On April 28, 2011, the Centers for Disease Control announced an investigation into an outbreak of Salmonella Typhimurium. Illness appeared to be associated with exposure to clinical and teaching microbiology laboratories and occurred among students in microbiology teaching laboratories and employees in clinical microbiology laboratories. Multiple ill persons reported working specifically with Salmonella bacteria in microbiology laboratories. The New Mexico Department of Health found that the outbreak strain was indistinguishable from a commercially available Salmonella Typhimurium strain used in laboratory settings. This commercially available strain was known to be present in several teaching or clinical laboratories associated with ill students or employees infected with the outbreak strain. The data suggested that this strain was the source of some of these illnesses. Additionally, several children who lived in households with a person who worked or studied in a microbiology laboratory became ill with the outbreak strain.