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Biomedical subjects

R P Kitching

Publications and source records attributed to R P Kitching.

90 records · Page 5Linked to original sources
PubMed1987

Capripox in Bangladesh.

In 1984 capripox entered Bangladesh developing into a severe epidemic causing high mortality in the indigenous goat population. Although at present mainly confined to the western districts the disease has spread to some central and northern districts and unless controlled could spread further. Clinically and biochemically the strain is closely related to a strain previously isolated in central India. It has been shown that restriction endonuclease analysis of the genome of field isolates of capripoxvirus can provide a useful epidemiological technique in investigating outbreaks of capripox.

Animals↗
PubMed1987

Enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against foot-and-mouth disease virus. III. Evaluation of antibodies after infection and vaccination.

Investigations using a liquid-phase blocking sandwich enzyme-linked immunosorbent assay (ELISA) for the measurement of antibodies against foot-and-mouth disease virus (FMDV) in sera from sheep and from cattle are reported, and results compared with those obtained by virus neutralization (VN) tests. Serum antibody titres in sheep after primary vaccination and in cattle challenged with a natural aerosol after vaccination were similar by ELISA and VN. However, the antibody levels detected in sera of cattle during early infection and of vaccinated cattle after intradermolingual challenge were clearly greater by ELISA than by VN. The ELISA titres in cattle sera following synthetic peptide vaccination indicated some relationship to protection and were clearly different from those recorded by VN. On the other hand, the antibody levels following conventional vaccination showed that ELISA and VN titres in cattle sera were related to protection. Although there was a good agreement between the ELISA antibody titre and protection for the four vaccines used, by VN the titre which afforded protection varied depending on the vaccine used. The ELISA was considered therefore to be more reliable than the VN and may prove useful for evaluating the immunological response of animals following infection and following vaccination.

Animals↗
PubMed1987

Mechanical transmission of capripox virus and African swine fever virus by Stomoxys calcitrans.

Stomoxys calcitrans can act as an efficient mechanical vector of capripox virus and African swine fever virus. Capripox virus was transmitted to a susceptible goat by flies infected 24 hours previously and the virus survived in some flies for at least four days. African swine fever virus was transmitted to susceptible pigs by flies infected one hour and 24 hours previously and the virus survived in these flies for at least two days without apparent loss of titre.

African Swine Fever↗
PubMed1987

Infection of cattle by airborne foot-and-mouth disease virus: minimal doses with O1 and SAT 2 strains.

Equipment has been constructed and methods developed for exposing individual cattle to two strains of foot-and-mouth disease (FMD) virus in aerosols to determine the minimal infective dose by the respiratory route. The aerosols used were produced either artificially by a spinning-top aerosol generator, in which case they were of homogeneous small particle size (less than 3 micron in diameter) or else they were derived naturally from infected pigs, in which case the particles were heterogeneous in size. Two strains of FMD virus were used: an O1 strain of UK origin and a SAT 2 strain from South Africa. The lowest doses which initiated infection were 12.5 TCID50 of O1 BFS virus and 25 TCID50 of SAT 2 virus, infectivity having been assayed in primary bovine thyroid cell cultures. Following exposure to low doses of virus (range 12 to 316 TCID50) 33 per cent of the cattle exposed to O1 BFS virus and 27 per cent exposed to SAT 2 virus were infected but did not develop detectable vesicular lesions.

Aerosols↗
PubMed1987

A single vaccine for the control of capripox infection in sheep and goats.

A single vaccine against capripox was developed to protect sheep and goats throughout the capripox enzootic area. The vaccine was stable and safe to use, and provided substantial protection against capripox for at least a year. Preliminary field trials in the Middle East indicated that the vaccine was effective in controlling capripox in indigenous breeds of sheep and goats.

Animals↗
PubMed1986

Capripox in the Yemen Arab Republic and the Sultanate of Oman.

Capripox was shown to be endemic in all the provinces of the Yemen Arab Republic and the Sultanate of Oman. Investigations into outbreaks of capripox indicated that some strains of capripox virus were infecting both sheep and goats and this was confirmed by inoculating experimental sheep and goats with isolates derived from field cases. The husbandry methods prevalent in the Middle East predispose to the rapid spread of capripox and annual vaccination of all sheep and goats must be considered as the only effective method of controlling the disease.

Aging↗
PubMed1986

Genomic relationship between capripoxviruses.

Capripoxvirus DNAs from field isolates and vaccine samples were analysed by digestion with the restriction enzyme Hind III. The patterns of fragments generated by digestion with Hind III are sufficiently similar to show that all capripoxviruses are closely related, although patterns of different isolates can be grouped in a way which correlates with the animal of origin. The close relatedness was also demonstrated by the high level of sequence homology detected using the Southern Cross hybridization system. Despite the sequence homology, the molecular weights of the genomes of different isolates varied from 73 to 91 MDa. The presence of two rapidly reannealing restriction fragments in the Hind III digests of capripoxvirus DNA indicated the presence of terminal cross-links.

Animals↗
PubMed1986

Studies on the major common precipitating antigen of capripoxvirus.

The proteins of sheep pox, goat pox, sheep and goat pox and lumpy skin disease (Neethling) viruses were labelled with [35S]methionine. The major structural polypeptides of these viruses co-migrated on polyacrylamide gels, demonstrating the very close biochemical relationship between them. Using the agar gel immunodiffusion (AGID) test with radiolabelled antigen preparations, a major common precipitating antigen was identified. This co-migrated on polyacrylamide gels with one of the major structural polypeptides [mol. wt. 67000 (67K)]. The use of [35S]methionine-labelled antigen preparations considerably improved the sensitivity of the AGID test as a diagnostic test for capripoxvirus antibody detection.

Animals↗
PubMed1986

Insect transmission of capripoxvirus.

Capripoxvirus was transmitted between sheep using Stomoxys calcitrans as a vector. Attempts to transmit capripoxvirus between sheep and between goats using biting lice (Mallophaga species), sucking lice (Damalinia species), sheep head flies (Hydrotaea irritans) and midges (Culicoides nubeculosus) were unsuccessful, although capripoxvirus was isolated from sheep head flies that had previously fed on infected sheep.

Animals↗
PubMed1986

Passive protection of sheep against capripoxvirus.

The close antigenic relationship between strains of capripox was shown by passively immunising sheep with serum against capripoxviruses isolated from a sheep and from a goat. Sheep immunised with immune serum to Oman sheep pox or Yemen goat pox resisted challenge with Yemen goat pox or Nigeria sheep pox respectively. Lambs born to sheep previously infected with isolates of capripox from the Sudan, India and Nigeria were also protected against challenge with Yemen goat pox.

Animals↗
PubMed1986

Comparison of the external dimensions of capripoxvirus isolates.

No significant difference was found between the external dimensions of the M forms of isolates of sheep pox virus from Nigeria, sheep and goat pox virus from Kenya and lumpy skin disease virus from South Africa. Earlier reports that isolates of capripoxvirus can be distinguished by their relative sizes could not be substantiated.

Animals↗
PubMed1985

Clinical and antigenic relationship between isolates of sheep and goat pox viruses.

Isolates of sheep pox and goat pox from Nigeria, Sudan, Kenya, Yemen Arab Republic, Turkey, Pakistan and India were inoculated into British breeds of sheep and goats. Although the isolates displayed a host preference the gross clinical pathology of the disease produced by the different isolates was indistinguishable. The Yemen, Nigeria and India isolates could not be distinguished using homologous and heterologous antisera in neutralisation tests. Animals that had recovered from infection with one isolate were resistant to challenge with any of the other isolates and a single vaccine for use against sheep pox and goat pox is described. The classification of the malignant pox diseases of sheep and goats is discussed.

Africa↗
PubMed1985

Transmission of capripoxvirus.

The transmission of capripoxvirus to sheep, using an aerosol suspension of a Yemen isolate of the virus, was demonstrated. Capripoxvirus was also transmitted by contact to sheep and goats kept with animals infected with virus isolates from the Yemen, Sudan, India and Nigeria. The incubation period for capripoxvirus infection in sheep and goats was approximately eight to 12 days. Animals that had well developed clinical signs transmitted capripoxvirus more rapidly than animals which died of peracute disease or animals that had only mild clinical signs.

Aerosols↗
PubMedDate not supplied

The application of biotechnology to the control of foot-and-mouth disease virus.

Biotechnology, which less than 10 years ago was heralded as an alternative to epidemiology in providing the answers to the control of foot-and-mouth disease (FMD), has not fulfilled its initial promise. Instead it is now complementing epidemiology by providing extremely sensitive and specific tools for identifying and characterizing strains of FMD virus in diagnostic material. Considerable advances in our understanding of the evolution of the virus in different field situations has been made possible by the development and application of polymerase chain reaction and nucleotide sequencing techniques. The individual genes of FMD virus can now be cloned into a number of vectors and separately expressed and studied in isolation from the other viral proteins. Biotechnology has not provided a safe and effective vaccine to replace the conventional tissue culture derived vaccine that would have made FMD a disease of the past. FMD remains the most economically significant animal disease having a major influence on the international trade of animals and their products. The world distribution of FMD has remained almost unchanged over the last 20 years and a balance has been maintained between improved surveillance and diagnostic technology and the ever increasing legal and illegal international movement of animals and reduction in veterinary resources. Research continues on peptide, recombinant and vector expressed virus protein vaccines which could at any time yield a breakthrough, not only for FMD control but, using similar technology, for control of other viral diseases, human and animal. Until this occurs, control and eradication of FMD still relies on classical epidemiological techniques, making use of new biotechnological methods.

Animals↗
PubMedDate not supplied

The interference by maternally-derived antibody with active immunization of farm animals against foot-and-mouth disease.

Foot-and-mouth disease (FMD) is a highly contagious disease affecting ruminants and pigs. In countries in which control of FMD relies predominantly on vaccination, young stock ingest specific anti-FMD virus antibodies in the colostrum. This maternally-derived antibody (MDA) provides immediate protection against infection with FMD virus, but also interferes with the development of active immunity following vaccination. However, susceptibility to infection precedes the ability to respond to vaccination in the presence of MDA. Currently available vaccines cannot overcome this inhibitory effect of MDA, and protection of young stock can only be provided by their isolation from FMD virus.

Animals↗
PubMedDate not supplied

The localization of persistent foot and mouth disease virus in the epithelial cells of the soft palate and pharynx.

After contact with foot and mouth disease virus (FMDV), cattle may become persistently infected, regardless of their pre-existing immune status or whether they develop clinical disease. The cellular sites of FMDV persistence have not previously been determined. The use of in-situ hybridization in combination with tyramide signal amplification (TSA) provided the first direct evidence that FMDV RNA is localized within the epithelial cells of the soft palate and pharynx during persistent infection, indicating that these cells remain persistently infected after contact with FMDV.

Animals↗