National Cancer Institute

 Once known as "traveler's disease," a tropical virus that produces skin sores and disfiguring scars might be quite at home in the southern United States.

Cutaneous leishmaniasis is transmitted by the bite of a sandfly carrying a single-celled parasite known as Leishmania, of which there are 30 known varietiesTrusted Source that may infect mammals.

Sandflies are blood-sucking insects roughly a fourth the size of a mosquito, small enough to avoid standard preventatives such as mosquito nets and window screens. Sandflies, like mosquitos, are disease-carrying "vectors"Trusted Source that feed on human and animal blood.

However, this might be changing. Data suggest that infections are appearing in persons in the United States who have no travel history, implying that the disease is spreading endemically within the country - a concerning new finding.

Researchers from the Centres for Disease Control and Prevention (CDC) presented their findings at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting this month.

The study has yet to be published in a peer-reviewed publication.

Researchers reviewed over 2,100 tissue samples submitted to the CDC for presumptive testing for cutaneous leishmaniasis between 2005 and 2019. The samples came from all fifty states, as well as Puerto Rico and the United States Virgin Islands. The illness was discovered.

Researchers have also discovered more conclusive evidence that these illnesses were genuinely prevalent and acquired in the United States.

First, they discovered that non-traveler samples frequently included Leishmania mexicana, one of the parasite's numerous types. Then, using DNA testing, the researchers discovered two genotypes, or distinct genetic fingerprints, among the Leishmania mexicana samples.

One of these genetic variants was discovered in 31% of all non-traveler samples, but only in fewer than 2% of persons who had been outside the nation. The discovery provides compelling evidence that the particular Leishmania mexicana variant is indigenous to the United States and is spreading among the local population.

Cutaneous leishmaniasis is spread by sandfly bites infected with the parasite Leishmania. The condition produces skin blisters and lesions that can leave scars for life.

The illness is more common in the tropics, India, Central and South America.

According to new CDC study, the illness may be present in portions of the southern United States.