Leishmaniasis is a complex group of vector-borne infections caused by protozoan parasites of the genus Leishmania, which are transmitted by female sandflies. The disease is present in 98 countries in Africa, Asia, Europe, and the Americas, where it affects some of the world’s poorest people. Major risk factors include malnutrition and displacement, as well as environmental changes like deforestation and urbanization.
Leishmaniasis manifests in clinically and epidemiologically diverse forms. Two of the main variations of the disease are:
1) Cutaneous leishmaniasis (CL), the most common form, causes skin ulcers on exposed areas of the body that leave scars and often lead to disability.
2) Visceral leishmaniasis (VL), also known as kala azar, causes fever, weight loss, enlargement of the spleen and liver, and anemia. It is fatal if left untreated. Following treatment, some patients develop post-kala-azar dermal leishmaniasis (PKDL), pleomorphic skin manifestations that are potential sources of VL transmission.
Each year, leishmaniasis causes over 1.3 million new infections and 20,000 – 30,000 deaths. Of new infections, an estimated 200,000 – 400,000 are VL, and 0.7 – 1.2 million CL.
The diagnostic landscape
Diagnosis and management of both VL and CL are complicated – partially because of the wide variety of ways in which each of the two can manifest. In both cases, there is a need for more appropriate diagnostic solutions.
CL diagnosis is often unavailable in the remote areas where most cases occur. Some parasite species transmit complicated forms of CL, which require different treatment approaches. Therefore, diagnostic solutions that can provide point-of-care testing, prognosis and parasite species identification are essential.
Better diagnostic solutions for VL are equally pressing. VL has high rates of mortality. Untreated patients contribute to transmission, and treatment itself is lengthy, toxic, and difficult to implement in resource-limited settings.
Right now, VL testing has been improved by the development and implementation of user-friendly, point-of-care strip tests. However, these are not able to distinguish between active diseases, subclinical infection, or past infection. In patients with impaired immune systems these tests are not sensitive enough to detect antibodies. A more sensitive test, ideally point-of-care test is needed.
FIND's strategic approach
FIND is prioritizing the development of improved diagnostic solutions for VL. Activities range from working on diagnosis in eastern Africa and in immunocompromised patients, to developing a test of cure for both VL and PKDL.
FIND is also working with partners to develop molecular testing for diagnosis of CL.
FIND works directly with industry and academia, which includes supporting biomarker research. Alongside this, FIND supports activities that create an enabling environment for development, and improved access to, technologies for accelerated control and elimination of leishmaniasis.