Suck It: The Ins and Outs of Mouth Pipetting

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If you ever find yourself working in an infectious disease laboratory, whether it’s of the diagnostic or research variety, the overarching goal is not to put any microbes in your eye, an open wound or your mouth. Easy enough, right? Wear gloves, maybe goggles, work in fume hoods and don’t mouth pipette. When working with pathogenic bacteria and viruses, priority number one is Do Not Self-Inoculate.

This is obvious for anyone who has worked in a shiny biology or chemistry lab or seen an episode of CSI: Crime Scene Investigation (we’re all friends here, just admit it), but one of the most commonly used pieces of equipment in labs prior to the 1970s was the leading cause of laboratory-derived infections: the honorable pipette. How could that be possible, you ask? By using one’s oral cavity with the pipette to measure and transfer liquids.

Today our manual pipettes are rather sophisticated, plastic-y devices perfectly calibrated for moving precisely exact milliliters, microliters and picoliters of valuable solution from one vessel to another, whether it’s of a urine sample, some spare radioactive material you have lying about or toxic solvents. But before the development of cheap mechanical pipettes in the ’70s, using your mouth to pipette solutions was more than a common sight, it was a way of the lab.

Former Centers for Disease Control (CDC) parasitologist, Dr. Mae Melvin (Lt), examines a collection of test tubes while her laboratory assistant mouth pipettes a culture to be added to these test tubes. Source: David Senser/CDC.

Don’t worry, reader, I heard you tentatively whisper, “just what exactly is mouth pipetting, dare I ask?”

Like so: insert an open-ended glass capillary tube into your mouth. Place the opposite, tapered end of the tube into a solution of your choice. Microbial stews, blood, cell culture, it is totally your call. With a method that carefully mimics the sucking of a straw, draw a solution upwards through your man-made pipette to your desired volume using the tension created by the reduced air pressure – yes, suction! Maintain the tension with your mouth. Do not suck too hard and inadvertently slurp the solution into your mouth. Careful now. Gently move the pipette end from one vessel and release your precious cargo into yet another vessel.

That is mouth pipetting.

A wonderful demonstration of mouth pipetting by Dr. Armand Frappier, a microbiologist and expert on tuberculosis. Look closely: you can see him draw a dark liquid slowly towards his mouth. What could it be? Soda, a culture of TB, serum for cell cultures? You can watch the entire video clip that this GIF is based upon here. Source: Musée Armand Frapper.

The sparsity of history on pipetting techniques (itself a shocking shortcoming, I’m sure you’ll agree), forbids us from generalizing the prevalence of this phenomena. But we do know that it was the source of a ridiculous number of accidents, whether swallowing a corrosive or toxic substance or an infection with one’s research material  (1). A survey of 57 labs in 1915 found that 47 infections  were associated with workplace practices and more than 40% of those were attributed to the practice of mouth pipetting. A longitudinal study of 921 workplace laboratory infections from 1893 and 1950 found that 17% were due to “oral aspiration through pipettes or to splashes of culture fluids into the mouth (2).”

Infection through the use of one’s oral cavity was such an occupational hazard that it warranted an article, “The Hazards of Mouth Pipetting,” from two gentleman working for the U.S. Army Biological Laboratories. In 1966 they wrote,

although the use of pipettes in the early chemistry laboratories undoubtedly led to accidental aspiration of undesirable toxic and poisonous substances, the first recorded laboratory infection due to mouth pipetting occurred in 1893 … [with] the case of a physician who accidentally sucked a culture of typhoid bacilli into his mouth …

compared with the equipment and procedures required to avoid other types of microbiological laboratory hazards, the method of avoiding pipetting hazards is so elementary, so simple, and so well-recognized that it seems redundant to mention it [emphasis added by author]. However, continued accidents and infections in laboratories illustrate, even today, that there is a lack of acceptance of the simple precautionary measured needed (2).

By the 1970s, mouth pipetting had fallen out of favor as swanky, mechanically adjustable and cheap pipettes flooded the market (3). They were not only infinitely safer but also far more accurate. Instead of drawing a semi-approximate volume of solution with the imperfect measuring device that is your mouth, standardized and calibrated pipettes were available that could zip up a solution to one’s desired volume. More precision. Better experimental results. Less contamination. More ergonomic. Fewer infections. Nowadays, mouth pipetting is explicitly banned from laboratories.

A woman mouth pipetting to select specimens of ectoparasites. Source: National Library of Medicine

And, indeed, you might think that this old school technique is thankfully old news and good for a giggle but mouth pipetting is still practiced in some countries. A study looking at the lab practices and biosafety measures of Pakistani lab technicians found that mouth pipetting was reported by 28.3% technicians (4). This paper was published just last year, in August of 2012. Another study in 2008 found that Nigerian technicians working in clinical laboratories were not only improperly vaccinated against many of the preventable diseases that they were testing for (!) as well as eating and drinking in the lab but 1 in 10 also reported mouth pipetting (5).

Lest you think this is just happening in developing countries, be rest assured that American teenagers and young adults will always find a creative way to  jeopardize their health. In 1998, a 19-year-old nursing student in Pennsylvania was  hospitalized for several days following infection with a unique strain of Salmonella paratyphi she was working with in a lab; the case report strongly suggests that mouth pipetting was the culprit behind this particular microbial misadventure (6).

Another article from 1995 assessing lab accidents found that 13% of laboratory-acquired infections were a result of mouth pipetting. That’s 92 accidents attributed to someone in a lab deliberately putting a pipette or capillary tube into their mouth and sucking up some solution laden with microbes (7). Clearly, we still have a way to go in dissuading people to stop using pipettes as straws.

A techician mouth-pipetitng environmental water samples in Malta. Image: E Mandelmann. Source: History of Medicine

A technician mouth pipetting environmental water samples in Malta. Image: E Mandelmann. Source: History of Medicine

Mechanical manual pipettes have been a godsend to technology and the sciences, saving researchers time and resources in measuring and transferring liquids. Pipettes now serve as an icon of the scientific pursuit of knowledge – we’re all familiar with the close up of the gloved hand and pipette tip hovering over some glowing liquid. It’s banal, efficient and ubiquitous. It’s the dogged, unsung hero of the lab but there were several decades when our method of pipetting was also a microbial misadventure in the waiting.

Resources

“There are reports of laboratory infections by means of the pipette with quite a variety of microorganisms. In the intestinal group: typhoid, Shigella, salmonella, cholera; among others, anthrax, brucella, diphtheria, hemophilus iniluenzae, leptothrix, meningococcus, Streptococcus, syphilis, tularemia; among viruses, mumps, Coxsackie virus, viral hepatitis, Venezuelan equine encephalitis, chikungunya, and scrub typhus.” Download this neat article on the history and epidemiology of lab-acquired infections here.

Want to see more pictures of mouth pipetting? Of course you do! I’ve been collecting them on the Body Horrors tumblr here, here, here, here and here. Here’s a sign. And here’s a riff on a meme.

References

1) AG Wedum. (1997) History and epidemiology of laboratory-acquired infections. J Am Bio Safety Assc. 2(1): 12-29

2) Phillips GB &Bailey SP (1966) Hazards of mouth pipetting. Am J Med Technol. 32(2): 127-9

3) JA Martin (April 13, 2001) The Art of the Pipette BiomedNet Magazine100

4) S Nasim et al (2012) Biosafety perspective of clinical laboratory workers: a profile of Pakistan. J Infect Dev Ctries. 6(8): 611-9

5) FO Omokhodion (1998) Health and safety in clinical laboratory practice in Ibadan, Nigeria. Afr J Med Med Sci. 27(3-4): 201-4

6)B Boyer et al (1998) The microbiology “unknown” misadventure. Am J Infect Control. 26(3):355-8

7) DL Sewel (1995) Laboratory-Associated Infections and Biosafety. Clin Micro Rev. 8(3): 389-405

ResearchBlogging.org
HILL, N. (1999). Laboratory-acquired Infections: History, Incidence, Causes and Preventions, 4th edition. Eds. C. H. Collins and D. A. Kennedy. Butterworth Heinemann, Oxford 1999. Pp. 324. ISBN 0 7506 4023 5. Epidemiology and Infection, 123 (1), 181-181 DOI: 10.1017/S0950268899002514

Nobel Prizes, Tropical Medicine & One Nazi Sympathizer

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Nobel Prizes! We all want one, don’t we? While fantasizing about heavy gold medallions and the Swedish Nobel Assembly, I wondered how many of the Nobel Laureate prizes in Physiology and/or Medicine have gone towards scientists studying infectious diseases, immunology and the tropical medicine field. Snooze button alert, am I right? This is the product of a one-track mind so you have my apologies. But! If it’s any consolation, there’s a story hidden in this article of a Nobel Laureate Nazi sympathizer that infected mental patients with malaria to cure them of their psychoses. Science!

Let’s get down to numbers. As of 2011, this prize has been awarded 101 times to 199 scientists for their research in this field.  In recent years, the Nobel Prize has often been awarded jointly to two or three scientists for either collaborative research or for research that is similar in scope and specialty. Of those 101 occasions, 22 of these awards have been given to 39 researchers for their work in infectious diseases, virology, parasitology and/or immunology. Only one woman is on this list, Françoise Barré-Sinoussi, for her incredible work with Luc Montagnier in identifying HIV at the height of the HIV/AIDS epidemic in the 1980s.

The Nobel Medal for Physiology or Medicine is embossed with the Genius of Medicine "holding an open book in her lap, collecting the water pouring out from a rock in order to quench a sick girl's thirst". Description from NobelPrize. Click for image source.

(FYI, there have been nine years in which the Nobel Prize ceremony and awards did not occur due to the disruption of the two World Wars – in 1915 to 1918, 1921, 1925 and 1940 to 1942. Those Nazi’s again!)

So roughly one-fifth of the Nobel Prizes in medicine have gone to scientists making breakthroughs in the study of infectious diseases or in the immunological response to those diseases, indicating how crucial this particular field of medicine is to the scientific community. We’re not talking dermatology or podiatry here, folks.

In the early years, the Assembly awarded prizes for game-changing advances in the research of big killer diseases of the day – diptheria, tuberculosis and malaria, to name a few. The development of a yellow fever vaccine (1951), discoveries of vital antibiotics that are still used today globally (1939, 1945 and 1952), and the finding that HPV causes cervical cancer (2008) are just a few of the discoveries that the Nobel Assembly considered so revelatory to the field of medicine. Until the past century, how infectious diseases entered the body, their mechanisms of pathogenesis and even their treatment was largely unknown. Malaria is transmitted by mosquitoes? Not known till 1899 and Sir Ronald Ross’s discovery of the parasite hiding inside the stomach of an Anopheles mosquito was justly recognized by the Nobel Assembly in 1902. Lice transmit typhus? Charles Nicolle’s finding won him a good amount of money and worldwide recognition/obscurity in 1928. In 1954, a trio of American researchers were awarded the Nobel for identifying a method to culture the polio virus, launching the beginning of the end of polio’s affliction on humanity.

Many of the awarded discoveries laid the foundation for productive research that has led to profound advancements in disease and pest control, the emergence of the field of public health, development of the pharmaceutical industry and the industrial production of vaccines, antibiotics, and antivirals. Life-changing stuff, ya’ll. Flipping through this list is a reminder of how far we’ve come in the past century in establishing our domain over bacteria and viruses that previously wiped us out with shocking regularity. In fact, some of their findings and methods are so commonplace, hell! even banal, in today’s laboratories that it’s like stepping into a science time-warp reading about their discoveries. Thanks to these scientists, we possess the complex knowledge of genetics, immunology, antibiotics, vaccines and their respective methods to identify, culture and combat new diseases.

The list of winners is below and includes the year they were awarded, their country of origin and the award’s justification from the Nobel Assembly in quotes; those quotes come from the official website of the Nobel Prize. I’ve included in the list a few winners awarded for their work in immunology and antibiotics; while these are not strictly related to infectious diseases, their research laid a strong foundation for future infectious disease work and, well, they’re related and it’s important so get over it.

Scroll past this engrossing list that I’ve compiled for your disease-seeking pleasure.

1901
Emil Adolf von Behring (Germany) “for his work on serum therapy, especially its application against diphtheria, by which he has opened a new road in the domain of medical science and thereby placed in the hands of the physician a victorious weapon against illness and deaths”. Victorious weapon! I’d think the flowery language alone should do the trick. In any case, von Behring developed a diphtheria antitoxin, known as a “serum”, by repeatedly injecting a horse with diphtheria toxin.

"A Future Pharmacy". An editorial cartoon mocking Emil Adolf Von Behring and his discovery of serum therapy, in which a diphtheria antitoxin was developed by repeatedly exposing a horse to the diphtheria toxin. Click for source.

1902
Sir Ronald Ross (United Kingdom) for his discovery that malaria is transmitted by mosquitoes.

1905
Robert Koch (Germany) “for his investigations and discoveries in relation to tuberculosis”.

1907
Charles Louis Alphonse Laveran (France) “in recognition of his work on the role played by protozoa in causing diseases”.

1927
Julius Wagner-Jauregg (Austria) “for his discovery of the therapeutic value of malaria inoculation in the treatment of dementia paralytica”. In 1927, Wagner-Jauregg received the  Prize for his discovery of pyrotherapy, the treatment of mental disease by febrile diseases. Besides being a Nobel Laureate, Wagner-Jauregg was also a Nazi sympathizer, anti-semite and racial hygienist. A charmer of a man who forced sterilization upon the mentally ill and the criminal and the so-called “father of fever therapy”(1).

Mustachioed Wagner-Jauregg stands behind a mental patient receiving malarial pyrotherapy. Click for image source.

Since 1887, he had been investigating the phenomenon of how fever, as induced by tuberculosis or St. Anthony’s Fire, may reduce the effects of psychosis caused by tertiary syphilis. Bacterial infections didn’t seem to do the trick in terms of bringing about recurrent high fevers and so in 1917 Wagner-Jauregg turned to the malaria parasite. Turns out, malaria is an excellent specimen for this sort of thing and led to its usage as an established treatment for paralytic dementia and neurosyphilis. An application of quinine would end the fever therapy, eliminating the infection and leaving the patient free of his psychoses. For this hot discovery, Wagner-Jauregg is the only psychiatrist to have ever won the Nobel for investigative fieldwork on mental illness.

1928
Charles Jules Henri Nicolle (France) for his discovery that lice transmitted typhus. Nicholle was a master researcher of infectious diseases and made many discoveries regarding the pathology and epidemiology of brucellosis, leishmaniasis, measles, rinderpest, scarlet fever, Mediterranean spotted fever, toxoplasmosis, trachoma and tuberculosis. Nicholle’s typhus work was performed in Tunisia using chimpanzees and toque macaques (2).

Vials and tablets of prontosil, an industrial dye discovered to have antibacterial properties by Gerhard Domagk. Click for source.

1939
Gerhard Domagk (Germany) “for the discovery of the antibacterial effects of prontosil”. Prontosil was the first drug to be found effective against bacterial infections and Domagk made quick use of this fact – as a streptococcal infection threatened his daughter, his treatment with prontosil prevented the therapeutic amputation of her arm.

1945
Sir Alexander Fleming (United Kingdom), Sir Ernst Boris Chain (United Kingdom), and Howard Walter Florey (Australia) “for the discovery of penicillin and its curative effect in various infectious diseases”.

1951
Max Theiler Union (South Africa) “for his discoveries concerning yellow fever and how to combat it”. He had an enormous forehead. His award is the only one that has gone towards a virus vaccine.

1952
Selman Abraham Waksman (United States) for his discovery of streptomycin, the first antibiotic effective against tuberculosis”. Waksman coined the term “antibiotic”.

There's really no reason why I'm including this photo of Selman Waksman here aside from the fact that it's so gloriously Science!-y. Lab coat, check. Flask of something liquid, check. Mood lighting, check. Click for image source.

1954
John Franklin Enders, Thomas Huckle Weller and Frederick Chapman Robbins (all from the United States) “for their discovery of the ability of poliomyelitis viruses to grow in cultures of various types of tissue”. Their work laid the groundwork for Jonas Salk’s development of the polio vaccine.

1958
Joshua Lederberg (United States) “for his discoveries concerning genetic recombination and the organization of the genetic material of bacteria”.

1966
Peyton Rous (United States) “for his discovery of tumour-inducing viruses”. In 1911, Rous found that some cancers can be transmitted by viruses, known as retroviruses. Forty years later, he was awarded for his work.

1969
Max Delbrück, Alfred D. Hershey and Salvador E. Luria (all from the United States), “for their discoveries concerning the replication mechanism and the genetic structure of viruses”. The trio discovered that bacterial resistance to bacteriophages (viruses that infect bacteria) was a result of random mutations.

1972
Gerald M. Edelman (United States) and Rodney R. Porter (United Kingdom) used immunoglobins sourced from human blood to identify the chemical structure of antibodies.

1976
Baruch S. Blumberg and D. Carleton Gajdusek (United States) “for their discoveries concerning new mechanisms for the origin and dissemination of infectious diseases”. These guys were awarded for their research on kuru, a disease caused by human prions. Fun fact: Blumberg also discovered the hepatitis B virus and developed the diagnostic test and vaccine for it.

1984
Niels K. Jerne (Denmark), Georges J.F. Köhler (Federal Republic of Germany) and César Milstein (Argentina and the United Kingdom) “for theories concerning the specificity in development and control of the immune system and the discovery of the principle for production of monoclonal antibodies”.

1989
J. Michael Bishop and Harold E. Varmus (United States) “for their discovery of the cellular origin of retroviral oncogenes”.

1997
Stanley B. Prusiner (United States) “for his discovery of Prions – a new biological principle of infection”.

2005
Barry J. Marshall and J. Robin Warren (Australia) “for their discovery of the bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease”. Marshall is famously known for downing culture medium loaded with H. pylori to directly prove that the bacterium is responsible for causing ulcers.

2006
Andrew Z. Fire and Craig C. Mello (United States) “for their discovery of RNA interference, [otherwise known as] gene silencing by double-stranded RNA”.

2008
Harald zur Hausen (Germany) “for his discovery of human papilloma viruses causing cervical cancer”, along with Françoise Barré-Sinoussi and Luc Montagnier (France) “for their discovery of the human immunodeficiency virus”.

Resources

The Nobel Prize website has a fleshed-out timeline for every Laureate and includes their biography, a short article about their research, the lecture they delivered to the Nobel Assembly and much much more.

References
(1) Howes OD et al (2009) Julius Wagner-Jauregg, 1857–1940. Am J of Psy. 166(4): 409.
(2) Schultz MG and Morens DM. (2009) Charles-Jules-Henri Nicolle. Emerg Infect Dis. 15(9): 1520-22. Accessed online.

ResearchBlogging.orgSchultz, M. (2009). Charles-Jules-Henri Nicolle Emerging Infectious Diseases, 1519-1522 DOI: 10.3201/eid1509.090891

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

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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. Moving on! 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.

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
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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