Leishmaniasis: Battle Scars

Aliases: It is currently known as leishmaniasis, but historically it went by the misleadingly adorable name “Jericho buttons”, due to the high number of cases near the city of Jericho.

Leishmaniasis is an old disease that has been made new, thanks to humanity’s propensity for destruction. It originates in the Old World, and while it still wreaks havoc there, it has also found new frontiers. It follows at the heels of poverty, conflict, and environmental disturbance- including urbanization, deforestation, and climate change- and afflicts some of the poorest people on the planet3.

Like many other diseases, leishmaniasis has spread by piggybacking on the effects of suffering. It usually affects the poor and malnourished, and it opportunistically infects the immunocompromised (people with weak or suppressed immune systems), such as those who are HIV positive1. Unfortunately, it has been very successful. There are an estimated 1.3 million new cases of leishmaniasis each year, and 20,000-30,000 fatalities3. The disease is now found in 90 countries, spanning the tropics, subtropics, and southern Europe, and has reached every continent except Antarctica and Australia2.

War has played a significant role in the modern resurgence of leishmaniasis. Armed conflict increases the ranks of susceptible people, by displacing and depriving them. The large-scale deployment of troops to regions where the disease is endemic (normally occurs) has also caused a jump in the number of cases1. Operation Iraqi Freedom exposed many US soldiers to the pathogen; troops reported being repeatedly bitten by sandflies. As a consequence, case numbers in the US reached levels that hadn’t been seen since WWII4. We may finally have an answer to Edwin Starr’s classic question: “War, what is it good for?” 

leishmaniasis
Good god, y’all.

Cause: Leishmaniasis is caused by more than 20 species of protozoan, aptly named Leishmania, that are transmitted by the bite of infected sandflies. This disease knows how to get around: a whopping 90 species of sandfly can transmit the pathogen, and it has about 70 animal reservoir host species, including humans3.

Consequence: There are three forms of leishmaniasis: visceral (aka kala-azar; the most serious form), cutaneous (the most common form), and mucocutaneous. Visceral leishmaniasis (VL) symptoms can be a long time coming. It can take anywhere from months to years after the infected bite for symptoms to emerge2. These include irregular fever, weight loss, enlargement of the liver and spleen, and anemia. VL is fatal, if untreated. There are an estimated 200,000-400,000 new cases a year, with 90% occurring in 6 countries: Bangledesh, Brazil, Ethiopia, India, South Sudan, and Sudan. Cutaneous leishmaniasis (CL) causes skin lesions, usually ulcers, on exposed parts of the body3, which occur within a few months of transmission2, and can leave permanent scars and disability in their wake. Over two thirds of the million or so new cases of CL each year occur in 6 countries: Afghanistan, Algeria, Brazil, Columbia, Iran, and the Syrian Arab Republic. Mucocutaneous leishmaniasis (ML) is generally a secondary infection resulting from untreated CL2. It destroys the mucous membranes of the nose, mouth, and throat. Ninety percent of ML cases occur in 3 countries: Bolivia, Brazil and Peru3.

Cure: Leishmaniasis is very treatable3. VL is most effectively treated with liposomal amphotericin (B L-AMB), however there is growing interest in combination therapy, in the hopes of reaching shorter treatment times1. There are myriad treatments for CL, ranging from topical ointments to cryotherapy4. Which is best remains a matter of debate1. All three forms of leishmaniasis can be combatted with preventative measures, including insecticide treated bed nets, sandfly control, disease surveillance, and control of reservoir hosts3.

References

  1. Antinori, S, L Schifanella, & M Corbellino. (2012). Leishmaniasis: new insights from an old and neglected disease. European Journal of Clinical Microbiology and Infectious Disease. 31: 109-118.
  1. Leishmaniasis. Centers for Disease Control and Prevention. 10 January 2013. Web. 13 March 2015.
  1. Leishmaniasis. World Health Organization. February 2015. Web.13 March 2015.
  1. Weina, PJ, RC Neafie, G Wortmann, M Polhemus, & NE Aronson. (2004). Old world leishmaniasis: an emerging infection among deployed US military and civilian workers. Clinical Infectious Diseases, 39: 1674-1680.

Image source: Creative Commons, http://commons.wikimedia.org/wiki/File:JerichoButtons.jpg