Should doctors prepare for an outbreak of this ancient disease?

By John Murphy, MDLinx
Published October 1, 2019

Key Takeaways

Is leprosy an emerging disease among homeless people in Southern California? That’s what Marc K. Siegel, MD, wrote in a recent editorial in The Hill. Dr. Siegel is a clinical professor of internal medicine at New York University School of Medicine and a Fox News medical correspondent.

Dr. Siegel, however, is not a specialist in leprosy.

“Diseases are reemerging in some parts of America, including Los Angeles County, that we haven’t commonly seen since the Middle Ages,” he noted.

One of those archaic diseases is typhus, which is challenging to treat in homeless people and people in poverty, Dr. Siegel said. But he also warned about an even more disturbing illness from the Dark Ages.

“I also believe that homeless areas are at risk for the reemergence of another deadly ancient disease—leprosy,” he wrote.

More than 200,000 new cases of leprosy (also known as Hansen’s disease) occur worldwide each year, including 100 to 200 new cases in the United States, according to the CDC.

Dr. Siegel cited an article published in the August 2019 issue of JAMA Dermatology, in which researchers reviewed the number of leprosy cases seen by the Los Angeles County Hansen’s Disease Clinic. During a 45-year period (from 1973 to 2018), the clinic handled 187 patients with leprosy, most of whom were Latino and of Mexican origin.

Leprosy is even more prevalent in Central America and South America, with more than 20,000 new cases per year. “Given that, there is certainly the possibility of sporadic cases of leprosy continuing to be brought across our southern border undetected,” Dr. Siegel hypothesized.

“And it seems only a matter of time before leprosy could take hold among the homeless population in an area such as Los Angeles County, with close to 60,000 homeless people and 75% of those lacking even temporary shelter or adequate hygiene and medical treatment,” he predicted. 

According to Dr. Siegel, these factors make for “a perfect cauldron” for the emergence of a contagious disease like leprosy. He added that “leprosy appearing among the homeless in L.A. is a sure recipe for instant public panic.”

As predicted, severalnews articles announced in rather panicked tones that leprosy has re-emerged in Los Angeles and that an outbreak is imminent among its homeless people.

But how accurate are these claims?

No apparent risk for an outbreak

Fortunately, none of this is actually happening, according to the Los Angeles County Department of Public Health.

For one, cases of leprosy are not currently on the rise. Los Angeles County has had a steady average of 2 cases of leprosy per year for the past decade, ranging between 0 and 4 cases annually.

“Los Angeles County Public Health has not identified any cases among persons experiencing homelessness,” the department stated. “Given the low number of cases and no evidence of local transmission, there is no risk for an outbreak.”

Leprosy is not easily transmitted. It requires prolonged and close contact for infection to occur. Also, patients being treated for the disease aren’t at risk for spreading it to others.

As the authors of the JAMA Dermatology article found, most cases occurred among foreign-born individuals. But no local transmission has been identified, the Los Angeles County Public Health Department reported.

No new cases

The news of a leprosy outbreak among LA’s homeless came as a surprise to Maria Teresa Ochoa, MD, who oversees the Los Angeles County Hansen’s Disease Clinic and who coauthored the JAMA Dermatology article.

“I can’t believe it, it’s seriously frustrating,” Dr. Ochoa told the Associated Press. “Nobody is talking about new cases.”

Dr. Ochoa, an associate clinical professor of dermatology at the University of Southern California’s Keck School of Medicine in Los Angeles, also dismissed the notion that cases of leprosy are flowing into the United States across the Mexican border. She explained that the reason why most of the individuals with leprosy in her article were Latino is due to demographics—her clinic is located in an area of Los Angeles with a large Latino population.

Dr. Ochoa emphasized one of the points brought up in the JAMA article: Leprosy is so rare in the United States that when it does occur, the disease often goes unrecognized, which can delay the diagnosis and lead to increased morbidity in patients.

In other words, don’t expect an outbreak of leprosy anytime soon. But if you suspect you’ve encountered one of the rare 100 to 200 US cases per year, be sure to confirm the diagnosis quickly.

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