L Haas

University of Veterinary Medicine Hannover, Hanover, Lower Saxony, Germany

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Publications (52)110.66 Total impact

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    Article: Bernd Liess
    Veterinary Microbiology 02/2013; 162(1):302. DOI:10.1016/j.vetmic.2012.11.010 · 2.73 Impact Factor
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    ABSTRACT: Profiles of blood cell counts were evaluated for 15 calves from three different farms. These calves showed petechia in the mucous membranes and in the skin and prolonged secondary bleeding after puncture. The clinical course of the disease could be observed in eleven calves. With exception of one case, the blood cell counts indicated a severe anaemia, leukocytopenia and thrombocytopenia. Out of these 15 calves, six calves survived and the other nine calves died or had to be euthanized due to the severity of the disease. Necropsy of these nine calves revealed petechia in the skin, subcutis, muscles, in inner organs and all serous membranes. Pathohistological examination showed a depletion of the bone marrow and lymphatic tissue in eight calves. These findings confirmed the diagnosis of bovine neonatal pancytopenia (BNP) for eight of these nine calves. Bluetongue virus serotype 8 was tested negatively using PCR. Bovine virus diarrhoea virus (BVDV) was negatively tested using immunofluorescence and cell culture and salmonella species were negatively tested in seven dissected calves. A cluster of toxins was negatively tested in one of the dissected calves. All 15 calves had high antibody titres for BVDV. The BVDV-antibody titres from twelve dams with affected calves were positive in six cases and not detectable in the other six cases. In three of the six dams with not detectable BVDV-antibody titres, calves were fed with colostrum of a further dam with high BVDV-antibody titres. In the further three dams without detectable BVDV-antibody titres, we could not ascertain which colostrum has been fed to the calves. BVDV-specific antigen could not be detected in any of the samples from the calves and dams tested. Using the activity of the gamma-glutamyl-transferase, we assumed a sufficient supply with colostrum for the examined calves.The cause for the occurrence of these BNP cases was due to bone marrow depletion.The reason for the bone marrow depletion remained unclear. However, it was obvious that the BNP described here is highly likely caused by colostrum from cows with positive BVDV-antibody titres.
    Berliner und Münchener tierärztliche Wochenschrift 01/2011; 124(7-8):329-36. · 0.93 Impact Factor
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    ABSTRACT: A haemorrhagic diathesis has been observed in young calves since 2007 which is described as bovine neonatal pancytopenia (BNP) and presents a completely new disease. The objectives of our investigation were to test if BNP could be reproduced using colostrum of cows with a BNP history and pre-colostral calves from farms where BNP has not been observed. In the present experiment, 22 German Holstein calves from BNP-free farms were fed four to six hours after birth 2.5 l colostrum from cows which had been reported to have had at least one calf with BNP in the last lactation. We distinguished three different experimental groups according to the composition of the colostrum. In experimental group I, each of the six calves received colostrum of a single cow, in experimental group II all six calves received colostrum from the same cow and in experimental group III each of the ten calves received a colostrum mix from ten different cows. Clinical signs of BNP were observed in 50% of the calves in experimental group I, 67% of the calves in experimental group II and all calves in experimental group III. The lethality in the three experimental groups was significantly different with rates of 16.7%, 66.7% and 80%, respectively. Calves fed with a colostrum-mix in experimental group III had the highest lethality. Neither the farm nor the amount of the colostrum fed had a significant effect on the occurrence and course of BNP. The profiles for thrombocytes, leucocytes and erythrocytes significantly differed in dependence of the severity of BNP signs. Calves with non-lethal BNP showed thrombocytopenia with values below 100 G/l on the 1th to 3rd and the 7th to 11th day of life. In calves with lethal BNP, thrombocytes decreased under 50 G/l from day 5. In calves with non-lethal BNP, a decrease of the leucocytes under the threshold was present only for a short period of time. In calves with lethal BNP, leucocytes decreased in the first 5 days after birth continuously and increased on the 6th to the 8th day to normal values and then a rapid decrease occurred. Erythrocytes decreased under the normal threshold just in the last two days before the calves died or were euthanized. Thus, the present experiments showed that colostrum of cows with a BNP-history and vaccination with PregSure BVD from Pfizer caused lethal BNP. We can assume that the different reactions of the calves are due to immunogenetic reactions to colostral alloreactive antibodies. The reaction spectrum of calves depends on the presence of antigens which can react with these colostral antibodies. The experimental results can explain the different incidences of BNP within and among farms as well as between breeds.
    Berliner und Münchener tierärztliche Wochenschrift 11/2010; 124(9-10):390-400. · 0.93 Impact Factor
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    ABSTRACT: In a zoological collection, four black bears (Ursus americanus) died from neurological disease within six months. Independently in a geographically different zoo, two Thomson's gazelles (Eudorcas thomsoni) and 18 guinea pigs (Cavia porcellus f. dom.) suffered from neurological disorders. In addition, guinea pigs showed abortions and stillbirths. All affected animals displayed a non suppurative meningoencephalitis with intranuclear inclusion bodies. Immunohistology demonstrated equine herpes virus antigen and ultrastructurally herpes viral particles were detected. Virus isolation and molecular analysis identified neurotropic equine herpesvirus (EHV) 1 strains in both epizootics. There is serological evidence of a possible virus transmission from other equids to the affected animals. Cross-species transmission of EHV-1 should be considered in the management of captive wild equids and ungulates, particularly with respect to fatal disease in irreplaceable species.
    Veterinary Microbiology 11/2010; 149(3-4):456-60. DOI:10.1016/j.vetmic.2010.11.024 · 2.73 Impact Factor
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    ABSTRACT: To investigate the role of cytoskeletal components in canine distemper virus (CDV) replication, various agents were used that interfere with turnover of actin filaments and microtubules. Only inhibition of actin filaments significantly reduced viral infectivity. Analysis of the intracellular localization of the viral matrix (M) protein revealed that it aligned along actin filaments. Treatment with actin filament-disrupting drugs led to a marked intracellular redistribution of M protein during infection as well as transfection. In contrast, the localization of the CDV fusion (F) protein was not significantly changed during transfection. Thus, a M protein-actin filament interaction appears to be important for generation of infectious CDV.
    Archives of Virology 09/2010; 155(9):1503-8. DOI:10.1007/s00705-010-0737-6 · 2.28 Impact Factor
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    ABSTRACT: Due to its strong impact on economics and trading the Foot-and-Mouth-Disease (FMD) is one of the most important animal diseases within animal husbandry. Because no recent specific field observation for FMD exists in Germany, the risk assessment needs validated epidemiological models to prepare decision tools for FMD-outbreak management. The aim of this investigation was therefore to prepare a risk assessment for different transmission pathways to use for FMD-models in future. To prepare a FMD-transmission model the risk was assessed within a highly animal densed region in Germany by means of an expert survey. For each transmission pathway an assessment was given in the categories low, medium, high and severe. Some pathways were rated homogenously between the experts, but some were rated heterogeneously. Therefore areas were identified with common rating as well as areas, where further investigations to specify FMD-models are necessary.
    Berliner und Münchener tierärztliche Wochenschrift 03/2010; 123(3-4):89-95. · 0.93 Impact Factor
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    ABSTRACT: 2.4 Bovine Herpesvirus-Typ1-Infektionen (alle Formen) 2.8 Bösartiges Katarrhalfieber (BKF) 5.2 Herpesvirus-canis-Infektion 6.4 Feline Rhinotracheitis
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    ABSTRACT: Canine distemper virus (CDV) can enter the brain via infection of olfactory neurons. Whether olfactory ensheathing cells (OECs) are also infected by CDV, and if yes, how they respond to the virus has remained enigmatic. Here, we exposed adult canine OECs in vitro to several attenuated (CDV-2544, CDV-R252, CDV-Ond, CDV-OndeGFP) and one virulent CDV strain (CDV-5804PeGFP) and studied their susceptibility compared to Schwann cells, a closely related cell type sharing the phagocytizing activity. We show that OECs and Schwann cells were infected by CDV strains albeit to different levels. Ten days post-infection (dpi), a mild to severe cytopathic effect ranging from single cell necrosis to layer detachment was noted. The percentage of infection increased during 10 dpi and viral progenies were detected in each culture using virus titration. Interestingly, CDV-2544, CDV-OndeGFP, and CDV-5804PeGFP predominantly infected OECs, while CDV-Ond targeted Schwann cells. No significant differences were found between the virulent and attenuated CDV strains. The observation of a CDV strain-specific cell tropism is evidence for significant molecular differences between OECs and Schwann cells. Whether these differences are either related to strain-specific distemper pathogenesis or support a role of OECs during CDV infection and virus spread needs to be addressed in future studies.
    Virus Research 06/2009; 144(1-2):195-201. DOI:10.1016/j.virusres.2009.04.027 · 2.83 Impact Factor
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    ABSTRACT: The BeAn strain of Theiler's murine encephalomyelitis virus (TMEV) causes a demyelinating leukomyelitis in mice, which serves as an important animal model for multiple sclerosis in humans. The present report describes the generation and characterization of a TMEV-specific polyclonal antibody by immunization of rabbits with purified TMEV of the BeAn strain. The specificity of the antibody was confirmed by Western blotting and sequence analysis of the recognized antigen by high resolution mass spectrometry. The presence of TMEV-specific polyclonal antibodies in post-immunization sera was tested on TMEV-infected L-cells (murine lung tumor cell line) using an immunofluorescence assay. Additionally, the rabbit serum enabled virus detection in formalin-fixed and paraffin-embedded TMEV-infected BHK(21) cell pellets and brain tissue of TMEV-infected mice by immunohistochemistry. Immune electron microscopy revealed colloid gold-labeled picornavirus-typical paracrystalline arrays and non-aggregated viral particles of TMEV-infected BHK(21) cells. The present report demonstrates the applicability of the generated marker for investigating TMEV cell tropism and viral spread at a cellular and subcellular level in future studies.
    Journal of virological methods 06/2009; 160(1-2):185-8. DOI:10.1016/j.jviromet.2009.04.030 · 1.88 Impact Factor
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    ABSTRACT: Blood samples from sheep and/or goats from eight small ruminant flocks in the Turkish provinces of Aydin and Burdur were tested for the presence of Pestiviruses using an antigen-capture ELISA. From clinically affected animals, pathological and immunohistochemical findings were recorded. Post mortem examination of a virus-positive lamb showing abnormal fleece and paralysis of the hind legs revealed nonsuppurative meningoencephalomyelitis with hypomyelinogenesis. By immunohistochemistry Pestivirus antigen was detected in all parts of the brain including cerebellum, cerebral hemispheres and midbrain. Two Pestivirus isolates from a sheep and a goat kid, respectively, were isolated from samples that were positive in the antigen-capture ELISA. Genetic typing using the 5'-NTR (288bp) and N(pro) (738bp) showed that both were Border disease virus (BDV) isolates. By phylogenetic analysis, they formed a cluster clearly separated from the known clusters BDV-1 to BDV-6 and might therefore represent a new subgroup (BDV-7?). This is the first report confirming the occurrence and partial characterisation of BDV infection in small ruminants in Turkey.
    Veterinary Microbiology 11/2008; 135(3-4):374-9. DOI:10.1016/j.vetmic.2008.09.085 · 2.73 Impact Factor
  • Archives of Virology 02/2008; 153(5):951-6. DOI:10.1007/s00705-008-0055-4 · 2.28 Impact Factor
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    ABSTRACT: Sixteen bovine viral diarrhea virus (BVDV) isolates collected in Costa Rica between 1987 and 2006 from dairy cattle were analyzed by RT-PCR and determined to belong to BVDV species 1. Furthermore, eleven of these isolates were genotyped using the nucleotide sequences of the Npro region of the viral genome. Phylogenetic analysis indicated that all samples examined clustered within the BVDV-1b subtype.
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    ABSTRACT: Cholesterol is known to play an important role in stabilizing particular cellular membrane structures, so-called lipid or membrane rafts. For several viruses, a dependence on cholesterol for virus entry and/or morphogenesis has been shown. Using flow cytometry and fluorescence microscopy, we demonstrate that infection of cells by canine distemper virus (CDV) was not impaired after cellular cholesterol had been depleted by the drug methyl-beta-cyclodextrin. This effect was independent of the multiplicity of infection and the cellular receptor used for infection. However, cholesterol depletion of the viral envelope significantly reduced CDV infectivity. Replenishment by addition of exogenous cholesterol restored infectivity up to 80%. Thus, we conclude that CDV entry is dependent on cholesterol in the viral envelope. Furthermore, reduced syncytium formation was observed when the cells were cholesterol depleted during the course of the infection. This may be related to the observation that CDV envelope proteins H and F partitioned into cellular detergent-resistant membranes. Therefore, a role for lipid rafts during virus assembly and release as well is suggested.
    Journal of Virology 05/2007; 81(8):4158-65. DOI:10.1128/JVI.02647-06 · 4.65 Impact Factor
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    ABSTRACT: Congenital dysfunction of the keratinisation of the epithelium was diagnosed in two female German Angus calves born on the same farm. The relationship coefficient between the two affected Angus calves was 34.38%. The clinical findings were similar to ichthyosis congenita as the alterations of the skin were present at birth and the levels of zinc in the blood were not decreased. However, parakeratosis could not be completely excluded as skin alterations were partly parakeratotic. On account of the close relationship between the two affected calves a genetic cause is likely for the present cases.
    DTW. Deutsche tierärztliche Wochenschrift 02/2007; 114(1):25-9. · 0.41 Impact Factor
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    ABSTRACT: The antigenic relationship between the phocine distemper virus (PDV) strain causing the epidemic in 2002 and the PDV strain of 1988, canine distemper virus from two dogs and one marten, and one measles virus strain was investigated in vivo and in vitro using monospecific polyclonal and monoclonal antibodies directed against five different proteins of canine or phocine distemper virus (N, P, M, F, H). Epitopic mapping revealed no difference between the PDV strains causing the epidemics in 1988 or 2002. However, the use of these antibodies allowed discrimination between different morbilliviruses including a vaccine strain of canine distemper virus. The major differences among the investigated morbilliviruses were found in the H protein.
    Archives of Virology 02/2007; 152(8):1559-64. DOI:10.1007/s00705-007-0970-9 · 2.28 Impact Factor
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    ABSTRACT: Aphakia and further malformations of both eyes were diagnosed in a female German Holstein calf. Besides aphakia of the left eye, the calf exhibited microphthalmia, glaucoma and a hypoplastic uveoscleral tissue. Additional findings in the right eye were buphthalmus and glaucoma. Instead of aphakia, pathohistological and investigations revealed a very small (microphakia) and luxated lens. Neither the clinical nor the pathological examination revealed further malformations of other organs. A BVD infection could be excluded as cause for the ocular malformations observed. A deficiency or excess of vitamine A was unlikely because this would have also applied to all other calves born at the same time on the farm. An inbreeding coefficient of 3.168% for the malformed calf and the exclusion of environmental causes for these malformations of the eyes let us suppose a hereditary problem.
    DTW. Deutsche tierärztliche Wochenschrift 10/2006; 113(9):355-7. · 0.41 Impact Factor
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    ABSTRACT: A case of ectopia cordis pectoralis was diagnosed in a black and white coloured German Holstein calf. The heart and pericard were displaced through a fissure in the breastbone. The heart was connected with the thoracic cavity by its large vessels. Besides of the ectopia cordis no other defects of the heart were noticed. The liver was deformed and many organs showed passive hyperaemia. The calf was well developed and died under birth. The lungs were not ventilated. The malformed calf was inbred on a bull used for artificial insemination with an inbreeding coefficient of 3.125%. The ectopia cordis probably resulted from the fissure of the breastbone.
    DTW. Deutsche tierärztliche Wochenschrift 08/2006; 113(7):281-4. · 0.41 Impact Factor
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    ABSTRACT: Classical swine fever (CSF) is a notifiable disease of domestic pigs and wild boar. It is caused by the highly contagious CSF virus and in its acute form the disease generally results in high morbidity and mortality. Due to the great economical impact an outbreak can cause to the pig industry it is one of the most important swine diseases worldwide. To limit the damage in the case of a new outbreak it is necessary to identify the virus as fast as possible. This information helps epidemiologists to trace the origin of the virus and to follow the virus spread. Genetic typing revealed that CSF virus genotypes, subgroups and types show a regional distribution making it an important tool for epidemiologists. Meanwhile, besides epidemiological data and nucleotide sequences from European isolates, information from isolates from South- and Central America, the Caribbean, Asia and recently from South Africa have become available. The data are stored in a database in the EU Reference Laboratory for CSF, accessible by the WWW (http://viro08.tiho-hanno ver.de). A new module was implemented that allows efficient automated genotyping.
    DTW. Deutsche tierärztliche Wochenschrift 05/2006; 113(4):134-8. · 0.41 Impact Factor
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    ABSTRACT: Bovine viral diarrhoea (BVD) control/eradication programmes based on the test and removal of persistently infected cattle without use of vaccination were first introduced by the Scandinavian countries in the early 1990s. Within the last 10 years the programmes have proven to be very successful and have served as a blueprint for several other European regions. However, in areas with high cattle densities, intense animal trade and high BVD prevalence this control approach is risky, because there is a high probability that herds, which have been cleared of persistently infected (PI) animals and have become partly or fully susceptible to reintroduction of the virus, will come in contact with a BVD virus (BVDV) infected animal. A combination of the test and removal strategy with subsequent systematic vaccination of cattle could overcome this problem. The goals of vaccination in such a programme is protection against reintroduction of BVDV into herds free from PI cattle and foetal protection of pregnant animals accidentally exposed to the virus. Two-step vaccination is based on the use of inactivated BVDV-1 vaccine for priming followed by a live attenuated vaccine booster 4 weeks later. The immune response elicited by such a vaccination scheme has proven to be long lasting and foetal infection after challenge with BVDV-1 and BVDV-2 was prevented in pregnant animals 5 months after vaccination. These findings suggest that the implementation of a two-step vaccination in the initial phase of control programmes in addition to test and removal of PI animals in areas with high cattle densities and endemic BVD is practical and efficacious.
    Preventive Veterinary Medicine 12/2005; 72(1-2):109-14; discussion 215-9. DOI:10.1016/j.prevetmed.2005.08.011 · 2.51 Impact Factor

Publication Stats

811 Citations
110.66 Total Impact Points

Institutions

  • 1992–2009
    • University of Veterinary Medicine Hannover
      • • Institute of Pathology
      • • Institute of Virology
      Hanover, Lower Saxony, Germany
  • 1997
    • University of South Australia
      • School of Pharmacy and Medical Sciences
      Tarndarnya, South Australia, Australia
  • 1990
    • Institute of Human Virology
      Maryland City, Maryland, United States