Advances in leishmaniasis

Governed by parasite and host factors and immunoinflammatory responses, the clinical spectrum of leishmaniasis encompasses subclinical (inapparent), localised (skin lesions), and disseminated infection (cutaneous, mucosal, or visceral). Symptomatic disease is subacute or chronic and diverse in presentation and outcome. Clinical characteristics vary further by endemic region. Despite T-cell-dependent immune responses, which produce asymptomatic and self-healing infection, or appropriate treatment, intracellular infection is probably life-long since targeted cells (tissue macrophages) allow residual parasites to persist. There is an epidemic of cutaneous leishmaniasis in Afghanistan and Pakistan and of visceral infection in India and Sudan. Diagnosis relies on visualising parasites in tissue or serology; culture and detection of parasite DNA are useful in the laboratory. Pentavalent antimony is the conventional treatment; however, resistance of visceral infection in India has spawned new treatment approaches--amphotericin B and its lipid formulations, injectable paromomycin, and oral miltefosine. Despite tangible advances in diagnosis, treatment, and basic scientific research, leishmaniasis is embedded in poverty and neglected. Current obstacles to realistic prevention and proper management include inadequate vector (sandfly) control, no vaccine, and insufficient access to or impetus for developing affordable new drugs.