Leishmaniasis is a parasitic infection by a protozoa belonging to the genus Leishmania. The disease is transmitted by a certain species of sand fly, and it is not spread though human to human transmission. Today, 1.5 million cases of skin leishmaniasis and 500,000 cases of visceral leishmaniasis are reported each year. The disease is prevalent in tropical and subtropical countries where incidents are reported from the rainforests in Central and South America to the deserts in West Asia.
Majority of visceral leishmaniasis cases are reported in Bangladesh, Brazil, Nepal, and Sudan. The disease is also found in Mexico, central and South America, southern Europe, Asia (excluding Southeast Asia), Middle East, and East and North Africa.
Types and symptoms of leishmaniasis
There are four basic types of leishmaniasis: cutaneous or skin form, diffuse cutaneous, mucocutaneous, and visceral leishmaniasis. The skin form manifests as skin ulcers that affect the exposed areas of the skin such as the face, arms, and legs. Diffused cutaneous type appears as leprosy-like disseminated chronic skin lesions that can be very difficult to treat. The mucocutaneous type appears as lesions on the mucosal area of the nose, mouth, and throat. While the visceral leishmaniasis affects the internal organs such as the spleen and the liver. Its symptoms include high fever, weight loss, and inflammation of the liver and spleen with anemia. If left untreated, the patient could die in 2 years from infection.
Mode of transmission of leishmaniasis
Leishmaniasis is said to be transmitted mainly through a bite from an infected sand fly. Sand flies are minute insects, smaller than mosquitoes, whose bite and flight are almost unnoticeable because of its size. They are infected with Leishmania from feeding on infected people, and they pass the infection on to another person when they are feeding usually from dusk till dawn. Leishmaniasis can also be transmitted through needle sharing or transfusion of an infected blood.
Treatment of leishmaniasis
The cutaneous type of leishmaniasis can heal on its own, but a scar usually develops from the lesion. However, if doctors see signs of spreading through the mucosal or other parts of the body, a topical paromycin can be given. Big lesions on the face are also contained by giving sodium stibogluconate, meglumine, or pentamininde.
The mucosal type is treated with a 4 weeks course of pentavalent antimony, and amphotericin B deoxycholate is used to combat advanced form of mucosal leishmaniasis.
Visceral leishmaniasis on the other hand needs serious treatment to avoid complications. Antibacterial medication is given to combat secondary bacterial infection, and blood transfusion might be needed if internal bleeding has occurred. Pentavalent antimonial compounds are also effective against the parasite; however, the parasite has developed immunity against the medication in some parts of the world.
Prevention of leishmaniasis
The best way to prevent leishmaniasis is to avoid sand fly bites by wearing protective clothing and insect repellent. People visiting countries with leishmaniasis cases are advised to use insect nets during the night, and as much as possible, avoid staying outdoors.