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Biomedical subjects

U Truyen

Publications and source records attributed to U Truyen.

At least 19 recordsLinked to original sources

Mapping neutralizing and non-neutralizing epitopes on the capsid protein of feline calicivirus.

Neutralizing epitopes on feline calicivirus (FCV) capsid protein were mapped using chimeric capsid proteins recombinant between two FCV isolates that do not show any cross-neutralization. The three chimeric proteins examined were expressed in murine L929 cells employing an MVA/T7 vaccinia virus expression system and inoculated into major histocompatibility complex haplotype-matched C3/HN mice. Based on the neutralizing antibody titre the neutralizing epitope(s) could be mapped to the 5' hypervariable region of the E region or potentially to the C region. The epitopes of some non-neutralizing antibodies were mapped with the same chimeric proteins to the regions B or D and F of the FCV capsid protein.

Animals↗

Parvovirus infections in wild carnivores.

Various parvoviruses infect carnivores and can cause disease. In this review article the knowledge about infections of free-ranging or captive carnivores with the feline parvoviruses, feline panleukopenia virus, and canine parvovirus, including the antigenic types CPV-2a and -2b, as well as Aleutian disease of mink virus and minute virus of canines are summarized. Particular emphasis is placed on description of the evolution of canine parvovirus which apparently involved wild carnivore hosts.

Animals↗

Genetic characterization of feline parvovirus sequences from various carnivores.

Infections with viruses of the feline parvovirus subgroup such as feline panleukopenia virus (FPV), mink enteritis virus (MEV) and canine parvovirus (CPV-2) [together with its new antigenic types (CPV-2a, CPV-2b)] have been reported from several wild carnivore species. To examine the susceptibility of different species to the various parvoviruses and their antigenic types, samples from wild carnivores with acute parvovirus infections were collected. Viral DNA was amplified, and subsequently analysed, from faeces or formalin-fixed small intestines from an orphaned bat-eared fox (Otocyon megalotis), a free-ranging honey badger (Mellivora capensis), six captive cheetahs (Acinonyx jubatus), a captive Siberian tiger (Panthera tigris altaica) and a free-ranging African wild cat (Felis lybica). Parvovirus infection in bat-eared fox and honey badger was demonstrated for the first time. FPV-sequences were detected in tissues of the African wild cat and in faeces of one cheetah and the honey badger, whereas CPV-2b sequences were found in five cheetahs and the bat-eared fox. The Siberian tiger (from a German zoo) was infected with a CPV-type 2a virus. This distribution of feline parvovirus antigenic types in captive large cats suggests an interspecies transmission from domestic dogs. CPV-2 sequences were not detected in any of the specimens and no sequences with features intermediate between FPV and CPV were found in any of the animals examined.

Acinonyx↗

Feline panleukopenia virus revisited: molecular characteristics and pathological lesions associated with three recent isolates.

The low incidence of clinical signs or pathological lesions compatible with feline panleukopenia in cats has created the perception among practitioners that the disease has disappeared since the emergence of canine parvovirus type 2 in the late 1970s. Three parvoviruses that were recently isolated from a domestic cat and 2 cheetahs in cell culture or detected by means of the polymerase chain reaction were shown to be typical feline parvoviruses. Phylogenetic comparison with other FPV isolates did not reveal a particular African cluster.

Acinonyx↗

[Distribution of antigen types of canine parvovirus in Switzerland, Austria and Germany].

In this study the distribution of the various antigenic types of canine parvovirus in Switzerland, Austria, and Germany was investigated. From 14 samples from Switzerland, 35 samples from Austria, and 82 samples from Germany exclusively the new antigenic types CPV-2a and CPV-2b were isolated. Most of these isolates had a Ser-Val mutation at amino acid 297, which was shown to be prevalent in recent CPV isolates from various parts of the world. These findings are discussed with regard to the use of modified live virus vaccines.

Animals↗

Emergence and recent evolution of canine parvovirus.

This review summarizes the current knowledge about the emergence of canine parvovirus from an ancestor virus similar to feline panleukopenia virus most likely from a wild carnivore host. The recent evolution of CPV, namely the emergence of new antigenic types, their biological properties and global distribution are also discussed.

Animals↗

Characterisation of a potentially abortigenic strain of feline calicivirus isolated from a domestic cat.

Feline calicivirus (FCV) was isolated from one of four dead fetuses delivered by ovariohysterectomy from a queen with an acute FCV infection. The most prominent lesions in the fetuses were petechial haemorrhages in the skin. The virus isolated was characterised as FCV by antigenic analysis and cDNA sequence analysis. This is the second report of abortion associated with acute FCV infection.

Abortion, Veterinary↗

Recent developments in the epidemiology of virus diseases and BSE.

There is a continuous change in viral epidemics with respect to clinical symptoms, their duration or disappearance and the emergence of new diseases. This can be observed both in human and animal diseases. This evolution of virus diseases is mainly related to three factors: etiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: 1) mutations such as recombination and reassortment; 2) selection for resistance or susceptibility. The epidemiology of newly emerged virus diseases in man and animals, such as AIDS and hemorrhagic fevers, and bovine spongiform encephalopathy (BSE), canine hemorrhagic gastroenteritis or respiratory syndrome in horses will be discussed.

Africa↗

Feline calicivirus capsid protein expression and capsid assembly in cultured feline cells.

The capsid protein of feline calicivirus (FCV) was expressed by using plasmids containing cytomegalovirus, simian virus 40, or T7 promoters. The strongest expression was achieved with the T7 promoter and coinfection with vaccinia virus expressing the T7 RNA polymerase (MVA/T7pol). The FCV precursor capsid protein was processed to the mature-size protein, and these proteins were assembled in to virus-like particles.

Animals↗

Tissue distribution of virus replication in cats experimentally infected with distinct feline calicivirus isolates.

Four specific pathogen-free (SPF) cats were each inoculated with one of two genetically and antigenically well characterized feline caliciviruses originally isolated from cats with acute respiratory disease (FCV-KS100/2), or with chronic stomatitis (FCV-KS20). Two cats of each group were euthanized at day 10 post infection and two cats at day 28. No clear differences between the clinical disease induced by the two isolates could be observed, and no apparent differences in the tissue spectrum were seen between day 10 and 28. No persistent virus shedding was observed over the 4-week period of this experiment.

Animals↗

Survey on viral pathogens in wild red foxes (Vulpes vulpes) in Germany with emphasis on parvoviruses and analysis of a DNA sequence from a red fox parvovirus.

The seroprevalence of canine parvovirus (CPV), canine distemper virus (CDV), canine adenovirus (CAV) and canine herpesvirus (CHV) infections in red foxes (Vulpes vulpes) was determined in fox sera collected between 1991 and 1995. A total of 500 sera were selected and the seroprevalences were estimated to be 13% (65 of 500 sera) for CPV, 4.4% (17 of 383 sera) for CDV, 35% (17 of 485 sera) for CAV, and 0.4% (2 of 485 sera) for CHV, respectively. No statistically significant differences were observed between the two (rural and suburban) areas under study. Parvovirus DNA sequences were amplified from tissues of free-ranging foxes and compared to those of prototype viruses from dogs and cats. We report here a parvovirus sequence indicative of a true intermediate between the feline panleukopenia virus-like viruses and the canine parvovirus-like viruses. The red fox parvoviral sequence, therefore, appears to represent a link between those viral groups. The DNA sequence together with a significant seroprevalence of parvovirus infections in foxes supports the hypothesis that the sudden emergence of canine parvovirus in the domestic dog population may have involved the interspecies transmission between wild and domestic carnivores.

Adenoviruses, Canine↗

No evidence for a role of modified live virus vaccines in the emergence of canine parvovirus.

In this study the early evolution and potential origins of canine parvovirus (CPV) were examined. We cloned and sequenced the VP2 capsid protein genes of three German CPV strains isolated in 1979-1980, as well as two feline panleukopenia virus (FPV) vaccine viruses that were previously shown to have some restriction enzyme cleavage sites in common with CPV. Other partial VP2 gene sequences were obtained by amplifying CPV DNA from paraffin-embedded tissues of dogs which were early parvovirus disease cases in Germany in 1978-1979. Sequences were analysed with respect to their evolutionary relationships to other CPV and FPV isolates. Those analyses did not support the hypothesis that CPV emerged as a variant of an FPV vaccine virus. Neither did they reveal ancestral sequences among the very early CPV isolates examined. Other possible sources for the origin of CPV are examined, including the involvement of viruses from wild carnivores.

Animals↗

Antigenic and genetic analysis of canine parvoviruses in southern Africa.

Canine parvovirus (CPV) is a significant pathogen of domestic and free-ranging carnivores all over the world. It suddenly appeared at the end of the 1970s and most likely emerged as a variant of the well known feline panleukopenia virus (FPV). During its adaptation to the new host, the domestic-dog, the virus has changed its antigenic profile twice giving rise to two new antigenic types, CPV-2a and CPV-2b. These new types have replaced the original type CPV-2 in the United States of America, Europe and Japan. However, no data about the prevalence of the new antigenic types on the African continent are available. In this study, 128 recent parvovirus isolates from South Africa and Namibia were antigenically typed with type-specific monoclonal antibodies. No original CPV-2 viruses were found and its complete replacement by the new antigenic types conforms to the situation in other parts of the world. The predominant strain found in southern Africa was CPV-2b (66%), which differs from the situation in Europe and Japan where CPV-2a is the most prevalent type. Analysis of the capsid protein DNA-sequences of four selected African isolates gave no hint of a specific African parvovirus lineage.

Animals↗

Sequence analysis of the lymphotropic Aleutian disease parvovirus ADV-SL3.

About 98% of the DNA sequence of the lymphotropic Aleutian disease parvovirus isolate ADV-SL3 was determined and analysed. The sequence revealed that this isolate was a type-1 ADV strain, supporting that the currently used typing of ADV viruses does not correlate with virulence or pathogenicity. ADV-SL3 had a very high overall homology of 99.5% to the prototype strain ADV-G at the DNA level. Comparative sequence analyses with various ADV isolates of known virulence did not reveal a consensus sequence that could obviously be responsible for the apparently unique biological properties of this virus strain.

Aleutian Mink Disease Virus↗