Leishmaniasis - How to prevent a neglected tropical disease

Lisa Stockdale, Research Assistant at Centre for Immunology and Infection, HYMS, is one of last year's successful MPH: International students.  This paper's fascinating review of our current knowledge around prevention of Leishmania not only won the DoHS 2012 Masters Dissertation Prize, but has been also selected for presentation at a prestigious international conference on Leishmania in Brazil next month.

Leishmaniasis is an intracellular parasitic infection transmitted to humans via the sandfly. Approximately 350 million people are at risk of contracting the disease and an estimated 1.6 million new cases occur annually. Of the two main forms, visceral and cutaneous, the visceral form is fatal in 85-90% of untreated cases. This systematic review aims - for the first time - to identify and evaluate the current evidence base for the use of various preventative methods against human leishmaniasis.

A literature search was performed of the relevant database repositories for primary research conforming to a priori inclusion and exclusion criteria.

A total of 84 controlled studies were identified, implementing four broad categories of preventative interventions: animal reservoir control, vector population control, human reservoir control and a category for multiple concurrently implemented interventions. The primary studies investigated a heterogeneous mix of outcome measures using a range of different methods.

This review highlights an absence of high quality research measuring human-specific outcomes across all intervention categories. The apparent inability of study findings to be generalizable across different geographic locations, points towards gaps in knowledge regarding the biology of transmission of Leishmania in different settings. More research is needed which investigates human infection as the primary outcome
measure as opposed to intermediate surrogate markers, with a focus on developing a human vaccine.