Tsagmo Ngoune Jean Marc, Sharma Parul, Crouzols Aline, Petiot Nathalie, Rotureau Brice
Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Institut Pasteur, Université Paris Cité, Paris, France.
Sorbonne Université, ED515 Complexité du Vivant, Paris, France.
Elife. 2025 Jun 16;12:RP91602. doi: 10.7554/eLife.91602.
Schuster et al demonstrated that bloodstream slender forms of African trypanosomes are readily transmissible to young tsetse flies where they can complete their complex life cycle (Schuster et al., 2021). In their experimental conditions, a single slender parasite was sufficient for productive infection. Here, we compared the infectivity of slender and stumpy bloodstream forms in adult flies with a mature immune system, and without using any chemical compounds that would alter the insect immune response and/or promote the infection. After ingestion of slender forms, infected flies were observed only in 1 out of 24 batches of non-immunocompetent teneral flies and with a high number of parasites. In contrast, infected flies were detected in 75% (18/24) of the batches infected with stumpy parasites, and as few as 10 stumpy parasites produced mature infections in immune adult flies. We discuss that, although Schuster et al. have demonstrated the intrinsic capacity of slender form trypanosomes to infect young and naive tsetse flies, highlighting the remarkable plasticity and adaptability of these protists, this phenomenon is unlikely to significantly contribute to the epidemiology of African trypanosomiases. According to both experimental and field observations, stumpy forms appear to be the most adapted forms for African trypanosome transmission from the mammalian host to the tsetse fly vector in natural conditions.
舒斯特等人证明，非洲锥虫的血流细长型很容易传播给年轻的采采蝇，在采采蝇体内它们可以完成复杂的生命周期（舒斯特等人，2021年）。在他们的实验条件下，单个细长型寄生虫就足以引发有效感染。在此，我们比较了细长型和粗短型血流形态在具有成熟免疫系统的成年采采蝇中的感染性，且未使用任何会改变昆虫免疫反应和/或促进感染的化合物。摄入细长型锥虫后，仅在24批无免疫能力的 teneral 采采蝇中的1批中观察到受感染的采采蝇，且寄生虫数量很多。相比之下，在感染粗短型寄生虫的批次中，75%（18/24）检测到受感染的采采蝇，并且在免疫成年采采蝇中，低至10个粗短型寄生虫就能引发成熟感染。我们讨论认为，尽管舒斯特等人已经证明了细长型锥虫感染年轻且未接触过病原体的采采蝇的内在能力，突出了这些原生生物显著的可塑性和适应性，但这种现象不太可能对非洲锥虫病的流行病学产生重大影响。根据实验和实地观察，在自然条件下，粗短型似乎是非洲锥虫从哺乳动物宿主传播到采采蝇媒介的最适应形态。
