Leishmaniasis is a parasitic disease caused by the Leishmania parasite. This parasite typically lives in infected sand flies. You can contract leishmaniasis from a bite from an infected sand fly.
There are three forms of the disease. Different species of the parasite cause each form. Cutaneous leishmaniasis affects your skin and is usually not serious. Visceral leishmaniasis damages your internal organs and can be life-threatening. Visceral leishmaniasis is also known as kala azar. Mucocutaneous leishmaniasis can lead to partial or complete destruction of the mucous membranes found in your nose, throat, and mouth.
The sand flies that carry the parasite typically reside in tropical and subtropical environments. Fatal epidemics have occurred in areas of Africa, such as Sudan, Kenya, and Ethiopia.
Unfortunately, affected regions are often remote and unstable, with limited resources for treating this disease. Doctors Without Borders calls leishmaniasis one of the most dangerous neglected tropical diseases.
Three forms of leishmaniasis are cutaneous, visceral, and mucocutaneous, which is rare. Different species of the Leishmania parasite are associated with each form. Experts believe that there are about 20 Leishmania species that can transmit the disease to humans.
Visceral leishmaniasis is sometimes known as systemic leishmaniasis. It usually occurs two to eight months after being bitten by a sand fly. It damages internal organs, such as your spleen and liver. It also affects your immune system through damage to those organs. The condition is almost always fatal if it’s not treated.
Cutaneous leishmaniasis only causes ulcers on your skin. It’s the most common form of leishmaniasis. Treatment may not always be necessary, but it can speed healing and prevent complications.
A rare form of the disease is called mucocutaneous leishmaniasis. It can occur several months after skin ulcers heal. This type of leishmaniasis affects the mucous membranes of the nose and palate. It’s usually considered a subset of cutaneous leishmaniasis. However, it’s more serious. It doesn’t heal on its own and always requires treatment.
Leishmaniasis is due to protozoan parasites from the Leishmania species. You get leishmaniasis from being bitten by an infected sand fly.
The parasite lives and multiplies inside the female sand fly. The insect is most active in humid environments during the warmer months and at night, from dusk to dawn. Domestic animals, such as dogs, can serve as reservoirs for the parasite. Transmission can occur from dog to sand fly to human.
Humans can also transmit the parasite between each other through a blood transfusion or shared needles.
The disease is found everywhere in the world except Australia and Antarctica. However, about 95 percent of cutaneous cases occur in the Americas, the Mediterranean basin, central Asia, and the Middle East.
Over 90 percent of visceral cases occur in:
- South Sudan
If you live in or travel to the tropical or subtropical areas of these countries and regions, you’re at a much higher risk of contracting the disease. Environmental and climate factors heavily influence the spread of the disease.
According to the World Health Organization (WHO), poverty is a determining factor for the disease. Leishmaniasis often occurs in areas where the following conditions are common:
- large migrations caused by urbanization, emergency situations, or environmental changes
People who have weakened immune systems are also at increased risk of this condition. Leishmaniasis can also speed the advancement of HIV into AIDS. You’re at increased risk of developing a more serious case of leishmaniasis if you’re infected with HIV.
People can carry some species of Leishmania for long periods without becoming ill. Symptoms depend on the form of the disease.
The main symptom of this condition is painless skin ulcers. Cutaneous symptoms may appear only one to two weeks after being bitten by the sand fly. However, sometimes symptoms will not appear for months or years.
In people with the mucocutaneous form of the disease, symptoms usually appear one to five years after skin lesions heal. These are primarily ulcers in the mouth and nose or on the lips. Other symptoms may include:
- stuffy or runny nose
- nose bleeds
- difficulty breathing
Symptoms often don’t appear for months after the bite. Most cases are apparent two to six months after infection. Symptoms include:
- weight loss
- fever that lasts for weeks or months
- enlarged spleen
- enlarged liver
- decreased production of red blood cells (RBCs)
- other infections
- night sweats
- thinning hair
- scaly skin
- dark, ashen skin
It’s important to tell your doctor if you lived in or visited a place where leishmaniasis is common. That way your doctor will know to test you for the parasite. If you have leishmaniasis, your doctor will use other tests to determine which species of Leishmania is the cause.
Diagnosing Cutaneous Leishmaniasis
Your doctor may take a small amount of skin for a biopsy by scraping one of the ulcers. They’ll examine the samples under a microscope or in a culture to identify the parasite. A culture is a way to see if there are parasites in a sample. It gives a small amount of parasites the opportunity to grow to detectable levels.
Diagnosing Visceral Leishmaniasis
Many times, people don’t remember a bite from a sand fly or a skin sore. This condition may be hard to diagnose.
A doctor may first perform a physical exam to look for an enlarged spleen or liver. They may then perform a bone marrow biopsy or take a blood sample for examination. They’ll check these samples for the parasite. Diagnosis may take two to four weeks if a culture is necessary.
Antiparasitic drugs, such as amphotericin B, treat this condition.
Cutaneous ulcers will often heal without treatment. However, treatment can speed healing and reduce scarring. It can also prevent the development of further disease. Ulcers on the face that cause disfigurement may require plastic surgery.
Visceral disease always requires treatment. Several medications are available. The main types of medicine used are compounds that contain antimony. These include meglumine antimoniate and sodium stibogluconate.
These lesions don’t heal naturally. They always require treatment.
Liposomal amphotericin B and paromomycin can treat mucocutaneous leishmaniasis. WHO launched an advocacy campaign to help reduce the price of these drugs. The program reduced the price of liposomal amphotericin B by 90 percent and meglumine antimoniate by 60 percent. The hope is that lowering the cost will make it easier for people to get these treatments.
Cutaneous complications may include:
- other infections due to a weakened immune system, which can be life-threatening
Visceral leishmaniasis is often fatal. However, death often occurs due to complications of the disease and not the disease itself. If you have HIV or AIDS, you’re at high risk of getting this disease. The complications are also often resistant to treatment.
There’s no vaccine or prophylactic medication available. The only way to prevent leishmaniasis is to avoid getting bitten by a sand fly.
Follow these steps to help prevent being bitten by a sand fly:
- Wear clothing that covers as much skin as possible. Long pants, long-sleeved shirts tucked into pants, and high socks are recommended.
- Use insect repellent on any exposed skin and on the ends of your pants and sleeves. The most effective insect repellants contain DEET.
- Spray indoor sleeping areas with insecticide.
- Sleep on the higher floors of a building. The insects are poor fliers.
- Avoid the outdoors between dusk and dawn. This is when sand flies are most active.
- When indoors, use screens and air conditioning.
- Use a bed net tucked into your mattress. Sand flies are much smaller than mosquitos. Spray the net with insecticide containing pyrethroid if possible.
Buy bed nets, insecticides, and repellents before traveling to high-risk areas.
Sores can result in permanent scars and disfigurement. Treatment may reduce their severity.
Medication can cure the disease. However, treatment is most effective when started before damage to your immune system occurs.
Visceral leishmaniasis is often fatal within two years if it’s not treated properly.