A San Diego County resident is among 40 people nationwide to become infected with salmonella bacteria linked to kratom, the controversial tropical herb that many have begun using to treat opioid addiction despite an import ban from the U.S. Food and Drug Administration.
According to the county Health and Human Services Agency, a 44-year-old, whose gender and city of residence were not released, became ill in January.
Testing performed by the U.S. Centers for Disease Control and Prevention confirmed that symptoms were caused by the same subspecies of the salmonella bacteria that has now produced cases in 27 states.
Dr. Eric McDonald, chief of the county's Epidemiology and Immunization Services Branch, said Friday that the resident has recovered.
"This person was not hospitalized and has had no long-term complications," McDonald said.
That has not always been the case since the outbreak started in October.
The CDC's latest report, issued Friday, added 12 cases to the outbreak total, reaching 40 cases since its last update on Feb. 20. So far, 14 people have been sick enough to require hospital stays, but no one has died. Ages of the salmonella patients range from 6 to 67.
State public health departments have interviewed 24 people who have been infected, and 17 have reported consuming kratom in pills, powder or tea.
Also called thang, kakuam, thom, ketom and biak, kratom's Latin name is mitragyna speciosa. In the coffee family, the evergreen is native to southeast Asia.
Though it's legal in most states, the CDC is recommending that no one consume kratom because the salmonella contamination has not been narrowed to a specific source.
Used as medicine in countries such as Thailand, Indonesia and Malaysia since the 19th century, kratom has recently become quite controversial in the United States. The FDA instituted an import ban on the plant in 2014, and there has been talk of classifying it as a schedule 1 controlled substance.
The city of San Diego banned possession and distribution of any substance containing mitragynine, the herb's active ingredient, in 2016.
In 2017, the CDC said it is aware of 36 deaths among kratom-using Americans, and the San Diego County Medical Examiner's Office has determined that 10 local deaths since 2014 have been associated with mitragynine.
But the public has pushed back hard, noting that most of the deaths involved people with other drugs in their systems, or other significant medical conditions, that could have contributed to their deaths. Kratom, many say, has helped them kick opioid habits or push back chronic pain.
Dr. Charles White, department head and professor of pharmacy at the University of Connecticut School of Pharmacy, recently published a research paper that assesses kratom's pharmacological properties in the American Journal of Health-System Pharmacy.
He said that it's clear that the plant works like an opioid, but it's not the same as the drugs fueling America's opioid epidemic.
"It's not derived from opium," White said. "It has a very different chemical structure, but it does stimulate opioid receptors in the brain."
In animal models, White said, kratom's value as a stimulant "appears to be pretty modest overall in comparison to a pure opioid" and could function in similar ways to methodone or soboxone, two drugs commonly used to help treat opioid addiction. There is also evidence, again in animal models, that kratom has anti-inflammatory properties often sought by those suffering from chronic pain.
But none of that, he cautioned, has yet been definitively proved in humans. Researchers know that many results found in animals look much different in people.
And, White added, it's unclear exactly how kratom interacts with other opioids in a person's system.
"We know it is a potent blocker of other drugs," White said. "The issue is that, if you take other drugs at the same time, you might not be able to get them out of your system because kratom is blocking your liver enzymes."
On the other hand, the researcher said he considers the tropical plant to be "a very interesting chemical compound." Significant restrictions, he said, could slow the pace of scientific discovery for this plant. Adding marijuana to the most-restrictive tier of the nation's drug schedule, he said, significantly slowed understanding of how some of the compounds in cannabis could be used for legitimate medical purposes, such as treatment of severe seizures in children.
"Making this a schedule 1 drug comes with the risk of setting yourself up to never finding out what the pharmacological benefits are that this substance has to give," White said. "The things we're learning today about marijuana are things we should have learned 50 years ago."