[Epizootic of S. heidelberg in poultry breeding flocks raised commercially]

It was noted that under the conditions of industrial raising of adult birds the epizootic of Salmonella heidelberg could assumme an acute course with a clinical manifestation. After its short-term acute manifestation the infection acquired a protracted course. Mortality correlated directly with the age of the birds. Isolated and identified were a total of 117 Salmonella heidelberg strains from carcasses, cloacal samples, eggs, and litter. Regardless of the short-term Salmonella harbouring the deep litter was shown to predispose to reinfections. The isolation of eight strains of S. heidelberg from the egg shell and the yolk of freshly laid eggs as well as the negative microbial findings in one- and two-fold fumigated eggs corroborate the idea of the additional entering of Salmonella organisms through the shell. These also point to the fact that fumigation carried out up to the third hour following laying may contribute to the raising of disease-free broilers. Treatment with furazolidon and chloramphenicol in combination or the application of salmocid at the rate of 250 milligram microgram of feed in the course of ten days suppresses the acute manifestation of the disease and restores the productivity of birds, having no effect on the harbouring of the infection in the flock.