Leishmaniasis is a parasitic infection. It is caused by a trypanosomatid protozoan of the genus Leishmania. Vectors are involved in its transmission and different species of sandflies spread the protozoa. There are three clinical presentations of the leishmaniasis:
- Cutaneous (skin)
- Mucosal (mucus membrane)
- Visceral (affects internal organs, this is the most serious form of infection)
This tropical disease is classified as Neglected Tropical Disease (NTD). It is directly linked to social, environmental, climatological factors as well as poverty.
What is Leishmaniasis?
Leishmaniasis is a spread by female sandflies. There are different species of the Leishmania parasite that can cause infection.There is no medication or vaccine that can prevent or protect one from leishmaniasis.
Symptoms of Leishmaniasis
The symptoms of leishmaniasis are seen according to its type. These include:
The symptoms appear after about a few weeks or months of initial bite from an infected sand fly. In some cases, the symptoms can show up after many years. These symptoms include sores, ulcers, or scabs on the skin. The lymph nodes near these sores can be swollen. The scabs or sores can lead to pain or may be painless. These sores may take many years to heal and usually leave scars.
When the cutaneous leishmaniasis spreads to the mucous membranes of the nose and mouth, it leads to muscocutaneousleishmaniasis. The symptoms includes feeling a stuffy nose, frequent nose bleeds, mouth sores, nose sores, etc. The symptoms can be seen many years after the cutaneous leishmaniasis is cured. In some cases, muscocutaneousleishmaniasis can lead to facial disfiguration, if not treated.
Visceral leishmaniasis occurs when the parasite infects the internal organs like spleen, liver and bone marrow. The symptoms can occur after weeks, months or years of initial sand fly bite. These symptoms usually show up when the immune system becomes weak. Fever, weight loss, enlarged liver, enlarged spleen, anemia, low white blood cell count, etc. are symptoms of visceral leishmaniasis. The infection can prove to be fatal, if left untreated.
Leishamiasis spreads through the bite of female phlebotomine sand flies. These flies get infected with Leishmania parasites after a blood meal of an infected mammal like a dog, rodent or humans. Sand fly is a very small insect, that is smaller than a mosquito. Thus, very hard to see and it does not make any sound. There bites are also not painful. But they leave a red ring and thus,can be recognized as a sand fly bite.
Sand flies are active at twilight, evening and night-time hours. They usually bite when disturbed, while resting.
Other modes of transmission, although rare, can include transmission of infected blood, sharing needles, or infection from an infected pregnant mother to her baby.
Blood work is conducted to observe direct visualization of the Leishman-Donovan bodies (amstigotes). They are round, small bodies of about 2 to 4 micrometers in diameter with a cytoplasm, nucleus and rod-shaped kinetoplast. However, today, enzyme-linked immunosorbent assay (ELISA), direct agglutination test(DAT) and antigen coated dipsticks are performed. These tests are not standard tests as they are not very specific and sensitive.
The treatment depends on the region where the disease was acquired, the type of infection and the species of Leishmania. Liposomal amphotericin B is recommended in India, South America and the Mediterranean regions. In Africa, a combination of paromomycin along with pentavalentantimonialsgiven.
Prevent sand fly bites by sleeping under insecticide sprayed mosquito nets. Stay indoors from dusk to dawn when living in sand fly active areas. If you go outside, wear long sleeved shirts, long pants, socks and tuck your shirt into pants. Make sure you apply insect repellents containing DEET on the uncovered skin.However, use DEET containing repellents on children between 2 to 6 years old sparingly and avoid it completely on children under the age of 2 years.
There are no drugs or vaccines to prevent leishmaniasis. Protection from sand fly bites is the only way to prevent this dreaded disease.
Written by: Saptakee sengupta
Date last updated: April 06, 2015