PubMed Health⌕ Search

Biomedical subjects

H Bourhy

Publications and source records attributed to H Bourhy.

At least 37 records · Page 2Linked to original sources
PubMed1997

Evolution of European bat lyssaviruses.

Forty-seven European bat lyssaviruses (EBL) and two African insectivorous bat lyssaviruses (Duvenhage viruses) were selected for a comparison to be made of their evolutionary relationships. Studies were based on direct sequencing of the PCR-amplified products of the 400 nucleotides coding for the amino terminus of the nucleoprotein. Phylogenetic relationships were analysed after bootstrap resampling using the maximum parsimony and the neighbour-joining methods. Analyses of both the nucleotide and amino acid sequences placed these viruses in three separate clusters, namely genotype 4 (Duvenhage), genotype 5 (EBL1) and genotype 6 (EBL2). Evolutionary analysis of the nucleoprotein gene of EBL1 and EBL2 indicated low intrinsic heterogeneity mainly due to synonymous substitutions. In addition, both EBL1 and EBL2 evolved into at least two genetically distinguishable lineages (a and b) following geographical drifting. We can speculate that subsequently the lineages EBL1a and EBL1b were introduced into parts of northern Europe from two different geographical directions; EBL1b was probably introduced most recently and was from North Africa. Eptesicus serotinus appears to be the principal reservoir for EBL1 and Myotis dasycneme and M. daubentonii the reservoirs for EBL2.

Amino Acid Sequence↗
PubMed1996

Rabies encephalitis in a patient with AIDS: a clinicopathological study.

A 46-year-old man was bitten by a dog in Mali; anti-rabies vaccination was incomplete. Three months later he was admitted to hospital with fever and diarrhea. Human immunodeficiency virus (HIV) serology was positive and CD4 count was 70/mm3. His status worsened rapidly with confusion hydrophobia and hypersialorrhea. Despite anti-rabies serotherapy and vaccination, he died suddenly 12 days after admission. Immunofluorescence on cerebral tissue samples established rabies encephalitis. Neuropathology showed mild encephalitis with occasional Babès nodules and rare perivascular mononuclear cuffs. Intraneuronal Negri inclusion bodies were remarkably diffuse and abundant. They were clearly demonstrated by immunocytochemistry and electron microscopy. Apoptotic neurons were identified in the brain stem and hippocampus in the vicinity of inflammatory foci. In contrast, apoptosis could not be demonstrated in non-inflammatory areas, even where Negri bodies were numerous. There was no associated HIV encephalitis or opportunistic infection. The occurrence of rabies encephalitis in AIDS represents a random association, but is probably not exceptional as rabies is endemic in many countries and the AIDS epidemic is spreading worldwide. In this case, although the incubation duration and clinical presentation were comparable to those in classical rabies the T-cell-mediated immunosuppression may account for the weak inflammatory reaction and unusually abundant viral multiplication. This observation confirms that all those at risk for rabies, particularly immunocompromised patients, should receive complete anti-rabies treatment including vaccines and specific immunoglobulins, as soon as possible after infection.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Genetic polymorphism in the rabies virus nucleoprotein gene.

In an attempt to compare intrinsic and extrinsic genetic diversity of the lyssavirus genotypes, 69 rabies virus isolates from various part of the world were partially sequenced and compared to 13 representative isolates of the 6 lyssavirus genotypes. The analysis of their phylogenetic relationships, performed on the complete nucleoprotein (N) coding gene (1350 bases), established that the rabies virus isolates all belonged to genotype 1 and that at least 11 phylogenetic lineages could be identified in accordance with their geographical localization and species of origin. These lineages diverged mostly by the accumulation of synonymous mutations. Stabilizing selection, possibly related to host specificity, limits amino acid sequence and antigenic drift. Analyses were also performed either on the highly variable 400-base region coding for the amino terminus of the N protein or on the 93-base noncoding region corresponding to the 3' end of the N mRNA, the intergenic N-phosphoprotein (M1) region, and the 5' end of the M1 mRNA. These shorter nucleotide sequences were shown to provide phylogenetic data suitable for the completion of large epidemiological studies, but with less robustness. This latter noncoding sequence, despite a 3.1 times higher mutation rate than its adjacent coding N gene, followed a parallel evolutionary pattern.

Amino Acid Sequence↗
PubMed1993

Structure and expression in baculovirus of the Mokola virus glycoprotein: an efficient recombinant vaccine.

The sequence of the glycoprotein gene of the Mokola virus, the more divergent element of the Lyssavirus genus, has been determined and the predicted protein structure compared to its counterpart in rabies vaccine strains. A global similarity of 54.3% was observed. The divergence affects particularly the rabies antigenic sites involved in the B-cell response. This provides a molecular basis for the absence of cross-protection between Mokola and rabies viruses and argues for the necessity of a specific anti-Mokola vaccine. Toward this goal, a cDNA copy of the glycoprotein gene was cloned into the baculovirus and expressed in Spodoptora frugiperda cells. A recombinant protein was produced in substantial amounts at the surface of the insect cells. Although less strongly glycosylated than the native viral glycoprotein produced in BHK-21 cells, the recombinant protein is antigenically and immunologically similar, it is recognized by specific monoclonal antibodies, and protects mice against an intracerebral challenge with Mokola virus. It therefore constitutes the first experimental genetically engineered vaccine against a rabies-related virus, and fulfills the international standard for protection.

Amino Acid Sequence↗
PubMed1993

Molecular diversity of the Lyssavirus genus.

The sequence of 5568 nucleotides of the 3' moiety of the Mokola virus genome (serotype 3 of lyssaviruses) encompassing the nucleoprotein (N), phosphoprotein, matrix protein, and glycoprotein genes is presented and compared to that of the vaccinal strains of serotype 1. It allowed us to determine consensus sequences derived from the transcriptional start/stop signals and the order of protein conservation (nucleoprotein > matrix protein > phosphoprotein) in lyssaviruses. The sequences of the N gene of a fox rabies virus isolate from France (serotype 1), Lagos bat virus (serotype 2), Duvenhage virus (serotype 4), two European bat lyssaviruses (EBL) subtype 1, and two EBL subtype 2 were also determined to study the genetic diversity throughout the whole Lyssavirus genus and reinvestigate the classification of this genus. Six clearly distinct genotypes can be distinguished according to their percentage of amino acid similarity. Genotypes 2 (Lagos bat virus) and 3 (Mokola virus) are the most phylogenetically distant from the vaccinal and classical rabies viruses of genotype 1. Genotypes 4 (Duvenhage virus) and 5 (EBL1) are closely related to each other. Genotype 6 is represented by EBL2. Compared to the N proteins of the four principal serotypes of the Vesiculovirus genus (vesicular stomatitis virus serotype New Jersey and serotype Indiana, Chandipura virus, and Piry virus), the N gene of lyssaviruses exhibits a lower genetic variability.

Amino Acid Sequence↗
PubMed1993

Taxonomy and evolutionary studies on lyssaviruses with special reference to Africa.

Currently, the Lyssavirus genus is composed of four serotypes and the ungrouped European bat lyssaviruses (EBL). Using previously described PCR amplification and direct sequencing methods, the N genes of 70 representative lyssaviruses collected from 40 different countries were examined. From the results, a phylogenetic tree with six branches (genotypes) was constructed: genotypes 1-4 correlated with the classification of serotypes 1-4 and in addition EBL 1 and EBL 2 were identified as two further genotypes (5 and 6). Analysis of the 51 rabies (genotype 1) viruses in the study identified nine distinct groups which could be correlated with their geographical origins. A comparison of the six genotypes with four principal Vesiculovirus serotypes showed that their relationship was closer than that of even the two most closely related Vesiculovirus serotypes. Antigenic site sequences of isolates from vaccine/treatment failures were similar to vaccine and field strains, suggesting that failures were not due to genetic variation at the N protein level.

Africa↗
PubMed1992

A modified rapid enzyme immunoassay for the detection of rabies and rabies-related viruses: RREID-lyssa.

This paper presents a modification of the previously described Rapid Rabies Enzyme Immuno-Diagnosis test (RREID) by using biotinylated antibodies, streptavidin conjugate and a mixture of monospecific polyclonal antibodies against several lyssaviruses. In the modified technique (RREID-lyssa), microplates were sensitized with a mixture of purified antibodies against ribonucleoprotein (RNP) from Pasteur virus (Lyssavirus serotype 1), European Bat Lyssavirus (EBL, unclassified) and Mokola virus (Lyssavirus serotype 3). Bound RNP was detected by the same antibodies labelled with biotin and peroxidase-strepavidin conjugate. These techniques were used for the detection of RNP of different Lyssavirus serotypes (rabies and rabies-related viruses). For lyssavirus specimens of serotype 1, the threshold of detection of RREID and RREID-lyssa were similar. However, a smaller amount of labelled antibodies was needed when biotinylated antibodies were used. For specimens infected by rabies-related strains (serotypes 2, 3, 4 and EBL), the threshold of detection of the RREID-lyssa was between two and 512 times lower than with the RREID. The sensitivity and the specificity of the RREID-lyssa for rabies virus (serotype 1) when tested on a small field trial (53 specimens) were found to be identical to the RREID. Consequently, RREID-lyssa can be a useful tool for diagnostic laboratories that receive specimens infected by rabies-related viruses.

Animals↗
PubMed1992

Molecular epidemiology of rabies virus in France: comparison with vaccine strains.

A molecular epidemiological study of the rabies virus currently prevalent in France was carried out by directly sequencing polymerase chain reaction-amplified genes. The rabies virus pseudogene psi was chosen as the most divergent genomic area, and as such the best 'clock' for measuring virus evolution. Sequence comparisons between 12 wild rabies virus isolates indicated strong conservation whatever the host and wherever the virus had been isolated. This holds true for a unique wild reservoir, the fox. On the other hand, a good correlation between genetic and geographical criteria indicates a slow evolution of the wild virus in parallel with the spatio-temporal progression of the epizootic. In contrast to their intrinsic homogeneity (about 2% divergence), the wild isolate sequences showed a marked divergence from those of vaccine seed strains (about 14.7%). This finding invites world-wide molecular epidemiological studies, particularly in countries in which vaccination failures have been reported.

Animals↗
PubMed1992

Antigenic and molecular characterization of bat rabies virus in Europe.

The predominant role of Eptesicus serotinus in the epizootic of bat rabies in Europe was further outlined by the first isolation of the rabies virus from this species in France. The distribution of the virus was studied in naturally infected E. serotinus bats at the time of death and suggested that the papillae of the tongue and the respiratory mucosa may play a role in virus production and excretion. The analysis of 501 French rabies virus isolates from various animal species by antinucleocapsid monoclonal antibodies indicated that transmission of the disease from bats to terrestrial animals is unlikely. The antigenic profile of two isolates from French bats corresponded to that of European bat lyssavirus type 1 (EBL1). Comparisons of 12 different isolates from bats with antinucleocapsid and antiglycoprotein monoclonal antibodies and by direct sequencing of the polymerase chain reaction amplification product of the N gene indicated that EBL1, EBL2, Duvenhage virus (serotype 4 of lyssavirus), and the European fox rabies virus (serotype 1) are phylogenetically distant. They formed four tight genetic clusters named genotypes. EBL1 was shown to be antigenically and genetically more closely related to Duvenhage virus than to EBL2. We propose that EBL1 and EBL2 constitute two distinct genotypes which further serologic characterization will probably classify as new serotypes. We also report a simple method for the rapid characterization of EBL based on the digestion of the polymerase chain reaction product of the N gene by three restriction endonucleases.

Animals↗
PubMed1992

[Rabies encephalomyelitis with myocarditis and pancreatitis. Report on a case recently imported into France].

We report the case of a 29 year-old man who died from rabies in France, following a dog-bite during a trip in Mexico. Although it was clinically suspected, the diagnosis was uncertain until he died because of digestive, cardiac and psychiatric misleading symptoms associated to the neurologic disorders. Post mortem diagnosis was based upon virological study in immunofluorescence on cerebral smears, viral isolation on cell-culture, and ELISA. It was confirmed by light microscopy examination which showed numerous Negri bodies, and ultrastructural study of the rhabdovirus in the central nervous system. Extranervous lesions, especially myocarditis and pancreatitis, were observed and their meaning is discussed. The physician is exceptionally confronted to the diagnosis of human rabies in France. Nevertheless, the lack of compulsory antirabic vaccination and the increase of touring in enzootic countries increase the risk of infection. As an intra vitam diagnosis in frequently lacking, the diagnosis of rabies infection needs a complete post mortem virological study as well as an histological and ultrastructural examination of the central nervous system.

Adult↗
PubMed1991

Rabies-specific production of interleukin-2 by peripheral blood lymphocytes from human rabies vaccinees.

Cell-mediated immunity induced by rabies vaccination was studied in humans by the determination of specific interleukin-2 (IL-2) production in a large number of donors (postexposure immunized patients and pre-exposure immunized laboratory workers). Peripheral blood lymphocytes (PBL) from 35 donors were tested for IL-2 production after in vitro stimulation by different rabies and rabies-related viruses. IL-2 responses were compared to antibody recognition of these different virus serotypes by sera from the same individuals. IL-2 was produced by PBL from more than 85% of donors after stimulation with inactivated and purified rabies viruses (IPRV) prepared from either Pittman Moore (PM) or Pasteur Virus (PV) strains. IL-2 was also produced by 65 and 45% of donor PBL stimulated with IPRV from the European Bat Lyssavirus (EBL) and Mokola (Mok) rabies-related virus strains respectively. No correlation was found between the production of IL-2 by PBL and the levels of virus neutralizing antibody (VNAb). Moreover, 50, 25 and 35% of donors produced IL-2 after stimulation of their PBL with ribonucleoprotein (RNP) from PV-, EBL- and Mok-viruses, respectively. These results obtained with a large number of human rabies vaccinees and using an assay specific to T-cell activation confirm the significant cross-reactivity of T-cell responses directed against rabies and rabies-related viruses. This study shows that IL-2 production could be used for the study of cell-mediated immunity and T-cell memory induced in humans by rabies vaccination.

Adult↗
PubMed1991

PCR technique as an alternative method for diagnosis and molecular epidemiology of rabies virus.

We have investigated the PCR amplification technique of viral nucleic acids as an alternative protocol for diagnosis and epidemiological studies of rabies virus. A primer set mapping in the nucleoprotein cistron allowed a specific and sensitive amplification of infected brain material, fulfilling the diagnosis requirements. One hundred samples checked by Southern or dot-blot analysis using both radioactive and non-radioactive probes showed identical results in parallel with routine techniques. For molecular epidemiological studies we selected another set of conserved primers flanking the highly evolutive pseudogene (psi gene) region. This set was found to be efficient for all tested fixed rabies virus strains or wild rabies virus isolates as well as the rabies-related Mokola virus. We describe a progressive characterization of the strain that could be extended from rapid typing by a limited panel of restriction enzymes, to the ultimate identification of the nucleotide sequence by an original direct sequencing technique of amplified segments.

Animals↗
PubMed1990

From rabies to rabies-related viruses.

Antigenic differences between rabies virus strains characterized with monoclonal antibodies presently define at least four serotypes within the Lyssavirus genus of the Rhabdoviridae family: classical rabies virus strains (serotype 1), Lagos bat virus (serotype 2), Mokola virus (serotype 3) and Duvenhage virus (serotype 4). The wide distribution of rabies-related virus strains (serotypes 2, 3 and 4) and above all, the weak protection conferred by rabies vaccines against some of them (principally Mokola virus) necessitates the development of new specific vaccines. We first determined the complete nucleotide sequence of a rabies virus strain of serotype 1 (Pasteur virus) and characterized the structure of the viral genes and their regulatory sequences. We then extended this study to the Mokola virus genome. Five non-overlapping open reading frames were found in both viruses and had similar sizes and positions in both. Similarities were also found in the mRNA start and stop sequences and at the genomic extremities. Comparison of both genomes helps to analyze the basis of the particular antigenicity of these two serotypes. The sequence homology in the region coding for the viral glycoprotein was only 58% between the two viruses, compared with 94% between different rabies virus strains within serotype 1. This comparison, extended to other unsegmented negative strand RNA viruses, gives new insight into the understanding of rhabdoviruses and paramyxoviruses. Furthermore, molecular cloning provides a rationale for the genetic engineering of a future vaccine.

Amino Acid Sequence↗
PubMed1989

Complete cloning and molecular organization of a rabies-related virus, Mokola virus.

Mokola virus is a rabies-related virus responsible for both animal and human encephalitis cases in Africa. We report here the construction of a genomic library containing overlapping cDNA clones encompassing the entire genome. Five overlapping clones were sufficient to cover the genome (about 12 kb in size). Mokola virus was shown to share the same genomic organization as the rabies virus genome and also identical transcription signals. cDNA probes characterized six different transcripts by Northern blotting experiments; five of them corresponded in size and location to rabies virus mRNAs, and one of particular interest corresponded to a bicistronic RNA which included the genes for the phosphoprotein and the matrix protein. Comparison of the 3' and 5' end sequences of the Mokola genome with those of other members of the Lyssavirus genus showed a high homology and led us to propose a genus-specific consensus sequence. However, the latter appeared to vary widely throughout the Rhabdoviridae family.

Base Sequence↗
PubMed1989

Comparative field evaluation of the fluorescent-antibody test, virus isolation from tissue culture, and enzyme immunodiagnosis for rapid laboratory diagnosis of rabies.

The rabies tissue culture infection test (RTCIT) and rapid rabies enzyme immunodiagnosis (RREID) were compared to the fluorescent-antibody test (FAT) with field specimens. At the French National Reference Center for Rabies, 15,248 specimens were analyzed by FAT and RTCIT, and 2,290 of those specimens were also tested by RREID; 818 other specimens were tested by FAT and RREID in 12 laboratories located in Africa, Asia, and Latin America. The sensitivities and specificities of RREID and RTCIT were comparable. This study showed that both tests can be used as backup procedures to confirm FAT. RREID is also strongly recommended for epidemiological studies and for laboratories which are not equipped for performing FAT.

Africa↗