Summary Clinical and laboratory findings are recorded from a series of 15 cases (aged one to 16 years) of sudden‐onset chronic diarrhoea with weight loss, progressing in many cases to emaciation and death, associated with the emergence of fourth stage cyathostome (trichoneme) larvae in large numbers through the colonic and caecal mucosae. Apart from a single incident in mid‐October, disease only occurred in winter and spring (January to May). Characteristic features included hypoalbuminaemia, increased α and β plasma globulin levels and neutrophilia without left shift. Faecal egg counts were frequently negative and eosinophilia and anaemia were not features. Horses treated in the early stages responded well to larvicidal doses of fenbendazole (60 mg/kg bodyweight) but in cases where this therapy was delayed for weeks or months the prognosis was poor.

Danofloxacin is a new fluoroquinolone antibacterial, developed specifically for veterinary use. Its in vitro activity and pharmacokinetic properties have been investigated to assess its potential for use in the therapy of respiratory disease in cattle. The minimum inhibitory concentration of danofloxacin against 90% (MIC90) of contemporary European and North American field isolates of Pasteurella haemolytica, Pasteurella multocida and Haemophilus somnus, the most important bacterial respiratory pathogens of cattle, was 0.125 micrograms/ml. The plasma and lung kinetics of danofloxacin following parenteral administration of 1.25 mg/kg were evaluated in two studies. Danofloxacin was rapidly absorbed following intramuscular and subcutaneous injection and bioavailability was virtually complete (101% and 94% respectively). Plasma concentration profiles of danofloxacin were similar for intramuscular and subcutaneous routes with no significant differences in the area under the plasma concentration-time curves (AUC) following one, three or five consecutive daily doses, although slightly higher peak plasma concentrations were achieved by the intramuscular route. Following intramuscular administration, the mean peak lung concentration of danofloxacin was 4.1 times greater than that of plasma. Similarly, the AUC for lung tissue was 3.7 times greater than that for plasma. These data indicate that danofloxacin should be particularly appropriate for the therapy of bacterial respiratory disease in cattle.

SUMMARYThe efficacy of danofioxacin, a new quinolone antimicrobial agent, was tested in vitro by the micro-broth method with nine field strains of Mycoplasma gallisepticum (Mg) and eight of M. synoviae (Ms) and comparison was made with oxytetracycline and tylosin tartrate. The virulent S6 strain of Mg was also included for reference. All Mycoplasma strains, including a strain of Mg that was resistant to tylosin tartrate, were susceptible to danofioxacin with minimal inhibitory concentrations ranging from £ 0.008 to 0.5 μg/ml. A commercially produced test system (Sensititre®), using micro-plates whose wells were predosed with antimicrobial agents and then dried, was also investigated. Results with the same three antimicrobials were in agreement with those obtained by the micro-broth method. With the exception of the tylosin resistant strain, the Mg strains were more susceptible to erythromycin than the Ms strains. Conversely, Ms strains were susceptible to apramycin, while the Mg strains appeared to be resistant.

1. Ninety-three cases of primary infective gastroenteritis are reviewed. In only one instance was a known pathogen isolated.2. The clinical features, epidemiology and postmortem findings are discussed.3. A serologically homogeneous strain ofBact. coliis described which was isolated in over 90% of cases.4. A discussion follows on the significance of these findings.