Home About us Contact
|
Home About us Contact | ||
|
|
||
Virus Strains (virus + strain)
Selected AbstractsStrain-dependent viral dynamics and virus-cell interactions in a novel in vitro system supporting the life cycle of blood-borne hepatitis C virus,HEPATOLOGY, Issue 3 2009Hussein Hassan Aly We developed an in vitro system that can be used for the study of the life cycle of a wide variety of blood-borne hepatitis C viruses (HCV) from various patients using a three-dimensional hollow fiber culture system and an immortalized primary human hepatocyte (HuS-E/2) cell line. Unlike the conventional two-dimensional culture, this system not only enhanced the infectivity of blood-borne HCV but also supported its long-term proliferation and the production of infectious virus particles. Both sucrose gradient fractionation and electron microscopy examination showed that the produced virus-like particles are within a similar fraction and size range to those previously reported. Infection with different HCV strains showed strain-dependent different patterns of HCV proliferation and particle production. Fluctuation of virus proliferation and particle production was found during prolonged culture and was found to be associated with change in the major replicating virus strain. Induction of cellular apoptosis was only found when strains of HCV-2a genotype were used for infection. Interferon-alpha stimulation also varied among different strains of HCV-1b genotypes tested in this study. Conclusion: These results suggest that this in vitro infection system can reproduce strain-dependent events reflecting viral dynamics and virus-cell interactions at the early phase of blood-borne HCV infection, and that this system can allow the development of new anti-HCV strategies specific to various HCV strains. (HEPATOLOGY 2009.) [source] Experimental hepatitis A virus (HAV) infection in cynomolgus monkeys (Macaca fascicularis): evidence of active extrahepatic site of HAV replicationINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 1 2010Luciane A. Amado Summary This work studied the replication sites of hepatitis A virus (HAV) in cynomolgus monkeys (Macaca fascicularis) after intravenous inoculation. The cynomolgus monkeys were inoculated with the Brazilian hepatitis A virus strain (HAF-203). Monkeys were euthanized on days 15, 30, 45 and 60 postinoculation (pi). Liver samples, submandibular salivary gland, mesenteric lymph node and tonsils were removed for virological and pathological evaluation. Immunofluorescence analyses on liver and salivary gland sections using confocal laser scanning microscopy revealed the presence of HAV antigen (HAV Ag). The presence of HAV genome was monitored by real-time PCR. The HAV RNA was detected at 7 days postinoculation (dpi), concomitantly in serum, saliva and faeces. The highest HAV viral load was observed in faeces at 15 dpi (105 copies/ml), followed by serum viral load of 104 copies/ml at 20 dpi and saliva viral load of 103 copies/ml at 7 dpi. The animals showed first histological and biochemical signs of hepatitis at 15 dpi. The HAV antigen (Ag) was present from day 7 until day 60 pi in the liver and salivary glands. The HAV replicative intermediate was also detected in the liver (4.5 × 104 copies/mg), salivary glands (1.9 × 103 copies/mg), tonsils (4.2 × 101 copies/mg) and lymph nodes (3.4 × 101 copies/mg). Our data demonstrated that the salivary gland as an extrahepatic site of early HAV replication could create a potential risk of saliva transmitted infection. In addition, the cynomolgus monkey was confirmed as a suitable model to study the pathogenesis of HAV human infection. [source] Fifteen years of Env C2V3C3 evolution in six individuals infected clonally with human immunodeficiency virus type 1JOURNAL OF MEDICAL VIROLOGY, Issue 11 2007Bernd Kupfer Abstract The study of the evolution of human immunodeficiency virus type 1 (HIV-1) requires blood samples collected longitudinally and data on the approximate time point of infection. Although these requirements were fulfilled in several previous studies, the infectious sources were either unknown or heterogeneous genetically. In the present study, HIV-1 env C2V3C3 (nt 7029-7315) evolution was examined retrospectively in a cohort of hemophiliacs. Compared to other cohorts, the area of interest here was the infection of six hemophiliacs by the same virus strain, that is, the infecting viruses shared an identical genome. As expected, divergence from the founder sequence as well as interpatient divergence of the predominant virus strains increased significantly over time. Based on the V3 nucleotide sequences, CCR5 usage was predicted exclusively throughout the whole period of infection in all patients. Interestingly, common patterns of viral evolution were detected in the patients of the cohort. Four amino acid substitutions within the V3 loop emerged and persisted subsequently in five (positions 305 and 308 of the HXB2 gp120 reference sequence) and six patients (positions 325 and 328 in HXB2 gp120), respectively. These common changes within the V3 loop are likely to be enforced by HIV-1 specific immune response. J. Med. Virol. 79:1729,1739, 2007. © 2007 Wiley-Liss, Inc. [source] Effective poxvirus removal by sterile filtration during manufacture of plasma derivatives,JOURNAL OF MEDICAL VIROLOGY, Issue 4 2005A. Berting Abstract As a consequence of the September 2001 terrorist events, programs to protect against further such acts including potentially the use of biological warfare agents have been launched in the USA and elsewhere. As part of these initiatives, Vaccinia virus was procured for the pre-emptive vaccination of key personnel against smallpox as well as population-wide protection after an eventual exposure. The introduction of this live virus into a population at a relatively large scale represents a theoretical challenge for the safety of the blood supply, and potentially for plasma for fractionation. To strengthen further the demonstration of safety margins for plasma derived products against Vaccinia virus, the capacity of sterile filtration procedures to remove the virus was investigated. An infectivity assay for the Vaccinia virus strain which represents the majority of smallpox vaccine stocks available currently was used to investigate the potential removal of this virus by sterile filtration processes during the manufacture of plasma derivatives. Vaccinia virus behaves as predicted based on its size, i.e., an artificially added virus load is removed about 10,000-fold by the sterile filtration procedures tested. As the current investigation covered a range of different protein concentrations, filter materials and filters from different manufacturers, the results obtained are considered to be widely applicable. The current investigation supports further the high safety margins of plasma derivatives against any potential Vaccinia virus content of plasma for fractionation. As the large size is a general feature of Orthopox viruses, the results would also provide assurance against poxviruses identified more recently, for example, Monkeypox virus. J. Med. Virol. 75:603,607, 2005. © 2005 Wiley-Liss, Inc. [source] Genetic characterization of the M RNA segment of a Balkan Crimean-Congo hemorrhagic fever virus strain,JOURNAL OF MEDICAL VIROLOGY, Issue 3 2005Anna Papa Abstract Crimean-Congo hemorrhagic fever (CCHF) virus causes one of the most severe diseases in humans, with a mortality rate of up to 30%. It is transmitted to humans by the bite of hard ticks or by contact with blood or tissues from human patients or infected livestock. Balkan Peninsula is an endemic region of the disease, and sporadic cases or even outbreaks are observed every year. The M RNA segment encodes for the glycoprotein precursor of two surface glycoproteins Gn and Gc. Up to now complete M RNA CCHF virus sequences have been published from strains isolated in Nigeria, China, Pakistan, Tajikistan, and Russia. In the present study, the genetic characterization of the complete nucleotide sequence of the M RNA segment of a Balkan CCHF virus strain, Kosovo/9553/2001, isolated in summer of 2001 from a human fatal case in Kosovo is reported. This is the first published complete M nucleotide sequence of a CCHF virus strain isolated in Balkans. It was found that the Balkan strain is similar to the Russian strain, both strains differing from all other completely sequenced CCHF virus strains by approximately 22% at the nucleotide level forming an independent clade in the phylogenetic tree. J. Med. Virol. 75:466,469, 2005. © 2005 Wiley-Liss, Inc. [source] Identification of a new genotype H wild-type mumps virus strain and its molecular relatedness to other virulent and attenuated strainsJOURNAL OF MEDICAL VIROLOGY, Issue 2 2003Georgios Amexis Abstract A single clinical isolate of mumps virus designated 88-1961 was obtained from a patient hospitalized with a clinical history of upper respiratory tract infection, parotitis, severe headache, fever and lymphadenopathy. We have sequenced the full-length genome of 88-1961 and compared it against all available full-length sequences of mumps virus. Based upon its nucleotide sequence of the SH gene 88-1961 was identified as a genotype H mumps strain. The overall extent of nucleotide and amino acid differences between each individual gene and protein of 88-1961 and the full-length mumps samples showed that the missense to silent ratios were unevenly distributed. Upon evaluation of the consensus sequence of 88-1961, four positions were found to be clearly heterogeneous at the nucleotide level (NP 315C/T, NP 318C/T, F 271A/C, and HN 855C/T). Sequence analysis revealed that the amino acid sequences for the NP, M, and the L protein were the most conserved, whereas the SH protein exhibited the highest variability among the compared mumps genotypes A, B, and G. No identifying molecular patterns in the non-coding (intergenic) or coding regions of 88-1961 were found when we compared it against relatively virulent (Urabe AM9 B, Glouc1/UK96, 87-1004 and 87-1005) and non-virulent mumps strains (Jeryl Lynn and all Urabe Am9 A substrains). J. Med. Virol. 70: 284,286, 2003. © 2003 Wiley-Liss, Inc. [source] Yellow Fever,Associated Viscerotropic Disease in Barcelona, SpainJOURNAL OF TRAVEL MEDICINE, Issue 3 2008Jose Muñoz MD Yellow fever vaccine is a live, attenuated viral preparation from the 17D virus strain. Since 1996, 34 cases of yellow fever vaccine,associated viscerotropic disease (YEL-AVD) have been described. We report a new case of YEL-AVD. Given the potential risks associated with the vaccine, physicians should consider vaccination only for patients truly at risk for exposure to yellow fever, especially for primovaccination. [source] Complete Nucleotide Sequence of a Coxsackievirus B4 Strain that Establishes Infection in ICR Mice Pancreas and Induces Glucose IntoleranceTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 5 2008Mi Zhou Abstract Some coxsackievirus B serotypes are potentially diabetogenic. Previous studies revealed that the virulence and the tissue damage varied with the genetics of the virus strain as well as with the genetics of the mice. A single amino acid variation can alter virulence and tropism in both murine and in vitro models. However, the genetic determinants of this phenomenon have not been determined. In this study, infections with a laboratory strain of coxsackievirus B4 resulted in a diabetes-like syndrome in ICR mice, characterized by chronic pancreatic inflammation together with dysregulation in glucose metabolism, loss of pancreatic acinar tissue and persistent infection in islets. To characterize the genetic determinants involved in the mouse pancreas adaptation, the laboratory strain of coxsackievirus B4 was cloned for molecular characterization. Comparing the whole genome sequence of this virus strain with the other coxsackievirus B4 strains revealed some differences. Altogether 15 nucleotides were changed, resulting in 10 amino acid substitutions, which might be responsible for the pathogenic phenotype of this strain in mice. Anat Rec, 291:601,609, 2008. © 2008 Wiley-Liss, Inc. [source] Structure of NS1A effector domain from the influenza A/Udorn/72 virusACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2009Shuangluo Xia The nonstructural protein NS1A from influenza virus is a multifunctional virulence factor and a potent inhibitor of host immunity. It has two functional domains: an N-terminal 73-amino-acid RNA-binding domain and a C-terminal effector domain. Here, the crystallographic structure of the NS1A effector domain of influenza A/Udorn/72 virus is presented. Structure comparison with the NS1 effector domain from mouse-adapted influenza A/Puerto Rico/8/34 (PR8) virus strain reveals a similar monomer conformation but a different dimer interface. Further analysis and evaluation shows that the dimer interface observed in the structure of the PR8 NS1 effector domain is likely to be a crystallographic packing effect. A hypothetical model of the intact NS1 dimer is presented. [source] Sandfly fever virus outbreak in CyprusCLINICAL MICROBIOLOGY AND INFECTION, Issue 2 2006A. Papa Abstract A major outbreak of febrile syndrome occurred during 2002 among the Greek Army forces in Cyprus. Serological and molecular investigations revealed that the causative agent was a Sicilian-like phlebovirus. A virus strain was isolated from a blood sample taken on the first day of the disease. Phylogenetic analysis of partial L RNA segment sequences revealed that the strain from Cyprus differed from sandfly Sicilian virus by 6.7% at the nucleotide level. [source] Genetic immunity and influenza pandemicsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2006Sergey N. Rumyantsev Abstract In addition to the great number of publications focused on the leading role of virus mutations and reassortment in the origin of pandemic influenza, general opinion emphasizes the victim side of the epidemic process. Based on the analysis and integration of relevant ecological, epidemiological, clinical, genetic and experimental data, the present article is focused on the evolution of ,virus , victim' ecological systems resulting in the formation of innate (i.e. genetic, constitutional) immunity in the involved species and populations. This kind of immunity functions today as the greatest natural barrier to the pandemic spread of influenza among humans and ecologically related kinds of animals. Global influenza pandemics can arise when the worldwide population contains at least a minimum number of people susceptible to a known or mutant influenza virus. Special attention is paid in this article to individual tests for the presence of this barrier, including the implications of specific findings for public health policy. Such tests could be based on in vitro observation of the action of relevant virus strains on primary cell cultures or on their cellular or molecular components extracted from individuals. The resources of the Human Genome Project should also be utilized. [source] Fifteen years of Env C2V3C3 evolution in six individuals infected clonally with human immunodeficiency virus type 1JOURNAL OF MEDICAL VIROLOGY, Issue 11 2007Bernd Kupfer Abstract The study of the evolution of human immunodeficiency virus type 1 (HIV-1) requires blood samples collected longitudinally and data on the approximate time point of infection. Although these requirements were fulfilled in several previous studies, the infectious sources were either unknown or heterogeneous genetically. In the present study, HIV-1 env C2V3C3 (nt 7029-7315) evolution was examined retrospectively in a cohort of hemophiliacs. Compared to other cohorts, the area of interest here was the infection of six hemophiliacs by the same virus strain, that is, the infecting viruses shared an identical genome. As expected, divergence from the founder sequence as well as interpatient divergence of the predominant virus strains increased significantly over time. Based on the V3 nucleotide sequences, CCR5 usage was predicted exclusively throughout the whole period of infection in all patients. Interestingly, common patterns of viral evolution were detected in the patients of the cohort. Four amino acid substitutions within the V3 loop emerged and persisted subsequently in five (positions 305 and 308 of the HXB2 gp120 reference sequence) and six patients (positions 325 and 328 in HXB2 gp120), respectively. These common changes within the V3 loop are likely to be enforced by HIV-1 specific immune response. J. Med. Virol. 79:1729,1739, 2007. © 2007 Wiley-Liss, Inc. [source] Identification of genotype 4 hepatitis E virus strains from a patient with acute hepatitis E and farm pigs in Bali, Indonesia,JOURNAL OF MEDICAL VIROLOGY, Issue 8 2007I. Dewa Nyoman Wibawa Abstract A previous study revealed that antibodies to hepatitis E virus (HEV) (anti-HEV) are highly prevalent among healthy individuals and farm pigs in Bali, Indonesia, and suggested that HEV infection may occur via zoonosis among Balinese people. However, there were no reports of acute hepatitis E in Bali. To elucidate whether Balinese HEV strains recovered from infected humans and pigs have significant sequence similarity, serum samples obtained from 57 patients (age, mean,±,standard deviation, 31.1,±,11.9 years) with sporadic acute hepatitis and from one hundred and one 2- or 3-month-old farm pigs in Bali were tested for anti-HEV and HEV RNA. Among the 57 patients, 2 (3.5%) had high-titer IgM/IgA class anti-HEV antibodies and one of them had detectable HEV RNA (BaliE03-46). Overall, 58 pigs (57.4%) tested positive for anti-HEV, while 5 pigs (5.0%) had detectable HEV RNA. Based on the 412-nucleotide sequence within open reading frame 2, the BaliE03-46 isolate and the 5 swine HEV isolates recovered from the viremic pigs were phylogenetically classified in genotype 4, but were only 77.3,90.8% identical to the genotype 4 HEV isolates reported thus far in China, India, Japan, Taiwan, and Vietnam. The BaliE03-46 isolate of human origin shared high identities of 97.3,98.3% with 4 of the 5 Balinese swine isolates, but differed by 16.1% from the remaining swine isolate. These results suggest that indigenous HEV strains of genotype 4 with marked heterogeneity are circulating in Bali, Indonesia, and that pigs are reservoirs of HEV for Balinese people who have a habit of ingesting uncooked pigs. J. Med. Virol. 79: 1138,1146, 2007. © 2007 Wiley-Liss, Inc. [source] Genetic characterization of hepatitis C virus strains in Estonia: Fluctuations in the predominating subtype with timeJOURNAL OF MEDICAL VIROLOGY, Issue 4 2007Tatjana Tallo Abstract During the last decade, there has been a dramatic increase in intravenous drug use in young adults in Estonia with an increased incidence of both hepatitis B and C as a consequence. Since genetic data are limited regarding hepatitis C virus (HCV) strains in Estonia, the aim of the study was to characterize HCV strains in different risk groups to determine their relatedness to strains from other geographical regions. Three hundred fifty-three anti-HCV positive sera collected during 1994,2004 from hospitalized patients, blood donors and health care workers were used as source of HCV RNA. Two hundred nine (59%) of the sera were positive for HCV RNA by PCR directed to the 5,-UTR region. For 174 strains the HCV subtype was determined by analyses of the NS5B and/or the 5,UTR-core regions. 1b (71%) was the most common subtype followed by 3a (24%), 2c (2%), 1a (1%), and 2a (1%). The 1b and 3a strains were similar to strains from other regions of the former USSR. Within genotype 1b there were several HCV lineages. However, for 3a there seemed to be two separate introductions into Estonia. There was a relative shift from subtype 1b to 3a in 1999,2000 with a further replacement of 3a with 1b in intravenous drug users in 2001 and onwards (P,<,0.05). However, both subtypes were found to co-circulate in the community independent of risk factors. One patient was infected with the 2k/1b recombinant presumed to originate from St. Petersburg being the first isolate of this recombinant recovered outside Russia. J. Med. Virol. 79:374,382, 2007. © 2007 Wiley-Liss, Inc. [source] Rapid diversification of measles virus genotypes circulating in Morocco during 2004,2005 epidemics,JOURNAL OF MEDICAL VIROLOGY, Issue 11 2006Amal Alla Abstract Measles virus strains circulating in six different regions in Morocco during 2004,2005 were analysed. They were genotyped using two different methods: the recently developed method based on real-time PCR amplification and melting curve analyses, and the conventional method based on nucleic acid sequencing and phylogenetic analysis of 456 nucleotides of the 3,-region of the nucleoprotein (N) gene sequence. Five genotypes (A, B3.2, C2, D7 and D8) were shown to be circulating during this period. Previous studies on measles virus genotypes in Morocco (1998,2003) showed that only the genotype C2 was present and was considered to be endemic. Sequence comparison of the 2004,2005 viruses with other measles strains suggests that measles strains belonging to genotype B3.2 were probably imported from West Africa, whereas those belonging to genotypes D7 and D8 were imported from Europe. These studies which identify the route of importation of measles are important for developing strategies for measles elimination in Morocco. J. Med. Virol. 78:1465,1472, 2006. © 2006 Wiley-Liss, Inc. [source] Molecular detection and characterization of human enteroviruses directly from clinical samples using RT-PCR and DNA sequencingJOURNAL OF MEDICAL VIROLOGY, Issue 2 2006Miren Iturriza-Gómara Abstract Enteroviruses are common human pathogens associated with a wide spectrum of symptoms ranging from asymptomatic infection to acute flaccid paralysis and neonatal multi-organ failure. Molecular methods that provide rapid diagnosis and increased sensitivity have been developed for the diagnosis of enterovirus infection using oligonucleotide primers complementary to conserved sequences located in the 5, untranslated region (UTR), but data generated from these regions are not sufficiently discriminatory for typing due to the lack of correlation between their nucleic acid sequence and serotype specificity. Sequences derived from the gene encoding the capsid VP1 correlate with serotype, and therefore provide the opportunity for the development of molecular typing methods consistent with present serogical methods. In this study, oligonucleotide primers that amplify a region of the 5,UTR to detect enterovirus RNA, and the region encoding the enterovirus VP1 N-terminus to characterize virus strains were used in nested and semi-nested RT-PCRs, respectively. The ability of the VP1 RT-PCR to amplify diverse viruses within genotypes and genogroups was confirmed by the correct identification of both prototype strains, and strains circulating currently of the same genotypes. The mole-cular methods proved their utility through the detection of enteroviruses that failed to grow in cell culture, their subsequent characterization and the characterization of strains that failed to serotype in neutralization assays. Molecular methods increased significantly the sensitivity of detection (P,<,0.001) and of characterization (P,<,0.01) of enteroviruses when compared to classical methods. J. Med. Virol. 78:243,253, 2006. © 2005 Wiley-Liss, Inc. [source] Genetic characterization of the M RNA segment of a Balkan Crimean-Congo hemorrhagic fever virus strain,JOURNAL OF MEDICAL VIROLOGY, Issue 3 2005Anna Papa Abstract Crimean-Congo hemorrhagic fever (CCHF) virus causes one of the most severe diseases in humans, with a mortality rate of up to 30%. It is transmitted to humans by the bite of hard ticks or by contact with blood or tissues from human patients or infected livestock. Balkan Peninsula is an endemic region of the disease, and sporadic cases or even outbreaks are observed every year. The M RNA segment encodes for the glycoprotein precursor of two surface glycoproteins Gn and Gc. Up to now complete M RNA CCHF virus sequences have been published from strains isolated in Nigeria, China, Pakistan, Tajikistan, and Russia. In the present study, the genetic characterization of the complete nucleotide sequence of the M RNA segment of a Balkan CCHF virus strain, Kosovo/9553/2001, isolated in summer of 2001 from a human fatal case in Kosovo is reported. This is the first published complete M nucleotide sequence of a CCHF virus strain isolated in Balkans. It was found that the Balkan strain is similar to the Russian strain, both strains differing from all other completely sequenced CCHF virus strains by approximately 22% at the nucleotide level forming an independent clade in the phylogenetic tree. J. Med. Virol. 75:466,469, 2005. © 2005 Wiley-Liss, Inc. [source] Genetic characterization of new Dobrava hantavirus isolate from GreeceJOURNAL OF MEDICAL VIROLOGY, Issue 3 2003Kirill Nemirov Abstract The first complete genome sequence of Dobrava hantavirus isolated from yellow-necked mouse Apodemus flavicollis trapped in the northeastern Greece is described. The S, M, and L segments of the Greek isolate of Dobrava virus are 1673, 3635, and 6532 nucleotides (nt) long, respectively, and encode the nucleocapsid (N) protein of 429 amino acids (aa), glycoprotein precursor of 1135 aa, and the L protein of 2151 aa. N protein contains three cysteine residues conserved in all known hantaviruses, as well as structural domains responsible for the RNA binding and presumable interaction with the apoptosis enhancer Daxx. All cysteine residues and glycosylation sites that are conserved among G1G2 sequences of all hantaviruses species were also found in the Greek isolate. The L protein contains all the polymerase motifs and structural domains found in other hantavirus polymerases. Comparison of the Greek isolate of Dobrava virus with other hantaviruses showed the highest level of sequence homology with Dobrava virus isolate from Slovenia. Other hantaviruses carried by Murinae rodents (Saaremaa, Hantaan, Seoul, and Thailand viruses) were more divergent and hantaviruses carried by Arvicolinae or Sigmodontinae rodents showed the highest genetic diversity with the Greek isolate of Dobrava. The results of phylogenetic analyses confirmed these observations and showed a monophily of all the Dobrava virus strains that, in turn, shared more ancient ancestors first with Saaremaa virus and then with other Murinae-borne hantaviruses. J. Med. Virol. 69:408,416, 2003. © 2003 Wiley-Liss, Inc. [source] Characterization of tick-borne encephalitis virus from latvia: Evidence for co-circulation of three distinct subtypesJOURNAL OF MEDICAL VIROLOGY, Issue 4 2001Åke Lundkvist Abstract Viruses of the tick-borne encephalitis (TBE) antigenic complex within the family Flaviviridae cause a variety of diseases, including uncomplicated febrile illness, meningoencephalitis, and hemorrhagic fever. Different domesticated animals or wildlife species often act as reservoir hosts and ixodid ticks serve as vectors. Although TBE is a serious problem in Latvia, the knowledge concerning TBE virus (TBEV) strains circulating in the country is most limited. Only two strains (Latvia-1-96 isolated from a TBE patient, and RK1424 originating from an Ixodes persulcatus tick), which belonged to the Siberian and the Far Eastern subtypes of TBEV, respectively, have previously been characterized. In the present study, we concentrated on the western and central regions of Latvia, with predominantly Ixodes ricinus ticks. Five virus strains were isolated from serum samples of patients with clinical symptoms of an acute TBE infection. Nucleotide sequences encoding the envelope (E) protein of TBEV, which were recovered from the five TBEV isolates, showed the highest level of identity to the corresponding sequences of the prototype strain Neudoerfl and other European strains of the Western TBEV subtype characterized previously. Accordingly, phylogenetic analysis placed the new Latvian isolates within the Western genetic lineage of TBEV. Taken together with earlier observations, the results proved that all three TBEV subtypes are co-circulating in Latvia and indicated that the genetic diversity of TBEV within certain geographical areas is much more complex than previously believed. J. Med. Virol. 65:730,735, 2001. © 2001 Wiley-Liss, Inc. [source] Failure to infect rhesus monkeys with hepatitis C virus strains of genotypes 1a, 2a or 3aJOURNAL OF VIRAL HEPATITIS, Issue 3 2001J. Bukh The chimpanzee is the only recognized animal model for the study of hepatitis C virus (HCV). However, recently it was reported that rhesus monkeys were susceptible to HCV and developed hepatitis during infection. In the present study, we inoculated two rhesus monkeys each with HCV strain H77 (genotype 1a), strain HC-J6 (genotype 2a) or strain S52 (genotype 3a). Weekly serum samples were tested for liver enzyme values, HCV antibodies and HCV RNA. We did not find evidence of HCV infection in any of the monkeys during 24 weeks of follow-up. Our study demonstrates that rhesus monkeys are not readily infected with HCV and apparently do not represent a useful animal model for the study of HCV. [source] Monitoring exposure to avian influenza viruses in wild mammalsMAMMAL REVIEW, Issue 3 2009KACI K. VANDALEN ABSTRACT 1Avian influenza (AI) viruses primarily circulate in wild waterfowl populations and are occasionally transmitted to domestic poultry flocks. However, the possible roles of other wildlife species, such as wild mammals, in AI virus ecology have not been adequately addressed. 2Due to their habitat and behaviour, many wild mammals may be capable of transmitting pathogens among wild and domestic populations. Exposure to AI viruses has been reported in an array of wild and domestic animals. The presence of wild mammals on farms has been identified as a risk factor for at least one poultry AI outbreak in North America. These reports suggest the need for seroprevalence studies examining the exposure of wild mammals to AI viruses. 3Serological tests are routinely used to assess domestic poultry, domestic swine and human exposure to influenza A viruses, but these tests have not been validated for use in wild mammals. As such, some of these protocols may require adjustments or may be inappropriate for use in serology testing of wild mammals. Herein, we review these serological techniques and evaluate their potential usefulness in AI surveillance of wild mammals. We call for care to be taken when applying serological tests outside their original area of validation, and for continued assay verification for multiple species and virus strains. [source] Sequence analysis of measles virus strains collected during the pre- and early-vaccination era in Denmark reveals a considerable diversity of ancient strainsAPMIS, Issue 2 2002L. Siig Christensen A total of 199 serum samples from patients with measles collected in Denmark, Greenland and the Faroe Islands from 1964 to 1983 were analysed by PCR. Measles virus (MV) RNA could be detected in 38 (19%) of the samples and a total of 18 strains were subjected to partial sequence analysis of the hemagglutinin gene. The strains exhibited a considerable genomic diversity, which is at odds with the assumption that one genome type prevailed among globally circulating MV strains prior to the advent of live-attenuated vaccines. Our data indicate that the similarity of the various vaccine strains is attributed to their having originated from the same primary isolate. Consequently, it is implied that a small number of clinical manifestations of MV worldwide from which strains similar to the vaccine strain were identified were vaccine related rather than being caused by members of a persistently circulating ancient genome type. The Danish pre- and early-vaccination era MV strains seem to change the evolutionary spectrum of genome types A, C2 and E into one coherent group, suggesting that the genome types of MV strains circulating in the world at present do not represent far ranging evolutionary lineages but merely members of an evolutionary continuum of pre-vaccination era MV strains which by chance or due to an improved capability survived the worldwide partial herd immunity accomplished through vaccination. [source] Synthesis, Antiviral and Cytostatic Evaluation of Unsaturated Exomethylene and Keto D -Lyxopyranonucleoside AnaloguesARCHIV DER PHARMAZIE, Issue 6 2009Niki Tzioumaki Abstract This report describes the synthesis of unsaturated exomethylene lyxopyranonucleoside analogues as potential biologically active agents. Commercially available 1,2,3,4-tetra- O -acetyl-,- D -lyxopyranose 1 was condensed with silylated thymine and uracil, respectively, deacetylated and acetalated to afford 1-(2,3- O -isopropylidene-,- D -lyxopyranosyl)thymine 4a and 1-(2,3- O -isopropylidene-,- D -lyxopyranosyl)uracil 4b. The new derivatives 1-(2,3,4-trideoxy-4-methylene-,-pent-2-enopyranosyl)thymine 8a and 1-(2,3,4-trideoxy-4-methylene-,-pent-2-enopyranosyl)uracil 8b were prepared via two different key intermediates, 7a, b and 13a, b in order to elucidate the influence of 2,,3,-unsaturation and to clarify the difference between the keto and exomethylene group on the biological activity of the target molecules. Compounds 7a, b, 8a, b, and 13a, b were evaluated for their antiviral and cytostatic activity using several virus strains and cell lines. Whereas no marked antiviral activity was noticed, 13a and 13b showed a cytostatic activity that ranged between 7 and 23 ,M for 13a and 26 and 38 ,M for 13b against murine leukemia L1210, human lymphocyte Molt4/C8 and CEM cells, and human breast carcinoma MCF7 cells. [source] Sulfated membrane adsorbers for economic pseudo-affinity capture of influenza virus particlesBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009Lars Opitz Abstract Strategies to control outbreaks of influenza, a contagious respiratory tract disease, are focused mainly on prophylactic vaccinations in conjunction with antiviral medications. Currently, several mammalian cell culture-based influenza vaccine production processes are being established, such as the technologies introduced by Novartis Behring (Optaflu®) or Baxter International Inc. (Celvapan). Downstream processing of influenza virus vaccines from cell culture supernatant can be performed by adsorbing virions onto sulfated column chromatography beads, such as Cellufine® sulfate. This study focused on the development of a sulfated cellulose membrane (SCM) chromatography unit operation to capture cell culture-derived influenza viruses. The advantages of the novel method were demonstrated for the Madin Darby canine kidney (MDCK) cell-derived influenza virus A/Puerto Rico/8/34 (H1N1). Furthermore, the SCM-adsorbers were compared directly to column-based Cellufine® sulfate and commercially available cation-exchange membrane adsorbers. Sulfated cellulose membrane adsorbers showed high viral product recoveries. In addition, the SCM-capture step resulted in a higher reduction of dsDNA compared to the tested cation-exchange membrane adsorbers. The productivity of the SCM-based unit operation could be significantly improved by a 30-fold increase in volumetric flow rate during adsorption compared to the bead-based capture method. The higher flow rate even further reduced the level of contaminating dsDNA by about twofold. The reproducibility and general applicability of the developed unit operation were demonstrated for two further MDCK cell-derived influenza virus strains: A/Wisconsin/67/2005 (H3N2) and B/Malaysia/2506/2004. Overall, SCM-adsorbers represent a powerful and economically favorable alternative for influenza virus capture over conventional methods using Cellufine® sulfate. Biotechnol. Bioeng. 2009;103: 1144,1154. © 2009 Wiley Periodicals, Inc. [source] CRK adaptor protein expression is required for efficient replication of avian influenza A viruses and controls JNK-mediated apoptotic responsesCELLULAR MICROBIOLOGY, Issue 6 2010Eike R. Hrincius Summary The non-structural protein 1 (A/NS1) of influenza A viruses (IAV) harbours several src-homology domain (SH) binding motifs that are required for interaction with cellular proteins. The SH3 binding motif at aa212-217 [PPLPPK] of A/NS1 was shown to be essential for binding to the cellular adaptor proteins CRK and CRKL. Both regulate diverse cellular effector pathways, including activation of the MAP-kinase JNK that in turn mediates antiviral responses to IAV infection. By studying functional consequences of A/NS1,CRK interaction we show here that A/NS1 binding to CRK contributes to suppression of the antiviral-acting JNK,ATF2 pathway. However, only IAV that encode an A/NS1-protein harbouring the CRK/CRKL SH3 binding motif PPLPPK were attenuated upon downregulation of CRKI/II and CRKL, but not of CRKII alone. The PPLPPK site-harbouring candidate strains could be discriminated from other strains by a pronounced viral activation of the JNK,ATF2 signalling module that was even further boosted upon knock-down of CRKI/II. Interestingly, this enhanced JNK activation did not alter type-I IFN-expression, but rather resulted in increased levels of virus-induced cell death. Our results imply that binding capacity of A/NS1 to CRK/CRKL has evolved in virus strains that over-induce the antiviral acting JNK,ATF2 signalling module and helps to suppress the detrimental apoptosis promoting action of this pathway. [source] | ||||||||||||||||