Thomas W Vahlenkamp

University of Leipzig, Leipzig, Saxony, Germany

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Publications (79)174.23 Total impact

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    Full-text · Dataset · Sep 2015
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    Full-text · Dataset · Sep 2015
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    Kristin Heenemann · Michael Sieg · Antje Rueckner · Thomas W. Vahlenkamp
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    ABSTRACT: A novel polyomavirus was identified in a fatally diseased Gouldian finch ( Erythrura gouldiae ). The new polyomavirus, strain VL 1209, was detected using a broad-spectrum nested PCR.
    Full-text · Article · Sep 2015 · Genome Announcements
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    ABSTRACT: Paramyxoviruses constitute a large family of enveloped RNA viruses including important pathogens in veterinary and human medicine. Recently, feline paramyxoviruses, genus morbillivirus, were detected in cats from Hong Kong and Japan. Here we describe the discovery of several new feline paramyxoviruses. Infections with these diverse viruses were detected in urine samples from cats suffering from chronic kidney disease (CKD). No viral RNA was found in cats without clinical signs of uropathy highlighting an association between feline paramyxovirus (FPaV) infections and CKD. Phylogenetic analyses of the detected viruses showed that they represent at least two different species, one of them representing the feline morbilliviruses detected previously in Hong Kong and Japan. In addition, a new FPaV was detected sharing only 73 % homology on the nucleotide level of the viral L-gene to currently known paramyxoviral species.
    Full-text · Article · Aug 2015 · Virus Genes
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    ABSTRACT: Avian influenza H9N2 viruses have become panzootic in Eurasia causing respiratory manifestations, great economic losses and occasionally being transmitted to humans. To evaluate the replication properties and compare the different virus quantification methods, four Eurasian H9N2 viruses from different geographical origins were propagated in embryonated chicken egg (ECE) and Madin-Darby canine kidney epithelial cell systems. The ECE-grown and cell culture-grown viruses were monitored for replication kinetics based on tissue culture infectious dose (TCID 50), Hemagglutination (HA) test and quantitative real time RT-PCR (qRT-PCR). The cellular morphology was analyzed using immunofluorescence (IF) and cellular ELISA was used to screen the sensitivity of the viruses to amantadine. The Eurasian wild type-H9N2 virus produced lower titers compared to the three G1-H9N2 viruses at respective time points. Detectable titers were observed earliest at 16 h post inoculation (hpi), significant morphological changes on cells were first observed at 32 hpi. Few nucleotide and amino acid substitutions were noticed in the HA, NA and NS gene sequences but none of them are related to the known conserved region that can alter pathogenesis or virulence following a single passage in cell culture. All studied H9N2 viruses were sensitive to amantadine. The G1-H9N2 viruses have higher replication capabilities compared to the European wild bird-H9N2 probably due to their specific genetic constitutions which is prerequisite for a successful vaccine candidate. Both the ECE and MDCK cell system allowed efficient replication but the ECE system is considered as the better cultivation system for H9N2 viruses in order to get maximum amounts of virus within a short time period.
    Full-text · Article · Jul 2015 · Veterinary Research
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    ABSTRACT: Low pathogenic avian influenza virus of subtype H9N2 is panzootic in multiple avian species causing respiratory manifestations and severe economic losses. H9N2 co-circulate simultaneously with high pathogenic avian influenza virus subtype H5N1 in Egyptian chicken farms suggesting the possibility of reassortment. The aim of the present study was to isolate and characterize H9N2 from the recent outbreaks in chicken farms. Also the diversity of amantadine-resistant mutants among these isolates was tested by in situ ELISA and sequence analysis. Three influenza H9N2 viruses, designated A/chicken/Egypt/SCU8/2014, A/chicken/Egypt/SCU9/2014 and A/chicken/Egypt/SCU20/2014 were isolated from commercial broiler and broiler breeder chickens in specific pathogen free embryonated chicken eggs. The eight gene segments were amplified by RT-PCR, cloned, and subjected to full length sequencing. Phylogenetic analysis of these viruses revealed a close relationship between Egyptian, Middle Eastern and Israel isolates with an average of 96-99 % nucleotide homology and identified an ancestor relationship to low pathogenic H9N2 Quail/HK/G1/1997 prototype. The internal segments of the currently isolated viruses were derived from the same sub-lineage with no new evidence of reassortment. The three isolates were sensitive to amantadine as suggested by absence of mutations of M2 and confirmed by a phenotypic assay. In conclusion, avian influenza H9N2 virus is circulating in Egyptian chicken farms causing respiratory manifestations. Continuous monitoring of the molecular epidemiology and its impact on the virulence as well as emergence of new strains are necessary.
    Full-text · Article · Mar 2015 · Virus Genes
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    ABSTRACT: Rotaviruses of group A (RVA) are enteric pathogens with well documented zoonotic transmissions to humans. The segmented genome of the virus enables reassortment events which might alter host susceptibility and/or disease course. Genetic analysis of rotavirus in dogs so far only revealed RVAs with the VP7 and VP4 genome constellation G3P[3]. RVA G3P[3] have also been found in cats, humans, monkeys and bats. In the present study an unusual RVA of genotype G8P[1] is described which was isolated from an asymptomatically infected young dog. The dog did not show signs of diarrhoea. Analysis of full length segments of VP2, VP6 and VP7 as well as NSP1 to NSP5 revealed a typical bovine-like genotype constellation G8-P[1]-I2-Rx-C2-Mx-A3-N2-T6-E2-H3. Phylogenetic analysis supports the hypothesis of an interspecies transmission from a bovine/artiodactyl species or from humans to the young dog. The isolate is likely to represent a multiple reassortant virus.
    Full-text · Article · Oct 2014 · Journal of General Virology
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    ABSTRACT: Rotaviruses of group A (RVA) are enteric pathogens with well documented zoonotic transmissions to humans. The segmented genome of the virus enables reassortment events which might alter host susceptibility and/or disease course. Genetic analysis of rotavirus in dogs so far only revealed RVAs with the VP7 and VP4 genome constellation G3P[3]. RVA G3P[3] have also been found in cats, humans, monkeys and bats. In the present study an unusual RVA of genotype G8P[1] is described which was isolated from an asymptomatically infected young dog. The dog did not show signs of diarrhoea. Analysis of full length segments of VP2, VP6 and VP7 as well as NSP1 to NSP5 revealed a typical bovine-like genotype constellation G8-P[1]-I2-Rx-C2-Mx-A3-N2-T6-E2-H3. Phylogenetic analysis supports the hypothesis of an interspecies transmission from a bovine/artiodactyl species or from humans to the young dog. The isolate is likely to represent a multiple reassortant virus.
    No preview · Article · Oct 2014 · Journal of General Virology
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    ABSTRACT: Since the first outbreak of highly pathogenic avian influenza virus (HPAIV) subtype H5N1 in Bangladesh in 2007, the virus has been circulating among domestic poultry causing severe economic losses. To investigate the presence of HPAIV H5N1 in migratory birds and their potential role in virus spread, 205 pools of fecal samples from live migratory birds were analyzed. Here, the first virus isolation and genome characterization of two HPAIV H5N1 isolates from migratory birds (A/migratory bird/Bangladesh/P18/2010 and A/migratory bird/Bangladesh/P29/2010)are described. Full-length amplification, sequencing, and a comprehensive phylogenetic analysis were performed for HA, NA, M, NS, NP, PA, PB1, and PB2 gene segments. The selected migratory bird isolates belong to clade 2.3.2.1 along with recent Bangladeshi isolates from chickens, ducks, and crows which grouped in the same cluster with contemporary South and South-East Asian isolates. The studied isolates were genetically similar to other H5N1 isolates from different species within the respective clade although some unique amino acid substitutions were observed among them. Migratory birds remain a real threat for spreading pathogenic avian influenza viruses across the continent and introduction of new strains into Bangladesh.
    Full-text · Article · Sep 2014 · Virus Genes
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    ABSTRACT: Between 2006 and 2011 a series of disease conditions characterized by raised mortality and liver disorders occurred in turkey breeder flocks and in meat turkey flocks in Germany. The flocks were between 12 and 23 wk of age, and mostly hens were affected. Clinical signs were nonspecific and accompanied by mortality varying between 1% and 7%. Affected birds displayed swollen livers that were marbled with black and red spots and yellowish areas. The pericardium was filled with an amber fluid, and the coronary groove was extensively filled with fat. Spleens were swollen, and a serous fluid that seemed to leak from the liver was present in the body cavity. Histopathological findings in all but one case included fatty degeneration of hepatocytes with parenchymal collapse and associated hemorrhages. Some animals showed cholangitis and hepatitis with intranuclear inclusion bodies. In three cases with breeders, electron microscopy detected virus particles that were between 23 and 30 nm and similar to parvo- or picornavirus. In addition, picornavirus RNA was detected in the livers of one meat turkey flock. Investigations by PCR for circovirus, polyomavirus parvovirus, and aviadenovirus yielded negative results in all cases, but an aviadenovirus was isolated from livers twice and a reovirus from the intestines once. Supplementation with vitamin E and selenium seemed to improve the situation. The most likely diagnosis is lipidosis, a metabolic disorder with complex etiology, which has rarely been described in turkeys.
    No preview · Article · Sep 2014 · Avian Diseases
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    ABSTRACT: Circoviruses are known to infect pigs and birds and cause severe diseases with various clinical signs. Porcine circovirus-2 (PCV2), associated with severe economic losses, was detected in rodents, mosquitoes, cattle, and in calves affected with bovine neonatal pancytopenia (BNP). However, molecular and serological investigations on circovirus infections in cattle revealed inconsistent results. The aim of the study was to investigate the susceptibility and immune response of calves to experimental PCV2 inoculation. Animals were either intravenously inoculated with tissue-culture grown PCV2, with bone marrow from PCV2 positive and negative calves or immunized with a commercial inactivated PCV2 vaccine. The results showed that the animals inoculated with tissue-culture grown PCV2 and with PCV2 positive bone marrow displayed clinical signs including lymph node swelling, reddening of oral and ocular mucosa, and diarrhoea 7-18 days post inoculation (p.i.). PCV2-specific antibodies were detected in the tissue-culture grown PCV2-infected animals and in the PCV2-immunized animals from day 11 and 7 p.i. onwards, respectively, but were absent in both bone marrow inoculated groups. PCV2 was detected by real-time quantitative PCR only in blood samples of the tissue-culture grown PCV2-infected animals and in various tissues (e.g. spleen, lymph nodes, thymus), with high copy numbers in blood between day 4 (5.16log10 genomic copy number/ml) and 46 (5.33log10 genomic copy number/ml) p.i. In conclusion, the seroconversion and the detection of PCV2 in lymphoid tissues for more than five weeks p.i. revealed that host susceptibility of PCV2 is not solely restricted to pigs.
    Full-text · Article · Jul 2014 · Veterinary Microbiology
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    ABSTRACT: Low-pathogenic avian influenza viruses (LPAIVs) of subtype H9N2 have become widespread in poultry in many Asian countries with relevance to respiratory diseases of multifactorial origin. In Bangladesh, LPAIVs of subtype H9N2 co-circulate simultaneously with highly pathogenic avian influenza viruses (HPAIVs) of subtype H5N1 in commercial and backyard poultry. The aim of this study was to characterize LPAIVs of subtype H9N2 currently circulating in Bangladesh. The selected isolate A/Chicken/Bangladesh/VP01/2006 (H9N2) was propagated in chicken embryos. All eight gene segments were amplified by RT-PCR, cloned, and subjected to full-length sequencing. The sequence data obtained were compared with reference strains available in GenBank. Phylogenetic analysis of LPAIV H9N2 from Bangladesh revealed a close relationship to Indian, Pakistani and Middle Eastern isolates and identified an ancestor relationship to LPAIV H9N2 Quail/HK/G1/1997. The internal genes M and NP belong to lineage G1, whereas NS, PA, PB1 and PB2 belong to the prototype virus A/Chicken/Korea/38349-p96323/96. The internal genes showed high sequence homology to an HPAIV of subtype H7N3 from Pakistan, whereas the PB1 gene showed similarly high nucleotide homologies to recently circulating HPAIV H5N1 from Bangladesh, revealing two independent reassortment events. Examination of the hemagglutinin cleavage site of LPAIV H9N2 confirmed its low pathogenicity. The receptor-binding sites indicated a binding preference for human-type receptors. Several mutations in internal proteins are associated with increased virulence and altered host range, while other amino acids were found to be highly conserved among LPAIV H9N2 isolates.
    Full-text · Article · Jul 2014 · Archives of Virology
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    Parvin R · Heenemann K · Halami MY · Chowdhury EH · Islam MR · Vahlenkamp TW
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    ABSTRACT: Low pathogenic avian influenza viruses (LPAIV) of subtype H9N2 have become widespread in poultry in many Asian countries with relevance to respiratory diseases of multifactorial origin. The selected H9N2 isolate A/chicken/Bangladesh/VP01/2006 from Bangladesh was characterized and all eight gene segments were compared with the other contemporary isolates of Bangladesh and as well as other reference isolates available in GenBank. The gene sequence and phylogenetic analysis of Bangladeshi LPAIV H9N2 revealed close relationship with Indian, Pakistani and Middle Eastern isolates and maintained ancestor relation with LPAIV H9N2 Quail/HK/G1/1997. The internal genes showed phylogenetic relations between two different prototypes within H9N2 along with some other highly pathogenic avian influenza viruses (HPAIV). Among the six internal genes all showed high sequence homology with a HPAIV of subtype H7N3 from Pakistan, whereas the PB1 gene showed similarly high nucleotide homologies with recently circulating HPAIV H5N1 from Bangladesh revealing two independent reassortment events between two distinct HPAIV of subtypes H7N3 and H5N1. The reported HPAIV H7N3 from Pakistan has all internal genes and a Bangladeshi HPAIV H5N1 has PB1 gene like LPAIV H9N2, therefore H9N2 has to be the donor of those genes.
    Full-text · Conference Paper · Jun 2014
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    ABSTRACT: To investigate the prevalence of the recently described genogroup VI canine noroviruses (CNVs) in dogs in Europe, we tested 510 serum samples from dogs in 14 European countries for anti-IgG CNV antibodies. Seropositive dogs were found throughout Europe. Dogs with antibodies against human noroviruses were also found.
    Full-text · Article · Mar 2014 · Clinical and vaccine Immunology: CVI
  • Mohammad Yahya Halami · J. Voss · H. Müller · M. Freick · T. W. Vahlenkamp

    No preview · Conference Paper · Mar 2014
  • Heenemann K · Halami MY · Nieper H · Vahlenkamp TW

    No preview · Conference Paper · Mar 2014
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    ABSTRACT: Objective-To compare cytotoxic effects and antiviral efficacy of 9 nucleoside reverse transcriptase inhibitors (NRTIs) against FIV in feline peripheral blood mononuclear cells. Sample-Peripheral blood mononuclear cells obtained from 3 specific pathogen-free cats. Procedures-3 of the 9 NRTIs had not been previously assessed in feline cell lines. Cytotoxic effects were determined by colorimetric quantification of a formazan product resulting from bioreduction of a tetrazolium reagent by viable peripheral blood mononuclear cells; uninfected cells from 1 cat were used in these assays. Cells from all 3 cats were infected with a pathogenic clone of FIV, and in vitro antiviral efficacy of each NRTI was assessed with an FIV p24 antigen capture ELISA. Results-Cytotoxic effects in feline peripheral blood mononuclear cells were observed only at concentrations > 10 μM for all 9 NRTIs. Comparison of the cytotoxic effect at the highest concentration investigated (500μM) revealed that didanosine and amdoxovir were significantly less toxic than abacavir. All drugs induced a dose-dependent reduction of FIV replication. At the highest concentration investigated (10μM), there was no significant difference in antiviral efficacy among the test compounds. Conclusions and Clinical Relevance-The evaluated NRTIs had low cytotoxicity against feline peripheral blood mononuclear cells and appeared to be safe options for further in vivo evaluation for the treatment of FIV-infected cats. There was no evidence suggesting that the newly evaluated compounds would be superior to the existing NRTIs for reducing FIV burden of infected cats.
    No preview · Article · Mar 2014 · American Journal of Veterinary Research
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    ABSTRACT: Two new strains of porcine circovirus type 2 virus (PCV2), strains Ha09 and Ha10, were detected in calves in Germany, and the complete genome of each virus has been sequenced and analyzed. Phylogenetic analysis suggests that these strains belong to the PCV2b genotype cluster, a highly prevalent genotype found worldwide.
    Full-text · Article · Jan 2014 · Genome Announcements
  • Timm C Harder · Ursula Siebert · Peter Wohlsein · Thomas Vahlenkamp
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    ABSTRACT: Influenza A viruses (IAV), members of the Orthomyxoviridae, cover a wide host spectrum comprising a plethora of avian and, in comparison, a few mammalian species. The viral reservoir and gene pool are kept in metapopulations of aquatic wild birds. The mammalian-adapted IAVs originally arose by transspecies transmission from avian sources. In swine, horse and man, species-adapted IAV lineages circulate independently of the avian reservoir and cause predominantly respiratory disease of highly variable severity. Sporadic outbreaks of IAV infections associated with pneumonic clinical signs have repeatedly occurred in marine mammals (harbour seals [Phoca vitulina]) off the New England coast of the U.S.A. due to episodic transmission of avian IAV. However, no indigenous marine mammal IAV lineages are described. In contrast to marine mammals, avian- and equine-derived IAVs have formed stable circulating lineages in terrestrial carnivores: IAVs of subtype H3N2 and H3N8 are found in canine populations in South Korea, China, and the U.S.A. Experimental infections revealed that dogs and cats can be infected with an even wider range of avian IAVs. Cats, in particular, also proved susceptible to native infection with human pandemic H1N1 viruses and, according to serological data, may be vulnerable to infection with further human-adapted IAVs. Ferrets are susceptible to a variety of avian and mammalian IAVs and are an established animal model of human IAV infection. Thus, a potential role of pet cats, dogs and ferrets as mediators of avian-derived viruses to the human population does exist. A closer observation for influenza virus infections and transmissions at this animal-human interface is indicated.
    No preview · Article · Nov 2013 · Berliner und Münchener tierärztliche Wochenschrift
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    ABSTRACT: an apoptosis event. We also displayed that caspase activity and apoptosis are induced at late during CCHFV infection. Apoptosis is an important mechanism by which virus infected cells are eliminated from the host. Many viruses have evolved strategies to delay or suppress apoptosis in order to secure efficient virus replication, assembly and egress of infec-tious viral particles. In this study, we have been interested to investigate if CCHFV infection can regulate the apoptosis at early post infection. Our data displayed that caspase activation are suppressed/delayed early post infection both upstream and on executor caspase level, insitu. In addition, we suggest that the multifunctional virus structural protein, NP, is involved in regulation of apoptotic pathways in infected cells. In this study, we also suggest that both mitochondrial pathway and death receptors apoptotic pathways are regulated during infection at early and late post infection but in different manner. Since the first outbreak of highly pathogenic avian influenza virus (HPAIV) of subtype H5N1 in Bangladesh in 2007 the virus continues to circulate among domestic poultry causing severe economic losses. To investigate migratory birds as possible source of virus introduction genome characte-rization of two HPAIV H5N1 isolates from migratory birds (A/migratory bird/Bangladesh/P18/2010 and A/migratory bird/Bangladesh/P29/2010) was performed. After full length amplification and sequence analysis of the gene segments encoding HA, NA, M and NS a comprehensive phyloge-netic analysis was performed by comparing the gene segments with other Bangladeshi isolates and representative isolates of all clades described in the H5 nomenclature. The Bangladeshi H5N1 isolates from different birds and poultry were broadly grouped into two clades. The majority of isolates from 2007 to 2010 belong to clade 2.2.2 whereas the recent isolates from chickens and crows of 2011 along with the selected migratory bird isolates described here are grouped into clade 2.3.2.1. The selected isolates revea-led multiple basic amino acids 338QRERRRKR*G346 at their HA clea-vage site similar to other isolates from clade 2.3.2.1. The receptor binding site of HA molecule contained avian like (SAa 2, 3 Gal) receptor specifi-city. The results verified the presence of HPAIV among migratory birds in Bangladesh. Further detailed analyses will reveal whether migratory birds may represent the source of the newly introduced clade 2.3.2.1 virus which was meanwhile diagnosed in Bangladesh from different avian species.
    Full-text · Conference Paper · Sep 2013

Publication Stats

1k Citations
174.23 Total Impact Points

Institutions

  • 2000-2015
    • University of Leipzig
      • Institut für Virologie
      Leipzig, Saxony, Germany
  • 2001-2014
    • North Carolina State University
      • • Department of Population Health and Pathobiology
      • • College of Veterinary Medicine
      Raleigh, North Carolina, United States
  • 2005-2012
    • Friedrich Loeffler Institute
      Griefswald, Mecklenburg-Vorpommern, Germany
  • 2007
    • Universidade Federal de Pelotas
      • Veterinary Faculty (FVet)
      São Francisco de Paula, Rio Grande do Sul, Brazil
  • 1995-1999
    • Universiteit Utrecht
      • • Department of Infectious Diseases and Immunology
      • • Division of Virology
      Utrecht, Utrecht, Netherlands
  • 1997
    • Biomedical primate research centre
      • Department of Virology
      Rijswijk, South Holland, Netherlands