By Brenda L. Mooney

Maps of the geographic distribution of cutaneous leishmaniasis (CL

BETHESDA, MD – Military physicians stumped by a diagnosis might want to consider leishmaniasis in personnel returning from Iraq or Afghanistan, according to a new report.

The sand fly-transmitted disease was much more in the news years ago when a larger number of servicemembers were deployed to the Middle East, but the problem persists, according to a new report. The Defense Medical Surveillance System reported about 1,000 cases from 2005 to 2014, and more than 500 cases were confirmed between 2002 and 2004, according to a report from the national Centers for Disease Control and Prevention.

Now, a rise in ecotourism as well as the presence of the disease in immigrants from some countries is increasing cases in the United States, emphasize new guidelines published in the journal Clinical Infectious Diseases.1

The parasitic infection, dubbed “Baghdad Boil” by troops stationed in the area, is being identified 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 sand fly, 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 have been reported to have been acquired in Texas and Oklahoma. Creation of the new guidelines, however, was prompted by the increase in travelers, military servicemembers 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 sand fly bite often is painless, and symptoms of the infection might not show up for a month or longer, further complicating the diagnosis.

While more than 20 types of Leishmania parasites cause human infection, the three main clinical syndromes, often determined by the specific parasite, are:

  • Cutaneous leishmaniasis (CL): CL causes skin sores, such as bumps or lumps that may turn into ulcers with a central crater or scab over. It is the most common type of leishmaniasis, with an estimated 700,000 to 1.2 million cases worldwide every year, according to the national Centers for Disease Control and Prevention (CDC).
  • Mucosal leishmaniasis (ML): CL can metastasize to mucous membranes, especially the mouth and nose, resulting in ML. Most often occurring when the patient is infected by Leishmania parasites from Central or South America. If left untreated, ML can cause serious scarring and deformity.
  • Visceral leishmaniasis (VL): The most serious form, active VL is a systemic infection that is almost always fatal if not treated. CDC estimates there are 200,000 to 400,000 new cases of VL a year, with symptoms including weeks to months of high fevers, significant weight loss, an enlarged spleen and low blood counts.

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 (FDA) 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.

How many deployed troop were exposed to the illness? From 2005 to 2014, nearly a 1,000 cases of leishmaniasis were diagnosed in active component, Reserve/Guard and other military beneficiaries serving in the Middle East, the vast majority of them in Army personnel, according to DoD statistics. The national Centers for Disease Control and Prevention reported that, from August 2002 to February 2004, military medicine identified 522 parasitologically confirmed cases of CL in deployed troops.

Many more cases could have been undiagnosed. A U.S. Department of Agriculture study four years ago reported that, in one scenario studied, military personnel in Iraq were being bitten between 100 and 1,000 times per night by sand flies.

Since the 1970s, the Walter Reed Army Institute of Research’s Leishmania Diagnostic Laboratory has been the only College of American Pathologists-certified diagnostic laboratory that specializes in the full spectrum of leishmaniasis diagnostics. The facility has a variety of assays to assist military practitioners with the diagnosis and to help determine optimal treatment.

 

  1. Aronson N, Herwaldt BL, Libman M, Pearson R, et. al. Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH). Clin Infect Dis. (2016). doi: 10.1093/cid/ciw670First published online: November 14, 2016.