Behind Enemy Lines: Cutaneous Leishmaniasis in Returning US Troops from the Middle East

By Rebecca Kreston | November 4, 2011 1:25 pm

The Soviet invasion of Afghanistan from 1979 to 1988, by all accounts, did not go as well as they had anticipated. The locals were unsupportive of their efforts against the Mujahideen, the notoriously craggy terrain regularly chewed through soldiers’ boots, the Soviet army was frequently unable to provide suitable equipment, food and water to its own troops, and so on.

Along with these less than encouraging battlefield realities, the Soviet military suffered from a smorgasbord of infectious ills. It is estimated that throughout the nine-year occupation of Afghanistan, the annual attack rate of infectious diseases amongst Soviet troops ranged from a jaw-dropping 53% to 69%. A striking 67% of soldiers required hospitalization for a serious illness (1). Several researchers examining the medical side of the conflict have made the pointed remark that many of the Soviet-constructed hospitals were filled with their own military personnel rather than the Afghani population that they were originally intended for.

Soviet soldiers in Afghanistan in 1988 Image: Unknown. Image: Mikhail Evstafiev. Click for source.

Viral hepatitis and typhoid were largely responsible for disabling troops – there were 115,308 cases of hepatitis and 31,080 of typhoid fever. Another 269,544 cases have been attributed to plague, malaria, cholera, diphtheria, meningitis, shigellosis, amoebic dysentery, pneumonia, typhus, paratyphus and other illnesses. The sheer variety of diseases and magnitude of those infected is astonishing, even to an infectious disease scholar. That’s an impressively multitudinous bacteria-virus-parasite swap meet! I’m trying hard not to imagine Afghanistan as one massive pulsating, sandy petri dish right now.

 Though the origins of these diseases are simple to identify, the logistics of and solutions to preventing them are often more complicated: a consistent shortage in clean drinking water and access to laundered uniforms, poorly enforced sanitation standards, an insufficiently nutritious diet, and the omnipresence of rodents, lice and mosquitoes were responsible for causing the vast majority of diseases (1). These guys were just shipped into the desert and mountains completely unequipped and unprepared for what was lying in wait for them.

That an epidemic can be as worthy an opponent on the battlefield as one’s enemy is not a new concept. Throughout history, from Xerxes to Napoleon to Robert E. Lee, commanders have had to regularly contend with field sanitation and disease prevention and control. Diseases such as typhus, diarrheal disorders, respiratory ills, and infected wounds have oftentimes decided the victor of a conflict. What’s of interest here is that the United States has similarly ventured into Afghanistan and, for the most part, emerged unscathed from the health problems that bedeviled the Soviets. The U.S. military has accomplished a significantly better job of protecting their troops from the Middle East’s endemic infections during Operation Enduring Freedom and Operation Iraqi Freedom.

However, there is one little nasty buggy and the troubling disease it transmits that is endemic in both Afghanistan and Iraq and that has bested the US military – the sandfly Phlebotomus and the protozoan parasite Leishmania. This disgraceful couple have been around for millennia; it’s thought that the biblical plague of boils described in Exodus 9:9, the “breaking out in sores on man and beast throughout the land of Egypt”, was in fact an epidemic of cutaneous leishmaniasis (2).

Scanning electron micrograph of an adult Phlebotomine sandfly, species unknown. They are known for their hirsute features. Image: Science Photo Library. Source: CVBD. Click for source.

First, the insect. Phlebotomus are biting midges that fly in short hops close to the ground. They sound adorable but alas! Active at twilight and night, the females feed by lacerating the skin and sucking the pooling blood that’s formed from the painful bite. They prefer living in covered, humid areas with organic debris. Sandflies can live both outside and inside human dwellings, though most research seems to find that transmission events occur within the home, as more women and children are infected than men.

And now to the protozoan brute of the matter, leishmaniasis. This is indeed a global parasite, withstanding tropical to temperate climates in more than 100 countries. Southeast Asia and Australasia are the only regions with suitable, supportive climates that have been spared. There are five clinical presentations of leishmaniasis – cutaneous, visceral (kala azar), mucocutaneous, post-kala azar dermal leishmaniasis and diffuse cutaneous leishmaniasis – that may be found throughout these countries and for each presentation several species may be responsible, testifying to the protozoa’s adaptability and expression of unique local flavors.

Cutaneous leishmaniasis (CL), known as “oriental sore”, “Jericho buttons” and “Baghdad boil”, produces painless ulcerative lesions found on the face, arms and legs. It is typically confined to the skin but is also capable of going Four Loko on its host, racing through the lymphatic channels and turning into the deadly visceral leishmaniasis (VL). Not all that common but not entirely unlikely either. There are an estimated 1.5 million ongoing cases of CL with a global prevalence rate of 12 million (3). Ninety percent of all cases of CL occur in just seven countries, in Afghanistan, Algeria, Brazil, Iran, Peru, Saudi Arabia and Syria (4). The WHO has pinpointed Kabul in Afghanistan as the epicenter of CL cases in the world (5).

Transmission of leishmania strongly relies on environmental factors that can support the sandfly – certain kinds of scrub vegetation, an amiable climate as well as a wild or domesticated reservoir host. Dogs, and humans have been found to be the urban reservoirs of leishmania in Afghanistan, though desert rodents may also serve as reservoir throughout parts of the Middle East (6)(3).

In the lower center of the image, a dozen or so Leishmania parasites can be seen infecting a macrophage in the amasitote form. Image: Bushra Moiz. Click for source.

The parasite lives and replicates within the cells of the immune system, specifically the monocytes and macrophages. By hiding away in the immune system’s cells, the very ones responsible for capturing and devouring rogue microbes and parasites, leishmania effectively avoids any immunological confrontation. Using proton pumps and acid phosphatases, the parasite is able to resist degradation by proteolysis, further ensuring its survival within the macrophage. It is for this reason that the disease can be exasperatingly difficult to treat – in many cases, infection can last up to three years. Treating these buggers can also be a long, costly process which may only clear up the clinical disease and not even eradicate the persistent parasite. Current treatments include cutterage or cryotherapy, topical ointments, and local and systemic use of pentavelent antimony which can be rather toxic (7). For a good review of the methods: check out reference (7) below!

Initially, a case of CL innocuously starts as a bug bite that just won’t go away. In time, it develops into a mean-looking, open wet or dry lesion. Size can vary from a few millimeters to several centimeters in diameter. Multiple disfiguring lesions can sprout from the original lesion until a necrotic process ultimately forms and the infection is resolved. Most lesions among Iraqis and Afghanis occur on the face, the part of the body most often exposed in that climate and culture. For this very reason, some communities will deliberately infect children in a discrete region with scrapings from a lesion in an attempt to infect them early on, avoiding disfiguring scars and protecting future marriage prospects. Life-long immunity results from infection, so once you’ve had your dalliance with this protozoa, it’s over.

An unknown soldier based in the Middle East with cutaneous leishmaniasis, dated 1917. Image: Matson Collection. Click for sourece

Of course, the latest American military campaigns in the Middle East have given US troops ample opportunity for intense sandfly exposure (7). And they have been infected. As of 2007, at least 1300 soldiers have been diagnosed with leishmaniasis (mostly CL but a few isolated cases of VL) since deployment to both countries; many speculate that the number may be as high as 2,500, due to underreporting or misdiagnoses by physicians unfamiliar with this exotic disease (8). I’ve been unable to find the latest numbers for 2011 but I can imagine that they’ve added a few hundred to those estimates.

This wasn’t the case during the Gulf War, in which only 32 ground troops contracted CL and VL among 500,000 Western troops (9). Leishmaniasis is rare in northern Saudi Arabia and Kuwait and had not been described as an endemic infection in the locals, expatriate guest workers or any of the Allied troops stationed in the region during World War II. Also, most combat troops were stationed in the open desert rather than in oases or urban areas where the sandfly vector and its rodent reservoirs thrive. They were also deployed in the cooler winter season, a seasonally inopportune time for the sandfly (10).

Prior to the invasion of Afghanistan, the US Defense Intelligence Agency’s Armed Forces Medical Intelligence Center (woof, what a mouthful) anticipated that leishmaniasis might be a problem and called for appropriate provisions to be made – education, insect repellant, bed netting and the like. Overall, the American military has strongly enforced sanitation standards thanks to the existence of a professional non-commissioned officer (NCO) corp with the authority to do so (11). However, military sources have indicated that insect repellant and bed nets were frequently in short supply in the early years, and that many unit commanders failed to emphasize the risk to their troops (8). One paper has reported that 80% of a surveyed 310 infected troops had reported using insect repellents but that a 26% of those had also noted that repellents were occasionally unavailable (7).

Having served nine months in Iraq, Sgt. Eric DiVona awaits treatment for cutaneous leishmaniasis at the Walter Reed Army Medical Center in 2004. Image: AP. Click for source

Soldiers have also had to contend with other tropical delights such as malaria, Q fever, brucellosis but prevention and control measures have largely kept other infections in check among deployed military personnel (12). Overall, the importance of practicing preventative medicine in the military theatre cannot be understated. Fighting conflicts abroad means unavoidable exposure to that country’s climate, geography and attendant health problems. And the most recent conflicts in Afghanistan and Iraq have engendered an attendant destabilization of already weakened public health measures, increased the rate of population migration as well as provoked profound societal insecurity. All of these factors have historically done wonders for the spread and transmission of infectious diseases. I wonder if Franklin D. Roosevelt’s knew how multifaceted his observation that “war is a contagion” really is.

As long as wars and so-called “foreign engagements” continue, it is vital to anticipate the types of health challenges troops should anticipate as well as understand that a soldier’s time overseas can have lasting, multifactorial impacts on their health. Infectious diseases are just one of the many hazards of war. Though they may not factor into war planning, they will be one of the many groups welcoming your invasion and long-term occupation of their home. The Soviets learned the hard way that it’s important to know one’s enemy.

Resources
A really fantastic article, and an important source for this post, about the epidemiological lessons learned in the Soviet-Afghan War.

So, parasites. They have weird life cycles that I find can be a bit tedious to talk about in these articles. Talking about people putting things in their mouth that they shouldn’t and performing  rituals that compromise their health is so much cooler than talking about what insect bit what and which parasite morphed from an amastigote to promastigote, and then traveled from the blood stream to the liver and so on. If you like that kind of stuff, check out this nice graphic from Nature explaining the particulars of leishmaniasis.

For an understanding of how a leishmaniasis diagnosis affects US soldiers, please visit the story “GIs Battle Baghdead Boil” from CBS.

References
(1) Lt Col LW Grau and Maj WA Jorgensen (1997) Beaten by the Bugs: The Soviet-Afghan War Experience. Military Review. 6: 30-7 Download the PDF here.
(2) R.W. Ashford (2000) The leishmaniases as emerging and reemerging zoonoses. Int J for Parasitology. 30(12): 1269-1281
(3) RL Jacobson (2011) Leishmaniasis in an Era of Conflict in the Middle East. Vector-Borne Zoonotic Dis 11(3):247-58. Epub 2010 Sep 16.
(4) Desjeux P et al. (2000) Leishmania/HIV co-infection, south-western Europe 1990–1998. Geneva, World Health Organization. Ref: WHO/LEISH/2000.42 Download the PDF here.
(5) World Health Organization. (Aug 10, 2004) World Health Organization action in Afghanistan aims to control debilitating leishmaniasis. Accessed Oct 5, 2011
(6) MR Wallace, BR Hale, GC Utz, PE Olson, KC Earhart, SA Thornton and KC Hyams. (2002) Endemic infectious diseases of Afghanistan. Clin Infect Dis.  15:34(Suppl 5): S171-207
(7) PJ Weina, RC Neafie, G Wortmann, M Polhemus, NE Aronson. (2004) Old world leishmaniasis: an emerging infection among deployed US military and civilian workers. Clin Infect Dis. 1;39(11):1674-80. Epub 2004 Nov 9.
(8) B Furlow (June 3, 2007) “US Army reports fewer cases of leishmaniasis, but a complex threat persists.EPI NEWS. Accessed: Oct 5, 2011
(9) KC Hyams, J Riddle, DH Trump, JT  Graham. (2001) Endemic infectious diseases and biological warfare during the Gulf War: a decade of analysis and final concerns. Am. J. Trop. Med. Hyg. 65(5): 664–670
(10) KC Hyams, K Hanson, FS Wignall, J Escamilla, EC Oldfield III. (1995) The Impact of Infectious Diseases on the Health of U.S. Troops Deployed to the Persian Gulf during Operations Desert Shield and Desert Storm. Clin Infect Dis. 20(6): 1497-1504
(11) LW Grau and MAJ WA Jorgensen. (1995) Medical Support in a Counter-guerrilla War: Epidemiologic Lessons Learned in the Soviet-Afghan War . U.S. Army Med Depart J. Accessed Oct 17, 2011
(12) NE Aronson, JW Sanders, KA Moran. (2006) In Harm’s Way: Infections in Deployed American Military Forces. Clin Infect Dis. 15;43(8):1045-51. Epub 2006 Sep 14.

This post was chosen as an Editor's Selection for ResearchBlogging.org

Weina, P., Neafie, R., Wortmann, G., Polhemus, M., & Aronson, N. (2004). Old World Leishmaniasis: An Emerging Infection among Deployed US Military and Civilian Workers Clinical Infectious Diseases, 39 (11), 1674-1680 DOI: 10.1086/425747

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Body Horrors

Body Horrors looks at the history, anthropology and geography of infectious diseases and parasites.

About Rebecca Kreston

Rebecca Kreston is an infectious disease scholar trained in microbiology and epidemiology. She obtained her Biology degree from Reed College and her Masters of Science in Tropical Medicine from Tulane University. She's lived in tropical jungles, beaches and deserts around the world and has been exposed to several of the diseases that she studies. She currently lives in New Orleans, is a second year medical student and regularly battles insects of the Diptera, Siphonaptera and Hymenoptera orders.

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