Disease Overview:
– Leishmaniasis is caused by parasites transmitted by infected sandflies.
– It manifests in various forms like cutaneous, mucocutaneous, and visceral leishmaniasis.
– Visceral leishmaniasis is the most severe and can be fatal if untreated.
– Different Leishmania species cause specific forms of the disease.
– Risk factors include malnutrition, deforestation, and suppressed immune systems.
– The disease affects around 12 million people globally, with an estimated 500,000 new cases of visceral leishmaniasis annually.
Transmission and Vector:
– Leishmaniasis is primarily transmitted by female phlebotomine sandflies.
– Sandflies become infected when feeding on infected hosts.
– In the New World,
Lutzomyia
is the main genus transmitting the disease to humans.
– Outside the New World,
Phlebotomus
is considered the vector.
– Non-human animals can act as reservoirs and transmit the parasite to sandflies.
Diagnosis and Treatment:
– Diagnosis involves visualizing amastigotes in samples from blood, marrow, or skin lesions.
– Staining methods like Leishman or Giemsa stains are used for identification.
– PCR tests are available for detecting Leishmania DNA.
– Treatment options include drugs like paromomycin, liposomal amphotericin B, and miltefosine.
– Topical treatments vary based on the Leishmania strain, with limited evidence supporting heat therapy for cutaneous leishmaniasis.
Prevention and Control:
– Prevention strategies include using insect repellents, bed nets, and insecticide-impregnated dog collars.
– Environmental management can help reduce sandfly breeding sites.
– Proper diagnosis and treatment contribute to control efforts.
– Research is ongoing for human vaccines, while effective vaccines for dogs exist.
– Public health practices may help control or eliminate leishmaniasis without a vaccine.
Global Impact and Historical Perspectives:
– Leishmaniasis is a neglected tropical disease with a significant impact on public health.
– The disease has a substantial economic burden in endemic regions.
– Efforts are being made to raise awareness and funding for control programs.
– Historical roots of the disease can be traced back to ancient texts and the 18th century.
– Notable researchers like Leishman and Donovan contributed to understanding and identifying the parasite.
Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus Leishmania. It is generally spread through the bite of phlebotomine sandflies, Phlebotomus and Lutzomyia, and occurs most frequently in the tropics and sub-tropics of Africa, Asia, the Americas, and southern Europe. The disease can present in three main ways: cutaneous, mucocutaneous, or visceral. The cutaneous form presents with skin ulcers, while the mucocutaneous form presents with ulcers of the skin, mouth, and nose. The visceral form starts with skin ulcers and later presents with fever, low red blood cell count, and enlarged spleen and liver.
| Leishmaniasis | |
|---|---|
| Other names | Leishmaniosis |
 | |
| Cutaneous leishmaniasis in the hand of a Central American adult | |
| Pronunciation |
|
| Specialty | Infectious disease |
| Symptoms | Skin ulcers, fever, low red blood cells, enlarged liver |
| Causes | Leishmania parasites spread by sandflies |
| Prevention | Bug nets, insecticide |
| Frequency | 4–12 million |
| Deaths | 24,200 (2015) |
Infections in humans are caused by more than 20 species of Leishmania. Risk factors include poverty, malnutrition, deforestation, and urbanization. All three types can be diagnosed by seeing the parasites under microscopy. Additionally, visceral disease can be diagnosed by blood tests.
Leishmaniasis can be partly prevented by sleeping under nets treated with insecticide. Other measures include spraying insecticides to kill sandflies and treating people with the disease early to prevent further spread. The treatment needed is determined by where the disease is acquired, the species of Leishmania, and the type of infection. Some possible medications used for visceral disease include liposomal amphotericin B, a combination of pentavalent antimonials and paromomycin, and miltefosine. For cutaneous disease, paromomycin, fluconazole, or pentamidine may be effective.
About 4 to 12 million people are currently infected in some 98 countries. About 2 million new cases and between 20 and 50 thousand deaths occur each year. About 200 million people in Asia, Africa, South and Central America, and southern Europe live in areas where the disease is common. The World Health Organization has obtained discounts on some medications to treat the disease. It is classified as a neglected tropical disease. The disease may occur in a number of other animals, including dogs and rodents.