Biteau Nicolas, Asencio Corinne, Izotte Julien, Rousseau Benoit, Fèvre Muriel, Pillay Davita, Baltz Théo
Microbiologie Fondamentale et Pathogénicité, UMR 5234, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France.
Animalerie A2, Université de Bordeaux, Bordeaux, France.
PLoS Negl Trop Dis. 2016 Jan 6;10(1):e0004350. doi: 10.1371/journal.pntd.0004350. eCollection 2016 Jan.
Trypanosoma brucei gambiense, transmitted by the tsetse fly, is the main causative agent of Human African trypanosomosis in West Africa and poses a significant health risk to 70 million people. Disease progression varies depending on host immunity, but usually begins with a haemo-lymphatic phase, followed by parasite invasion of the central nervous system. In the current study, the tropism of T. b. gambiense 1135, causing a low level chronic 'silent' infection, was monitored in a murine model using bioluminescence imaging and PCR. A tropism to the reproductive organs, in addition to the central nervous system, after 12-18 months of infection was observed. Bioluminescent analysis of healthy females crossed with infected males showed that 50%, 62.5% and 37.5% of the female mice were subsequently positive for parasites in their ovaries, uteri and brain respectively. Although PCR confirmed the presence of parasites in the uterus of one of these mice, the blood of all mice was negative by PCR and LAMP. Subsequently, bioluminescent imaging of the offspring of infected female mice crossed with healthy males indicated parasites were present in the reproductive organs of both male (80%) and female (60%) offspring. These findings imply that transmission of T. b. gambiense 1135 occurs horizontally, most probably via sexual contact, and vertically in a murine model, which raises the possibility of a similar transmission in humans. This has wide reaching implications. Firstly, the observations made in this study are likely to be valid for wild animals acting as a reservoir for T. b. gambiense. Also, the reproductive organs may act as a refuge for parasites during drug treatment in a similar manner to the central nervous system. This could leave patients at risk of a relapse, ultimately allowing them to act as a reservoir for subsequent transmission by tsetse and possibly, horizontally and vertically.
冈比亚布氏锥虫通过采采蝇传播，是西非人类非洲锥虫病的主要病原体，对7000万人构成重大健康风险。疾病进展因宿主免疫力而异，但通常始于血液淋巴阶段，随后寄生虫侵入中枢神经系统。在本研究中，使用生物发光成像和PCR在小鼠模型中监测了引起低水平慢性“无症状”感染的冈比亚布氏锥虫1135的嗜性。在感染12 - 18个月后，观察到除中枢神经系统外，该寄生虫对生殖器官也有嗜性。对健康雌性与感染雄性杂交后的生物发光分析表明，分别有50%、62.5%和37.5%的雌性小鼠的卵巢、子宫和大脑随后检测到寄生虫呈阳性。尽管PCR证实其中一只小鼠的子宫中存在寄生虫，但所有小鼠的血液经PCR和环介导等温扩增检测均为阴性。随后，对感染雌性小鼠与健康雄性杂交后代的生物发光成像显示，雄性（80%）和雌性（60%）后代的生殖器官中均存在寄生虫。这些发现表明，冈比亚布氏锥虫1135在小鼠模型中可通过水平传播（很可能是通过性接触）和垂直传播，这增加了在人类中发生类似传播的可能性。这具有广泛的影响。首先，本研究中的观察结果可能适用于作为冈比亚布氏锥虫储存宿主的野生动物。此外，生殖器官在药物治疗期间可能像中枢神经系统一样成为寄生虫的庇护所。这可能使患者面临复发风险，最终使其成为采采蝇后续传播的储存宿主，并且可能通过水平和垂直传播。
