By Air Force Senior Airman Josie Kemp
Special to American Forces Press Service
LACKLAND AIR FORCE BASE, Texas, Jan. 28, 2010 - A tiny bug bite recently prompted a boy in Kenya, Africa, to walk alone for eight hours and admit himself to a clinic that specializes in parasitic diseases. Insect bites in that region can be life-threatening, and now are affecting many U.S. servicemembers serving in Iraq and Afghanistan.
Air Force Col. (Dr.) James Swaby, chief of the 59th Medical Wing clinical research division here, and principal investigator for the Vector-borne and Infectious Disease Field Diagnostic Development Initiative, recently led a team of military entomologists and physicians into Kenya for Vector Surveillance Analytical System field testing and analysis.
This program develops tests for rare infectious and parasitic diseases of military importance such as Leishmaniasis, which is known in Kenya as Kala-Azar.
"We went to Kenya primarily to conduct research and to develop techniques that we can use in the field under the most austere conditions to identify diseases while they are still in the insects that transmit them," Swaby said.
"We're trying to verify a set of laboratory tests we have developed that are freeze-dried for use in the field on insects, and environmental samples to determine risks in an area, before we begin seeing human cases," he said. "For the Kenya mission, we focused on Leishmaniasis."
Sand flies are known to carry and transmit Leishmaniasis, or Leish, in Kenya. Entomologists surveyed the Kenya area for places suitable for sand fly life, speaking with patients suffering from Kala-Azar to help in determining where the flies live. The team then assembled and hung traps to catch the flies.
Once the flies were trapped, they were sorted and tested using the Ruggedized Advanced Pathogen Identification Device, or RAPID, which detects and identifies various microbes associated with infectious diseases.
"We brought physicians along on this mission as part of their graduate medical education," Swaby said. "We did not provide patient care or diagnostic testing, but we did confer with physicians there who were treating individuals suffering from infectious diseases. It gave us a great deal of information, which was very helpful."
Lt. Col. (Dr.) Todd Vento, infectious disease fellow, and Capt. (Dr.) Becky Abell, emergency medicine resident, both Army physicians assigned to Brooke Army Medical Center at Fort Sam Houston, Texas, were members of Swaby's team. Additional members included Air Force entomologists 2nd Lt. Earl Thomas and Maj. Keith Blount from Brooks City-Base in San Antonio.
"Understanding a patient's environment and how they may have contracted an infection allows the physician to provide better treatment," Vento said.
Leishmaniasis has affected military operations since ancient times, and it's well known by medical entomologists. It is transmitted through the bite of a sand fly and is widespread in many tropical, subtropical and temperate regions of the world, including Iraq and Afghanistan.
No vaccines or preventive medicines are available for people who are exposed to Leishmanias or the sand flies that carry the parasite. The two most common forms of Leishmanias are cutaneous - affecting the skin -- and visceral -- affecting internal organs. Kala-Azar is a form of visceral Lieshmaniasis.
The disease most recently caught the attention of U.S. military leaders when soldiers and airmen serving in Iraq and Afghanistan began presenting with infections.
"There were 1,287 known cases through 2006," said Blount, who saw multiple cases first-hand during a tour of duty in Iraq in 2003. "When I was in Iraq, it was a one-way ticket back to the states, where you'd receive IV medication for several weeks."
Cutaneous Leishmaniasis, which most commonly affects servicemembers, may begin as a bump near a sand fly bite. Over time, these bumps become much larger skin lesions.
"An active case looks pretty bad, and it leaves some pretty nasty scars, but clinicians think it is self-limiting, with no long-term effects," Blount said.
Visceral Leishmaniasis is a slightly less common form of the parasite, but considerably more dangerous. It is a potentially life-threatening illness that produces fever, weakness, weight loss, and enlargement of the liver and spleen. Typically, skin lesions aren't associated with visceral Leishmaniasis.
"We thought we'd see visceral Leish in our military population, but we didn't know when," Blount said. "The incubation period can be really long; someone can be bitten and infected, and it might not show up for months or years. As it turns out, there were only a few cases, although I think more will surface in the coming years."
The life-threatening nature of viceral Leishmaniasis highlights the importance of this study for both doctors and residents.
"To see visceral Leish as really rare, and I saw 20 patients at the Kala-Azar clinic alone who had it," Abell said. "I never thought I'd have the opportunity in my life to see that."
These types of missions provide a unique training opportunity for residents, fellows and staff to gain real-world experience with rare diseases, conduct basic research, as well as providing infection control and prevention in a Third World country before they deploy to such areas as Haiti to provide humanitarian medical support.
"I'll likely never see this condition again," Vento said. "American doctors see this condition in textbooks and we read about how to treat it, but to actually see and talk to patients and observe how the staffing in the clinics works, it gives me a much better appreciation for medicine on a global scale. This trip was immensely rewarding, and something that I will never forget."
The team members are testing samples obtained in Kenya and hope to play a part in developing prevention and management techniques to protect people at risk of contracting Leishmaniasis.
"Entomologists don't have a lot of opportunities to go in and actually interact with patients who suffer from the diseases they try to prevent," Swaby said. "Physicians rarely have the opportunity to go into the wild and see how the patients they treat get diseases. By working together, we're all learning a tremendous amount.
"I hope this program can continue," he added. "It's an exceptional opportunity for everyone, and it goes way beyond the value of the research alone."
(Air Force Senior Airman Josie Kemp serves in the 59th Medical Wing public affairs office.)