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P M Biggs

Publications and source records attributed to P M Biggs.

At least 19 recordsLinked to original sources

The World Veterinary Poultry Association: the beginnings and first 25 years.

The World Veterinary Poultry Association (WVPA) was formed in 1959, the honour of being the first President of the Association going to Professor de Blieck and that of Secretary to Dr R.F. Gordon, who had both championed its formation. The First WVPA Conference (the name "Congress" was not applied until the third meeting) took place in Utrecht in 1960. The second Conference (1962) and the third Congress (1965) were in Cambridge and Paris, respectively. The fourth Congress, in Belgrade (1969), was a landmark one for two reasons: firstly, submitted papers were introduced, and secondly, the notion of a WVPA journal, later to be called Avian Pathology, was first discussed. A year later (1970) the journal came into being, Professor Klimes (Czhechoslovakia), the driving force behind its creation, being the first Editor-in-Chief, with Professor Kosic (Yugoslavia) as production Editor. Due to the ill health of Professor Klimes, Peter Biggs was confirmed as Editor-in-Chief in 1973. A charitable company, Avian Pathology Ltd, was formed in 1980, under which Avian Pathology was published. Dr L.N. (Jim) Payne succeeded Dr Biggs as Editor-in-Chief in 1988. The fifth and six Congresses were in Munich (1973) and Atlanta, Georgia, USA (1977), respectively. Four years later, at the Oslo Congress, it was agreed that the rather crude logo adopted at the fourth Congress should improved. This was done and is the current logo. On the 25th anniversary (1985) of the first WVPA Congress, the eighth Congress was held in Jerusalem. Membership had increased to almost 1000, with members in 39 countries, 22 of which had branches of WVPA. In 4 years it will be time to publish an account of the second 25 years in the history of the WVPA.

Animals↗

The Leeuwenhoek Lecture, 1997. Marek's disease herpesvirus: oncogenesis and prevention.

There are a number of neoplasias for which a herpesvirus is an essential part of the aetiology. Of these, Marek's disease is the most common and provides excellent opportunities for the study of a herpesvirus-induced tumour both experimentally and under natural conditions in the field. Marek's disease is caused by an alpha herpesvirus; it differs from the other oncogenic herpesviruses which are gamma herpesviruses. It is a ubiquitous virus in poultry populations of the world and is highly cell-associated and contagious, yet only a proportion of infected fowl develop tumours. Evidence is presented to suggest that at least one of the reasons for a wide variation in the incidence of the disease is a temporal interplay between virulent viruses and viruses of low or no virulence. The viral genes associated with the oncogenicity of Marek's disease virus (MDV) are discussed and it is concluded that it is likely that several genes are involved. Finally, a brief history of vaccination to control Marek's disease is given and mode of action discussed. It is concluded that the mechanism of protection is mainly through an antiviral cell mediated immune response, resulting in a lowered challenge virus burden. Marek's disease viruses over the past 40 years have been evolving greater oncogenicity, some of which are not adequately controlled by the vaccines that are currently available. It is suggested that for MDV to produce tumours, there is a need for the cytolytic infection phase and that infection must be with an MDV which possesses a functional gC, ICP4 for maintaining latency which allows the expression of at least the 1.8 kb family, pp38, meq, and possibly pp14 genes, for maintaining the tumour state and possibly initiating this state. Intervention in this process reduces the chance of tumour formation and incidence in a population which can occur through natural or man-mediated infection with non-pathogenic MDVs.

Animals↗

Gordon memorial lecture. Vaccines and vaccination--past, present and future.

1. Immunisation was first practised as early as the 10th century when small doses of smallpox material administered by unusual routes were used to immunise against smallpox. The procedure was introduced into England in the early part of the 18th century. 2. The next major development was the use by Jenner of cowpox to vaccinate against smallpox in the late 18th century. 3. Some eighty years later came the classic studies of Pasteur developing vaccines for fowl cholera, anthrax and rabies. 4. The studies of Jenner and Pasteur established the major principles of vaccination which are in use to this day. 5. The major viral diseases of the domestic fowl were recognised during the 1920s and 1930s and in most cases vaccines were developed within 5 years of the discovery of the viral nature of the cause of each disease. 6. The desirable properties of poultry vaccines required by the user and producer are not completely fulfilled by currently available vaccines. 7. There is a need to use the opportunities provided by modern biotechnology and immunology to search for and develop vaccines that better fulfil the desirable properties of poultry vaccines. 8. There are a number of strategies available for the development of novel vaccines, some of which are appropriate for the needs of poultry vaccines.

Animals↗

Infectious animal disease and its control.

The control of infectious diseases in the main food-producing animals is considered and the main factors involved in the epizootiology of disease are presented. The properties of infectious agents and their natural history together with factors that influence the spread and development of disease are summarized. The factors in intensive animal husbandry that affect the occurrence of infectious disease and its control are considered. These include population density, population movement, management, hygiene and genetic constitution of the host. They encourage the appearance of new diseases, changes in the character of established diseases and the development of pathogenicity in infectious agents that were previously of no importance. Intensive animal husbandry has also increased the importance of multifactorial disease, which includes diseases that require more than one infectious agent or one or more infectious agents plus other factors for their cause. The methods of control of infectious disease currently available are described and the success and difficulties of their control on a global, national and local (farm or enterprise) basis are considered. Examples of diseases of global importance where national and world programmes of control and eradication have been of varying success are described. Examples of diseases that are enzootic throughout the world and the procedures used for their control are also described. The technological opportunities for the improvement of the control of infectious disease in the future are discussed. It is considered that developments in molecular biology and immunology will provide improvements in diagnostic tools and will revolutionize the development of animal resistance to disease and the production and use of vaccines.

Animal Diseases↗

Restriction endonuclease analysis of Marek's disease virus DNA and homology between strains.

The restriction endonuclease patterns of viral DNA obtained from serotypes 1 and 2 strains of Marek's disease virus have been compared and homology between the strains examined by hybridization. The results have shown that HPRS 16 (serotype 1) DNA has a structure similar to its attenuated variant HPRS 16/att except for a few fragments that are present only in the virulent strain. Evidence was obtained which suggested that these restriction fragments contained repeat sequences and that insertion of heterogeneous DNA occurred at these sites during attenuation of HPRS 16. The restriction enzyme patterns of HPRS 24 (serotype 2) differed substantially from those of HPRS 16 and HPRS 16/att and reassociation experiments showed that HPRS 24 shares less than 10% homology with either HPRS 16 or herpesvirus of turkeys (serotype 3).

Base Sequence↗

The epidemiology of avian herpesviruses in veterinary medicine.

There are ten avian herpesviruses, which have been isolated from eight orders. Six of these are of veterinary importance: Pacheco's parrot disease virus, pigeon herpesvirus, duck plague virus, infectious laryngotracheitis virus, herpesvirus of turkeys and Marek's disease virus. The knowledge on the epidemiology of each virus and the disease it causes is discussed. Features in common to infections with most avian herpesviruses are: infection is persistent in individuals and ubiquitous in populations; virus is shed for long periods of time after infection although in some cases erratically; infection does not necessarily result in disease and at least in some avian herpesvirus infections the incidence of disease is affected by the pathogenicity of the virus; the genetic constitution of the host and stress factors affecting the host. It is concluded that man's interference with the natural history of host species often increases the threat and incidence of disease unless preventive action is taken.

Animals↗

Herpes virus of turkey vaccine: viraemias in field flocks and in experimental chickens.

In a field survey of viraemias due to vaccination of chickens with herpes virus of turkey, variation was encountered in titres and percentages of birds viraemic. The incidence of viraemias was much lower in sick than in healthy birds in flocks undergoing mortality from Marek's disease. In a concurrent experiment the same strain of chicken and the same commercial vaccine were used as in the field flocks affected with Marek's disease. A high incidence of viraemia and 84.6 per cent protection against Marek's disease were obtained with single vaccination at one day of age. Revaccination at 21 days of age produced no measurable benefits in the same experiment.

Age Factors↗

Marek's disease--the disease and its prevention by vaccination.

Marek's disease (MD) is a common lymphoproliferative disease of the domestic chicken caused by a cell associated herpesvirus. Vaccines used for the prophylaxis of MD have been derived from non-pathogenic field Marek's disease virus (MDV), pathogenic MDV and the herpesvirus of turkeys (HVT). Vaccines derived from MDV have been developed by attenuation of virus strains which produce the acute form of MD and virus strains which produce the classical form. They have also been developed by suitable modification, where necessary, of non-pathogenic MDV. All MDV derived vaccines have to be used in the cell associated form. The turkey herpesvirus vaccine can be used in either the cell associated or cell free lyophilized form. All these types of vaccine appear to be safe and to provide significant levels of protection under field conditions.

Animals↗

Characterization of a new serotype of Marek's disease herpesvirus.

The HPRS-24 strain of Marek's disease herpesvirus was selected for closer study from a group of virus isolates that appeared apathogenic under standard test conditons. Protection studies revealed an immunological relationship between this virus strain and acute Marek's disease herpesvirus. In chicken kidney cell cultures, the HPRS-24 strain caused small and slowly developing plaques, and the proportion of infected cells was less than with other strains. In chicken embryo fibroblast cultures, this virus multiplied rapidly, yielding a comparatively high proportion of infected cells. Electron microscopic studies revealed that infected fibroblasts contained more enveloped virus particles than those infected with other strains of Marek's disease herpesvirus. Infectious cell-free virus was extracted from cultured fibroblasts with titres high enough for use in neutralization studies. Cross-neutralization, immunofluorescence and precipitin tests served for serological comparison of the HPRS-24 strain with turkey herpesvirus and representatives of acute and classical Marek's disease herpesvirus. Antibody titres were 4-10 times higher against the homologous than against the heterologous virus strains. Qualitative differences between precipitating "A" antigens were characterized by spur line patterns of precipitation bands. These results suggest that the group of Marek's disease and turkey herpesviruses consists of at least three serological types. One of them is represented by the HPRS-24 strain of apathogenic Marek's disease virus. The other two types comprise pathogenic strains of Marek's disease virus and their attenuated variants, and turkey herpesvirus.

Animals↗