-hACE2 transgenic mice inoculated with the complementation-derived virions exhibited no detectable disease, even after intracranial inoculation with the highest possible dose. Thus, the trans-complementation platform can be safely used at BSL-2 laboratories for research and countermeasure development.
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http://dx.doi.org/10.1016/j.cell.2021.02.044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901297PMC
April 2021

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition).

Autophagy 2021 Jan 8;17(1):1-382. Epub 2021 Feb 8.

University of Crete, School of Medicine, Laboratory of Clinical Microbiology and Microbial Pathogenesis, Voutes, Heraklion, Crete, Greece; Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology (IMBB), Heraklion, Crete, Greece.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
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http://dx.doi.org/10.1080/15548627.2020.1797280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996087PMC
January 2021

Isothermal Recombinase Polymerase Amplification-Lateral Flow Point-of-Care Diagnostic Test for Heartland Virus.

Vector Borne Zoonotic Dis 2021 Feb 2;21(2):110-115. Epub 2020 Dec 2.

Department of Internal Medicine-Infectious Diseases and University of Texas Medical Branch (UTMB), Galveston, Texas, USA.

The detection of novel or re-emergent pathogens necessitates the development of rapid, easy-to-use diagnostic tests that can be readily adapted and utilized in both clinical laboratories and field settings. Heartland virus (HRTV) is the first pathogenic responsible for serious and fatal cases in the United States. We developed a qualitative test based on recombinase-polymerase-amplification coupled with lateral flow reading (RPA-LF) for rapid detection of HRTV. The RPA-LF detected HRTV with a limit of detection of 1.19-1.54 plaque-forming unit equivalents/reaction. In addition, the RPA-LF was able to detect 0.6075 copies/μL of HRTV nucleoprotein gene-containing plasmid. We evaluated six clinical samples that were previously found to be real-time PCR positive for HRTV and found five out of six samples to be positive by RPA-LF, yielding 83.3% concordance with real-time PCR. All six samples had Ct values between 29 and 39 by real-time PCR. We also determined that the HRTV primers and probe do not cross-react with other tick-transmitted viruses such as Bourbon and Powassan, or other related viruses, including Lonestar tick virus and Sunday canyon virus (100% specificity). This is the first isothermal amplification test developed for a tick-borne virus, which will allow for rapid differentiation between HRTV and other pathogens producing similar clinical manifestations.
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http://dx.doi.org/10.1089/vbz.2020.2670DOI Listing
February 2021

Prophylactic and Therapeutic Inhibition of In Vitro SARS-CoV-2 Replication by Oleandrin.

bioRxiv 2020 Jul 15. Epub 2020 Jul 15.

With continued expansion of the COVID-19 pandemic, antiviral drugs are desperately needed to treat patients at high risk of life-threatening disease and even to limit spread if administered early during infection. Typically, the fastest route to identifying and licensing a safe and effective antiviral drug is to test those already shown safe in early clinical trials for other infections or diseases. Here, we tested oleandrin, derived from the plant and shown previously to have inhibitory activity against several viruses. Using Vero cells, we found that prophylactic oleandrin administration at concentrations down to 0.05 μg/ml exhibited potent antiviral activity against SARS-CoV-2, with an 800-fold reduction in virus production, and a 0.1 μg/ml dose resulted in a greater than 3,000-fold reduction in infectious virus production. The EC values were 11.98ng/ml when virus output was measured at 24 hours post-infection, and 7.07ng/ml measured at 48 hours post-infection. Therapeutic (post-infection) treatment up to 24 hours after infection of Vero cells also reduced viral titers, with the 0.1 μg/ml dose causing greater than 100-fold reductions as measured at 48 hours, and the 0.05 μg/ml dose resulting in a 78-fold reduction. The potent prophylactic and therapeutic antiviral activities demonstrated here strongly support the further development of oleandrin to reduce the severity of COVID-19 and potentially also to reduce spread by persons diagnosed early after infection.

Importance: COVID-19, a pandemic disease caused by infection with SARS-CoV-2, has swept around the world to cause millions of infections and hundreds-of-thousands of deaths due to the lack of vaccines and effective therapeutics. We tested oleandrin, derived from the plant and shown previously to reduce the replication of several viruses, against SARS-CoV-2 infection of Vero cells. When administered both before and after virus infection, nanogram doses of oleandrin significantly inhibited replication by up to 3,000-fold, indicating the potential to prevent disease and virus spread in persons recently exposed to SARS-CoV-2, as well as to prevent severe disease in persons at high risk. These results indicate that oleandrin should be tested in animal models and in humans exposed to infection to determine its medical usefulness in controlling the pandemic.
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http://dx.doi.org/10.1101/2020.07.15.203489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7373128PMC
July 2020

Persistence of Severe Acute Respiratory Syndrome Coronavirus 2 in Aerosol Suspensions.

Emerg Infect Dis 2020 09 22;26(9). Epub 2020 Jun 22.

We aerosolized severe acute respiratory syndrome coronavirus 2 and determined that its dynamic aerosol efficiency surpassed those of severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome. Although we performed experiment only once across several laboratories, our findings suggest retained infectivity and virion integrity for up to 16 hours in respirable-sized aerosols.
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http://dx.doi.org/10.3201/eid2609.201806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7454081PMC
September 2020

Barrita Virus, a Novel Virus of the Patois Serogroup (Genus ; Family ).

Am J Trop Med Hyg 2020 07 21;103(1):190-192. Epub 2020 May 21.

Center for Tropical Diseases, Galveston, Texas.

During ecological investigations for arboviruses conducted in coastal Chiapas, Mexico, in 2007, isolate MP1078 was obtained from a pool of mosquitoes. Based on antigenic characterization, this isolate was classified as a strain of Patois virus (PATV) ( genus, family). Recently, we conducted nearly complete genome sequencing of this isolate to gain further insight into its genetic relationship with other members of the Patois serogroup. Based on the genetic characterization, we determined that MP1078 contains S, M, and L genome segments that are genetically distinct from other viruses within the Patois serogroup. Serological analyses confirmed the taxonomic classification of MP1078 as a new virus and species within the Patois serogroup, and we propose the name Barrita virus (BITV).
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http://dx.doi.org/10.4269/ajtmh.19-0906DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356424PMC
July 2020

An Infectious cDNA Clone of SARS-CoV-2.

Cell Host Microbe 2020 05 13;27(5):841-848.e3. Epub 2020 Apr 13.

Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA; Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, USA. Electronic address:

The ongoing pandemic of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), underscores the urgency to develop experimental systems for studying this virus and identifying countermeasures. We report a reverse genetic system for SARS-CoV-2. Seven complimentary DNA (cDNA) fragments spanning the SARS-CoV-2 genome were assembled into a full-genome cDNA. RNA transcribed from the full-genome cDNA was highly infectious after electroporation into cells, producing 2.9 × 10 plaque-forming unit (PFU)/mL of virus. Compared with a clinical isolate, the infectious-clone-derived SARS-CoV-2 (icSARS-CoV-2) exhibited similar plaque morphology, viral RNA profile, and replication kinetics. Additionally, icSARS-CoV-2 retained engineered molecular markers and did not acquire other mutations. We generated a stable mNeonGreen SARS-CoV-2 (icSARS-CoV-2-mNG) by introducing this reporter gene into ORF7 of the viral genome. icSARS-CoV-2-mNG was successfully used to evaluate the antiviral activities of interferon (IFN). Collectively, the reverse genetic system and reporter virus provide key reagents to study SARS-CoV-2 and develop countermeasures.
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http://dx.doi.org/10.1016/j.chom.2020.04.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153529PMC
May 2020

Protective immunity by an engineered DNA vaccine for Mayaro virus.

PLoS Negl Trop Dis 2019 02 7;13(2):e0007042. Epub 2019 Feb 7.

Vaccine & Immunotherapy Center, The Wistar Institute, Philadelphia, PA, United States of America.

Mayaro virus (MAYV) of the genus alphavirus is a mosquito-transmitted emerging infectious disease that causes an acute febrile illness, rash, headaches, and nausea that may turn into incapacitating, persistent arthralgias in some victims. Since its discovery in Trinidad in 1954, cases of MAYV infection have largely been confined there and to the northern countries of South America, but recently, MAYV cases have been reported in some island nations in the Caribbean Sea. Accompanying these reports is evidence that new vectors, including Aedes spp. mosquitos, recently implicated in the global spread of Zika and chikungunya viruses, are competent for MAYV transmission, which, if true, could facilitate the spread of MAYV beyond its current range. Despite its status as an emerging virus, there are no licensed vaccines to prevent MAYV infection nor therapeutics to treat it. Here, we describe the development and testing of a novel DNA vaccine, scMAYV-E, that encodes a synthetically-designed consensus MAYV envelope sequence. In vivo electroporation-enhanced immunization of mice with this vaccine induced potent humoral responses including neutralizing antibodies as well as robust T-cell responses to multiple epitopes in the MAYV envelope. Importantly, these scMAYV-E-induced immune responses protected susceptible mice from morbidity and mortality following a MAYV challenge.
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http://dx.doi.org/10.1371/journal.pntd.0007042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6366747PMC
February 2019

Peli1 facilitates virus replication and promotes neuroinflammation during West Nile virus infection.

J Clin Invest 2018 11 24;128(11):4980-4991. Epub 2018 Sep 24.

Department of Microbiology and Immunology.

The E3 ubiquitin ligase Pellino 1 (Peli1) is a microglia-specific mediator of autoimmune encephalomyelitis. Its role in neurotropic flavivirus infection is largely unknown. Here, we report that mice deficient in Peli1 (Peli1-/-) were more resistant to lethal West Nile virus (WNV) infection and exhibited reduced viral loads in tissues and attenuated brain inflammation. Peli1 mediates chemokine and proinflammatory cytokine production in microglia and promotes T cell and macrophage infiltration into the CNS. Unexpectedly, Peli1 was required for WNV entry and replication in mouse macrophages and mouse and human neurons and microglia. It was also highly expressed on WNV-infected neurons and adjacent inflammatory cells from postmortem patients who died of acute WNV encephalitis. WNV passaged in Peli1-/- macrophages or neurons induced a lower viral load and impaired activation in WT microglia and thereby reduced lethality in mice. Smaducin-6, which blocks interactions between Peli1 and IRAK1, RIP1, and IKKε, did not inhibit WNV-triggered microglia activation. Collectively, our findings suggest a nonimmune regulatory role for Peli1 in promoting microglia activation during WNV infection and identify a potentially novel host factor for flavivirus cell entry and replication.
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http://dx.doi.org/10.1172/JCI99902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6205407PMC
November 2018

Genetic Characterization of the Patois Serogroup (Genus ; Family ) and Evidence That Estero Real Virus is a Member of the Genus .

Am J Trop Med Hyg 2018 08 7;99(2):451-457. Epub 2018 Jun 7.

Center for Technological Innovation, Instituto Evandro Chagas, Ananindeua, Pará, Brazil.

Estero Real virus (ERV) was isolated in 1980 from ticks collected in El Estero Real, Sancti Spiritus, Cuba. Antigenic characterization of the isolate based on serological methods found a relationship with Abras and Zegla viruses and, consequently, the virus was classified taxonomically within the Patois serogroup. Given the fact that genetic characterization of Patois serogroup viruses has not yet been reported and that ERV is the only virus within the Patois serogroup isolated from ticks, we recently conducted nearly complete genome sequencing in an attempt to gain further insight into the genetic relationship of ERV with other Patois serogroup viruses and members of family ( order). With the exception of ERV, our sequencing and phylogenetic studies revealed the close relationship of the Patois serogroup viruses to each other, forming a clear divergent clade from other members of the genus ( family). Notably, our analysis also revealed that ERV forms a monophyletic clade that is closely related to species of the genus ( family) in all the genome segments. In light of these findings, we believe that the taxonomic classification of ERV should be revised.
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http://dx.doi.org/10.4269/ajtmh.18-0201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6090349PMC
August 2018

A recombinant virus vaccine that protects against both Chikungunya and Zika virus infections.

Vaccine 2018 06 26;36(27):3894-3900. Epub 2018 May 26.

Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA. Electronic address:

Chikungunya virus (CHIKV) and Zika virus (ZIKV) have recently expanded their range in the world and caused serious and widespread outbreaks of near pandemic proportions. There are no licensed vaccines that protect against these co-circulating viruses that are transmitted by invasive mosquito vectors. We report here on the development of a single-dose, bivalent experimental vaccine for CHIKV and ZIKV. This vaccine is based on a chimeric vesicular stomatitis virus (VSV) that expresses the CHIKV envelope polyprotein (E3-E2-6K-E1) in place of the VSV glycoprotein (G) and also expresses the membrane-envelope (ME) glycoproteins of ZIKV. This vaccine induced neutralizing antibody responses to both CHIKV and ZIKV in wild-type mice and in interferon receptor-deficient A129 mice, animal models for CHIKV and ZIKV infection. A single vaccination of A129 mice with the vector protected these mice against infection with both CHIKV and ZIKV. Our single-dose vaccine could provide durable, low-cost protection against both CHIKV and ZIKV for people traveling to or living in areas where both viruses are circulating, which include most tropical regions in the world.
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http://dx.doi.org/10.1016/j.vaccine.2018.05.095DOI Listing
June 2018

The Emergence of Severe Fever with Thrombocytopenia Syndrome Virus.

Am J Trop Med Hyg 2017 Oct 18;97(4):992-996. Epub 2017 Aug 18.

Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas.

Severe fever with thrombocytopenia syndrome (SFTS) is a newly recognized hemorrhagic fever disease found throughout Asia with a case fatality rate between 12% and 30%. Since 2009, SFTS has been reported in China throughout 14 Chinese Provinces. In addition, SFTS has been recognized in South Korea and Japan with the first confirmed cases reported in 2012. A similar disease, caused by the closely related Heartland virus, was also reported in the United States in 2009. SFTS is caused by SFTS virus, a novel tick-borne virus in the family , genus . Unlike other mosquito- and sandfly-borne bunyaviruses, SFTS virus has not been extensively studied due to its recent emergence and many unknowns regarding its pathogenesis, life cycle, transmission, and options for therapeutics remains. In this review, we report the most current findings in SFTS virus research.
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http://dx.doi.org/10.4269/ajtmh.16-0967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5637595PMC
October 2017

Identification of Blood Meals from Potential Arbovirus Mosquito Vectors in the Peruvian Amazon Basin.

Am J Trop Med Hyg 2016 Nov 12;95(5):1026-1030. Epub 2016 Sep 12.

Centers for Disease Control and Prevention, Atlanta, Georgia.

The transmission dynamics of many arboviruses in the Amazon Basin region have not been fully elucidated, including the vectors and natural reservoir hosts. Identification of blood meal sources in field-caught mosquitoes could yield information for identifying potential arbovirus vertebrate hosts. We identified blood meal sources in 131 mosquitoes collected from areas endemic for arboviruses in the Peruvian Department of Loreto by sequencing polymerase chain reaction amplicons of the cytochrome b gene. Psorophora (Janthinosoma) albigenu, Psorophora (Grabhamia) cingulata, Mansonia humeralis, Anopheles oswaldoi s.l., and Anopheles benarrochi s.l. had mainly anthropophilic feeding preferences; Aedes (Ochlerotatus) serratus, and Aedes (Ochlerotatus) fulvus had feeding preferences for peridomestic animals; and Culex (Melanoconion) spp. fed on a variety of vertebrates, mainly rodents (spiny rats), birds, and amphibians. On the basis of these feeding preferences, many mosquitoes could be considered as potential enzootic and bridge arbovirus vectors in the Amazon Basin of Peru.
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http://dx.doi.org/10.4269/ajtmh.16-0167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5094211PMC
November 2016

Extracellular Vesicles Mediate Receptor-Independent Transmission of Novel Tick-Borne Bunyavirus.

J Virol 2016 01 28;90(2):873-86. Epub 2015 Oct 28.

Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, USA Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, USA Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA

Unlabelled: Severe fever with thrombocytopenia syndrome (SFTS) virus is a newly recognized member of the genus Phlebovirus in the family Bunyaviridae. The virus was isolated from patients presenting with hemorrhagic manifestations and an initial case fatality rate of 12 to 30% was reported. Due to the recent emergence of this pathogen, there is limited knowledge on the molecular virology of SFTS virus. Recently, we reported that the SFTS virus NSs protein inhibited the activation of the beta interferon (IFN-β) promoter. Furthermore, we also found that SFTS virus NSs relocalizes key components of the IFN response into NSs-induced cytoplasmic structures. Due to the important role these structures play during SFTS virus replication, we conducted live cell imaging studies to gain further insight into the role and trafficking of these cytoplasmic structures during virus infection. We found that some of the SFTS virus NSs-positive cytoplasmic structures were secreted to the extracellular space and endocytosed by neighboring cells. We also found that these secreted structures isolated from NSs-expressing cells and SFTS virus-infected cells were positive for the viral protein NSs and the host protein CD63, a protein associated with extracellular vesicles. Electron microscopy studies also revealed that the isolated CD63-immunoprecipitated extracellular vesicles produced during SFTS virus infection contained virions. The virions harbored within these structures were efficiently delivered to uninfected cells and were able to sustain SFTS virus replication. Altogether, these results suggest that SFTS virus exploits extracellular vesicles to mediate virus receptor-independent transmission to host cells and open the avenue for novel therapeutic strategies against SFTS virus and related pathogens.

Importance: SFTS virus is novel bunyavirus associated with hemorrhagic fever illness. Currently, limited information is available about SFTS virus. In the present study, we demonstrated that extracellular vesicles produced by SFTS virus-infected cells harbor infectious virions. We sought to determine whether these "infectious" extracellular vesicles can mediate transmission of the virus and confirmed that the SFTS virions were efficiently transported by these secreted structures into uninfected cells and were able to sustain efficient replication of SFTS virus. These results have significant impact on our understanding of how the novel tick-borne phleboviruses hijack cellular machineries to establish infection and point toward a novel mechanism for virus replication among arthropod-borne viruses.
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http://dx.doi.org/10.1128/JVI.02490-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4702678PMC
January 2016

Long-Term Arthralgia after Mayaro Virus Infection Correlates with Sustained Pro-inflammatory Cytokine Response.

PLoS Negl Trop Dis 2015 23;9(10):e0004104. Epub 2015 Oct 23.

Institute for Human Infections and Immunity, Galveston, Texas, United States of America; Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America; Center for Biodefense and Emerging Infectious Diseases, Galveston, Texas, United States of America.

Mayaro virus (MAYV), an alphavirus similar to chikungunya virus (CHIKV), causes an acute debilitating disease which results in the development of long-term arthralgia in more than 50% of infected individuals. Currently, the immune response and its role in the development of MAYV-induced persistent arthralgia remain unknown. In this study, we evaluated the immune response of individuals with confirmed MAYV infection in a one-year longitudinal study carried out in Loreto, Peru. We report that MAYV infection elicits robust immune responses that result in the development of a strong neutralizing antibody response and the secretion of pro-inflammatory immune mediators. The composition of these inflammatory mediators, in some cases, differed to those previously observed for CHIKV. Key mediators such as IL-13, IL-7 and VEGF were strongly induced following MAYV infection and were significantly increased in subjects that eventually developed persistent arthralgia. Although a strong neutralizing antibody response was observed in all subjects, it was not sufficient to prevent the long-term outcomes of MAYV infection. This study provides initial immunologic insight that may eventually contribute to prognostic tools and therapeutic treatments against this emerging pathogen.
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http://dx.doi.org/10.1371/journal.pntd.0004104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4619727PMC
March 2016

Itaya virus, a Novel Orthobunyavirus Associated with Human Febrile Illness, Peru.

Emerg Infect Dis 2015 May;21(5):781-8

Our genetic analyses of uncharacterized bunyaviruses isolated in Peru identified a possible reassortant virus containing small and large gene segment sequences closely related to the Caraparu virus and a medium gene segment sequence potentially derived from an unidentified group C orthobunyavirus. Neutralization tests confirmed serologic distinction among the newly identified virus and the prototype and Caraparu strains. This virus, named Itaya, was isolated in 1999 and 2006 from febrile patients in the cities of Iquitos and Yurimaguas in Peru. The geographic distance between the 2 cases suggests that the Itaya virus could be widely distributed throughout the Amazon basin in northeastern Peru. Identification of a new Orthobunyavirus species that causes febrile disease in humans reinforces the need to expand viral disease surveillance in tropical regions of South America.
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http://dx.doi.org/10.3201/eid2105.141368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4412221PMC
May 2015

Hijacking of RIG-I signaling proteins into virus-induced cytoplasmic structures correlates with the inhibition of type I interferon responses.

J Virol 2014 Apr 29;88(8):4572-85. Epub 2014 Jan 29.

Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA.

Unlabelled: Recognition of viral pathogens by the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) family results in the activation of type I interferon (IFN) responses. To avoid this response, most viruses have evolved strategies that target different essential steps in the activation of host innate immunity. In this study, we report that the nonstructural protein NSs of the newly described severe fever with thrombocytopenia syndrome virus (SFTSV) is a potent inhibitor of IFN responses. The SFTSV NSs protein was found to inhibit the activation of the beta interferon (IFN-β) promoter induced by viral infection and by a RIG-I ligand. Astonishingly, we found that SFTSV NSs interacts with and relocalizes RIG-I, the E3 ubiquitin ligase TRIM25, and TANK-binding kinase 1 (TBK1) into SFTSV NSs-induced cytoplasmic structures. Interestingly, formation of these SFTSV NSs-induced structures occurred in the absence of the Atg7 gene, a gene essential for autophagy. Furthermore, confocal microscopy studies revealed that these SFTSV NSs-induced structures colocalize with Rab5 but not with Golgi apparatus or endoplasmic reticulum markers. Altogether, the data suggest that sequestration of RIG-I signaling molecules into endosome-like structures may be the mechanism used by SFTSV to inhibit IFN responses and point toward a novel mechanism for the suppression of IFN responses.

Importance: The mechanism by which the newly described SFTSV inhibits host antiviral responses has not yet been fully characterized. In this study, we describe the redistribution of RIG-I signaling components into virus-induced cytoplasmic structures in cells infected with SFTSV. This redistribution correlates with the inhibition of host antiviral responses. Further characterization of the interplay between the viral protein and components of the IFN responses could potentially provide targets for the rational development of therapeutic interventions.
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http://dx.doi.org/10.1128/JVI.03021-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993744PMC
April 2014

Arboretum and Puerto Almendras viruses: two novel rhabdoviruses isolated from mosquitoes in Peru.

J Gen Virol 2014 Apr 13;95(Pt 4):787-792. Epub 2014 Jan 13.

Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA.

Arboretum virus (ABTV) and Puerto Almendras virus (PTAMV) are two mosquito-associated rhabdoviruses isolated from pools of Psorophora albigenu and Ochlerotattus fulvus mosquitoes, respectively, collected in the Department of Loreto, Peru, in 2009. Initial tests suggested that both viruses were novel rhabdoviruses and this was confirmed by complete genome sequencing. Analysis of their 11 482 nt (ABTV) and 11 876 (PTAMV) genomes indicates that they encode the five canonical rhabdovirus structural proteins (N, P, M, G and L) with an additional gene (U1) encoding a small hydrophobic protein. Evolutionary analysis of the L protein indicates that ABTV and PTAMV are novel and phylogenetically distinct rhabdoviruses that cannot be classified as members of any of the eight currently recognized genera within the family Rhabdoviridae, highlighting the vast diversity of this virus family.
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http://dx.doi.org/10.1099/vir.0.058685-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3973475PMC
April 2014

Mayaro virus infection, Amazon Basin region, Peru, 2010-2013.

Emerg Infect Dis 2013 Nov;19(11):1839-42

During 2010-2013, we recruited 16 persons with confirmed Mayaro virus infection in the Peruvian Amazon to prospectively follow clinical symptoms and serologic response over a 12-month period. Mayaro virus infection caused long-term arthralgia in more than half, similar to reports of other arthritogenic alphaviruses.
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http://dx.doi.org/10.3201/eid1911.130777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3837653PMC
November 2013

Iquitos virus: a novel reassortant Orthobunyavirus associated with human illness in Peru.

PLoS Negl Trop Dis 2011 Sep 20;5(9):e1315. Epub 2011 Sep 20.

U.S. Naval Medical Research Unit Six, Lima, Peru.

Oropouche (ORO) virus, a member of the Simbu serogroup, is one of the few human pathogens in the Orthobunyavirus genus in the family Bunyaviridae. Genetic analyses of ORO-like strains from Iquitos, Peru, identified a novel reassortant containing the S and L segments of ORO virus and the M segment of a novel Simbu serogroup virus. This new pathogen, which we named Iquitos (IQT) virus, was first isolated during 1999 from a febrile patient in Iquitos, an Amazonian city in Peru. Subsequently, the virus was identified as the cause of outbreaks of "Oropouche fever" during 2005 and 2006 in Iquitos. In addition to the identification of 17 isolates of IQT virus between 1999 and 2006, surveys for neutralizing antibody among Iquitos residents revealed prevalence rates of 14.9% for ORO virus and 15.4% for IQT virus. Limited studies indicate that prior infection with ORO virus does not seem to protect against disease caused with the IQT virus infection. Identification of a new Orthobunyavirus human pathogen in the Amazon region of Peru highlights the need for strengthening surveillance activities and laboratory capabilities, and investigating the emergence of new pathogens in tropical regions of South America.
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http://dx.doi.org/10.1371/journal.pntd.0001315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3176741PMC
September 2011

Endemic Venezuelan equine encephalitis in the Americas: hidden under the dengue umbrella.

Future Virol 2011 ;6(6):721-740

Center for Tropical Diseases, Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX, USA.

Venezuelan equine encephalitis (VEE) is an emerging infectious disease in Latin America. Outbreaks have been recorded for decades in countries with enzootic circulation, and the recent implementation of surveillance systems has allowed the detection of additional human cases in countries and areas with previously unknown VEE activity. Clinically, VEE is indistinguishable from dengue and other arboviral diseases and confirmatory diagnosis requires the use of specialized laboratory tests that are difficult to afford in resource-limited regions. Thus, the disease burden of endemic VEE in developing countries remains largely unknown, but recent surveillance suggests that it may represent up to 10% of the dengue burden in neotropical cities, or tens-of-thousands of cases per year throughout Latin America. The potential emergence of epizootic viruses from enzootic progenitors further highlights the need to strengthen surveillance activities, identify mosquito vectors and reservoirs and develop effective strategies to control the disease. In this article, we provide an overview of the current status of endemic VEE that results from spillover of the enzootic cycles, and we discuss public health measures for disease control as well as future avenues for VEE research.
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http://dx.doi.org/10.2217/FVL.11.5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3134406PMC
January 2011

Guaroa virus infection among humans in Bolivia and Peru.

Am J Trop Med Hyg 2010 Sep;83(3):714-21

Naval Medical Research Center Detachment, Lima, Peru.

Guaroa virus (GROV) was first isolated from humans in Colombia in 1959. Subsequent isolates of the virus have been recovered from febrile patients and mosquitoes in Brazil, Colombia, and Panama; however, association of the virus with human disease has been unclear. As part of a study on the etiology of febrile illnesses in Peru and Bolivia, 14 GROV strains were isolated from patients with febrile illnesses, and 3 additional cases were confirmed by IgM seroconversion. The prevalence rate of GROV antibodies among Iquitos residents was 13%; the highest rates were among persons with occupations such as woodcutters, fisherman, and oil-field workers. Genetic characterization of representative GROV isolates indicated that strains from Peru and Bolivia form a monophyletic group that can be distinguished from strains isolated earlier in Brazil and Colombia. This study confirms GROV as a cause of febrile illness in tropical regions of Central and South America.
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http://dx.doi.org/10.4269/ajtmh.2010.10-0116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929076PMC
September 2010

Changes in the viral distribution pattern after the appearance of the novel influenza A H1N1 (pH1N1) virus in influenza-like illness patients in Peru.

PLoS One 2010 Jul 27;5(7):e11719. Epub 2010 Jul 27.

Virology Department, United States Naval Medical Research Center Detachment, Lima, Perú.

Background: We describe the temporal variation in viral agents detected in influenza like illness (ILI) patients before and after the appearance of the ongoing pandemic influenza A (H1N1) (pH1N1) in Peru between 4-January and 13-July 2009.

Methods: At the health centers, one oropharyngeal swab was obtained for viral isolation. From epidemiological week (EW) 1 to 18, at the US Naval Medical Research Center Detachment (NMRCD) in Lima, the specimens were inoculated into four cell lines for virus isolation. In addition, from EW 19 to 28, the specimens were also analyzed by real time-polymerase-chain-reaction (rRT-PCR).

Results: We enrolled 2,872 patients: 1,422 cases before the appearance of the pH1N1 virus, and 1,450 during the pandemic. Non-pH1N1 influenza A virus was the predominant viral strain circulating in Peru through (EW) 18, representing 57.8% of the confirmed cases; however, this predominance shifted to pH1N1 (51.5%) from EW 19-28. During this study period, most of pH1N1 cases were diagnosed in the capital city (Lima) followed by other cities including Cusco and Trujillo. In contrast, novel influenza cases were essentially absent in the tropical rain forest (jungle) cities during our study period. The city of Iquitos (Jungle) had the highest number of influenza B cases and only one pH1N1 case.

Conclusions: The viral distribution in Peru changed upon the introduction of the pH1N1 virus compared to previous months. Although influenza A viruses continue to be the predominant viral pathogen, the pH1N1 virus predominated over the other influenza A viruses.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011719PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910706PMC
July 2010

Venezuelan equine encephalitis and 2 human deaths, Peru.

Emerg Infect Dis 2010 Mar;16(3):553-6

Naval Medical Research Center Detachment, Lima, Peru.

Studies have suggested that enzootic strains of Venezuelan equine encephalitis (VEE) subtype ID in the Amazon region, Peru, may be less pathogenic to humans than are epizootic variants. Deaths of 2 persons with evidence of acute VEE virus infection indicate that fatal VEEV infection in Peru is likely. Cases may remain underreported.
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http://dx.doi.org/10.3201/eid1603.090970DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3322018PMC
March 2010
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