Leishmaniasis is a parasitic disease spread by the bite of infected sand flies. There are several different forms of leishmaniasis. The most common are cutaneous and visceral. The cutaneous type causes skin sores. The visceral type affects internal organs such as the spleen, liver, and bone marrow. People with this form usually have fever, weight loss, and an enlarged spleen and liver.

Leishmaniasis is found in parts of about 88 countries. Most of these countries are in the tropics and subtropics. It is possible but very unlikely that you would get this disease in the United States. But you should be aware of it if you are traveling to the Middle East or parts of Central America, South America, Asia, Africa or southern Europe.

Treatment is with medicines that contain antimony, a type of metal, or with strong antibiotics. The best way to prevent the disease is to protect yourself from sand fly bites:

• Stay indoors from dusk to dawn, when sand flies are the most active
• Wear long pants and long-sleeved shirts when outside
• Use insect repellent and bed nets as needed

Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. It is classified as a neglected tropical disease (NTD). Leishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of phlebotomine sand flies. There are several different forms of leishmaniasis in people. The most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow).

Leishmaniasis is found in people in focal areas of approximately 90 countries in the tropics, subtropics, and southern Europe. The ecologic settings range from rain forests to deserts. Leishmaniasis usually is more common in rural than in urban areas, but it is found in the outskirts of some cities. Climate and other environmental changes have the potential to expand the geographic range of the sand fly vectors and the areas in the world where leishmaniasis is found.

Leishmaniasis is found in people on every continent except Australia and Antarctica.

• In the Old World (the Eastern Hemisphere), leishmaniasis is found in some parts of Asia, the Middle East, Africa (particularly in the tropical region and North Africa, with some cases elsewhere), and southern Europe. It is not found in Australia or the Pacific islands.
• In the New World (the Western Hemisphere), it is found in some parts of Mexico, Central America, and South America. It is not found in Chile or Uruguay. Occasional cases of cutaneous leishmaniasis have been acquired in Texas and Oklahoma.

The number of new cases may vary or change over time and are difficult to estimate. For cutaneous leishmaniasis, estimates of the number of new cases per year have ranged from approximately 700,000 to 1.2 million or more. For visceral leishmaniasis, the estimated number of new cases per year may have decreased to <100,000, but previous estimates ranged up to 400,000 or more cases. The cases of leishmaniasis evaluated in the United States reflect travel and immigration patterns. For example, many of the cases of cutaneous leishmaniasis in U.S. civilian travelers have been acquired in common tourist destinations in Latin America, such as in Costa Rica.

Overall, infection in people is caused by more than 20 species (types) of Leishmania parasites, which are spread by about 30 species of phlebotomine sand flies; particular species of the parasite are spread by particular sand flies. The sand fly vectors generally are the most active during twilight, evening, and night-time hours (from dusk to dawn).

In many geographic areas where leishmaniasis is found in people, infected people are not needed to maintain the transmission cycle of the parasite in nature; infected animals (such as rodents or dogs), along with sand flies, maintain the cycle. However, in some parts of the world, infected people are needed to maintain the cycle; this type of transmission (human—sand fly—human) is called anthroponotic. In areas with anthroponotic transmission, effective treatment of individual patients can help control the spread of the parasite.

Causal Agent:

Leishmaniasis is a vectorborne disease that is transmitted by sand flies and caused by obligate intracellular protozoa of the genus Leishmania. Human infection is caused by more than 20 species. These include the L. donovani complex with 2 species (L. donovani, L. infantum [also known as L. chagasi in the New World]); the L. mexicana complex with 3 main species (L. mexicana, L. amazonensis, and L. venezuelensis); L. tropica; L. major; L. aethiopica; and the subgenus Viannia with 4 main species (L. [V.] braziliensis, L. [V.] guyanensis, L. [V.] panamensis, and L. [V.] peruviana). The different species are morphologically indistinguishable, but they can be differentiated by isoenzyme analysis, molecular methods, or monoclonal antibodies.

Life Cycle:

Leishmaniasis is transmitted by the bite of infected female phlebotomine sandflies. The sandflies inject the infective stage (i.e., promastigotes) from their proboscis during blood meals The number 1. Promastigotes that reach the puncture wound are phagocytized by macrophages The number 2 and other types of mononuclear phagocytic cells. Progmastigotes transform in these cells into the tissue stage of the parasite (i.e., amastigotes) The number 3, which multiply by simple division and proceed to infect other mononuclear phagocytic cells The number 4. Parasite, host, and other factors affect whether the infection becomes symptomatic and whether cutaneous or visceral leishmaniasis results. Sandflies become infected by ingesting infected cells during blood meals (The number 5, The number 6). In sandflies, amastigotes transform into promastigotes, develop in the gut The number 7 (in the hindgut for leishmanial organisms in the Viannia subgenus; in the midgut for organisms in the Leishmania subgenus), and migrate to the proboscis The number 8.

There are several different forms of leishmaniasis in people. Some people have a silent infection, without any symptoms or signs.

The most common form is cutaneous leishmaniasis, which causes skin sores. The sores typically develop within a few weeks or months of the sand fly bite. The sores can change in size and appearance over time. The sores may start out as papules (bumps) or nodules (lumps) and may end up as ulcers (like a volcano, with a raised edge and central crater); skin ulcers might be covered by scab or crust. The sores usually are painless but can be painful. Some people have swollen glands near the sores (for example, under the arm, if the sores are on the arm or hand).

The other main form is visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow) and can be life threatening. The illness typically develops within months (sometimes as long as years) of the sand fly bite. Affected people usually have fever, weight loss, enlargement (swelling) of the spleen and liver, and low blood counts—a low red blood cell count (anemia), a low white blood cell count (leukopenia), and a low platelet count (thrombocytopenia).

Mucosal leishmaniasis is an example of one of the less common forms of leishmaniasis. This form can be a sequela (consequence) of infection with some of the species (types) of the parasite that cause cutaneous leishmaniasis in parts of Latin America: certain types of the parasite might spread from the skin and cause sores in the mucous membranes of the nose (most common location), mouth, or throat.

Various laboratory methods can be used to diagnose leishmaniasis—to detect the parasite as well as to identify the Leishmania species (type). Some of the methods are available only in reference laboratories. In the United States, CDC staff can assist with the testing for leishmaniasis.

Tissue specimens—such as from skin sores (for cutaneous leishmaniasis) or from bone marrow (for visceral leishmaniasis)—can be examined for the parasite under a microscope, in special cultures, and by molecular tests. Blood tests that detect antibody (an immune response) to the parasite can be helpful for cases of visceral leishmaniasis; tests to look for the parasite (or its DNA) itself usually also are done.

Before considering treatment, the first step is to make sure the diagnosis is correct.

Treatment decisions should be individualized. Health care providers may consult CDC staff about the relative merits of various approaches. Examples of factors to consider include the form of leishmaniasis, the Leishmania species that caused it, the potential severity of the case, and the patient’s underlying health.

The skin sores of cutaneous leishmaniasis usually heal on their own, even without treatment. But this can take months or even years, and the sores can leave ugly scars. Another potential concern applies to some (not all) types of the parasite found in parts of Latin America: certain types might spread from the skin and cause sores in the mucous membranes of the nose (most common location), mouth, or throat (mucosal leishmaniasis). Mucosal leishmaniasis might not be noticed until years after the original sores healed. Ensuring adequate treatment of the cutaneous infection may help prevent mucosal leishmaniasis.

If not treated, severe (advanced) cases of visceral leishmaniasis typically are fatal.

No vaccines or drugs to prevent infection are available. The best way for travelers to prevent infection is to protect themselves from sand fly bites. To decrease the risk of being bitten, follow these preventive measures:

Avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active.

When outdoors (or in unprotected quarters):

• Minimize the amount of exposed (uncovered) skin. To the extent that is tolerable in the climate, wear long-sleeved shirts, long pants, and socks; and tuck your shirt into your pants. (See below about wearing insecticide-treated clothing.)
• Apply insect repellent to exposed skin and under the ends of sleeves and pant legs. Follow the instructions on the label of the repellent. The most effective repellents generally are those that contain the chemical DEET (N,N-diethylmetatoluamide).

When indoors:

• Stay in well-screened or air-conditioned areas.
• Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes.
• Spray living/sleeping areas with an insecticide to kill insects.
• If you are not sleeping in a well-screened or air-conditioned area, use a bed net and tuck it under your mattress. If possible, use a bed net that has been soaked in or sprayed with a pyrethroid-containing insecticide. The same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings).

Note:Bed nets, repellents, and insecticides should be purchased before traveling and can be found in hardware, camping, and military surplus stores. Bed nets and clothing that already have been treated with a pyrethroid-containing insecticide also are commercially available.

What is leishmaniasis?

Leishmaniasis is disease caused by a parasite. Sand flies can spread this parasite to people when they bite them.

Two common forms of leishmaniasis are cutaneous and visceral.

The most common symptom of cutaneous leishmaniasis is skin sores that can change in size and appearance over time. The sores may be closed, like a lump or a bump, or open (ulcer). Some people have swollen glands near the sores.

Common symptoms of visceral leishmaniasis are fever and weight loss. People with visceral leishmaniasis can also have an enlarged spleen and liver, low red blood cell count (anemia), low white blood cell count (leukopenia), and low platelet count (thrombocytopenia).

Some people with leishmaniasis never have symptoms.

Who is at risk?

Sand flies are found in some parts of Asia, the Middle East, Africa, Southern Europe, Mexico, Central America, and South America. Travelers going to these areas are at risk of being bitten by sand flies and getting infected.

See if leishmaniasis is a concern at your destination.

What can travelers do to prevent leishmaniasis?

There is no vaccine or medicine that prevents leishmaniasis. Travelers can protect themselves from infection by preventing sand fly bites.

Travelers can take the following steps to prevent sand fly bites:

• Cover exposed skin by wearing long-sleeved shirts, long pants, and hats.
• Stay and sleep in screened or air-conditioned rooms.
  • Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes.
  • If you are not sleeping in a well-screened or air-conditioned area, use a bed net and tuck it under your mattress. If possible, use a bed net that has been soaked in or sprayed with a pyrethroid-containing insecticide. The same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings).

• Use permethrin-treated clothing and gear (such as boots, pants, socks, and tents). You can buy pre-treated clothing and gear or treat them yourself:
  • Treated clothing remains protective after multiple washings. See the product information to find out how long the protection will last.
  • If treating items yourself, follow the product instructions carefully.
  • Do not use permethrin directly on skin.

• Use EPA-registered insect repellents with one of the following active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. Find an EPA-registered insect repellent that’s right for you.
• Always follow product directions and reapply as directed.
• If you are also using sunscreen, apply sunscreen first and insect repellent second.
• When using insect repellent on children:
  • Do not use products containing oil of lemon eucalyptus (OLE) or para-menthane-diol (PMD) on children under 3 years old.
  • Do not apply insect repellent to a child’s hands, eyes, mouth, cuts, or irritated skin.
  • Adults: Spray insect repellent onto your hands and then apply to a child’s face.

If you traveled and feel sick, particularly if you have a fever, talk to a healthcare provider, and tell them about your travel. Avoid contact with other people while you are sick.

What is leishmaniasis?

Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. Leishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of infected sand flies. There are several different forms of leishmaniasis in people. The most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow).

What are the symptoms and signs of cutaneous leishmaniasis?

Some people have a silent infection, without any symptoms or signs. People who develop clinical evidence of infection have one or more sores on their skin. The sores can change in size and appearance over time. The sores may start out as papules (bumps) or nodules (lumps) and may end up as ulcers (like a volcano, with a raised edge and central crater); skin ulcers may be covered by scab or crust. The sores usually are painless but can be painful. Some people have swollen glands near the sores (for example, under the arm, if the sores are on the arm or hand).

What are the symptoms and signs of visceral leishmaniasis?

Some people have a silent infection, without any symptoms or signs. People who develop clinical evidence of infection usually have fever, weight loss, enlargement (swelling) of the spleen and liver, and abnormal blood tests. People may have low blood counts, including a low red blood cell count (anemia), a low white blood cell count (leukopenia), and a low platelet count (thrombocytopenia).

How common is leishmaniasis in the world?

The number of new cases may vary or change over time and are difficult to estimate. For cutaneous leishmaniasis, estimates of the number of new cases per year have ranged from approximately 700,000 to 1.2 million or more. For visceral leishmaniasis, the estimated number of new cases per year may have decreased to <100,000, but previous estimates ranged up to 400,000 or more cases.

In what parts of the world is leishmaniasis found?

In the Old World (the Eastern Hemisphere), leishmaniasis is found in some parts of Asia, the Middle East, Africa (particularly in the tropical region and North Africa, with some cases elsewhere), and southern Europe. It is not found in Australia or the Pacific Islands.

In the New World (the Western Hemisphere), leishmaniasis is found in some parts of Mexico, Central America, and South America. It is not found in Chile or Uruguay.

Overall, leishmaniasis is found in parts of approximately 90 countries. The cases of leishmaniasis evaluated in the United States reflect travel and immigration patterns. For example, many of the cases of cutaneous leishmaniasis in U.S. civilian travelers have been acquired in common tourist destinations in Latin America, such as in Costa Rica. U.S. military personnel have become infected in various countries, such as Iraq and Afghanistan.

Is leishmaniasis found in the United States?

Not usually. Almost all of the cases of leishmaniasis diagnosed in the United States are in people who became infected while traveling or living in other countries.

Occasional cases of cutaneous leishmaniasis have been acquired in Texas and Oklahoma. No cases of visceral leishmaniasis are known to have been acquired in the United States.

How do people get infected with Leishmania parasites?

The main way is through the bite of infected female phlebotomine sand flies. Sand flies become infected by sucking blood from an infected animal or person. People might not realize that sand flies are present because:

• They do not make any noise;
• They are small: on average, they are only about one fourth the size of mosquitoes or even smaller; and
• Their bites might not be noticed (the bites can be painless or painful).

Sand flies usually are most active in twilight, evening, and night-time hours (from dusk to dawn). Although sand flies are less active during the hottest time of the day, they may bite if they are disturbed (for example, if a person brushes up against the trunk of a tree or some other site where sand flies are resting).

Some types (species) of Leishmania parasites also may be spread via contaminated needles (needle sharing) or blood transfusions. Congenital transmission (spread from a pregnant woman to her baby) has been reported.

Who is at risk for Leishmania infection?

People of all ages are at risk for infection if they live or travel where leishmaniasis is found. Leishmaniasis usually is more common in rural than in urban areas, but it is found in the outskirts of some cities. The transmission risk is highest from dusk to dawn because this is when sand flies generally are the most active. Examples of people who may have an increased risk for infection (especially with the cutaneous form) include adventure travelers, ecotourists, Peace Corps volunteers, missionaries, soldiers, ornithologists (people who study birds), and other people who do research (or are active) outdoors at night/twilight.

If I were bitten by an infected sand fly, when would leishmaniasis develop?

Some people have a silent infection, without any symptoms or signs.

The skin sores of cutaneous leishmaniasis usually develop within a few weeks or months of the sand fly bite.

People with visceral leishmaniasis usually become sick within months (sometimes as long as years) of when they were bitten.

What should I do if I think I might have leishmaniasis?

See your health care provider. Be sure to say where you have traveled and to mention the possibility of leishmaniasis.

How is leishmaniasis diagnosed?

The first steps are to check if you have been in a part of the world where leishmaniasis is found and if you have any symptoms or signs that might be from leishmaniasis.

CDC staff can advise your health care provider and can help with the laboratory testing for leishmaniasis. Tissue specimens—for example, from skin sores (for cutaneous leishmaniasis) or from bone marrow (for visceral leishmaniasis)—can be examined for the parasite under a microscope, in special cultures, and by molecular tests.

Blood tests that detect antibody (an immune response) to the parasite can be helpful for cases of visceral leishmaniasis; tests to look for the parasite itself (or its DNA) usually also are done.

Does leishmaniasis have to be treated?

Your health care provider can talk with CDC staff about whether your case of leishmaniasis should be treated and, if so, with what type of therapy.

The skin sores of cutaneous leishmaniasis usually heal on their own, even without treatment. But this can take months or even years, and the sores can leave ugly scars. Another potential concern applies to some (not all) types of the parasite found in parts of Latin America: certain types might spread from the skin and cause sores in the mucous membranes of the nose, mouth, or throat (mucosal leishmaniasis). Mucosal leishmaniasis might not be noticed until years after the original sores healed. Ensuring adequate treatment of the cutaneous infection may help prevent mucosal leishmaniasis.

If not treated, severe (advanced) cases of visceral leishmaniasis typically are fatal.

I plan to travel to an area of the world where leishmaniasis is found. What can I do to prevent infection?

No vaccines or drugs to prevent infection are available. The best way for travelers to prevent infection is to protect themselves from sand fly bites. To decrease the risk of being bitten, follow these preventive measures:

Avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active.

When outdoors (or in unprotected quarters):

• Minimize the amount of exposed (uncovered) skin. To the extent that is tolerable in the climate, wear long-sleeved shirts, long pants, and socks; and tuck your shirt into your pants. (See below about wearing insecticide-treated clothing.)
• Apply insect repellent to exposed skin and under the ends of sleeves and pant legs. Follow the instructions on the label of the repellent. The most effective repellents generally are those that contain the chemical DEET (N,N-diethylmetatoluamide).

When indoors:

• Stay in well-screened or air-conditioned areas.
• Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes.
• Spray living/sleeping areas with an insecticide to kill insects.
• If you are not sleeping in a well-screened or air-conditioned area, use a bed net and tuck it under your mattress. If possible, use a bed net that has been soaked in or sprayed with a pyrethroid-containing insecticide. The same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings).

NOTE: Bed nets, repellents, and insecticides should be purchased before traveling and can be found in hardware, camping, and military surplus stores. Bed nets and clothing that already have been treated with a pyrethroid-containing insecticide also are commercially available.

If I have already had leishmaniasis, could I get it again?

Yes. Some people have had cutaneous leishmaniasis more than once. Therefore, you should follow the preventive measures listed above whenever you are in an area where leishmaniasis is found.