oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 485 )

2018 ( 905 )

2017 ( 842 )

2016 ( 1225 )

Custom range...

Search Results: 1 - 10 of 486880 matches for " John A Lednicky "
All listed articles are free for downloading (OA Articles)
Page 1 /486880
Display every page Item
Detection and Isolation of Airborne Influenza A H3N2 Virus Using a Sioutas Personal Cascade Impactor Sampler
John A. Lednicky,Julia C. Loeb
Influenza Research and Treatment , 2013, DOI: 10.1155/2013/656825
Abstract: The air we breathe contains microorganisms that can cause infectious respiratory diseases. After two occupants of an apartment were diagnosed with influenza in February of 2013, efforts were made to detect and isolate airborne influenza virus using two different types of active air samplers: a Sioutas Personal Cascade Impactor Sampler (PCIS) and an SKC BioSampler. The PCIS collects size-fractionated particles by impaction on polytetrafluoroethylene filters, whereas the SKC BioSampler collects airborne particles in liquid media. Influenza H3N2 virus was collected by both types of air samplers. The PCIS collected a range of particle sizes containing influenza virus near one of the sick individuals but only ultrafine particles when the samplers were positioned farther away. Viable virus was present in the liquid collection media of the SKC BioSampler and some PCIS filters. These findings suggest that influenza patients produce ultrafine aerosol particles that contain viable virus. 1. Introduction Airborne microorganisms are typically present in the air we breathe and are potential causes of infectious diseases. Influenza viruses are among the respiratory pathogens that can be transmitted by airborne routes [1–4]. Breathing, coughing, sneezing, and talking during the course of influenza generate a cloud of airborne particles containing influenza virus. The airborne particles have diameters that range from a few millimeters (large droplets formed during coughing and sneezing) to submicron (<1?μm) (formed during breathing). Small particles (≤5?μm) including droplet nuclei from evaporated larger particles can remain airborne for hours (these concepts and their relevance to influenza viruses are discussed in [1, 3–14]). Presently, the US Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) state that influenza virus transmission occurs mostly by large-particle respiratory droplets that travel only a short distance from the source (1.829?m (6 feet) according to the CDC and 1?m (3.3 feet) according to the WHO) [15–17]. Noteworthy, deposition of influenza virus into the lungs (as small particles) versus the upper respiratory tract (as large droplets) may increase infection risk and illness severity [3, 9, 18–20]. Assessments of microbiological air quality are useful for studies of the airborne transmission of pathogens and of other biological particles in the air that may cause noninfectious diseases (such as allergy to pollen). The two principle methods of assessing microbiological air quality are passive monitoring and active
Design, assembly, and validation of a nose-only inhalation exposure system for studies of aerosolized viable influenza H5N1 virus in ferrets
Richard S Tuttle, William A Sosna, Deirdre E Daniels, Sara B Hamilton, John A Lednicky
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-135
Abstract: An aerosol generation and delivery system, referred to as a Nose-Only Bioaerosol Exposure System (NBIES), was assembled and function tested. The NBIES passed all safety tests, met expected engineering parameters, required relatively small quantities of material to obtain the desired aerosol concentrations of influenza virus, and delivered doses with high-efficacy. Ferrets withstood a mock exposure trial without signs of stress.The NBIES delivers doses of aerosolized influenza viruses with high efficacy, and uses less starting material than other similar designs. Influenza H5N1 and H3N2 viruses remain stable under the conditions used for aerosol generation and sample collection. The NBIES is qualified for studies of aerosolized H5N1 virus.Human infections caused by highly pathogenic avian influenza H5N1 viruses (H5N1) that arose from 2003-onwards have been rare (495 cases confirmed through April 21, 2010) but have a fatality rate of about 59% [1]. There is limited knowledge about the potential routes and determinants required for H5N1 transmission to and between humans. Human-to-human transmissions have rarely been reported, and have been limited, inefficient and un-sustained. In ferret transmission models, H5N1 are inconsistent in transmission by direct or indirect contact exposure, but direct intranasal exposure causes morbidity and sometimes, mortality (2, 3, and J. Lednicky, unpublished). In contrast, the 1918 pandemic influenza virus was easily transmissible human-to-human, and caused the deaths of between 20 - 40 million people worldwide for a lethality rate of 2.5%. Whereas the differences in transmissibility and lethality between the two viruses are not fully understood, performing well-controlled inhalation exposure studies of aerosolized viable H5N1 in appropriate animal models may improve our understanding of factors responsible for -the acquisition of H5N1 infections by humans and the virulence/lethality relative to route of transmission.Four modes are mo
Comparative Analysis of the Full-Length Genome Sequence of a Clinical Isolate of Human Parainfluenza Virus 4B
John A. Lednicky,Thomas B. Waltzek,Micah D. Halpern,Sara B. Hamilton
Scientifica , 2012, DOI: 10.6064/2012/871201
Abstract:
Comparative Analysis of the Full-Length Genome Sequence of a Clinical Isolate of Human Parainfluenza Virus 4B
John A. Lednicky,Thomas B. Waltzek,Micah D. Halpern,Sara B. Hamilton
Scientifica , 2012, DOI: 10.6064/2012/871201
Abstract: We are engaged in airborne transmission and epidemiology studies of respiratory pathogens, with particular interest in human parainfluenza virus type 4 (hPIV-4) and other lesser studied viruses. In this paper, hPIV-4 was detected in primary rhesus monkey kidney (PRMK) cells that had been inoculated with nasopharyngeal swab material obtained from a child with a mild upper respiratory tract illness. Attempts to isolate the virus in pure culture were hampered by the presence of a fast-growing simian spumavirus that was a contaminant of the PRMK cells. Total RNA was extracted from the PRMK cell culture, and PCR followed by sequencing of a subgenomic section of the fusion protein gene suggested the hPIV-4 was subtype 4B. At the time of this work, two complete but dissimilar hPIV-4B genomes had been deposited by others in GenBank. To gain better insights on hPIV-4B, and to test methods that we are developing for viral forensics, the entire genomic sequence of our virus was determined from archived RNA. The hPIV-4B genomic sequence that we determined conforms to the paramyxovirus “rule of six.” Here, we compare and contrast the genetic features of the three completely sequenced hPIV-4B genomes currently present in GenBank. Human parainfluenza viruses (hPIVs) are single-stranded, negative sense RNA viruses of the genus Rubulavirus, family Paramyxoviridae, which cause acute respiratory tract infections in children and adults. Four hPIV serotypes (hPIV 1–4) have been identified; serotype 4 is further subdivided into two antigenic subtypes: 4A and 4B [1, 2]. The epidemiology and clinical manifestations of hPIV 1–3 are well known, whereas comparatively little is known about hPIV4s, as they are difficult to isolate in cell culture and are absent from routine respiratory virus detection tests in most clinical virology laboratories [3–5]. Whereas hPIV4s were formerly mostly associated with mild respiratory illnesses in young people, recent studies indicate the viruses can cause more severe infections such as pneumonia in young and older patients (mentioned in [3–5]). The genomic cRNAs of hPIV-4 subtypes 4A and B are a little >17.0?kbp in length. Their viral genomes encode for nucleocapsid (NP), phospho (P), nonstructural (V), matrix (M), fusion (F), haemagglutinin-neuraminidase (HN), and large (L) proteins. Prior to this work, there were two complete hPIV-4B sequences in GenBank: those of strains 68–333 [6] and SKPIV-4 [7]. Primary monkey kidney (PMK) cells are inoculated with appropriate specimens for the detection of human parainfluenza viruses in many American
Ferrets develop fatal influenza after inhaling small particle aerosols of highly pathogenic avian influenza virus A/Vietnam/1203/2004 (H5N1)
John A Lednicky, Sara B Hamilton, Richard S Tuttle, William A Sosna, Deirdre E Daniels, David E Swayne
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-231
Abstract: Ferrets were successfully infected through intranasal instillation or through inhalation of small particle aerosols with four different doses of Influenza virus A/Vietnam/1203/2004 (H5N1). The animals developed severe influenza encephalomyelitis following intranasal or inhalation exposure to 101, 102, 103, or 104 infectious virus particles per ferret.Aerosolized Influenza virus A/Vietnam/1203/2004 (H5N1) is highly infectious and lethal in ferrets. Clinical signs appeared earlier in animals infected through inhalation of aerosolized virus compared to those infected through intranasal instillation.Human infections caused by H5N1 highly pathogenic avian influenza viruses (H5N1) that arose from 2003-onwards have been rare as evident by only 500 cases confirmed through 5 July, 2010. However, H5N1 have a fatality rate of about 59% [1]. In ferret transmission models, the H5N1 viruses were inconsistent in transmission by direct or indirect contact exposure including respiratory droplets, but direct intranasal exposure caused morbidity and sometimes, mortality [2,3]. In contrast, the 1918 pandemic influenza virus was easily transmissible, especially human-to-human, and caused the deaths of between 20 - 40 million people worldwide for a lethality rate of 2.5%, and experimental studies demonstrated efficient transmission ferret-to-ferret by respiratory droplets [4]. The differences in transmissibility and lethality between the two viruses is not fully understood, but the use of aerosol challenge may improve our understanding of factors responsible for transmission and lethality of the H5N1 viruses.There is limited knowledge about the potential routes and determinants required for H5N1 influenza virus transmission to and between humans, and it is not clear whether humans can be infected through inhalation of aerosolized contemporary H5N1 virus particles. Receptor distribution in the human airway is proposed to restrict efficient inter-human transmission of H5N1 influenza virus
Gas-permeable ethylene bags for the small scale cultivation of highly pathogenic avian influenza H5N1 and other viruses in embryonated chicken eggs
Sara B Hamilton, Deirdre E Daniels, William A Sosna, Eric R Jeppesen, Julie M Owells, Micah D Halpern, Kimberly S McCurdy, Jonathan O Rayner, John A Lednicky
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-23
Abstract: Virus yields acceptable for many applications were attained when influenza-, alpha-, flavi-, canine distemper-, and mousepox viruses were propagated in ECE sealed within ethylene breather bags.For many small-scale applications, ethylene breather bags can be used to encase ECE inoculated with various viruses.Embryonated (embryonating) chicken eggs (ECE) have long been used for isolating or propagating influenza and other viruses and certain bacteria such as Rickettsia [1-5]. Alpha-, corona-, flavi-, paramyxo-, and poxviruses are among the non-influenza viruses sometimes grown in ECE. For small-scale work with pathogens that must be worked with in BSL3 facilities, inoculated ECE are sometimes housed in small egg incubators kept within a BSC [such a practice is not practical for medium-to-large diagnostic operations, wherein ECE are placed in incubators within a bioBubble (Ft. Collins, CO) or similar barrier and containment enclosure]. Since ECE are fragile, accidental egg breakage is possible. Furthermore, diagnostic specimens inoculated into ECE may contain contaminating flora that form enough gas to break the egg shell. We sought a simple method to contain spillage from a broken ECE inoculated with dangerous pathogens, and explored the feasibility of using ethylene breather bags for that purpose. Ethylene breather bags are permeable to oxygen and carbon dioxide but retain water, and are used in the aquarium industry to transport live fish. Chicken embryo survival was examined and the yield of various influenza and other viruses in bagged eggs was determined.No differences were detected in the survival of chicken embryos in bagged vs non-bagged 7 - 12 day old ECE after five days of incubation without rotation as performed for virus-inoculated ECE. Noteworthy, especially during summer months, up to 20% attrition (death of non-inoculated ECE) occurred with some batches, regardless of whether the ECE were bagged or not bagged. Since the ECE are checked and culled if dea
Higher titers of some H5N1 and recent human H1N1 and H3N2 influenza viruses in Mv1 Lu vs. MDCK cells
Sara B Hamilton, Diane E Wyatt, Brett T Wahlgren, Maureen K O'Dowd, Jane M Morrissey, Deirdre E Daniels, John A Lednicky
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-66
Abstract: The 50% tissue culture infectious dose and plaque forming titer of many influenza A subtype H1N1, H3N2, and H5N1 viruses was higher in Mv1 Lu than in MDCK cells.The yields of influenza subtype H1N1, H3N2, and H5N1 viruses can be higher in Mv1 Lu cells than in MDCK cells.The infectivity of influenza viruses can differ among the various primary cells and continuous cell lines used for such measurements [1,2]. As the term "infectivity" has many meanings in virology, in this manuscript, infectivity is broadly defined as the ability of a virus particle to enter a host cell and form viable progeny virions. Measures of infectivity depend not only on the inherent susceptibility of a particular type of cell for a given influenza virus, but also on the methodology used for infecting the cells [such as the length of time the virus is left in contact with the cells, as the affinity/avidity of a virus for its receptor(s) may vary according to cell type], the quasispecies distribution within a particular influenza virus stock, and other variables.Accurate viable virus counts are essential for inhalation exposure studies with aerosolized viruses [3], for correlation of viable count to genome equivalence in level of detection studies, and other relevant work with influenza viruses. Quantitative RT-PCR methods are not suitable, as they do not distinguish between viable and non-viable virus particles. Indeed, infectious influenza virus particles comprise a minor subpopulation of biologically active particles (BAP) within a viral population [4]. The other BAP include interferon suppressing particles [4,5], defective interfering particles [4,6], and noninfectious cell-killing particles [4,7].Madin-Darby canine kidney (MDCK) epithelial cells are widely used for the isolation of human influenza A and B viruses and the determination of influenza A virus titers [1,8-11]. However, we (S. Hamilton and J. Lednicky, unpublished) and others [2,12] have observed that all things equal, the cytopa
Genetically distant American Canine distemper virus lineages have recently caused epizootics with somewhat different characteristics in raccoons living around a large suburban zoo in the USA
John A Lednicky, Jean Dubach, Michael J Kinsel, Thomas P Meehan, Maurizio Bocchetta, Laura L Hungerford, Nicolene A Sarich, Kelley E Witecki, Michael D Braid, Casandra Pedrak, Christiane M Houde
Virology Journal , 2004, DOI: 10.1186/1743-422x-1-2
Abstract: Phylogenetic analyses of subgenomic CDV fusion (F) -, phosphoprotein (P) -, and complete hemagglutinin (H) – gene sequences indicated that distinct American CDV lineages caused the distemper epizootics. The 1998 outbreak was caused by viruses that are likely from an old CDV lineage that includes CDV Snyder Hill and Lederle, which are CDV strains from the early 1950's. The 2000 and 2001 viruses appear to stem from the lineage of CDV A75/17, which was isolated in the mid 1970's. Only the 2001 viruses formed large syncytia in brain and/or lung tissue, and during primary isolation in-vitro in Vero cells, demonstrating at least one phenotypic property by which they differed from the other viruses.Two different American CDV lineages caused the raccoon distemper outbreaks. The 1998 viruses are genetically distant to the 2000/2001 viruses. Since CDV does not cause persistent infections, the cycling of different CDV lineages within the same locale suggests multiple reintroductions of the virus to area raccoons. Our findings establish a precedent for determining whether the perceived differences in mortality rates are actual and attributable in part to inherent differences between CDV strains arising from different CDV lineages.Canine distemper virus (CDV) (family Paramyxoviridae, genus Morbillivirus) is a single-stranded (negative-sense) enveloped RNA virus that is highly contagious and transmitted predominantly by aerosols [1]. Long known to cause potentially lethal disease among members of the Canidae, Mustelidae, and Procyonidae, CDV has recently been detected as a cause of morbidity and mortality in large felids [2], fresh-water seals (Phoca sibirica) [3], and various other animals. CDV killed more than 10,000 Caspian seals (Phoca caspica) in year 2000 [4], and decimated an African wild dog (an endangered species) breeding pack [5], demonstrating that CDV epidemics can be catastrophic. It also killed 1/3 of the Serengeti lions (Panthera leo) in 1994, whereas mortality du
Residual correlations between decay products of $\pi^0\pi^0$ and $p\Sigma^0$ systems
Stavinskiy, A.;Mikhailov, K.;Erazmus, B.;Lednicky, R.
High Energy Physics - Phenomenology , 2007,
Abstract: Residual correlations between decay products due to a combination of both correlations between parents at small relative velocities and small decay momenta are discussed. Residual correlations between photons from pion decays are considered as a new possible source of information on direct photon fraction. Residual correlations in $p\gamma$ and $p\Lambda$ systems due to $p\Sigma^0$ interaction in final state are predicted based on the $p\Sigma^0$ low energy scattering parameters deduced from the spin-flavour SU$_6$ model by Fujiwara et al. including effective meson exchange potentials and explicit flavour symmetry breaking to reproduce the properties of the two-nucleon system and the low-energy hyperon-nucleon cross section data. The $p\gamma_{\Sigma^0}$ residual correlation is concentrated at $k^* \approx 70$ Mev/$c$ and its shape and intensity appears to be sensitive to the scattering parameters and space-time dimensions of the source. The $p\Lambda_{\Sigma^0}$ residual correlation recovers the negative parent $p\Sigma^0$ correlation for $k^* > 70$ Mev/$c$. The neglect of this negative residual correlation would lead to the underestimation of the parent $p\Lambda$ correlation effect and to an overestimation of the source size.
Residual correlations between decay products of $π^0π^0$ and $pΣ^0$ systems
A. Stavinskiy,K. Mikhailov,B. Erazmus,R. Lednicky
Physics , 2007,
Abstract: Residual correlations between decay products due to a combination of both correlations between parents at small relative velocities and small decay momenta are discussed. Residual correlations between photons from pion decays are considered as a new possible source of information on direct photon fraction. Residual correlations in $p\gamma$ and $p\Lambda$ systems due to $p\Sigma^0$ interaction in final state are predicted based on the $p\Sigma^0$ low energy scattering parameters deduced from the spin-flavour SU$_6$ model by Fujiwara et al. including effective meson exchange potentials and explicit flavour symmetry breaking to reproduce the properties of the two-nucleon system and the low-energy hyperon-nucleon cross section data. The $p\gamma_{\Sigma^0}$ residual correlation is concentrated at $k^* \approx 70$ Mev/$c$ and its shape and intensity appears to be sensitive to the scattering parameters and space-time dimensions of the source. The $p\Lambda_{\Sigma^0}$ residual correlation recovers the negative parent $p\Sigma^0$ correlation for $k^* > 70$ Mev/$c$. The neglect of this negative residual correlation would lead to the underestimation of the parent $p\Lambda$ correlation effect and to an overestimation of the source size.
Page 1 /486880
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.