The epidemiology of salmonella infection of calves: the role of dealers

Abstract

SUMMARYSalmonellas were detected in the environment of 10 of the 12 calf dealers' premises studied. The cleaning and disinfection routines were often ineffective and salmonellas were isolated from 7-6 % and 5-3 % of the wall and floor samples before disinfection and 6-8 % and 7-6 % afterwards. Eight different salmonella serotypes were detected, of which the commonest were Salmonella typhimurium, predominantly phage type DT204C, and S. dublin. Plasmid profiles were used to fingerprint S. typhimurium DT204C and the results indicated that with the exception of one of the premises, prolonged salmonella-persistence in the environment was not occurring.Three separate epidemics of salmonellosis in calves were studied by use of plasmid profile analysis. The results illustrated the role of dealers, and their subcontractors, in the dissemination of salmonellas. The study concludes with suggestions for methods to reduce the spread of salmonellas in the calf marketing chain.

Observations on Disinfection Regimens Used on Salmonella enteritidis Infected Poultry Units

“…Salmonella are very resistant to desiccation and can survive in empty dry livestock buildings for many months (Wray et al, 1990;Bale et al, 1993) if disinfection has been ineffective and may even enter a viable but nonculturable state in response to contact with sublethal concentrations of disinfectant (Roszak et al, 1983;McKay, 1992). This bacterial survival strategy may be reversed if the dormant cells are ingested when the full virulence of the organisms may be recovered (Singh et al, 1986).…”

The epidemiology of Salmonella Typhimurium in cattle: plasmid profile analysis of definitive phage type (DT) 204c

“…Although PP type E predominated and constituted 44431% of all isolates, 42 other PPTs were detected. The descriptive epidemiology of some of these different types has been described previously [6,71 and it is of interest to note that type 0, which was relatively frequent during 1986, was seldom detected thereafter. Again, types A, B, J, 2, 6 and 9 were associated with a number of incidents and then rarely detected subsequently.…”

“…These were carried out as described previously [6]. Thus, a disk diffusion test was employed with Sensitest …”

Salmonella Dublin infection in Queensland dairy cattle

“…Of the 36 farms investigated over a 13 year period, 7 had introduced cattle from .. .................................................................... .......................................................... interstate, and 15 had recently purchased calves or adult cattle from sale yards or other farms. 'I'his highlights the risk of introducing Salmonella through calf dealers (Wray et al 1990) and mirrors the spread of S Dublin into the eastern states of the USA by adult and calf movements (Robinson et a1 1985). 'I'his highlights the risk of introducing Salmonella through calf dealers (Wray et al 1990) and mirrors the spread of S Dublin into the eastern states of the USA by adult and calf movements (Robinson et a1 1985).…”