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BETHESDA, MD – Ecotourists are bringing home more than suntans, artisan souvenirs, and a deepened concern about climate change.
Joining military personnel returning from Iraq and Afghanistan and some immigrants, they are also much more likely to have leishmaniasis, according to new guidelines published in the journal Clinical Infectious Diseases.
The parasitic infection is being seen in more and more U.S. patients, but the diagnosis often eludes physicians, according to the report authored by Uniformed Services University researchers and colleagues.
Among the strategies to address leishmaniasis in the new guidelines, released by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH), are rapid diagnostic tests and cutting-edge treatments.
The Leishmania parasite, which is transmitted by the bite of the nearly invisible sandfly, is found in more than 90 countries around the world — including Mexico and those in Central and South America, Asia, Africa, the Middle East, and southern Europe.
Guideline authors point out that the infection rarely occurs in the United States, although a few cases acquired in Texas and Oklahoma have been reported. Creation of the new guidelines, however, was prompted by the increase in travelers, military service members, and immigrants with leishmaniasis being seen in the United States, they add.
"Leishmaniasis is an increasingly common infection in ecotourists traveling to Central and South America. Travelers visiting the jungle in the Amazon basin have a high likelihood of being exposed," explained lead author Naomi E. Aronson, MD, of the Uniformed Services University. "The cutaneous and mucosal forms of the infection cause serious scarring, and visceral leishmaniasis can be deadly, so timely diagnosis and treatment managed by an infectious diseases physician is vital."
Emergency physicians should be aware that the sore at the site of an infected sandfly bite often is painless, and symptoms of the infection might not show up for a month or longer, further complicating the diagnosis.
Although more than 20 types of Leishmania parasites cause human infection, the three main clinical syndromes, often determined by the specific parasite, are:
Aronson suggested that clinicians should question patients with these symptoms about travel outside of North America. In addition, she said, CL can be tested by polymerase chain reaction (PCR) or by doing a culture to identify the type of Leishmania and determine how aggressively it should be treated. The blood test rK39 provides a rapid result if VL is suspected, which would be confirmed with PCR or culture, the guidelines state.
In terms of treatment, oral miltefosine was approved by the Food and Drug Administration in 2014 for specific cases of cutaneous, mucosal, and visceral leishmaniasis. "It may become a game-changer for treating leishmaniasis as it is a pill that can be used for all three leishmaniasis syndromes, depending on the parasite species responsible for the infection," Aronson noted.