Recent trends in human salmonellosis in England and Wales: the epidemiology of prevalent serotypes other than Salmonella typhimurium.

In the period 1960-70 meat and poultry products caused over 70% of successfully investigated outbreaks of human salmonellosis. The number of human incidents of salmonellosis declined from 1960 to 1966, but then more than doubled between 1966 and 1971. This increase was mainly due to a threefold increase of incidents of salmonella serotypes other than Salmonella typhimurium. The serotypes which increased most and contributed significantly to this trend were S. enteritidis, S. panama, S. stanley, S. virchow, S. agona, S. 4,12:d:- and S. indiana.Strong evidence exists that these serotypes have a path of infection from animal feedingstuffs to the pig and poultry animal reservoirs to pork and poultry foods to man. Cattle appear to be a less important source than pigs and poultry and this may be because the nature and content of their feed is different.The importance of the control of the pig and poultry reservoirs of salmonella infections is stressed and a significant role of animal feedingstuffs in the maintenance of these reservoirs strongly suggested.