The Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), and several state partners investigated a multistate outbreak of Salmonella infections linked to kratom products.
As of May 24, 2018, 199 people infected with the outbreak strains of Salmonella were reported from 41 states. Washington state reported 16 illnesses. Illnesses started on dates ranging from January 11, 2017, to May 8, 2018. Ill people ranged in age from less than 1 to 75 years (median 38). Among ill people, 52 percent were male. Of 132 people with available information, 50 (38 percent) were hospitalized. No deaths were reported.
This outbreak was detected when a cluster of people infected with Salmonella I 4,,12:b:- was identified by CDC PulseNet. During the investigation, health and regulatory officials in several states and the FDA collected various leftover and unopened kratom products to test for Salmonella contamination. As additional strains of Salmonella were identified in kratom products, subsequent searches of the CDC PulseNet database identified more ill people infected with some of these strains, including Salmonella serotypes Heidelberg, Javiana, Okatie, Weltevreden, and Thompson. These ill people were added to the outbreak investigation.
State and local health officials interviewed ill people to ask about the foods they ate and other exposures before they became ill. Seventy-six (74 percent) of 103 people interviewed reported consuming kratom in the form of pills, powder, or tea. Most people reported consuming the powder form of kratom. People who reported consuming kratom, purchased it from retail locations in several states and from various online retailers.
Epidemiologic and laboratory evidence indicated that kratom was the likely source of this multistate outbreak. Kratom is a plant consumed for its stimulant effects and as an opioid substitute. Eighty-five different DNA fingerprints of Salmonella bacteria were identified in samples of kratom products. The FDA compiled a list of contaminated kratom products, provided by several retail locations and online retailers. Several companies issued recalls of kratom products because of these findings.
This outbreak investigation has been deemed over. However, some kratom products that were contaminated with Salmonella have not yet been recalled and may still be available for purchase or in people’s homes.