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A "neglected tropical disease" has now become an endemic in the United States.
Cutaneous leishmaniasis, which is typically caused by parasites spread by sand fly bites and results in numerous issues, including depression and stigma, has now been found among American non-travelers, Scientific American reports. The disease is considered an endemic in the Middle East, Asia, Africa and Latin America and wasn't believed to be widely present in U.S. states other than Texas, where most cases were presumed to have been contracted by travelers returning from Mexico.
The U.S. has seen an increase in reported cases involving people with no international travel history during the past decade, which led to speculation that the disease was contracted domestically. A U.S. Centers for Disease Control and Prevention team discovered that the cases among American non-travelers varied from those involving returning travelers, leading to the belief that cutaneous leishmaniasis was an endemic in the U.S.
Researchers recently described the analysis of 2,133 tissue samples sent to the CDC to be tested between 2005 and 2019 while presenting data at the annual American Society of Tropical Medicine and Hygiene meeting on October 19. The study, which hasn't yet been published, found that most positive examples of cutaneous leishmaniasis involved people who traveled internationally, however, 86 other cases were among those who didn't leave the U.S.
Genetic sequencing revealed two distinct "strains," including one that was present in most of the patients who traveled abroad and another commonly found among those who stayed in the U.S.
“This species of parasite has a different genetic signature in travelers and non-travelers,” said Vitaliano Cama, a microbiologist with the CDC who worked on the study, via Scientific American. “That’s a trend we hadn’t seen before.”
The disease isn't fatal, but can result in serious lasting symptoms.
“You get facial scarring for life, which causes all sorts of issues relating to depression and stigma,” said parasitologist David Molyneux of the Liverpool School of Tropical Medicine in England via Scientific American.