Leishmaniasis: What is it and What is Being Done?

Leishmaniasis is a parasitic disease caused by the Leishmania parasite. There are several kinds of Leishmaniasis that can occur in people, but cutaneous and visceral leishmaniasis are the most common. This infection is spread by bites from phlebotomine sand flies, which can be seen Figure 1 (CDC, 2013). Visceral Leishmaniasis is the most serious infection and is prevalent in 6 countries; Bangladesh, Brazil, Ethiopia, India, South Sudan and Sudan. Cutaneous leishmaniasis is more common, but less serious than visceral. It is prevalent in 10 countries including Afghanistan, Algeria, Brazil, Colombia, Costa Rica, Ethiopia, the Islamic Republic of Iran, Peru, Sudan and the Syrian Arab Republic (WHO, 2016).

With cutaneous leishmaniasis, sores appear on the skin of the infected person. These sores can get worse and become ulcers, but are usually never too serious. Usually, the sores from cutaneous leishmaniasis can heal on their own without treatment. With visceral leishmaniasis, the internal organs of the infected person are affected. When affected with this form of leishmaniasis, the person usually suffers from a fever, severe weight loss, swelling of internal organs (especially spleen and liver), low red and white blood cell count (CDC, 2016). If left untreated, visceral leishmaniasis can be fatal. According to a study by Alvar et al. in 2012, there are about 20-40,000 deaths per year as a result of leishmaniasis disease.

Leishmaniasis is a public health issue since a total of roughly 88 countries are burdened with the disease, which can be seen in figure 2. Additionally, the disease continues to spread due to large migrations of people, urbanization, and poor irrigation. The disease is also made worse by individual risk factors that occur in the affected countries. Risk factors such as HIV, malnutrition, and genetic mutations can increase the severity of the disease (Desjeux, 2004).

The saliva from non-infected sand flies might be the future in Leishmaniasis vaccines. According to a study conducted where a group of rhesus monkeys were bitten by uninfected sandflies and then were infected with leishmaniasis. When they were bitten by uninfected flies first, they seemed to have built up an immunity to the disease. The emergence of this new research is important since many people are migrating or traveling to countries where leishmaniasis is endemic. As a result, they will not have been exposed to the saliva from the sand flies, therefore are at a higher risk of contracting the disease. Additionally, there is really no effective vaccine for the disease, and since the disease is most common in less developed countries, it is crucial that an accessible and effective form of protection is offered (Oliviera, 2015).

Figure 1: Life cycle of leishmaniasis parasite (CDC)

Figure 2: Map of the leishmaniasis disease (WHO)

Works Cited:

Leishmaniasis in high-burden countries: An epidemiological update based on data reported in 2014. (2016, June 3). World Health Organization Weekly Epidemiological Record, 22(91), 285-296.

Center for Disease Control: Biology. (2013, January 10). https://www.cdc.gov/parasites/leishmaniasis/biology.html

Desjeux, P. (2004, September). Leishmaniasis: Current situation and new perspectives. Comparative Immunology, Microbiology and Infectious Diseases, 27(5), 305-318.

Alvar, J., Vélez, I. D., Bern, C., Herrero, M., Desjeux, P., Cano, J., Boer, M. D. (2012, May 31). Leishmaniasis Worldwide and Global Estimates of Its Incidence. PLoS ONE, 7(5). doi:10.1371/journal.pone.0035671

Oliviera, F. (2015, July 13). Sand-Fly Vaccine Provides Protection in Monkeys Against Leishmaniasis. National Institute of Allergy and Infectious Disease.