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To determine patterns of sequence variability (absence of specific genes) among Salmonella
frequently isolated from cattle (but infrequently associated with human diseases) and the
genetic sequences of highly pathogenic strains of Salmonella.
Findings: Many of the most frequently isolated types of Salmonella found in cattle and ground beef rarely show up as causes of human disease. The reason for this is unknown, but one of the most plausible explanations is that all Salmonella are not equally capable of causing disease. In other words, some organisms, although they are classified as �salmonella� pose little threat to health individually-�sheep in wolves� clothing.� By comparing the DNA of Salmonella isolates from humans, cattle, and beef, it will be possible to develop specific genetic markers for Salmonella and predict which organisms should receive the most attention.