Well, that’s nasty… another reason not to ever go Texas! The disease spreads through sandflies…
Leishmaniasis, a parasitic disease once primarily associated with travelers returning from tropical regions, is raising concerns as unique, locally-spread strains of the parasite are being detected in the United States, according to a recent study presented at the Annual Meeting of the American Society of Tropical Medicine and Hygiene.
Traditionally, cases of leishmaniasis in the U.S. were sporadic and limited to individuals who had traveled to endemic regions in Central and South America, the Middle East, the Mediterranean, and Central Asia. However, this new research suggests that a distinct strain of the Leishmania parasite, belonging to the species Leishmania mexicana, is now being transmitted locally by U.S. sandflies. The findings are raising alarm among health experts, as they indicate that leishmaniasis may be gaining a foothold within the country.
The study, conducted by researchers who genetically sequenced over 2,000 tissue samples from patients suspected of having cutaneous leishmaniasis across 50 U.S. states, Puerto Rico, and the U.S. Virgin Islands between 2005 and 2019, identified a concerning trend. As of 2018, over 80 cases of locally-acquired human leishmaniasis were reported in the U.S., with Texas being a hotspot for these infections.
Of the samples analyzed, 164 were found to be of the L. mexicana species, with 32% of them occurring in Texas. The analysis also revealed two distinct strains of L. mexicana, ACT and CCC, with the CCC strain being more common in nontravelers, particularly in Texas. The researchers concluded that leishmaniasis may be endemic in the United States, underscoring the need for heightened surveillance and awareness.
Another pressing concern is the potential spread of visceral leishmaniasis, a more severe and often fatal form of the disease. Researchers have warned that U.S. sand fly populations may be acquiring L. infantum, the parasite responsible for visceral leishmaniasis, through infected imported dogs. Importing dogs from endemic regions, such as Turkey, has become more common, and some of these dogs can transmit the parasite to their puppies. This situation, combined with the warming climate facilitating the expansion of sand fly habitats, has led to the need for a new risk assessment tool to screen imported dogs and help control infection.
While the tool has yet to be tested, experts believe that implementing flea- and tick-insecticide impregnated collars on dogs is one of the most straightforward ways to control the disease, as dogs are a primary reservoir. In light of these findings, vigilance and preventive measures are crucial in managing the emergence of leishmaniasis in the United States.