Salmonella isolated from humans, animals and other sources in Canada, 1983–92

Abstract

A total of 89760 human and 22551 non-human isolates of salmonella were serotyped in Canada during the period 1983–92. There were 2180 reported outbreaks associated with 10065 cases during the 10-year period. The most common salmonella serovars isolated from human and non-human sources were S. typhimurium and S. hadar. The third and fourth most common serovars from human sources were S. enteritidis and S. heidelberg, respectively, and from non-human sources they were S. heidelberg and S. infantis. The number of S. typhimurium isolations from human and non-human sources showed a downward trend over the 10-year period. A total of 222 outbreaks of S. typhimurium associated with 1622 cases occurred. The S. hadar isolations from human and non-human sources reached a peak during the years 1987–90 and declined thereafter. The number of human isolates of S. enteritidis increased until 1985 and fluctuated at a level of 8·3–12·8% of all human isolates thereafter. Seventy-three outbreaks of S. enteritidis infection associated with 568 cases occurred. More than 50% of the S. enteritidis infections in humans were caused by phage type (PT) 8. During the review period, infections caused by PT4 were less common and were almost exclusively found in people who had travelled abroad. The annual isolation rates of S. heidelberg from human and non-human sources increased steadily during the period. Bacteriophage typing of serovars from outbreaks showed that contaminated food products of poultry and bovine origin were common sources of human infection. Salmonella typhi was identified as the cause of 43 small outbreaks affecting 116 persons.