Leishmaniasis is a parasitic infection which transmits to humans and animals via the phlebotomine female sandfly. Its transmission is similar to that of malaria which spreads via the bite of the female Anopheles mosquito. The female sandfly needs a blood meal in order for her eggs to survive and develop, and if the human or animal that provides the meal carries the parasite, she may acquire the infection.
The female sandfly which has acquired the parasite for leishmaniasis may subsequently take a blood meal from a human or animal which does not have the infection, and she may transmit it to them. This completes the transmission cycle and enables the spread of leishmaniasis to continue. The medical condition is not common in the United States, but it is continuously present or endemic in many developing countries where millions of people have leishmaniasis.
In regions of the world where there is much poverty, inadequate nutrition, poor housing, gender discrimination, illiteracy, and displacement, leishmaniasis is especially prevalent. These populations also tend to have insufficient immunity against infectious diseases in general (Centers for Disease Control, 2010).
Leishmaniasis especially occurs in parts of the Western Hemisphere such as some regions of Mexico, Central America, and South America. In the Eastern Hemisphere, the disease is common in certain parts of Asia, the Middle East, Africa, and southern Europe. It also affects Americans who travel to endemic regions of the world and acquire the parasitic infection there.
Groups at Risk
United States military personnel who spend time in Iraq or Afghanistan may acquire leishmaniasis. Others who are also at risk for the disease include ecotourists, adventure travelers, Peace Corps volunteers, missionaries, and individuals who conduct research on birds. Anyone who is active outside at night in endemic regions of the world, whether for research or something else, will have a predisposition for leishmaniasis.
Phlebotomine Sandfly
Scientists know of approximately 500 phlebotomine species, but only about 30 of them will transmit leishmaniasis. Phlebotomine sandflies are present in intertropical and temperate regions of the world. They are insects two to three millimeters in size and breed in forest areas, caves, or the burrows of small rodents. Their small size enables them to pass through openings which mosquitoes and some other insects cannot.
The phlebotomine sandfly does not make any noise when she flies, and like mosquitoes, she will be most active outside from dusk to dawn. Their bite to a human may or may not be painful.
Sources
- Centers for Disease Control. (2010). Leishmaniasis. Retrieved December 10, 2011.
- World Health Organization. (2011). Leishmaniasis. Retrieved December 10, 2011.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact their physician for advice.
Michael Koger - Dr. Koger obtained his medical education at Meharry Medical College and specialized in Internal Medicine.
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