According to new evidence provided by the U.S. Centers for Disease Control and Prevention (CDC), an indigenous American strain of cutaneous leishmaniasis has been identified in U.S. patients who have not traveled abroad. This suggests that the illness is being locally transmitted by American sandflies. The scientific community is increasingly concerned that visceral leishmaniasis, a more fatal form of the disease, could become endemic in U.S. sandflies, particularly due to the influx of unscreened dogs from abroad that carry the infectious agent.
Genetic analysis confirms the presence of a uniquely American variant of cutaneous leishmaniasis, raising the potential that local sandflies may become carriers of more dangerous forms of the disease via imported canines.
The revelations stem from a recent study led by CDC scientist Marcos de Almeida, presented at the Annual Meeting of the American Society of Tropical Medicine and Hygiene (ASTMH). The research was prompted by an unexplained increase in domestic cases of cutaneous leishmaniasis—a skin disease causing potential disfigurement—over the past decade. A significant number of patients had no international travel history, which led CDC researchers to employ genetic sequencing tools on tissue samples from affected individuals.
The findings reveal that a strain of Leishmania mexicana affecting non-travelers exhibits a subtly divergent genetic makeup, indicating that these infections were precipitated by a distinctive American genotype of the pathogen, propagated by local sandfly populations.
Mary Kamb, MD, MPH, affiliated with CDC’s Division of Parasitic Diseases and Malaria, notes that although the majority of these cases are concentrated in Texas, sandflies capable of transmitting leishmaniasis are prevalent in various regions of the U.S., particularly the southern states. Cutaneous leishmaniasis results in skin ulcers that may take considerable time to manifest post-exposure. Although medication is available for treatment, untreated cases can lead to severe disfigurement. The World Health Organization reports that this form of leishmaniasis impacts up to one million people globally, predominantly in the Middle East, central Asia, northern Africa, and Latin America.
Awareness about cutaneous leishmaniasis as a probable diagnosis for skin lesions is growing in Texas. Kamb attributes this partly to a history of cases in individuals returning from Mexico and an increasing acknowledgment of the potential for local transmission. Nevertheless, inadequate awareness in other states complicates assessments of local transmission elsewhere.
The CDC aims to facilitate the identification of locally-acquired cases in new areas by associating domestic cases with a unique strain. Vitaliano Cama, Ph.D., a senior advisor at CDC’s Division of Parasitic Diseases and Malaria, speculates that climate changes could be contributing to the sandfly’s increased ability to survive and reproduce, potentially allowing leishmaniasis to emerge in new locations.
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Mounting Concerns: Could More Deadly Variants Also Establish Locally via Imported Canines?
The rising evidence of cutaneous leishmaniasis in domestic sandfly populations is amplifying apprehensions that visceral leishmaniasis, a life-threatening variant, could also become endemic in the U.S. This is mainly due to the feeding of these sandflies on imported, unscreened dogs carrying the pathogen.
Caused by a closely related parasite known as Leishmania infantum, visceral leishmaniasis affects internal organs and is responsible for the deaths of 20,000 to 30,000 individuals worldwide each year. Currently, no preventive medications are available, although treatments do exist that can have serious side effects.
A symposium at the ASTMH Annual Meeting presented a new risk-assessment tool designed to enhance screening processes at entry points into the country. Christine Petersen, DVM, PhD, FASTMH, director of the Center for Emerging Infectious Diseases at the University of Iowa, emphasized the need for rigorous systems to mitigate the risk of introducing Leishmania infantum into domestic sandfly populations.
Petersen mentioned that treatment options exist for infected dogs, but relapses are common, necessitating regular monitoring and treatment. She advocates for the use of topical insecticides on infected canines to prevent further spread.
Daniel Bausch, MD, MPH&TM, FASTMH, President of ASTMH, called for a global approach to combat these diseases, particularly as climate change enables pathogen-carrying insects to extend their geographic reach.
Frequently Asked Questions (FAQs) about Leishmaniasis in the United States
What disease is the CDC warning about?
The U.S. Centers for Disease Control and Prevention (CDC) is warning about the increasing presence of cutaneous leishmaniasis in the United States. There is also concern about the potential for the more lethal form of the disease, visceral leishmaniasis, gaining a foothold in the country.
What is the source of this new strain of cutaneous leishmaniasis?
The new strain of cutaneous leishmaniasis is uniquely American and is being transmitted by domestic sandflies. Genetic sequencing tools were employed to analyze tissue samples from patients, and it was found that this strain has a distinct genetic fingerprint, separate from those found in imported instances of the disease.
Are there any areas more affected than others?
Most of the infections were found in individuals living in Texas. Sand flies capable of transmitting leishmaniasis are also found in many parts of the country, particularly in the southern United States.
What is the role of imported dogs in the transmission of the disease?
Unscreened imported dogs carrying the pathogen are a significant concern. These dogs can potentially lead to the establishment of visceral leishmaniasis in domestic sandfly populations.
How was the data for this study collected?
The study was led by CDC scientist Marcos de Almeida and involved the genetic sequencing of tissue samples from patients affected by the disease. It was presented at the Annual Meeting of the American Society of Tropical Medicine and Hygiene (ASTMH).
What are the symptoms of cutaneous leishmaniasis?
Cutaneous leishmaniasis typically produces skin ulcers that may take weeks or months to emerge after exposure to the sandfly bite. If allowed to progress, the disease can result in disfiguring scars.
Are there medications available for treating leishmaniasis?
Yes, there are medications to treat infections of both cutaneous and visceral leishmaniasis. However, some medications for treating visceral leishmaniasis can potentially cause serious side effects.
What are the broader implications of this discovery?
The findings indicate a need for greater public awareness and potentially better screening processes, especially for imported dogs. The study also highlights how changes in climate conditions could be creating more suitable environments for sand fly survival and reproduction.
How many people are affected by cutaneous leishmaniasis globally?
According to the World Health Organization, cutaneous leishmaniasis affects up to one million people annually, mainly in the Middle East, Central Asia, Northern Africa, and Latin America.
Is there a risk assessment tool to handle this issue?
Yes, a new risk assessment tool was outlined to promote better screening at ports of entry, especially concerning the growing number of dogs entering the country from regions where the disease is common.
More about Leishmaniasis in the United States
- CDC Official Website
- Annual Meeting of the American Society of Tropical Medicine and Hygiene
- World Health Organization on Leishmaniasis
- Texas Department of State Health Services on Leishmaniasis
- University of Iowa Center for Emerging Infectious Diseases
- Johns Hopkins University Research on Tropical Diseases
- Climate Change and Vector-Borne Diseases
- Leishmaniasis in Imported Dogs: Risk Assessment and Management
- Leishmania Parasite Genetics and Strains
- Leishmaniasis Medications and Side Effects
10 comments
Public health has to step up its game, esp with the climate changes. It’s like a Pandora’s box, don’t know what’ll come out next.
Scary stuff indeed! I’m particularly concerned about imported dogs being a carrier. People need to be more responsible when it comes to pet importation.
So is this something we should be testing for regularly now? Considering how disfiguring it can be, early detection seems crucial.
can’t believe this is happening in Texas of all places! Makes you wonder what other diseases might be lurking around the corner.
Climate change strikes again, huh? So now we’re seeing tropical diseases move into new areas. Should be a wake-up call for all of us.
Good read but leaves me with more questions than answers. Specifically, how do we deal with this on a broader scale? It’s one thing to identify a problem and another to solve it.
Wow, this is seriously alarming. never thought that tropical diseases like leishmaniasis could become a domestic issue in the US. What’s next?
Makes me think twice about my upcoming trip to the southern US. Perhaps some preventive measures are in order?
Just read the whole thing and I’m amazed. never heard of leishmaniasis before today, and now I find out it could be in my own backyard.
First COVID, now this? It feels like we’re in a constant battle with infectious diseases. What’s the endgame here?