Leishmania are unusual in being able to survive long-term in the mature phagolysosome compartment of macrophages and other phagocytic cells in their mammalian hosts. Key to their survival in this niche, Leishmania amastigotes switch to a slow growth state and activate a stringent metabolic response. The stringent metabolic response may be triggered by multiple stresses and is associated with decreased metabolic fluxes, restricted use of sugars and fatty acids as carbon sources and increased dependence on metabolic homeostasis pathways. Heterogeneity in expression of the Leishmania stringent response occurs in vivo reflects temporal and spatial heterogeneity in lesion tissues and includes non-dividing dormant stages. This response underpins the capacity of these parasites to maintain long-term chronic infections and survive drug treatments.

利什曼原虫能够在其哺乳动物宿主的巨噬细胞和其他吞噬细胞的成熟吞噬溶酶体区室中长期存活，这是不寻常的。利什曼原虫无鞭毛体转换到缓慢生长状态并激活严格的代谢反应是它们在这个生态位中生存的关键。严格的代谢反应可能由多重压力触发，并与代谢通量降低、糖和脂肪酸作为碳源的限制使用以及对代谢稳态途径的依赖性增加有关。利什曼原虫严格反应表达的异质性在体内发生反映病变组织的时间和空间异质性，包括非分裂休眠阶段。这种反应巩固了这些寄生虫维持长期慢性感染和在药物治疗中存活的能力。