Leishmaniasis is a disease caused by the protozoan parasite of the genus leis mania. This disease is transmitted via the phlebotomine sand fly. There are a number of species of this sand fly but only 30 have been found to cause this condition. Leishmaniasis threatens about 350 million people in 88 countries. An estimated 12 million people are believed to be infected today and that 1 to 2 million new cases occur every year. Leishmaniasis is a disease related to poverty. It is associated with malnutrition, poor housing, weakness of immune system, and lack of resources.
Only the female sand fly is known to transmit the parasites. When a female sand fly bites an infected person, that fly will develop the parasite over a period of 4 to 25 days. The sand fly will then transmit the parasite to humans via bite when it looks for blood. The phlebotomine sand flies are found in intertropical and tropical countries such as the Middle East, Central America, South America, Asia, Southern Europe and Africa.
The four types of this disease are:
- coetaneous leishmaniasis: This is the most common form of the disease.
- diffuse cutaneous leishmaniasis: This can resemble skin lesions of leprosy and are difficult to treat.
- mucocutaneous leishmaniasis: This causes tissue damage to the mouth and nose, and, when left untreated, it may progress to visceral leishmaniasis which is considered to be fatal because the parasites invade the vital organs.
- visceral leishmaniasis: This is considered to be fatal because the parasites invade the vital organs. This type of leishmaniasis is known to cause epidemics with high fatality rates. Epidemics usually occur in regions that are difficult to access such as Libo Kemkem, Ethiopia, Wajir, Kenya, Upper Nile and Southern Sudan. More than half of the population of a certain village in the west Nile country died from visceral leishmaniasis.
The prominent symptoms of this disease are skin sores. These skin sores erupts from weeks to months after bitten. Other consequences include fever and damaged spleen, liver and anemia. Leishmaniasis can be diagnosed by direct visualization of amastigotes. Samples are aspirated from the skin lesions, bone marrow, spleen and lymph nodes.
The common types of therapies are meglumine antimoniate (Glucantime) and sodium stibogluconate (Pentostam). There is no exact explanation on how this medication disrupts the parasite but theories said that it interrupts with energy production and metabolism. In many parts of the world these two therapies have been resistant to some types of leishmaniasis. The resistance depends on the type of species that caused leishmaniasis.
The use of amphotericin is the new treatment of choice. Some cases have been reported to be also resistant with this medication but usually resistant infections happen when there is co-infection with HIV.
Vaccines are currently being developed in order to become immune with this disease. Some genomic sequences of leishmaniasis have been found to be potential for vaccine development. Another study has also been conducted regarding DNA vaccines and antigens. These studies are still currently being evaluated for vaccine development.