Biomedical subjects
Publications and source records attributed to P Whittlestone.
The paper considers societal and technology changes which are causing us to rethink hospital design. It calls for technology decentralisation and bed flexibility to allow for seasonal and severity patient beds. The authors conclude that is not the end of the hospital but the beginning of an exciting new era.
The activities of danofloxacin, a novel fluoroquinolone, and two other antimicrobials were determined in vitro against field isolates of seven Mycoplasma species of veterinary importance isolated from cattle, swine and poultry in five European countries. The minimum inhibitory concentrations (MIC) of danofloxacin, tylosin and oxytetracycline were determined against a total of 68 isolates. Danofloxacin showed excellent activity against isolates of all Mycoplasma species (range 0.008 to 0.5 microgram ml-1), but in some isolates there was evidence of reduced sensitivity to tylosin (range 0.008 to 2.0 micrograms ml-1) and oxytetracycline (range 0.008 to over 16.0 micrograms ml-1). Danofloxacin was more active than other antimicrobials against M hyopneumoniae, M dispar and M bovigenitalium, and showed activity similar to that of tylosin against M bovis and M gallisepticum. Tylosin was the most active against M synoviae and M hyosynoviae. Generally, oxytetracycline showed the poorest activity, but was superior to tylosin against M bovigenitalium. A second (final) MIC reading was taken for all isolates 14 or 21 days after the initial reading, and MIC values rose during that time. However, the increase seen in danofloxacin values (typically one to two dilutions) was less than that seen for tylosin and oxytetracycline. It is concluded that danofloxacin is highly active in vitro against all of the Mycoplasma species tested, and thus shows great potential for the treatment of respiratory and other infections caused by Mycoplasma species in cattle, pigs and poultry.
Explore the source record for details and available documents.
The Pig Health Control Association launched a control scheme for Aujeszky's disease in Britain in January 1978. Participating herds must not show clinical signs suggestive of Aujeszky's disease and must be serum-sampled every six months for the absence of antibodies. Importations are allowed only from listed herds, or through hysterectomy or hysterotomy, embryo transfer, or artificial insemination (the donor animals in each case having been serologically screened beforehand). During the subsequent eight years, 103 herds have qualified, and at the end of 1985, 49 herds (average size 249 sows) were listed. Despite a high degree of inter-herd stock movements, no clinical or serological evidence of Aujeszky's disease has occurred, and the disease has not arisen in any herd established from the listed herds. During the same period, Aujeszky's disease was spreading in Britain and an eradication programme began in March 1983. By the end of 1985, 502 herds not on the Pig Health Control Association's scheme comprising 421,825 pigs had been slaughtered, together with 259 serologically positive animals in 69 other herds. The Pig Health Control Association's register has provided a safe source of stock.
A control scheme for swine dysentery was initiated in Britain by the Pig Health Control Association in January 1978. To qualify, herds must not show clinical signs suggestive of swine dysentery or, if any suspicious signs arise, laboratory tests must be negative for Treponema hyodysenteriae. In addition, a range of pharmaceutical compounds that might mask the disease or its laboratory diagnosis may not be used routinely after weaning, either for treatment or as food additives. Qualifying herds can import pigs only from other qualifying herds or via hysterectomy/hysterotomy or embryo transfer methods; artificial insemination is also permitted. During the first six years, 91 herds qualified at some stage, and at the end of 1983, 56 herds (average size 200 sows) were still listed. By this date, 72 herds had imported stock from 36 other qualifying herds; despite this degree of inter-herd connection, no evidence of swine dysentery has occurred within the scheme since its inception, nor has this disease appeared in herds established entirely from listed herds. It seems, therefore, that freedom from swine dysentery (unlike enzootic pneumonia) can be readily maintained in a controlled group of pig herds identified by these monitoring methods.
A pilot control scheme for atrophic rhinitis was initiated in Britain by the Pig Health Control Association in January 1977. To qualify, herds must have maintained a low degree of turbinate damage and not shown clinical signs of atrophic rhinitis over a period of at least two years. Qualifying herds can import pigs only from other qualifying herds or via hysterectomy/hysterotomy methods. During the first five years, 45 herds qualified at some stage, and at the end of 1982, 34 herds (comprising about 7200 sows) were still listed. Although the scheme is not related to particular infectious agents, atrophic rhinitis has not appeared within it or in herds established entirely from listed herds, despite the fact that 31 of the 45 qualifying herds had imported stock from 15 other qualifying herds.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Following recovery from mycoplasmal respiratory disease animals are resistant to reinfection. The mechanism of this immunity is not well understood; usually there is poor correlation between circulating antibody levels and the degree of resistance to reinfection, but more work is needed to both man and animals on the significance of the different classes and types of circulating antibody. Because mycoplasmal infection of the respiratory tract is largely confined to the epithelial surface, it seems likely that local immunity will prove to be important. The levels of specific immunoglobulins, particularly IgA, in respiratory tract secretions may be related to immunity. It is probably, however, that cell-mediated immunity is the main determinant of resistance to mycoplasmal respiratory disease: firstly, there is evidence in several diseases that lymphocytes can be transformed by mycoplasmal antigen and there are some indications thatthe degree of this cell-mediated immunity might correlate with resistance to infection; secondly, antigen has produced skin reactions indicative of delayed hypersensitivity in some mycoplasmal diseases. Vaccination with inactivated vaccines has not produced satisfactory immunity; attenuated mycoplasma strains or temperature-sensitive mutants seem more likely to afford adequate protection against respiratory diseases caused by mycoplasmas.
Explore the source record for details and available documents.
Mycoplasma pulmonis was isolated from the pneumonic lung of a rat. Two groups of mycoplasma-free rats were inoculated, one with a culture of the M. pulmonis strain which had been cloned four times (group A) and the other with a lung homogenate of the rat from which the strain had been isolated (group B). A third group (C) consisted of uninoculated control animals. Each group was kept in strict isolation and allowed to breed so that the progeny was naturally exposed to any pathogens present in the inoculated animals. After different periods of exposure, rats were autopsied, respiratory tracts and inner ears were cultured for mycoplasmas and bacteria, and sera were tested for complement-fixing antibodies to murine mycoplasmas.In group-A rats, M. pulmonis was consistently isolated from the inner ears or lungs from 50 to 715 days after exposure. Complement-fixing antibody to M. pulmonis was detected 20 days after inoculation, but in the naturally exposed progeny antibody took longer than 50 days to develop. Antibodies to the other known mycoplasmas of murine origin, M. arthritidis and M. neurolyticum, were never found. Purulent otitis interna was consistently found from day 55 onwards, while lung lesions were first observed at 85 days and persisted to 715 days. Pulmonary lesions developed more slowly in inoculated parents than in exposed progeny. Similar results were found in group-B rats, which were examined up to 441 days after inoculation. Uninoculated group-C rats were examined up to 768 days of age, but M. pulmonis was not recovered; of the 54 animals whose serum was tested all were negative to the three species of mycoplasmas, except one which had a titre of 16 with M. pulmonis. Pneumonia, bronchiectasis or lymphoreticular hyperplasia were not seen in any of these control rats. Bacterial respiratory pathogens were not isolated from rats in any of the groups, nor was antibody to Sendai virus detected.The results suggest that M. pulmonis alone can cause pneumonia and bronchiectasis in rats since mechanical carry-over of another pathogen with the initial cloned inoculum is very unlikely and there was no evidence for the participation of any other rat pathogen. The respiratory disease induced by the cloned culture was comparable with that induced by the lung homogenate, and with the well-known syndrome of chronic respiratory disease and bronchiectasis in the rat.
Hysterectomy-produced, colostrum-deprived (HPCD) pigs and naturally born, enzootic-pneumonia-free (EPF) pigs were compared with respect to their susceptibility to two strains of enzootic pneumonia induced by intranasal inoculation of suspensions of ground pneumonic tissue. All but one of the HPCD pigs developed enzootic pneumonia, whereas the EPF pigs commonly failed to develop the disease; secondly, the pneumonic lesions were more extensive in the HPCD pigs.When the dose of inoculum was increased in EPF pigs, the resulting pneumonic areas were larger.In a small, in-contact experiment the disease was also more readily transmitted to HPCD pigs than to EPF pigs.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.