WRAIR: The Center for Infectious Disease Research

Leading the fight against the Army's - and the world's - Deadliest Adversaries

By Craig Collins - May 27, 2014

Infectious diarrhea has historically been a substantial cause of morbidity for deployed U.S. military personnel and continues to the present day in those deployed overseas. Pathogenic bacteria, including Shigella, Campylobacter (pictured), and enterotoxigenic Escherichia coli, are principal causative agents. WRAIR and the Navy Medical Research Center are working together on the development of effective countermeasures to prevent of abate bacterial diarrhea, with most efforts aimed at vaccine research and development. CDC photo

Since 2003, when U.S. troops were deployed to Southwest Asia, where sand flies thrive, more than 3,500 troops have been diagnosed with CL. To date, there is no vaccine, prophylaxis, or FDA-approved drug treatment for CL; WRAIR is the only institution in the world with a dedicated CL drug development program. Currently, the treatment for CL involves killing the parasite through the intravenous introduction, or injection, of toxic heavy metals called antimonial salts. However, Phase III trials of antibiotic creams developed by WRAIR researchers, conducted under a U.S./French/Tunisian partnership, demonstrated a greater than 80 percent cure rate, presenting the possibility of a safe, nontoxic, first-line treatment for CL that patients could apply themselves. The results of the study were published in the New England Journal of Medicine in February 2013.

WRAIR’s Leishmania Diagnostics Laboratory specializes in the development of diagnostic assays that will help both military and civilian clinicians diagnose the disease and differentiate between its forms. Investigators have successfully diagnosed suspected leishmaniasis lesions from species all over the globe, from the Middle East to Latin America.

Entomology

To better understand the vectors that spread these diseases – Leishmania-carrying sand flies; the Anopheles genus of mosquitoes that carry malaria; Aedes aegypti, the mosquito that carries yellow fever and dengue; the Culex mosquitoes that carry West Nile virus and encephalitis; and other arthropods – WRAIR investigators study them both in the field and in a global network of insectaries, anchored by WRAIR’s 964-square-foot facility in Maryland. The facility, which opened its doors – multiple, mosquito-proof doors – in 2000, is the starting point for all of WRAIR’s repellent, drug, and vaccine research for vector-borne diseases. The Anopheles mosquitoes used in WRAIR’s malaria challenge studies are bred, hatched, raised, and fed a blood meal with the Plasmodium parasite in the insectary.

Arthropod Vector Rapid Detection Device (AV-RDD)

Sgt. Michael Sanford, a laboratory technician at the Walter Reed Army Institute of Research in Silver Spring, Md., demonstrates how to use the arthropod vector rapid detection device (AV-RDD), May 3, 2012. The AV-RDDs detect pathogens in mosquitoes and sand flies that cause malaria, dengue, and leishmaniasis. Walter Reed Army Institute of Research photo

The products most often associated with the Entomology Branch are those that reduce the risk of being bitten by a carrier – either personal protective measures, such as topical repellents, treated uniforms, and bed nets, or vector controls such as pesticides. Topical repellents are too expensive for many people who live in the most mosquito-infested parts of the world, and the most effective one developed to date, DEET, has fallen out of favor among U.S. service members, for various reasons.

Out of necessity, WRAIR’s entomologists spend time studying whether people are willing to use a repellent or not – and increasingly, they don’t like DEET. “It’s sticky and it eats plastics,” said Cmdr. Dan Szumlas, director of the Entomology Branch. “Nothing works like topical repellents, but if people don’t want to use them, then obviously they’re not effective at all. So we’re looking at different kinds of spatial repellents, or insecticides, that have that effect that people can use either on their uniforms, or on a device on their body, or in a device you can put in the middle of a group, and protect everyone from bites.” Branch investigators are developing a new generation of both topical repellents – such as picaridin, which is now available to troops – and spatial repellents.

The Entomology Branch also conducts basic research into vector and parasite biology, and its field workers assist in worldwide vector surveillance efforts. Increasingly, given the enormity of such a task, this work is performed jointly, in partnership with several agencies, including the U.S. Department of Agriculture, the Naval Medical Research Center – which maintains several laboratories of its own – and the WRAIR’s own Walter Reed Biosystematics Unit (WRBU) headquartered at the Smithsonian Institution’s branch in Suitland, Md. Together, investigators from these institutions are participating in the Mosquito Barcoding Initiative (MBI), led by Dr. Yvonne-Marie Linton, a senior National Research Council fellow on assignment from the Natural History Museum in London.