Melioidosis is a rare disease caused by bacterial infection with Burkholderia pseudomallei, bacteria found in tropical and subtropical Asia and Australia. The bacteria that cause melioidosis are not typically found in the United States. Yet, 2 adults and 2 children from 4 households in 4 different states contracted this disease. One adult and one child died and the other two patients suffered persistent neurological or bone damage from the infection. So, how did 4 people in 4 different states, who had not traveled, wind up with melioidosis?

A CDC investigation used forensic science, genomic sequencing, and phylogenetic analysis to determine that an aromatherapy spray manufactured in India and sold by Walmart caused these cases of melioidosis in the United States. Phylogenetic analysis is a method for identifying how closely related organisms are. In this case, the scientists used the sequence of the genes in the bacteria isolated from the patients, found in a recalled bottle of aromatherapy spray, and in databases to definitively identify the culprit.

Read more in Aromatherapy Spray the Source of Mysterious Cases of Bacterial Infection

Cover image details