An infection caused by Leishmania (a group of parasitic protozoa) is called Leishmaniasis. Typically, these parasites are found in tropical and subtropical parts of the world. While it may cause severe ulcers on the skin, in some cases, it may negatively affect internal organs, which can be fatal. Commonly, doctors treat this infection with anti-parasitic medicines.
In other words, leishmaniasis is a group of health conditions caused by different types of Leishmania parasites, which people often get from sand fly bites. Without treatment, it can cause life-threatening conditions. Generally, leishmanial parasites are protozoa (one-celled organisms that are very small and cannot be seen without a microscope). The most common forms of leishmaniasis are cutaneous and visceral leishmaniasis. Typically, it is difficult to estimate how many people are infected because it does not always cause symptoms. According to some data, about 1.5 million people develop symptoms of leishmaniasis each year.
Types of Leishmaniasis
Healthcare professionals have divided this infection into 3 categories. These include cutaneous, mucosal (also called mucocutaneous), and visceral.
Cutaneous Leishmaniasis
When this parasite infects the skin, it causes an infection called cutaneous leishmaniasis (CL). Usually, those who develop it experience bumps on the skin that may turn into ulcers over time. CL often takes a long time to heal. In rare cases, people can develop bumps and ulcers that affect multiple parts of the skin (also known as diffuse cutaneous leishmaniasis). Some people may develop symptoms again, even after successful treatment.
Mucosal Leishmaniasis
Most of the time, mucosal leishmaniasis (ML) is a complication of CL. In this case, ulcers appear in the nose, mouth, or throat (mucous membranes). ML rarely improves without treatment, and can be fatal if it is left untreated.
Visceral Leishmaniasis
This is one of the most serious types of leishmaniasis, and it is caused by a specific type of this parasite. It is called visceral leishmaniasis (VL), also known as kala-azar. It negatively affects the internal organs (including the liver and spleen). While the symptoms may appear within a few months, in some cases, it may take a year or more to experience symptoms. It is important to know that VL worsens quickly and can be fatal without treatment.
What Are The Symptoms of Leishmaniasis?
People usually experience different symptoms because they depend on several factors. These include the type and severity of the infection, overall health, sex, and age. Check some general symptoms of leishmaniasis below:
- Large, slow-healing ulcers on the skin
- Fever
- Unusual weight loss
- Abdominal swelling (caused by enlarged spleen)
- Scabs or a crust where a sand fly bit you
- Ulcers or sores in the nose, throat, or mouth
- Chills
- Cold sweats
- Swollen lymph nodes
- Weakness
- Extreme tiredness (fatigue)
- Dark or discolored patches of skin
Immediately contact your healthcare professional if any of the previous symptoms occur without an obvious reason. Otherwise, it may lead to life-threatening complications.
Causes
This infection occurs due to a parasite called Leishmania that lives in humans and animals (including rodents, foxes, cats, possums, and dogs). While people cannot get this parasite directly from a dog, doctors have found that it can pass to other dogs. Commonly, humans get this parasite through the bite of a phlebotomine sand fly. In rare cases, people can get infected through sharing needles with an infected person, a blood transfusion, or from a pregnant woman to the fetus.
Where is Leishmaniasis Most Commonly Found?
Generally, this parasite is present in more than 90 countries around the world. Each part of the world has different types of this parasite. Healthcare professionals often use the terms “Old World Leishmaniasis” and “New World Leishmaniasis”. Old World leishmaniasis is often found in the Eastern Hemisphere. For example:
- The Middle East
- Southern Europe
- Certain parts of Africa (such as North Africa and tropical regions)
- Some parts of Asia
Commonly, New World leishmaniasis is found in the Western Hemisphere. These include:
- Central America
- South America
- Some parts of Mexico
While leishmaniasis occurs rarely in the United States, there are some people who have it in Texas and Oklahoma.
Risk Factors
While anyone can develop leishmaniasis, doctors have identified some factors that may increase your risk. Examples include:
- People who live in rural areas of tropical regions or areas with inadequate sanitation
- HIV infection and other health conditions that weaken the immune system (such as cancer)
- Malnutrition
- Poverty
- Living or traveling in endemic areas
- Age – Older adults (over 60 years old) and children are more likely to develop severe symptoms when they are infected with Leishmania.
- Sleeping outdoors or on the ground without using preventive measures (including insecticide-treated bed nets)
What Are The Potential Complications of Leishmaniasis?
While not everyone who develops leishmaniasis will experience complications, some people may experience life-threatening ones. Check some examples below:
- Bacterial infections (secondary infections) – In this case, bacterial infections can worsen the ulcers or sores on the skin.
- Scarring – In some cases, cutaneous and mucosal leishmaniasis can cause permanent damage to the skin, mouth, and nose (including severe scarring).
- Relapse – Sometimes, the symptoms disappear with treatment, but can return after a period. When skin ulcers return, they are called leishmaniasis recidivans, and people often need additional treatment.
- Septal perforation or collapse – This complication causes a hole in the tissue between the passages of the nose (septum). In this case, the nose structure can break down, which causes disfigurement, infections, and breathing issues.
- Pneumonia and gastrointestinal (GI) infections – People with leishmaniasis can experience respiratory infections as well as infections in other organs in the body.
Check below also for additional complications of visceral leishmaniasis:
- Severe bleeding
- Hemophagocytic lymphohistiocytosis – This is a serious condition that causes organ damage. Without treatment, it can be fatal.
- Post kala-azar dermal leishmaniasis (PKDL) – It is a large, bumpy rash that mostly appears on the face, but may also affect other parts of the body. PKDL often lasts a long period and may cause severe scarring.
- Sepsis – This is a life-threatening bacterial infection that requires immediate treatment.
This article does not contain a full list of complications, but your doctor may recommend some tips to reduce the risk or even prevent the previous ones.
How to Prevent Leishmaniasis?
While it is not always possible to prevent this infection, doctors often recommend the following tips to reduce the risk. Examples include:
- Wear long-sleeved shirts and socks to prevent bites
- Use insect repellents that contain DEET
- Kill sand flies indoors by spraying living and sleeping areas with insecticide
- Sleep in a room with closed windows or that contains screens
- Use netting and screens that have very small holes because sand flies are smaller than mosquitoes
Diagnosis
Most of the time, the diagnosis of leishmaniasis starts with a physical examination in which doctors will check for abnormalities linked to the disease. However, to confirm or rule out this parasitic infection, they will take different body fluids for testing. These include tissue from ulcers, spleen, lymph nodes, or bone marrow. For example:
- Needle biopsy – This test is used to remove a small sample of the bone marrow, lymph nodes, or spleen for testing. It helps identify Leishmania.
- Skin biopsy – When doctors suspect CL, they can take a sample of affected skin for testing. This test often helps diagnose cutaneous or mucosal leishmaniasis.
- Blood tests – Sometimes, doctors may take a sample of blood to check for infection in the blood.
Treatment
Usually, this infection is treated with anti-parasitic medicines. They often come in different forms, including pills, creams or lotions, and liquids that doctors may give you in an IV (intravenous) catheter. Physicians may also recommend thermotherapy, cryotherapy, or laser therapy for people with cutaneous leishmaniasis. Check the most common prescribed medicines below:
- Paromomycin
- Miltefosine
- Amphotericin
- Pentavalent antimonials (including sodium stibogluconate)
Frequently Asked Questions
Is leishmaniasis curable?
This infection can be cured only when doctors identify and treat it with medicines immediately. Generally, the cure rate is more than 90% for visceral leishmaniasis and about 75% for mucosal leishmaniasis. However, when these types of leishmaniasis are left untreated, they become more difficult to treat.
When should I go to the ER?
Immediately call 911 or go to the nearest emergency room (ER) if any of the following symptoms occur. Examples include:
- Jaundice (yellowing of the skin and eyes)
- Trouble breathing
- High fever (over 103 degrees F or 40 degrees C)
- Abdominal swelling
- Cyanosis (blue skin, lips, or nails caused by reduced oxygen levels in the blood)
How do I take care of myself?
Administer the pills exactly as recommended by your doctor. Physicians may also teach you how to clean and take care of the wounds while they are healing. You should contact your physician if you notice the symptoms of leishmaniasis return.
Can leishmaniasis spread from person to person?
In most cases, leishmaniasis does not spread directly from one person to another. The infection is usually transmitted through the bite of an infected female phlebotomine sand fly. However, in rare situations, it can spread through blood transfusions, organ transplants, shared needles, or from a pregnant woman to her baby.
How long does it take for symptoms of leishmaniasis to appear?
The incubation period varies depending on the type of leishmaniasis and the species of Leishmania. Cutaneous leishmaniasis symptoms often appear within a few weeks to several months after a sand fly bite, while visceral leishmaniasis may take several months or even more than a year before symptoms develop.
Can leishmaniasis come back after treatment?
Yes. Although treatment is often effective, some people experience a relapse, particularly those with weakened immune systems. In addition, certain people who recover from visceral leishmaniasis may later develop post-kala-azar dermal leishmaniasis (PKDL), while others with cutaneous leishmaniasis may develop new skin lesions after apparent recovery.
Who is at the highest risk of developing severe leishmaniasis?
People with weakened immune systems, including those with HIV/AIDS, organ transplant recipients, individuals receiving chemotherapy, young children, older adults, and people with poor nutrition, are at a greater risk of developing severe disease and complications, especially visceral leishmaniasis.
Can I travel to areas where leishmaniasis is common safely?
Yes. If you are traveling to an area where leishmaniasis is endemic, you can reduce your risk by wearing protective clothing, applying insect repellents containing DEET, sleeping under fine-mesh insecticide-treated bed nets, and avoiding outdoor activities from dusk until dawn when sand flies are most active.
Does recovering from leishmaniasis provide lifelong immunity?
Recovery may provide some immunity against the same species of Leishmania, but it does not guarantee lifelong protection. Because there are multiple species of the parasite, it is still possible to become infected again, especially when traveling to or living in endemic regions.
Is there a vaccine available to prevent leishmaniasis?
Currently, there is no widely approved vaccine for leishmaniasis for routine use in humans. Researchers continue to study several vaccine candidates, but prevention currently relies on avoiding sand fly bites, controlling sand fly populations, and promptly diagnosing and treating infected individuals. Ask your healthcare provider if you have any other questions.
