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Biomedical subjects

J K Cook

Publications and source records attributed to J K Cook.

At least 37 records · Page 2Linked to original sources
PubMed1986

Infectious bronchitis immunity: its study in chickens experimentally infected with mixtures of infectious bronchitis virus and Escherichia coli.

The live infectious bronchitis (IB) vaccine, H120, protected chickens against intranasal challenge with a mixture of Escherichia coli strains (E. coli Pool) and IB virus (IBV) strains of the same (Massachusetts) serotype as H120; it usually also protected against challenge with the E. coli Pool and IBV strains of other serological types. When these challenge strains were themselves used as vaccines they usually protected against challenge with a mixture of the E. coli Pool and an IBV strain of the Massachusetts serotype (VF69-149) or an IBV strain not of the Massachusetts serotype (HVI-116). Poor protection, when observed, was most common in those experiments involving a minority of the IBV strains that had been incriminated in recent outbreaks of disease in vaccinated flocks of chickens. Much lower concentrations of IBV strain VF69-149 and E. coli O18 were found in the nose, trachea and spleen of H120-vaccinated chickens killed at different times after they were given a mixture of these organisms than were found in these sites in similarly challenged unvaccinated chickens. Some protection against challenge with IBV and the E. coli Pool was also observed in chickens vaccinated with an inactivated IBV strain; it was much less effective than that obtained following vaccination with the corresponding live IBV strain.

Administration, Intranasal↗
PubMed1985

The experimental infection of chickens with mixtures of infectious bronchitis virus and Escherichia coli.

By inoculating chickens intranasally with a collection of strains of infectious bronchitis virus (IBV) of the Massachusetts serotype and of Escherichia coli of different serotypes, a pool of viral and bacterial strains was selected which, on inoculation, consistently produced a highly lethal disease closely resembling the natural disease produced by these two organisms. The conditions for reproducing the experimental disease were not rigorous in that, within broad limits, the size of the viral and bacterial inocula were not important; neither were the times at which both organisms were administered in relation to each other. The breed or strain of chicken used was important and the resistance of chickens to fatal infection increased with age. When the E. coli strains of the pool were inoculated intranasally without the IBV component, the chickens remained well; bacteriological examination of chickens inoculated with one of the E. coli strains, O18, revealed little evidence of invasion of the tissues or even of persistence of the inoculated E. coli strain in the upper respiratory tract. A minority of the IBV strains examined were lethal for chickens when inoculated without E. coli but many of them only produced a substantial mortality when the E. coli were included in the inoculum; IBV strains in this latter category included the vaccine strains H52 and H120. High concentrations of IBV strain M41 and E. coli O18 persisted in the upper respiratory tract for a number of days after they had been inoculated together. Much lower concentrations of IBV M41 were found in the internal organs, such as the spleen; E. coli O18 was only found in these sites in some of the inoculated chickens. Coliform organisms proliferated in the upper respiratory tract of chickens inoculated with IBV alone; they were rarely found in their internal organs.

Animals↗
PubMed1983

The use of an enzyme-linked immunosorbent assay to detect IgG antibodies to serotype-specific and group-specific antigens of fowl adenovirus serotypes 2, 3 and 4.

A sensitive enzyme-linked immunosorbent assay (ELISA) has been developed which can detect serotype and group-specific antibodies (IgG) to fowl adenovirus serotypes 2, 3 and 4. The chickens produced principally type-specific antibodies after a single oral inoculation of virus which enabled that strain to be identified by the ELISA. However, inoculation of an heterologous serotype, although inducing strain-specific antibodies to itself, also induced high levels of antibody to the group-specific antigens. This masked the serotype-specific antibodies in the ELISA to the first serotype. The ELISA, which has similar sensitivity to the serum neutralisation test, could be used as a rapid, easily performed test to identify fowl adenovirus-specific antibodies.

Adenoviridae↗
PubMed1979

Taxonomic studies on strains of avian infectious bronchitis virus using neutralisation tests in tracheal organ cultures.

The antigenic relationships of 24 strains of avian infectious bronchitis virus (IBV) were investigated by serum neutralisation tests performed in chick embryo tracheal organ cultures. The serum dilution that neutralised 100 median ciliostatic doses (CD50) of virus was estimated from the linear relationship between varying concentrations of each virus strain and the neutralisation titre of homologous antiserum; this dilution defined 1 antibody unit. Antisera diluted to contain 20 antibody units were then tested by neutralisation against 1.5--2.5 log10 CD50 of each strain. Clusters of both strains and antisera in turn were established by methods of numerical taxonomy using as measures of resemblance Euclidean distance and correlation coefficient, and by analysis by principal components. These analyses identified a group of 8 similar strains; neutralisation of the remaining 16 strains was slight. Similar results were obtained by classifying antisera, except that a further group of 3 antisera was demonstrated, each having a neutralising capacity for most strains. Implications for vaccine formulation are discussed.

Animals↗
PubMed1979

The susceptibility of chicken kidney and oviduct organ cultures to a vaccine strain of avian infectious bronchitis virus.

The minimal infectious dose of the H52 strain of infectious bronchitis virus for organ cultures of oviduct and kidney was compared in chickens of different ages. Organ cultures of oviduct were found to be highly susceptible to infection regardless of the age of chicken and no difference in susceptibility could be demonstrated between cultures of the magnum and uterus regions of the mature oviduct. Kidney organ cultures were less susceptible and resistance to infection increased significantly (P less than 0.001) with the age of the chicken from which cultures were prepared.

Age Factors↗
PubMed1978

Growth comparisons of avian infectious bronchitis virus strains in organ cultures of chicken tissues.

Six strains of avian infectious bronchitis virus (IBV) were used to inoculate explants of a range of 15 chicken tissues and virus growth kinetics observed over a period of 96 hours thereafter. Similar patterns of virus production were given by all 6 strains from explants of any particular tissue such as the nasal turbinates, trachea, lung, air sacs and oviduct. Nevertheless, significant differences in behaviour between strains were noted for different tissues and in the efficiency with which certain tissues produced virus. It is suggested that the method has a potential value in determining the virulence of different strains of IBV by comparing their pathogenesis of chicken tissues in vitro.

Animals↗
PubMed1976

The use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis virus.

A study has been made of the use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis (AIB) virus from both naturally and experimentally infected chickens. Six strains of AIB virus were investigated, 3 of which had been isolated from natural outbreaks of disease. Two of the virus isolations from the outbreaks of AIB were made directly into tracheal organ cultures without passage in embryonated eggs. Organ cultures prepared from 20-day-old embryos were used since they were found to be somewhat more sensitive in virus assay than those derived from chickens of up to 31 days of age. Ciliostasis, which was used as the marker of infectivity, was complete by 3 days after inoculation with each strain of virus examined. Virus could be isolated from both respiratory and non-respiratory tissue in tracheal organ cultures and these cultures were found to be at least as sensitive as 9-day-old embryonated eggs in detecting AIB virus either in pathological material or in serial dilutions. When virus was assayed in both systems, the titres were very similar. It is considered, therefore, that chicken embryo tracheal organ cultures offer a reliable alternative system to embryonated eggs for studying AIB virus.

Animals↗
PubMed1976

Growth kinetic studies of avian infectious bronchitis virus in tracheal organ cultures.

An egg-adapted vaccine strain (H120) and an organ culture-passaged field strain (HV-10) of avian infectious bronchitis (AIB) virus were propagated in tracheal organ cultures and their growth kinetics examined using nine-day-old embryonated fowl eggs and chick tracheal explants for virus assay. When the H120 strain was assayed in embryonated eggs, titres were approximately log10 2-0 ID50 (50 per cent infectious dose) per ml higher than when assays were performed in tracheal explants. The HV-10 strain, assayed in tracheal explants, yielded higher titres than did the H120 strain, but when assayed in embryonated eggs, yielded only minimal and variable virus titres.

Coronaviridae↗
PubMed1976

Organ culture studies on the efficiency of infection of chicken tissues with avian infectious bronchitis virus.

Long-term organ cultures of a range of tissues collected from specific pathogen-free chickens were employed to determine their susceptibility, and their capacity for subsequent virus production, following inoculation with avian infectious bronchitis (AIB) virus. When inoculated with approximately 2-0 log10 median ciliostatic doses (CD50) of a classical highly egg-adapted vaccine strain (H120) of AIB virus, 9 of 23 tissues were shown to be susceptible, namely the nasal turbinates, trachea, air sac membranes,lungsasal turbinates, trachea, air sac membranes, lungs, proventriculus mucosa, thyroid, kidney, ovary and oviduct. When the remaining 14 tissues were inoculated with a high dose of virus (6.8 log10 CD50), the conjunctiva, caecel tonsil, testis and bursa of Fabricius were susceptible whereas the oesophagus and cloaca responded minimally. Inoculation of the same range of tissues with a high or low dose of a field strain (HVI9) of AIB virus produced similar results, except for a number of individual variations in response, due possibly to strain differences in pathogenicity. Determinations of the minimal infectious dose requirements of the susceptible tissues revealed that the efficiency of infection with the H120 strain was highest for the nasal turbinate and tracheal tissues, and thereafter, in order of decreasing efficiency, were the air sac membranes, lung, oviduct, proventriculus mucosa, conjunctiva, kidney, ovary, bursa of Fabricius, thyroid, testis, caecal tonsil, cloaca and oesophagus. The relevance of these results is discussed in connection with the early events in the pathogenesis and the clinical syndrome of AIB infection in chickens.

Animals↗