Search PubMed⌕ Search

Biomedical subjects

J Blancou

Publications and source records attributed to J Blancou.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Ancient methods of surveillance and control of rinderpest].

Using the many documents available on the history of rinderpest, it is possible to accurately describe the practical measures adopted for rinderpest surveillance and control from Antiquity to the 19th Century. Surveillance was based on clinical diagnosis, post-mortem examination, animal inoculation, and also on the knowledge of the conditions under which infection occurred: aetiology, pathogenesis, susceptible species, virulent material, mode of infection, incubation period, etc. The historical facts are assembled and compared, with comments on each of these points. Control was based upon the application of general disease control measures, attempts at vaccination, and treatment. A study of these procedures makes it possible to compare their efficacy and describe the major steps of their implementation.

Animals↗
PubMed1993

Field diagnostic kits: a solution for developing countries?

An exact assessment of the animal health situation in a country is an essential element in formulating eradication and control programmes, and in regulating international trade in animals and animal products from that country. Due to a lack of human and technical resources, Veterinary Services in developing countries often lack precise knowledge on disease occurrence. Since the collection and transmission of reliable information on animal diseases in developing countries are major concerns of the Office International des Epizooties (OIE), a project aimed at improving this situation was implemented with international financial support. This project involved the development by the Centre for the Application of Methodology for the Diagnosis of Animal Diseases (CAMDA) of field kits for the diagnosis of the main diseases present in tropical Africa: rinderpest, peste des petits ruminants (PPR), contagious bovine pleuropneumonia (CBPP) and contagious caprine pleuropneumonia (CCPP). Several tests already exist, such as complement deoxyribonucleic acid (cDNA)-specific probes and polymerase chain reaction (PCR) for rinderpest and PPR, DNA probes and PCR for CBPP, capture enzyme-linked immunosorbent assay, the agglutination test and the immunobinding peroxidase test for CCPP, etc. With specific reference to these examples, the various problems faced by the OIE and CAMDA are reviewed.

Animals↗
PubMed1993

[Recent developments in the epidemiology and prevention of rabies].

Rabies is one of the oldest known diseases and man has been combatting it for many centuries. In many parts of the world, however, especially in the developing countries, success in controlling the disease will remain limited. Sanitary prophylaxis of rabies has reached its limit due to two factors: the difficulty of confining or eliminating all the vector animals, and the growing public opposition to the use of such measures. Medical prophylaxis can be undertaken in two ways: vaccination by the parental route or oral vaccination. The former has reached its limit in many developing countries, where its high cost is considered to outweigh the benefit to public health. Oral vaccination, on the other hand, has achieved spectacular success in Europe, where it is being used to progressively eliminate fox rabies. This technique could applied to dogs as soon as the scientific and technical prerequisites have been clearly defined.

Animals↗
PubMed1992

The role of the Office International des Epizooties in the standardisation of biologicals.

The Office International des Epizooties (OIE) is the World Animal Health Organisation created in 1924 in Paris. The following activities have been started in order to promote standardisation of biologicals: a) preparation of the OIE Manual of Standards for Diagnostic Tests and Vaccines; b) organisation of Reference Laboratories for diseases of Lists A and B; c) establishment, in cooperation with WHO, FAO and IAEA, of international standards for diagnostic tests with particular reference to the ELISA. The Manual will be distributed worldwide in 1992 and 1993 and this will contribute to an internationally unified approach to diagnosis and immunoprophylaxis, in other words to international harmonisation of veterinary biologicals. It is planned that future OIE Reference Laboratories, now being organised, will supply the necessary standards.

Animal Diseases↗
PubMed1992

Role of the Office International des Epizooties in protecting the health of free-ranging mammals.

The various activities undertaken by the Office International des Epizooties (OIE) since 1924 to protect the helth of free-ranging mammals are outlined and discussed. Two types of activity have been conducted over the years: --The first type promotes measures to protect the health of free-ranging mammals in order to safeguard the health of domestic animals and human beings. These measures have prevented the propagation of the highly contagious diseases of animals and the more serious zoonoses. --The second type aims at protecting the health of free-ranging mammals in order to maintain the fauna and the natural equilibrium. Ecological and epidemiological studies are promoted with a view to effective management of wildlife populations and overcoming the associated health risks. By virtue of its close contacts with officials in charge of animal health in 126 Member Countries, the OIE has made a noteworthy contribution to the protection of populations of free-ranging mammals.

Animals↗
PubMed1992

[Experimental infection of sheep with a rabies virus of canine origin: study of the pathogenicity for that species].

The effects of the inoculation of a canine strain of rabies virus in sheep were studied using ten animals which received different amounts of this virus. Two subjects, inoculated with 10(5.4) mouse intracerebral lethal doses 50% (MICLD50), died from rabies after 19 and 40 days of incubation. Clinical signs were anorexia, emaciation, nervous reactions and prostration before death. The virus was recovered from different parts of the central nervous system and salivary glands with high titres. Only three animals showed an antibody response, at very low levels.

Animals↗
PubMed1991

Effective postexposure treatment of rabies-infected sheep with rabies immune globulin and vaccine.

An experiment to assess the efficiency of the treatment recommended for humans after exposure to rabies was conducted in 68 sheep experimentally infected with a fox rabies virus. The infected sheep were divided into three groups and were given either a cell-culture vaccine (on the day of infection, then at day 3, 7, 14), human rabies immunoglobulin (26 IU kg-1 on the day of infection) or a combination of the vaccine immunoglobulin. The latter combination was the only treatment found to be effective in 100% of the animals, as 71% of the controls died. This model appears to be useful in assessing new regimens of postexposure treatment for humans as well as in the reconsideration of its feasibility, or validity, in animals.

Animals↗
PubMed1991

Identification of sylvatic Trichinella (T3) in foxes from France.

Thirty-three foxes (Vulpes vulpes) from a sample of 1912 collected in France were found to be infected with Trichinella spp. Four isolates were obtained for genetic identification. Isoenzymatic and biological analysis of these isolates revealed the presence of two distinct genetic types of Trichinella, Trichinella spiralis s.str. (T1) and Trichinella sp. (T3) (Trichinella nelsoni according to Soviet authors) in the fox population. The reproductive capacity index of these isolates in Wistar rats was high for T. spiralis and low for T3. This is the first report of T3 type from wild animals in France. The epidemiological implications are discussed.

Animals↗
PubMed1991

[Behavioral ecology of the transmission of rabies].

Red fox behavioural ecology was studied in a rabies-enzootic area in order to determine how population size is balanced despite rabies-induced mortality. The results suggest that the red fox rabies virus equilibrium evolves, and is due to the solitary behaviour pattern of the fox which reduces the risk of virus transmission from on territory to another; and to the subsequent autumn dispersal, which allows the local fox population to recover in the space of under a year. The hypothesis is put forward that rabies does not seem to regulate fox population size. There would therefore be no reason to fear a population explosion after oral immunisation of foxes against rabies.

Animals↗
PubMed1991

[Transmissibility and pathogenicity in the red fox of two rabies viruses isolated at a 10 year interval].

Two rabies virus strains collected from naturally infected foxes in France in 1976 and 1986 were inoculated in 2 groups each consisting of 10 foxes (approximately 50 lethal doses50 mouse intracerebral per fox). Another 20 healthy foxes were kept in the same cages as the inoculated animals in order to study the transmission of both strains. All the inoculated foxes became rabid and transmitted rabies to their cage companion. The intervals between death of the inoculated foxes and death of the cage companion were significantly more variable (P less than 0.001) with the earlier strain, from 1 to 33 days compared to the range obtained with the later strain, 10-14 days. However, the mean intervals did not differ. Epidemiological consequences of such a decrease in variability, if confirmed in the field could decrease the epidemiological extent of rabies. Viremia was demonstrated in 2 foxes inoculated with the later strain but we cannot assume this to be a characteristic of this strain compared with the earlier strain. Rabies virus (both strains) was isolated from the saliva of foxes 29 days or less before the onset of clinical symptoms. This last result raises the question of the time limit as regards security before onset of clinical symptoms in animals involved in human contamination.

Animals↗
PubMed1990

Efficacy of a baiting system for vaccinating foxes against rabies with vaccinia-rabies recombinant virus.

The efficacy of a vaccinia-rabies recombinant virus (10(8) TCID50) contained in a machine-made baiting system has been tested in 22 captive young foxes which were divided into three experimental groups of six and a control group of four foxes. Each fox in groups 1, 2 and 3 were fed one, two and three vaccine-baits, respectively, on successive days. The four unvaccinated foxes were housed separately. As shown by the incorporation of a tetracycline biomarker into their bones, all the baited foxes ingested at least one bait. Thirty days after baiting seroconversion to rabies was observed in 15 (83 per cent) of the foxes and seroconversion to vaccinia in 14 (78 per cent). Sixteen of the 18 (89 per cent) baited foxes resisted a rabies challenge 30 days after baiting. One cub was protected against rabies despite the absence of detectable anti-rabies antibody. The results demonstrate that the bait-sachet system permits a good release of the virus suspension into the mouth.

Animals↗
PubMed1990

Use of a vaccinia-rabies recombinant virus for the oral vaccination of foxes against rabies.

The vaccination of wild animals against rabies has been developed most extensively in Europe. Experiments have demonstrated the efficacy of a vaccinia-rabies recombinant virus administered by the oral route in foxes. The innocuity of this vaccine was tested in the target species as well as in several non-target wild and domestic species. Because of its safety and heat-stability, this recombinant virus should offer an excellent alternative to the attenuated strains of rabies virus currently used in the field. A large scale field trial was conducted in Belgium in October 1988 to assess the efficacy of this new vaccine-bait systems.

Animals↗
PubMed1990

Use of vaccinia rabies recombinant for oral vaccination of wildlife.

A vaccinia rabies recombinant virus was constructed and shown to induce the synthesis of rabies virus glycoprotein in infected cells and to induce rabies virus neutralizing antibodies and protection in susceptible animals. Active when orally administered, this recombinant is a good candidate for the development of vaccines for wild animal rabies vectors. This recombinant was found stable, safe for target and non-target animal species, and protective for most of the rabies vectors. After extensive experimental studies conducted under controlled conditions, it as used in limited field trials and in an extensive open field trial. The preliminary results confirmed its basic properties and potential for rabies eradication.

Animals↗
PubMed1990

Oral immunization of foxes with avirulent rabies virus mutants.

SAG1, a rabies virus strain bearing one mutation which abolishes virulence for adult animals, was constructed from the SADBern strain of rabies virus which has previously been used as live vaccine for oral immunization of foxes. SAG1 also bears an antigenic mutation which serves as an additional marker of the strain. Studies on mice and four species of wild rodents showed that SAG1 is totally avirulent whereas SADBern is still pathogenic after intracerebral, intramuscular or oral inoculation and thus could cause cases of rabies. Trials of oral vaccination performed on foxes with SAG1 indicate that it is as effective as SADBern. The SAG1 strain represents a significant progress in the search for an efficient and safe live rabies for the oral immunization of wild animals.

Animals↗
PubMed1990

Primary multiplication site of the vaccinia-rabies glycoprotein recombinant virus administered to foxes by the oral route.

The primary multiplication site of VVTGgRAB, a recombinant vaccinia virus (VV) expressing the rabies virus G glycoprotein, was studied in comparison with that of the parental VV Copenhagen strain, after oral administration to foxes. Foxes were fed with 10(8) TCID50 of either VVTGgRAB or VV and were sacrificed 12, 24, 48 or 96 h after inoculation. Both viruses were detected by viral isolation in the tonsils during the first 48 h after inoculation at titres between 10(2) and 10(4.3) TCID50/ml. Indirect immunofluorescence confirmed the presence of the virus in tonsils of some of the foxes. The polymerase chain reaction allowed the detection of VVTGgRAB in the tonsils of both of two foxes tested after 24 h, three of three foxes after 48 h, in the buccal mucosa of one of two foxes tested after 24 h and two of three foxes after 48 h and in the soft palate of one of two foxes tested after 24 h and one of three foxes after 48 h. VV was detected in the tonsils of one fox tested after 48 h, in the buccal mucosa of another fox tested after 24 h, and in the first fox after 48 h by the same reaction. Foxes were inoculated with virus isolated from fox tonsils 24 h after oral administration (with or without cell culture amplification) to perform back passages. No virus could be isolated in either case after this passage. The innocuity of VVTGgRAB was also demonstrated when foxes were inoculated with passaged virus.

Administration, Oral↗
PubMed1990

Utilisation and control of biotechnological procedures in veterinary science.

The author retraces the history of "biotechnology" and the successive stages of its application in veterinary sciences. An inventory is given of potential applications in animal health (diagnosis, prevention and treatment of diseases), genetics, animal reproduction (direct and indirect contributions) and nutrition (at the levels of fodder plants, fermentation or prefermentation of feed, and animal metabolism). The control of biotechnological procedures is discussed, with reference to categories of risk and ways of averting risk, and control at national and international levels. There is growing interest in the application of biotechnology to animal reproduction and to the diagnosis and treatment of animal diseases, but developing ways to prevent disease is slow because considerable time is needed to evaluate risks.

Animal Diseases↗