Investigation of the source of neonatal Salmonella dublin infection of calves was undertaken by carrying out caesarean section of cows with a history of excretion of S dublin following either S dublin enteritis or S dublin abortion. No evidence of transplacental infection was detected but six of 10 animals showed evidence of excretion of the organism in the faeces, vaginal discharge or milk in the period immediately following parturition. The strong probability of early infection as a result of contamination of the environment is therefore suggested.

Animals↗

PubMedDate not supplied

Studies on the pathogenesis of staphylococcal osteomyelitis in chickens. I. Effect of stress on experimentally induced osteomyelitis.

A single strain of Staphylococcus aureus was used to study the pathogenesis of osteomyelitis in chickens. The disease was consistently reproduced in 6-week-old broiler chickens when 1 X 10(5) or more organisms were given intravenously. Severe feed restriction, debeaking, and single or multiple injections of corticosteroids delayed the appearance and decreased the severity of lesions due to staphylococcal infection. This increased resistance was associated with increased numbers of circulating heterophils and monocytes. No correlation between the presence of tibial dyschondroplasia and osteomyelitis was found.

Animals↗

PubMedDate not supplied

Studies on the pathogenesis of staphylococcal osteomyelitis in chickens. II. Role of the respiratory tract as a route of infection.

Groups of 6-week-old broiler chickens were exposed to Staphylococcus aureus by aerosol, intratracheal or intravenous (control) inoculation. No lesions were produced by aerosol. A single dose of up to 5 X 10(10) organisms given intratracheally failed to produce any lesions. Single or repeated doses of 5 X 10(11) organisms given intratracheally resulted in osteomyelitis in a low proportion of chickens.

Aerosols↗