Chronic Trypanosoma cruzi infections are typically life-long, with small numbers of parasites surviving in restricted tissue sites, which include the gastro-intestinal tract. There is considerable debate about the replicative status of these persistent parasites. Here, we investigated T. cruzi proliferation in the colon of chronically infected mice using 5-ethynyl-2-deoxyuridine incorporation into DNA to provide snapshots of parasite replication. Highly sensitive imaging of infection foci at single cell resolution revealed that parasites are three times more likely to be in S-phase during the acute stage than during the chronic stage. By implication, chronic infections are associated with a reduced rate of parasite replication. Despite this, very few host cells survive infection for more than 14 days, suggesting that T. cruzi persistence continues to involve regular cycles of replication, host cell lysis and re-infection. Therefore, long-term persistence in the colon is more likely to be associated with reduced proliferation than with dormancy.

中文翻译：

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克鲁氏锥虫锥虫在慢性感染期间复制率降低

克鲁斯慢性锥虫感染通常是终生的，少数寄生虫会在包括胃肠道在内的受限组织部位存活。关于这些持久性寄生虫的复制状态有很多争论。在这里，我们调查了使用5-乙炔基-2-脱氧尿苷掺入DNA以提供寄生虫复制快照的慢性感染小鼠结肠中的克鲁斯锥虫增殖。以单细胞分辨率对感染灶进行高度敏感的成像显示，急性期处于S期的寄生虫比慢性期高三倍。言下之意，慢性感染与寄生虫复制率降低有关。尽管如此，很少有宿主细胞在感染后存活超过14天，这表明T。Cruzi持续性继续涉及复制，宿主细胞裂解和再感染的规则循环。因此，与休眠相比，长期留在结肠更可能与增殖减少有关。